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1NEPTUNE Canada: An Invitation to Science

NEPTUNE Canada:An Invitation to Science

2 NEPTUNE Canada: An Invitation to Science

Copyright © 2012 University of Victoria

The moral rights of the authors are asserted. Published by University of Victoria.

Issued in the following formats: ISBN 978-1-55058-478-3 (print) ISBN 978-1-55058-479-0 (PDF) ISBN 978-1-55058-480-6 (ePub) ISBN 978-1-55058-481-3 (iBook)

Library and Archives Canada Cataloguing in Publication

NEPTUNE Canada NEPTUNE Canada: An Invitation to Science/NEPTUNE Canada

Includes bibliographical references. Issued also in electronic format. ISBN 978-1-55058-478-3

1. NEPTUNE Canada. 2. Oceanographic research stations -- North Pacific Ocean.

I. Title.

GC59.15.N47 2012 551.460971 C2012-905067-9

ACKNOWLEDGEMENTS:

We would like to thank the scientists whose research inspired this publication and whose works are cited within. Data Analysis, Writing, and Graphics: Clio Bonnett and Alex Spicer Project Management: Maia Hoeberechts and Dwight Owens Editing: Dilumie Abeysirigunawardena, Martin Heesemann, Kim Juniper, Marjolaine Matabos, Steve Mihály, Kate Moran, Ajaya Ravindran, Martin Scherwath Photography: CSSF and NEPTUNE Canada Design: Lime Design www.limedesign.ab.ca

Thanks to funding from the Canadian Foundation for Innovation, Government of British Columbia, Natural Sciences and Engineering Research Council of Canada, Western Economic Diversification Canada, CANARIE

This publication is licensed under a Creative Commons License, Attribution-Noncommercial-No Derivative 3.0 Unported: see www.creativecommons.org. The text may be reproduced for non-commercial purposes, provided that credit is given to the original author(s).

To obtain permission for uses beyond those outlined in the Creative Commons License, please contact NEPTUNE Canada, University of Victoria at [email protected]

Suggested citation: NEPTUNE Canada (2012). NEPTUNE Canada: An Invitation to Science. Victoria, BC: University of Victoria.


PrefaceThis report is an overview of activities, observations and events on the NEPTUNE Canada ocean network between 8 December 2009 and 31 December 2010 – from our official launch through the first year of operation. This report offers a glimpse of sea and subsea conditions at the observation locations based on measurements by the instruments. It highlights scientific events observed on the network, touches on scientific research facilitated by NEPTUNE Canada, and contains a summary of basic data collected at each site. This report is for scientists, both those currently working with us and new potential colleagues, educators and students, policy makers, and those who have a scientific interest in oceans. We invite you to be part of our ongoing investigation of the northeast Pacific Ocean.

NEPTUNE Canada, a projected 25-year undertaking, provides online access for the international research community to conduct oceanographic experiments. The subsea infrastructure, an 812 km cabled observatory located off the coast of Vancouver Island, enables scientists to study phenomena through continuous long-term high temporal resolution observations not afforded by traditional ship-based ocean exploration. By collocating instruments of different types, researchers can study interactions among geological, chemical, physical, and biological processes that drive the dynamic earth-ocean system. The network spans diverse environments ranging from the coastal estuary to a mid-ocean ridge, providing scientists a unique platform to investigate interactions between related processes observed in different settings across the network. On land, through developments in information technology, we are working to automate detection of oceanic events, interactively adjust experiments and sampling protocols, and provide timely and reliable access to the growing data archive.

The wide variety of instruments and the range of data collected offer exciting opportunities for interdisciplinary studies and international collaboration. The instrumentation has room for expansion and can only reach its full potential with contributions from scientists, not only across Canada, but also around the globe. In this report we have highlighted a sampling of the research projects being carried out by our collaborating scientists, but certainly not all of them.

To contribute your ideas and comments or to start a scientific collaboration with NEPTUNE Canada, please contact us by mail, phone, email or through our website.

NEPTUNE Canada, a projected 25-year undertaking, provides online access for the international research community to con-duct oceanographic experiments.


Table of ContentsPreface .................................................................................................................................... 3

Table of Contents ............................................................................................................... 5

Acronym Reference List ................................................................................................... 6

1. Introduction .................................................................................................................. 9

1.1. Motivation .......................................................................................................... 9

1.2. Location .............................................................................................................. 9

1.3. NEPTUNE Canada Nodes ............................................................................11

1.4. Technology ......................................................................................................11

2. Year at a Glance ..........................................................................................................13

2.1. Highlights From the Year ............................................................................13

2.2. Science Activities ...........................................................................................16

2.3. Overview of Collected Data .......................................................................17

3. Site by Site Overview ..............................................................................................18

3.1. Folger Passage ................................................................................................18

3.2. Barkley Canyon ...............................................................................................24

3.3. ODP 889 ............................................................................................................34

3.4. ODP 1027..........................................................................................................40

3.5. Endeavour ........................................................................................................43

4. Network-Wide Observations ...............................................................................51

4.1. Seismograph Network .................................................................................52

4.2. West-Coast Tsunami-Meter ........................................................................53

4.3. Water Properties ............................................................................................54

References ...........................................................................................................................57

Appendix – Instrument Listings by Site ..................................................................60


Acronym Reference ListADCP Acoustic Doppler current profiler

BPR Bottom pressure recorder

CANARIE Canada’s Advanced Research and Innovation Network

CORK Circulation Obviation Retrofit Kit

COVIS Cabled Observatory Vent Imaging Sonar

CSSF Canadian Scientific Submersible Facility

CTD Conductivity-temperature-depth

DMAS Data Management and Archiving System

ENSO El Niño Southern Oscillation

ESONET European Seas Observatory Network

IODP Integrated Ocean Drilling Program

LIDO Listening to the Deep Ocean

mab metres above bottom

mbsf metres below seafloor

NEPTUNE Northeast Pacific Time-Series Undersea Networked

Experiments

ONC Ocean Networks Canada

ONCCEE Ocean Networks Canada Centre for Enterprise and Engagement

ROPOS Remotely Operated Platform for Ocean Sciences

VPS Vertical profiler system

7

Tripods, like the one shown here, hold and provide power through attached cables to our cameras, seen on the bottom right of the frame, at our various Barkley Canyon study sites.

8

The remotely operated vehicle, ROPOS, is able to carry out many

functions while on the seafloor or flying through the water column.


Introduction1.1 Motivation

NEPTUNE Canada is the world’s first regional-scale subsea cabled observatory network extending the internet into the northeast Pacific Ocean. The underwater instruments allow us to gather live, real-time data 24 hours a day and make it freely available to the world through the internet. Interdisciplinary research enabled by the network spans five major research themes: earthquakes and plate tectonics, fluid flow in the seabed, marine processes and climate change, deep-sea ecosystem dynamics, and engineering and computational research.

Research by scientists from diverse disciplines is facilitated by our network: biologists, geologists, geophysicists, chemists, engineers, oceanographers, climate scientists, computer scientists, and many more. They use the data to study climate change, greenhouse gas cycling, ocean productivity, marine mammals and fish stocks, non-renewable marine resources, earthquakes, tsunamis, and phytoplankton blooms. As our understanding of these topics increases, we expect researchers will increasingly use the instruments to study interconnections between them. Interdisciplinary research is crucial to understanding the complex processes governing our oceans.

NEPTUNE Canada is one of two networks managed by Ocean Networks Canada, the other being the VENUS coastal network. These networks are managed on behalf of the University of Victoria, the lead institution for a national consortium of universities and organizations involved in the project. The third component, Ocean Networks Canada Centre for Enterprise and Engagement (ONCCEE), is a federal Centre of Excellence in Commercialization and Research.

1.2 Location

The network is located in the northeast Pacific Ocean off the west coast of Vancouver Island, British Columbia. The subsea cable loop begins at the shore station in Port Alberni, passes through Barkley Sound, crosses the continental margin, and extends across the abyssal plain of the Juan de Fuca plate to a mid-ocean ridge. The Juan de Fuca plate, smallest of the Earth’s 13 major tectonic plates, is bounded by the Pacific plate to the south and west and the North American plate to the east (Figure 1). New ocean crust is formed along the volcanically active Juan de Fuca mid-ocean ridge, spreading outward to either side. Along its eastern boundary, the Juan de Fuca plate subducts beneath the North American plate. Subduction zones like this generate some of the world’s largest earthquakes, often associated with devastating tsunamis. NEPTUNE Canada’s array of sensitive instruments augment other land-based seismic networks in Canada and the United States, helping researchers better understand subduction processes and improve estimates of seismic risk.

NEPTUNE Canada is the world’s first regional-scale subsea cabled observatory network extending the internet into the northeast Pacific Ocean.


Some of the planet’s most productive marine biozones flourish in the mid-latitudes along continental west coasts, where prevailing winds and ocean currents combine to lift nutrient-rich deep-sea water toward the surface. This upwelling (page 20) supports rich and diverse marine ecosystems. Off southwestern Vancouver Island, upwelling plays a critical role in primary productivity, and consequently, in the life cycles of several important fish stocks, including Pacific salmon. Seafloor ecosystems and those in the overlying water column can be studied in detail by the subsea sensor network. The acoustic and optical sensors support real-time observation of physical, chemical, and biological processes in the water column. Gathering long time-series of data for these and other parameters will enable scientists to monitor effects of large-scale, complex processes such as climate change.

Figure 1. The NEPTUNE Canada network begins on the North American

plate, extending across the northern part of the Juan de Fuca

plate to the Pacific plate. Middle Valley is a partially funded future

node location.


1.3 NEPTUNE Canada Nodes

The network consists of an 812 km long fibre optic cable on the seabed spanning a 450,000 km2 region in the northeast Pacific offshore British Columbia and Washington. The network links five instrumented nodes (Figure 1, Table 1) located in a variety of ecological and geological settings. Study sites vary from the shallows of coastal Folger Passage (23-100 m), which is strongly influenced by coastal oceanographic processes, out to the depths of node ODP 1027 on the abyssal plain (2660 m). The Endeavour (2200 m) location is on the Endeavour segment of the Juan de Fuca Ridge, between the Juan de Fuca and Pacific plates, where the formation of new ocean crust drives hydrothermal venting.

Location Depth (m) Setting Principal Research Areas

Folger Passage 20 - 100 Continental shelf

• Ocean biogeochemistry• Terrestrial-marine interactions• Coastal physical oceanography• Phyto- and zooplankton• Fish• Marine mammals

Barkley Canyon 400 - 1000 Shelf/slope break; submarine canyon

• Exposed gas hydrates• Gas hydrate ecosystems• Accumulation/movement of sediment• Upwelling• Ecosystem dynamics

ODP 889 1250 Continental slope• Seafloor fluids and gases• Gas hydrates• Cascadia margin and earthquakes

ODP 1027 2660 Abyssal plain• Hydrologic conditions in sediment-capped

ocean crust• Tsunami propagation

Endeavour 2200 - 2400Mid-ocean

spreading ridge

• Plate tectonics• Seismicity• Hydrothermal vent systems• Vent ecology

1.4 Technology

The sensors and instruments across the NEPTUNE Canada ocean network will evolve over time; instruments can be removed and new instruments added to the various locations and future sites. Some instruments reside on instrument platforms while others, such as our broadband seismometers, are buried in the seafloor sediment. Other instruments are affixed to auxiliary platforms on the seafloor at distances from the instrument platforms. Instruments are connected to the network by extension cables,

Table 1. NEPTUNE Canada instrumented node locations including depth, setting, and principal research areas.


which in some cases can be connected/disconnected in-situ by a remotely operated vehicle . This approach gives the observatory a modular design, allowing us to connect more instruments later, or disconnect and recover individual instruments and platforms for servicing.

The instrument types include:

• Conductivity-temperature-depthsensors(CTD)• Acousticcurrentmeters• Hydrophones,sonars,echosounders• AcousticDopplercurrentprofilers(ADCP)• Bottompressurerecorders(BPR)• Chemicalandgassensorsformeasuringdissolvedgases• Seismometers,gravimeters,andaccelerometers• Videocamerasystems• Turbiditysensorsandsedimenttraps

A complete listing of instruments and parameters measured at each location are presented in the appendix.

Some instruments are designed specifically for NEPTUNE Canada, either by external collaborators and contractors or by the NEPTUNE Canada engineering team. Input from scientists in developing new technologies helps to improve the subsea network and expand scientific study opportunities. The NEPTUNE Canada engineering team assembles, tests, and prepares instruments for deployment at The University of Victoria’s Marine Technology Centre near Sidney, BC. NEPTUNE Canada’s engineering team works in close collaboration with the Canadian Scientific Submersible Facility (CSSF), the developers of the remotely operated vehicle ROPOS (Remotely Operated Platform for Ocean Sciences), which is used in the deployment and maintenance of most NEPTUNE Canada instruments.

Another critical component of the observatory is the Data Management and Archiving System (DMAS). The DMAS team develops software and maintains computer systems for controlling the observatory operations and receiving, indexing, and archiving all data produced by the instruments. DMAS transmits data in real-time via the internet to scientists and the public. DMAS also works with external collaborators in computer science and computer engineering to develop innovative data processing applications.


Year at a Glance2.1 Highlights From the Year

NEPTUNE Canada Goes Live

Perhaps the most exciting and gratifying achievement during the first year was the network’s operational launch on 8 December 2009. After a decade of concept development, science workshops, securing major infrastructure funding, building management and operations teams, contracting Alcatel-Lucent to design, manufacture, and install the observatory wet plant, installing instruments, and system commissioning, most of the observatory was in place and operational. With a click of a mouse, people everywhere were able to access both real-time and archived data through the internet. This occasion prompted a gala gathering at the University of Victoria, that was webcast live to a global audience. Distinguished speakers included representatives from the University of Victoria, provincial and federal governments as well as the Canada Foundation for Innovation and Canada’s Advanced Research and Innovation Network (CANARIE). Seven collaborating scientists also gave short presentations on the science they are pioneering through use of the network. All of the hard work and careful planning had finally paid off as the concepts and designs became reality.

Wally the Crawler

Wally the Crawler, an internet-operated deep-sea crawler (Figure 2), was taken on its first deep-sea walkabout on 19 December 2009. Wally is controlled via the internet by Laurenz Thomsen’s research group at Jacobs University in Bremen, Germany. This crawler is designed to conduct experiments on gas hydrate dynamics in Barkley Canyon. See Box 3 on page 28 for more Wally information.

Figure 2. Wally the Crawler sits on a gas hydrate outcrop 870 m below the sea surface.

With a click of a mouse, people everywhere were able to access both real-time and archived data through the internet.


Chilean Earthquake and Tsunami Detected

On 27 February 2010 a magnitude 8.8 earthquake — the seventh strongest earthquake ever recorded — struck Chile. As expected, the event was recorded by the three broadband seismometers buried in the seafloor sediments at Barkley Canyon, ODP 889, and ODP 1027 (Figure 3). Additionally, the gravimeter in the seafloor compliance apparatus at ODP 889 and bottom pressure recorders (BPRs) also detected the ground shaking. Following the earthquake, Chile was hit by a tsunami that propagated rapidly across the Pacific and reached British Columbia at 23:00 UTC, 16.5 hours after the quake. Scientists at Fisheries and Oceans Canada’s Institute of Ocean Science fed the data from the most seaward of the BPRs into their regional tsunami model, allowing them to simulate the propagating waves and the interaction of this wave field with the complex bathymetry of the British Columbia coast. The network of steep fjords and broad bays the waves encounter produce a wide variety of responses. Some cause the waves to resonate, while others dampen the waves. The 6 cm high tsunami wave measured at the BPR at ODP 1027 produced barely noticeable wave heights at some coastal tide gauge stations and 1 m waves at others. An understanding of this interaction is important because often the largest first-arrival tsunami waves do not produce the largest wave heights in the inlets. The Chilean tsunami caused elevated pressure readings at the deep-sea BPR for three days after the event, and hence the possibility of anomalous wave heights and currents over that period.

.

We’ve got an App for That

On 17 September 2010 we released mobile applications for the iPhone, iPod, iPad and Android (freely available in the Apple App Store and Android Marketplace). The applications display the latest readings from most of the sensors connected to the observatory in real-time, anywhere a data connection is available. The apps also display video from the seafloor cameras and recorded highlights from the NEPTUNE Canada YouTube channel.

Figure 3. The offshore Maule, Chile earthquake

(27 February 2010) recorded by the Seismograph Network. (Data from the broadband seismometer at ODP 1027,

NC27 HHZ)


New Boreholes Prepared

The D/V JOIDES Resolution scientific drill ship, a key vessel in the Integrated Ocean Drilling Program (IODP), was docked in Victoria over the summer of 2010 for three months of refit before embarking on IODP Expeditions 327 and 328 in July and September. Expedition 327 was focused on establishing new instrumented boreholes in the vicinity of the ODP 1027 location. During Expedition 328, Hole U1364A was drilled near the ODP 889 node and instrumented with a seafloor observatory (Circulation Obviation Retrofit Kit, or, CORK) that will be connected to NEPTUNE Canada in 2013. NEPTUNE Canada collaborates with IODP and are planning to connect additional boreholes at ODP 889, ODP 1027, and Middle Valley to the network.

Hydrophones Listening to the Deep

After many months of hard work, analyses of acoustic recordings from the Barkley Canyon and Folger Passage locations were incorporated into the Listening to the Deep Ocean (LIDO) website (www.listentothedeep.com/). LIDO was developed by a group of researchers led by Michel André at Spain’s Technical University of Catalonia. Their applications analyse data from hydrophones (Figure 4) attached to NEPTUNE Canada’s network, the European Seas Observatory NETwork (ESONET) and other networks around the world. The LIDO contribution to real-time assessment of the response of cetaceans to anthropogenic sound sources (ship noise, active acoustics, echosounders, etc.) represents a major step toward understanding the acoustic environment for marine organisms and informing the long-term management of noise pollution in the oceans.

Figure 4. A hydrophone before deployment, seen here at the University of Victoria’s Marine Technology Centre.


Broadband Seismometer Reveals Whale Behaviour

As data from the subsea network began to roll in, spikes at regular time intervals on some seismometer data were a mystery to seismologists. On closer inspection of the spikes (Figure 5), it was revealed that seismometers are well suited to observing abundance and behaviours of baleen whales (see http://gore.ocean.washington.edu/whales.html). For example, seismologist Garry Rogers (Geological Survey of Canada) noticed that a fin whale stopped calling for about 4.5 hours after the arrival of the T-phase waves (seismic energy travelling at sound velocity through the ocean) from a magnitude 5.1 earthquake that occurred on 12 November 2010 in the Fox Islands, Aleutian Island chain.

2.2 Science Activities

Cruises

Two maintenance and installation cruises were completed in 2010. During these cruises new devices, particularly at Endeavour were installed, and other instruments were retrieved, maintained, repaired, replaced, and re-deployed. The first 2010 cruise from 8 - 24 May was onboard the CCGS John P. Tully at Folger Passage, Barkley Canyon, ODP 889, and ODP 1027 locations. The fall cruise from 11 September – 10 October onboard the R/V Thomas G. Thompson focused on the Endeavour location where a cable was installed to connect the main Endeavour field instrument platform to the node, four instruments were deployed in the vent field, and a regional circulation mooring (see section 3.5) was installed. A variety of samples for specific research projects were also collected including push cores, scoops, gas-tight water, and suctions.

Figure 5. Fin whale calls stop for about 4.5 hours following a 5.1 magnitude

earthquake on 12 November 2010, at 9:46 (UTC) in the Fox Islands,

Aleutian Island chain.


NEPTUNE Canada Workshop

Scientists, students, technicians, and computer programmers attended the NEPTUNE workshop, on 12-14 April 2010, to view new software tools, update experiment plans, and explore future opportunities. The workshop included presentations from scientists participating in projects already underway, brainstorming on future experiments and potential new instruments to enhance the existing suite, and discussion of configuration problems and data needs. The final day allowed scientists to discuss the implications and feasibility of future experiments to study various topics including carbon dioxide uptake and ocean acidification, 3-D coastal-shelf-slope oceanography, geophysical processes at Endeavour, marine mammal tracking through use of hydrophone arrays, deep-water ecology and circulation, seismology, and plate tectonics.

2.3 Overview of Collected Data

During 2010, NEPTUNE Canada recorded data from over 270 individual sensors. One prodigious instrument, the BPR at ODP 889, produced10,368,000 measurements. Every day, an average of 10 million scalar measurements are received by DMAS and an average of 1000 raw files are recorded at the University of Victoria and backed up at the University of Saskatchewan.

In 2010, over 4600 users registered for accounts. In Canada, these users generated an average of 16 data products per day (not including NEPTUNE Canada staff). Most search requests came from Canada, but there were users from 61 countries in total with hydrophone and camera data the most accessed. The Oceans 2.0 software suite offers various tools such as Plotting Utility, SeaTube, and Data Search to explore NEPTUNE Canada data. All of these tools are available at http://www.neptunecanada.ca to registered users. Registration is free.


Site by Site Overview3.1 Folger Passage

Setting

Folger Passage is at the mouth of Barkley Sound, offshore Vancouver Island near Bamfield. This site has a variable seafloor composition including cobble, gravel, soft sandy sediment, and carbonate-rich detritus. Two instrument platforms, Folger Deep (100 m) and Folger Pinnacle (23 m), are installed at this location. Folger Deep was connected to the Folger Passage node in 2009. Folger Pinnacle was deployed in 2010, but not connected until 2011 due to time and weather constraints. The Folger Deep platform is situated on soft sediment at the mouth of an inlet channel. The Folger Pinnacle platform is secured to the top of a rocky reef characterised by large boulders, rock walls, and sharp pinnacles.

The waters of Folger Deep were the warmest of all the NEPTUNE Canada sites in 2010. The oxygen sensor at Folger Deep recorded oxygen levels at a maximum in the winter (7.22 ml/L) when downwelling of the oxygen rich water occurs and a minimum level in the summer (1.74 ml/L) when upwelling of the nutrient-rich but oxygen-depleted water occurs (Figure 6). Data, for this and all subsequent plots, were downloaded from NEPTUNE Canada archives at one minute sampling intervals for temperature, salinity, and oxygen. For instruments with sampling rates greater than 60 seconds, one minute decimated data were used. The data were visually inspected for obvious anomalous points, which were removed to produce these plots. Data were then filtered at 1 hour and 30 hours to eliminate tidal signatures.

Currents at the Folger Deep site tend to flow in two directions: the surface currents run in a northwest direction while the lower half of the water column trend in a southeast direction (Figure 7). The two-layer flow is characteristic of estuarine circulation, yet the directions are not consistent with the large-scale morphology of Barkley Sound and are likely controlled by local bathymetry. For more information on how to read progressive vector diagrams see Box 1 on page 19.

Figure 6. Seasonal oxygen, temperature,

and salinity trends at Folger Deep between October 2009 and

December 2010. An Aanderaa Optode on the Folger Deep

instrument platform was used to obtain oxygen readings, while the CTD on the same instrument

platform measured temperature and salinity.

The Folger Passage location is at the

mouth of Barkley Sound...


Figure 7. Progressive vector diagram summarizing data from an ADCP attached to the Folger Deep instrument platform (100 m) between January and August 2010. Surface currents run in a northwest direction while deeper water flows in a southeast direction. Inset shows data availability bar (top) and a magnitude frequency plot (bottom left).

Two major currents on British Columbia’s west coast, the California Current and Alaskan Current, carry water south and southwest respectively. Within the NEPTUNE Canada subsea network, currents are measured using ADCPs and acoustic current meters. Each location needs to be examined independently since local bathymetry and geological features can affect the water flow. Progressive vector diagrams use a selection of depths to visualize the large scale, general trends of current directions. Distance is not measured in this type of plot, but it is inferred from the velocity and direction of the current as well as the time interval measured. Each current vector is added onto the previous vector, starting from the (0,0) origin on a Cartesian co-ordinate grid where the instrument is located. The data are averaged over 15 minute intervals with velocities measured in m/s then converted to distance (km) on the x-y axis. The plotted line approximates the trajectory an individual water parcel might follow through time.

An ADCP attached to a platform prior to deployment.

Magnitude frequency plots (small inset graphs) count the number of times a particular velocity magnitude occurs, at intervals of 0.01 m/s. The higher the count, the more frequently a velocity magnitude occurred. Data availability bars indicate data presence and gaps over the time period of the plot. Data gaps were ignored for the progressive vector diagrams in this report.

Box 1

Currents Measured by NEPTUNE Canada Instruments


This coastal zone is ideal for studies of land-ocean interactions and coastal physical oceanography. At Folger Passage, estuarine circulation from Barkley Sound is influenced by the shelf dynamics of an eastern boundary current. These two regimes create a complex physical environment. The surface outflow caused by freshwater by the many sources in Barkley Sound drives a deep water inflow. This inflow is strongly influenced by upwelling (see Box 2) and downwelling conditions on the nearby continental shelf (Crawford and Thomson, 1991; Freeland and Denman, 1982; Ianson et al., 2003). The nutrient-rich, terrestrial freshwater discharge and the nutrient-rich, cool, salty upwelled water drive primary production to support a diverse and abundant ecosystem.

Upwelling is an important phenomenon that affects weather and ocean current patterns. In coastal regions, upwelling draws cold, nutrient-rich water upward to replace warm, sometimes nutrient-depleted surface waters that are blown offshore by wind. These cool, nutrient-rich waters often trigger blooms of phytoplankton, the primary producers in the world’s oceans. When phytoplankton grow and reproduce rapidly in the nutrient-rich water, they can reach such high concentrations that their colour is visible in the water. Diatoms and dinoflagellates are phytoplankton

typically responsible for large blooms off the coast of Vancouver Island.

Certain dinoflagellate species and some diatoms are capable of producing biotoxins. Algal blooms in which these species are highly concentrated can be toxic to some organisms, including humans. Toxins from phytoplankton consumed by shellfish and small planktivorous fish, can be passed up the food chain to larger fish, marine mammals, and humans.

Box 2

Coastal Upwelling

Two diatoms (Ditylum brightwellii) and a dinoflagellate (?Alexandrium sp.) from Bamfield, British Columbia, October 2007. Image courtesy of Clio Bonnett.


Organisms Observed at Folger Passage

Survey, installation, and maintenance work at Folger Passage revealed a highly prolific ecosystem between 10 and 100 m water depths. The Folger Pinnacle instrument platform is situated in a rockfish conservation area. The instruments are located atop a shallow reef, covered with dense mats of sponges, ascidians, and encrusting algae. There is high diversity and density of animals at Folger Pinnacle. The area is colonised by a large number of sessile (attached) organisms like sponges, cnidarians (anemones), bryozoans, tunicates, barnacles, and seaweed. We also encountered a wide diversity of rockfish (yellowtail, china, quillback, Puget Sound, black, blue, and unidentified juveniles) and other fish (such as kelp greenling, lingcod, ratfish, flatfish, wolf eels), molluscs (giant Pacific octopus, mussels, swimming scallops, gastropods), and echinoderms (vermillion, sunflower, rainbow, cushion and blood stars, California sea cucumbers, urchins).

The Folger Deep site has a soft sediment seafloor habitat. The benthic fauna is harder to observe because of poor visibility, characteristic of this area. Echosounder data indicate a dense zooplankton community and fish schools in the water column and hydrophones recorded the songs of whales and orcas in the area.

Figure 8. Folger Pinnacle community on shallow-water rocks (25 m), May 2010.

Figure 9. China rockfish (Sebastes nebulosus) at the Folger Pinnacle site. Image courtesy of Tom Byrd, Bamfield Marine Sciences Centre.


Instruments and Platforms

Instruments installed at the Folger Deep Platform (100 m) include an oxygen optode, ADCP, CTD, and a 3-frequency echosounder (Figure 10). Nearby are a hydrophone and a BPR.

2010 Experiments at Folger PassageThe west coast Vancouver Island coastal marine ecosystem research project, led by Ron Tanasichuk (Fisheries and Oceans Canada, Pacific Biological Station) seeks to examine biophysical determinants of primary and secondary production in a coastal marine ecosystem and their implications for fish and whales. The project utilizes ADCPs, echosounders, and hydrophones to measure currents, track krill/plankton migrations, and monitor fish and cetaceans.

Pawlowicz and McClure (2010) used 3-frequency echosounder data from Folger Deep to study events such as fish and zooplankton migrations as well as sea surface conditions related to winds and waves. The echosounder’s three transducers, at frequencies of 38, 123 and 210 kHz, convert electrical signals from the transmitter into acoustic pulses sent out into the water. When the pulses reach animals or other objects in the water, a portion of the energy is reflected back to the transducers at different intensities depending on the size and composition of the objects and biota encountered. Reflected energy is then converted by the transducers back into electrical signals. Data are processed to visualize these objects (reflectors) in the water column, allowing researchers to estimate distances, sizes, concentrations and movements of organisms and other objects in the water.

Zooplankton movements were found to vary on scales ranging from minutes to seasons. The most persistent migration is the diel migration: zooplankton leave the surface layers just before sunrise to escape predators and return at dusk to feed (Pawlowicz and McClure, 2010; Figure 11). They interpret the large, white shapes to likely be fish or possibly seals. The long, faint, linear traces are calculated to have the rise-rate of bubbles. Note that

Figure 10. Echosounder transducers on the

Folger Deep platform prior to deployment.


certain fish species, such as herring, expel bubbles from their gas bladders to actively control their buoyancy as well as to communicate. The weak, green, horizontal traces in the background are interpreted as non-migrating zooplankton.

John Ford (Fisheries and Oceans Canada, Pacific Biological Station) is using hydrophone data at Folger Passage and Barkley Canyon to monitor whale populations. The hydrophones can detect whale vocalizations, which may be used to study the seasonal shifts in different cetacean populations. Whale songs can be loud and detectable from distances of tens to hundreds of kilometers.

There are three genetically distinct subgroups within the orca populations off British Columbia’s coast. These subgroups have different ecological specializations and are called resident, transient, or offshore orcas. The residents hunt for fish, with an extreme sweet tooth for salmon. The transients have no predictable range and feed on marine mammals and hence are much quieter than the loquacious residents. Much less is known of the third group as they tend to stay offshore, patrolling the continental shelf in large groups, for sharks and other fish populations to prey upon. Ford is able to identify species and sub-populations because the sub-groups pass unique calls from generation to generation. There are approximately 12 distinct calls per pod. Northern resident orcas were identified by Ford as belonging to Orcas of the G-clan (Figure 12; John Ford, NEPTUNE Canada workshop contribution, 2010). These hydrophone recordings are also incorporated into the LIDO database where automated analyses and classification of vocalizations by marine mammals across the Pacific, Atlantic and Mediterranean are done. For more information on LIDO, refer to Section 2.1 Hydrophones Listening to the Deep.

Figure 11. Dusk migration of fish and zooplankton on 29 December 2009, as viewed by the 3-frequency echosounder. Data compiled by Pawlowicz and McClure (2010).


3.2. Barkley Canyon

Setting

Barkley Canyon encompasses a wide range of environments from the continental shelf edge at 400 m to the continental slope at 900 m water depth, and includes the presence of methane hydrates exposed at the seafloor. Located at the leading edge of the Cascadia subduction zone (see Box 5 on page 39), this site supports the study of the accretionary prism, where the sediments pile along the continental slope as they are scraped off the subducting or descending tectonic plate. This is also a location where pressure, temperature, gas saturation, and local chemical conditions are just right for gas hydrates to be stable. Gas hydrates have gas molecules, typically methane in marine environments, trapped within “cages” of water molecules. This gives them a crystalline structure that resembles ice and can appear as white to yellow mounds covered by sediment on the seafloor (Figure 13).

Figure 12. Northern resident orcas of the

G-clan using call type N23ii recorded 8 March 2010. Courtesy of John

Ford (Fisheries and Oceans Canada, Pacific Biological Station).

Figure 13. Gas hydrate mound observed at the

Barkley Canyon hydrates site. Inset image shows a close-up of exposed

gas hydrate. Both images were taken in July 2009.


Temperature and salinity are measured at the 400 m and the 1000 m instrument locations in Barkley Canyon (Figure 14). The shallower site varies more in salinity and temperature because it is strongly affected by currents and upwelling in contrast to the deeper measurements that remain more consistent over time.

The region is influenced by a major ocean current system. Off the coast, the west wind drift current splits to create the Alaska and the California currents (the California current system). The direction and strength of the currents regulate the upwelling/downwelling regime along the coast, with a flow towards the equator in summer (California current) and reversal in winter (Alaska current). In addition to these two currents, a large submarine canyon acts as a primary conduit for the transfer of sediment from the continental slope to the deep-sea.

Using the ADCPs from the Barkley Canyon shallow and deep instrument sites, the general current directions are determined (Figures 15 and 16). The shallower site shows currents flowing toward the northwest, while the deeper site shows currents moving in the southwest direction. Since the deeper site is located near the lower wall of the Canyon, it is expected to have different current directions than the shelf slope above because the geomorphic features of the canyon walls affect the fluid direction.

Figure 14. Temperature and salinity from the CTD at Barkley Upper Slope, between September 2009 and December 2010 (top); and the CTD attached to Barkley Pod 4 between October 2009 and December 2010 (bottom).


Organisms Observed at Barkley Canyon

Deep-sea organisms have evolved to deal with high pressure, no light, and low nutrients/food availability. Barkley Canyon instruments span a diversity of habitats, each associated with its own specialized biological community.

Despite low densities, a wide variety of organisms inhabit the Barkley Canyon study areas. All of the instrument locations at Barkley are characterized by a soft sediment seafloor. Video observations suggest that animal densities are higher at the shallower site compared with the deeper sites, although most of the species are present at all sites. Observed fish include sablefish, rockfish, flatfish, sharks, skates, hagfish, and eelpouts, with the most commonly observed being sablefish. The latter is observed in high abundance in fixed benthic camera recordings, possibly because of the influence of the camera lights. Molluscs inhabiting the area are bivalves, identified by their siphon at the sediment surface, gastropods, and cephalopods (giant Pacific octopus). Echinoderms include sea stars, brittle stars, sea cucumbers, sea pigs, and urchins. Various arthropods, mostly crustaceans (crabs, barnacles, and shrimp), are periodically seen in the area. While cnidarians (coral, anemones, sea pens, and jellyfish) and sponges are observed at all three instrument sites, they are more common at the shallower site. Throughout the water column and on the seafloor, miscellaneous organisms such as salps, ctenophores, and tunicates were recorded in the ROPOS dive videos.

On the seafloor at the gas hydrate sites, growth of chemosynthetic (see Box 8 on page 48) bacterial mats are fuelled by hydrogen sulphide produced by the oxidation of methane by another group of microbes living deeper within the sediments. Other chemosynthetic sulphide-oxidizing bacteria live in symbiosis with seep clams. Animals not dependent on this ecosystem but frequently observed via the Wally webcam include short-spine thornyheads, Pacific hagfish, grooved tanner crabs, and anemones.

Figure 15. Progressive vector diagram for

ADCP data from the Barkley Canyon Upper Slope instrument

platform (396 m) between January and December 2010.

Current tend to flow in a northwest direction.

Insets: data availability bar (top) and magnitude frequency plot

(bottom left).

Figure 16. Progressive vector diagram for

ADCP data from Pod 3 (893 m) at Barkley Canyon between January

and November 2010. Currents tend to flow in a southward

direction. Insets: data availability bar (top) and magnitude

frequency plot (bottom left).


Figure 17. A sea cucumber and brittle stars at Barkley Canyon.

Figure 18. A glass sponge (Pandalopsis? sp.)provides a home for some shrimp and brittle stars.


Deployed at a cold seep in the Barkley Canyon gas hydrate field, Wally is equipped with sensors that measure temperature, pressure, water currents, salinity, methane, and turbidity. Wally’s webcam provides researchers with a detailed view of the seafloor sediments and local marine life. At a depth of 870 m, Wally is connected to the Barkley hydrates platform by a 70 m long cable and navigates a series of numbered way markers arranged along a seafloor tour route known as “Wally Land.”

There are actually two crawlers, “Wally I” and “Wally II,” allowing one to be maintained on shore while the other is deployed. Each Wally crawls about on dual tractor treads, enabling a full range of forward, backward, and turning movements. Wally’s movements are remotely controlled via the internet by a research team in Bremen, Germany who monitor Wally’s position using its onboard compass and video camera. Wally II sports a custom-designed sediment microprofiler that scientists use to study oxygen, pH, salinity, temperature, and sulphide levels in seafloor sediments and bacterial mats. Wally is also equipped with a Franatech METS methane sensor, which has a detector

chamber protected against water and pressure by a silicone membrane. Gas molecules diffuse through the membrane and into the detector chamber along the partial pressure gradient between it and the ambient water. The concentration of methane in the chamber is compared to the concentration in the surrounding water. Over time, contamination of the sensor membrane from oil droplets seeping out of the seafloor obscures and biases these measurements, resulting in extended periods of unrealistic values prior to recovery and maintenance. Including Wally’s titanium frame, drive motors, sealed electronics chambers, wiring, lights, video cameras, and sensors, a crawler’s out-of-water weight is approximately 275 kg. Syntactic foam flotation blocks reduce the weight to 40 kg in water.

Box 3

Wally the Benthic Crawler

Map of Wally Land in the Barkley Canyon hydrate outcrops.

Wally the crawler sits atop some gas hydrates at the Barkley Canyon location.



Barkley Canyon is extensively instrumented (Figure 19) with seven different platforms spread across various sites. Each platform is equipped with instruments to monitor environmental conditions and their associated biological communities. Five of the seven instrument platforms (Table 2) are stationary; the benthic crawler Wally, in the gas hydrates field, is a mobile instrument platform and the vertical profiler system (VPS), located in shallower water at Barkley is designed to gather data profiles through the water column.

Figure 19. Map showing the instrument platforms within Barkley Canyon, 2010.


Platform Environment Instruments

Upper Slope(396 m)

Top of continental slope near

shelf/slope break

• BPR• Hydrophone• ADCP• CTD• Broadband seismometer

Pod 2(396 m)

Top of continental slope near shelf edge

• Black and white video camera system• Rotary sonar• ADCP• Acoustic current meter • Sediment trap

VPS* (396 m) Top of continental slope, near

shelf/slope break

• Radiometer• Echosounder• Fluorometer• CO2 sensor• CTD• Hydrophone• ADCP• Oxygen optode• Nitrate sensor

Wally the Crawler I(870 m)

Hydrate outcrops; canyon

• Webcam• CTD• Methane sensor• Acoustic current meter• ADCP• Fluorometer• Turbidity meter

Pod 1(984 m)

Canyon axis• Black and white video camera system• Hydrophone• Rotary sonar• Acoustic current meter

Pod 3(892 m)

Mid-canyon (east)• Black and white video camera system• Rotary sonar• ADCP• Acoustic current meter• Plankton pump

Pod 4(896 m)

Mid-canyon (west)

• CTD• Fluorometer• Colour video camera system• Microbial sensor

Table 2. List of Barkley Canyon

platforms together with description of deployment

environment and instruments associated with

each platform.

* indicates the platform was removed for repairs.


2010 Experiments at Barkley Canyon and Slope

Barkley Canyon covers a wide range of continental margin environments, where scientists can study the transport of sediment and nutrients between the continental shelf and the deep sea, subduction zone processes, stability of gas hydrate outcrops, and influences of the canyon and related upwelling on biological, ecological, and physical processes.

Water Column Studies

The VPS (Figure 20) is the centerpiece of a biophysical links experiment led by John Dower (University of Victoria). This study strives to examine the co-variability of physical and chemical properties of the water column at the shelf break. The VPS consists of a base platform that rests on the seafloor, and an instrumented float that can be raised and lowered through the water column. The onboard instruments generate water column profiles of salinity, temperature, dissolved gases, nutrients, dissolved organic matter, chlorophyll fluorescence, up/downwelling radiation, and currents. Plankton and fish are imaged with an echosounder and marine mammal vocalizations are detected with a hydrophone. These data also support research on topics such as biological productivity, eastern boundary current physics, and plankton lifecycles. The VPS malfunctioned in 2010 and was only able to complete one 200 m profile. It was recovered, repaired, tested, and is now scheduled for deployment in 2012.

Figure 20. The vertical profiler system instrument float and platform during recovery operations, May 2010.


Benthic Studies

Paul Snelgrove (Memorial University) and Anna Metaxas (Dalhousie University) head the Barkley benthic group whose focus is the study of physical and biological forcing conditions in the benthic boundary layer and their impact on the ecosystem dynamics. Four instrument platforms, or benthic pods with their associated satellite are used for these studies. The instrument platforms are located in three strategic areas: Pod 2 on the upper slope of the continental margin at 398 m depth, Pod 1 in the axis of the canyon at 980 m depth, and Pod 3 and 4 on the wall of the canyon at 890 m depth. This configuration is ideal for studying the relative influences of organic matter supply, sediment transport, and stochastic and seasonal changes in environmental conditions and their effects on benthic community dynamics in a slope canyon setting.

Organisms that crawl across the sediment surface and/or burrow within the sediments mix them up – a process known as bioturbation. At the University of Victoria, Katleen Robert and Kim Juniper studied bioturbation processes in Barkley Canyon (Robert and Juniper, 2012). Using video data, Robert determined that an area of 8.8 m2 was completely overturned in 90 days by benthic fauna such as flatfish, sea urchins, and sea stars. At the same site, Alex Hay and Doug Schillinger (University of Dalhousie) imaged the seafloor using a rotary sonar. Hourly images were generated, allowing scientists to study daily and seasonal sediment bedform changes due to bioturbation or currents. They noticed pits, approximately 50 cm in diameter that persisted for months at a time (Figure 22). Robert’s observations suggest these pits might be maintained by flatfish activity, such as when they bury themselves in the sediment.

Figure 21. This rockfish was observed on 29 January 2010 by the video

camera on Pod 2, which sits near the top of the continental slope close to the shelf edge of

Barkley Canyon.


Mairi Best (University of Victoria and Laurentian University) is studying the utility of skeletal assemblages in assessing biodiversity, habitat complexity, and geochemical cycling in modern marine environments. Mussel shells were deployed on the VENUS network in Saanich Inlet and on the NEPTUNE Canada network at the Barkley hydrates site during the May and September 2010 NEPTUNE Canada cruises. The shells were numbered, photographed, and weighed before and after deployment to determine net changes in chemical and physical properties and are observed using cameras and environmental sensors. By comparing data from this site with results from previous experiments deployed across tropical, temperate, and polar latitudes, Best will elucidate variation in elemental exchange and anthropogenic impact at a global scale.

The Barkley Canyon hydrates project, led by Ross Chapman (University of Victoria) and Laurenz Thomsen (Jacobs University), uses Wally and its suite of instruments to study gas hydrate benthic ecosystems and the accretion and dissolution of gas hydrate outcrops.

The observations made by Thomsen between January and September 2010 (Table 3) determined that the formation and dissociation of the gas hydrate outcrops and phytodetrial input are the main causes of short-term, small-scale variation in benthic community structure. During this observation time, there was a small destruction of the hydrate deposit, which was not due to pressure or temperature changes. Flow velocity and methane release are significantly correlated at hourly to daily periods (Laurenz Thomsen, NEPTUNE Canada workshop contribution, 2010).

Figure 22. Rotary sonar image used by Hay and Schillinger to study seafloor micro-relief. Numerous pits are visible in image. Rectangular pattern in upper part of image represents the instrument platform to which the sonar is affixed. Courtesy of Hay and Schillinger.


Measurement Type Measurement

Flow velocity >10 cm/s 22% of the time (1-22 cm/s range)

Temperature range 2.5-3.5 ˚C

Methane concentration 0.8-6.9 µmol/L

John Ford (Fisheries and Oceans Canada, Pacific Biological Station) is using hydrophone data from Barkley Canyon to detect cetacean vocalizations and study the seasonal occurrence of different species and populations. As Barkley Canyon is deeper and further offshore than the shallow, near-shore Folger Passage site, it is well situated to monitor orcas. The deeper sites recorded larger humpback and fin whales. Fin whale calls (Figure 23) are recorded by hydrophones as very intense, low frequency infrasonic pulses that propagate over long distances. The pulses last about one minute and occur at intervals of approximately 45 seconds.

Ford hopes to hear blue whales when they migrate to northeastern Pacific waters to feed. Sperm whales are also anticipated and can be detected by their unique “clicking” as the males locate prey and navigate (John Ford, NEPTUNE Canada workshop contribution, 2010). Michel André and LIDO also analyse the hydrophone data to study the effects of noise pollution on cetaceans and other marine mammals. Data from the North Atlantic and Mediterranean are also available at LIDO through ESONET. For more details, see section 2.1 Hydrophones Listening to the Deep.

3.3 ODP 889

Setting

The ODP 889 location lies 1258 m below sea level and about 18 km landward of the toe of the Cascadia subduction zone (Figure 24). This is a zone where much of the thick layer of sediments deposited on the eastern flank of the Juan de Fuca Ridge are scraped off or accreted as the tectonic plates collide (Davis and Hyndman, 1989; Hyndman et al., 1990; Westbrook et al., 1994). Convergence of the Juan de Fuca oceanic plate relative to the North American continental plate occurs in a direction roughly perpendicular to the continental margin and at a rate of roughly 42 mm/y (DeMets et al., 1990). The majority of the sediment supply has been contained by the elevated topography of the Juan de Fuca ridge.

Table 3. Measurements recorded by

Wally between January and September 2010 (courtesy of

Laurenz Thomsen).

Figure 23. Fin whale calls recorded at

Barkley Canyon Axis on 5 January 2010.

Courtesy of John Ford, Fisheries and Oceans

Canada, Pacific Biological Station.


The accreted sediments at the seaward-most thrust fault are approximately 2.7 km thick. At Site IODP U1364 the accreted sediments are nearly doubled to a thickness of approximately 5 km (Yuan et al., 1994). As sediments thicken and compact from accretion, pore waters are expelled from the sediment, and gases — primarily biogenic methane — contribute to the formation of gas hydrates in the upper few hundred metres of the sediment (Haacke et al., 2007; Hyndman and Davis, 1992; Hyndman et al., 1990; Riedel et al., 2010).

ODP 889 lies at a position landward of the prism toe where the pore water expulsion rate, estimated on the basis of the rate of growth of the accreted sediment, reaches a cross-margin maximum and where a clearly developed bottom simulating reflector, a seismic reflection at the sediment-gas hydrate interface created by the unequal densities of sediments and those that are gas hydrate-rich, marks the base of the gas hydrate stability field (Hyndman and Davis, 1992). At this location, a cold vent, known as bullseye, has formed along with significant concentrations of gas hydrates (Spence et al., 2000; Hyndman et al., 2001).

The annual seawater temperature at this site ranges from 2.75 to 3.16 oC and is on average 2.98 ± 0.12 oC (Figure 25). The currents at ODP 889 (Figure 26) trend in a southwest direction.

Figure 24. Cross section through the Cascadia subduction zone showing the deformation front (toe of accretionary prism) and accretionary prism (accumulated sediments) as well as the general motion (red arrow) of the oceanic Juan de Fuca plate subducting beneath the continental North American plate (courtesy of Clio Bonnett).

Figure 25. Temperature recorded by bottom pressure recorder (BPR) at ODP 889 between October 2009 and December 2010. BPR housing temperature was calibrated with a CTD. An offset was calculated from overlapping data in 2011 between the two instruments. The offset was then applied to the 2010 temperature data.


Organisms Observed at ODP 889

Situated on the continental slope, ODP 889 is home to a variety of deep-sea organisms. During ROPOS dives at this site, demersal fish were observed (rockfish, flatfish, thorny heads, and rattails) along with echinoderms (sea cucumbers, brittle stars, slime stars), molluscs (octopuses and squid), arthropods (tanner and king crabs), cnidarians (sea pens, coral, anemones), and bacterial mats. In the water column we noted various other organisms including squid, krill, jellyfish, siphonophores, and larvaceans.

Figure 26. Progressive vector diagram

from the acoustic current meter at ODP 889 between

June and December 2010. The general current flow was southwest as measured at a

single depth of 1256 m. Insets: data availability

bar (top) and magnitude frequency plot (left).

Figure 27. A brittle star wrapped

around a sea pen at ODP 889.



ODP 889 is connected to an instrument platform, which was deployed in September 2009, then replaced and re-connected to the node in May 2010. Instruments attached to the platform include a BPR, broadband seismometer with differential pressure gauge and acoustic current meter, seafloor compliance system (gravimeter and differential pressure gauge), controlled source electromagnetic system, acoustic sensor, and rotary sector scanning sonar.

2010 Experiments at ODP 889

Bullseye Vent Gas Hydrates

The controlled source electromagnetic experiment, led by Nigel Edwards (University of Toronto), uses electromagnetic pulses to characterize the distribution and evolution of gas hydrates below the seafloor. The seafloor compliance experiment, led by Ele Willoughby (University of Toronto), is designed to study the composition and evolution of gas hydrates. Seafloor compliance uses precise measurements (seafloor pressure and low-frequency ground deformation from gravity meters or broadband seismometers) to calculate seafloor stiffness which is, in turn, used to create a depth profile of the hydrate deposit. Stiffness is an indicator of the amount of gas hydrate present per unit volume (stiffness increases with hydrate presence). Gravity is used to measure ocean gravity waves to determine depth at a very fine scale.

Figure 28. A Pacific grenadier (Coryphaenoides acrolepsis) near ODP 889.


On 18 May 2010, an Imagenex multibeam sonar was installed at ODP 889 to allow for the study plumes of methane gas that escape from the seafloor in the “bubbly gulch” portion of the bullseye vent. At this location, methane percolates upward from gas pockets associated with gas hydrates beneath the seafloor. Although the gas hydrates are a frozen solid, there are fissures through which the methane escapes. After escaping, bubbles are detected in sonar readings. It is theorized that the bubbles are enclosed in a thin skin of hydrate where methane contacts the deep cold waters. By the time bubbles rise to 900-500 m water depths, the plumes largely disappear as the hydrate skin dissociates and the methane dissolves into seawater.

The Imagenex multibeam sonar was set up to perform a rotary scan (360o) with a 100 m range every hour. Unfortunately, there was a malfunction and the sonar head did not turn. This resulted in the sonar only looking in the ESE direction. Below are a series of sonar images that show a gas bubble plume appear and fade in the sonar beams over a time period of 4 hours on 29 October 2010. The bottom beams of the sonar are oriented parallel to the seafloor (visible as sonar reflections from the undulating ground), and the beam swath extends vertically 120o up over the top of the sonar. Such gas plumes were observed to appear roughly every 12 hours, correlating with tidal cycles.

Box 4

Gas Plume Activity at ODP 889

Sonar images of a gas plume 20-50 m above the Imagenex multibeam sonar at “bubbly gulch” near ODP 889, captured every hour on 29 October 2010 between midnight and 4 a.m. UTC. Sonar range is 100 m.


Seafloor Hydrology

The first ODP borehole at the 889 location was drilled in October 1992. In September 2010 IODP Hole U1364A was drilled nearby and instrumented with an Advanced CORK and will be connected to NEPTUNE Canada in 2013 (see Box 6 on page 40). A broad range of objectives will be addressed with this new installation. These include documenting the average state of pressure, constraining the vertical component of fluid flow from the consolidating sediments in this part of the Cascadia accretionary prism, and investigating the formation of gas hydrates. Other objectives have been subsequently added because of the multiple discrete subseafloor monitoring levels provided by the Advanced CORK configuration, advances in measurement resolution and sampling frequency, and knowledge gained from other monitoring experiments. These include determining the influence of gas hydrates and free gas on the mechanical properties of the host lithology, the response of the formation to seismic ground motion, and the magnitude of strain at the site caused by any episodic seismic or aseismic slip in this subduction setting. Instrumentation deployed at the time of drilling includes autonomously recorded seafloor and formation pressure sensors and seafloor temperature sensors. Sensors planned for deployment inside the sealed borehole casing at a later date will measure temperature, tilt, and seismic ground motion. In 2013, all instruments will be connected to the NEPTUNE Canada’s network. This will provide for a greater sampling rate, time accuracy, and monitoring lifetime than are possible with autonomous operation using battery power and local data storage.

A subduction zone (Bebout et al., 1996) is an area where two plates are converging, with one plate moving beneath the other. As the down-going (subducting) plate moves deeper, it transports water into depth where it is heated and released. The heat from the mantle and core causes the surrounding rocks to melt and become fresh magma for volcanic eruptions. The down-going plate is recycled in the Earth’s mantle. At the Cascadia subduction zone the ocean crust of the Juan de Fuca plate is subducting beneath the continental crust of the North American plate. At subduction zones, there usually is an area where the two plates become locked. This means that they are not slipping past each other and frictional stress can build up, storing

large amounts of energy. When this stress finally reaches a breaking point, it releases the energy that has been stored resulting in what is known as a “megathrust” earthquake (see e.g. http://www.iris.edu/hq/programs/education_and_outreach/animations/5).

The locked zones can hold for hundreds of years as the Cascadia subduction zone has done since 26 January 1700 when the last megathrust earthquake occurred in this area (Satake et al., 2003). The earthquake magnitude was estimated as 9.0 and it resulted in a tsunami that was recorded in Japan. Evidence of this earthquake can be confirmed by geological evidence (land level changes, tsunami traces, turbidite deposits), biological evidence (tree rings), and human records (Native American stories and Japanese records) (Satake et al., 1996; Satake et al., 2003; Satake and Atwater, 2007). Megathrust earthquakes tend to occur in this region approximately every 300-500 years.

Box 5

Cascadia Subduction Zone

Modeled tsunami caused by the 26 January 1700 megathrust earthquake. Image courtesy of Kenji Satake.


3.4 ODP 1027

Setting

The ODP 1027 location is 2660 m below the sea surface in the centre of a sedimented region known as Cascadia Basin. The Cascadia Basin extends from the base of the continental margin, where sediments entering the Cascadia subduction zone begins to accrete (see Box 5), to within the vicinity of the ridge crest, where bare crust occurs and at some locations is younger than 1 Ma (Davis et al., 1997). Based on measurements recorded by CTDs between 1 January and 31 December 2010, the annual average salinity and temperature are 34.6 psu and 1.78 ˚C respectively (Figure 29).

For over three decades, a funde-mental goal for scientific ocean drilling has been to understand the role of the presence and flow of water in marine geologic formations on processes like heat loss from the earth, chemical exchange between the Earth’s oceans and crust, support of subseafloor microbiological ecosystems, and the creation of methane-hydrates and ore deposits. The quality of direct observations is commonly compromised by a simple problem: boreholes create hydrologic “short circuits” that allow open exchange of water between subseafloor formations and the ocean. The resulting perturbations severely limit the utility of temperature and pressure observations and of water samples taken during or shortly after drilling operations.

As a solution to this problem, the CORK (Circulation Obviation Retrofit Kit) hydrologic observatory was designed to seal open holes and carry sensors and fluid samplers for long-term monitoring (Davis et al., 1992). A seal stops the flow of water

and permits the formation to recover from perturbations associated with drilling. A thermistor cable provides a downhole temperature profile and pressure measurements are representative of the open-hole sections drilled below casing (Becker and Davis, 2005). For more information on CORKs visit http://www.corkobservatories.org/.

Box 6

CORKs

Schematic of a deployed CORK. Based on Becker and Davis, 2005.


Organisms Observed at ODP 1027

The abyssal plain is a vast environment covering 54% of the Earth’s surface (Gage and Tyler, 1991). Deep-sea species are adapted to this cold, dark, high-pressure zone. Ecosystems rely heavily on food that falls from the surface, but little is known about trophic links among the organisms that inhabit deep-sea sediments. Despite a low density of organisms, ROPOS has enabled observations of a high diversity of benthic and demersal organisms during installation dives at this location. Fish (skates and rattails), echinoderms (sea cucumbers, sea stars, brittle stars, crinoids), molluscs (octopus and squid), cnidarians (sea pens), and arthropods (squat lobsters) were the main groups observed.

During remotely operated vehicle ascents and descents through the water column, a variety of pelagic organisms including molluscs (squid), cnidarians (jellyfish), arthropods (ostracods), and a variety of other organisms such as ctenophores, plankton, and salps were observed and recorded.

Location Instrumentation

Figure 29. Temperature and salinity recorded by CTD on ODP 1027 instrument platform during October 2009 - December 2010.

Figure 30. Jellyfish at 1220 m depth during remotely operated vehicle descent to ODP 1027.

Figure 31. Close-up of sea pen (Umbellula sp.) at ODP 1027.



One instrument platform was installed at the ODP 1027 location. It supports a CTD on the platform, 3 BPRs, CORK 1026B pressure and temperature instruments (see Box 6 on page 40), and a seismometer package (broadband seismometer and strong motion accelerometer). Additionally, an auxiliary platform connected to the seismometer holds an acoustic current meter and a differential pressure gauge. Seismologists use the differential pressure gauge to detect and filter tide and wave data from the seismic dataset.

2010 Experiments at ODP 1027

Ocean Crustal Hydrogeology

The Cascadia Basin, a sedimented portion of the abyssal plain with a few isolated outcropping seamounts, is an ideal location to study the three-dimensional nature of fluid flow in oceanic crust. This is done using several CORK (see Box 6) borehole observatories (Fisher et al., 2010). Instrument packages installed in these CORKs extend hundreds of metres down into igneous rock. Scientists are using CORKs to observe changes in pressure and temperature caused by earthquakes, storms, and hydrothermal convection. CORKs are also being used to investigate changes in regional plate strain that are caused by earthquakes on the plate boundaries (Davis et al., 2009).

Currently, one of the CORKs in the ODP 1027 area (CORK at ODP 1026B) is connected to the NEPTUNE Canada network, but more will be connected in the future. Besides providing real-time access to CORK data, the connection enhances the sampling frequency and time accuracy of the recorded data. The CORK at ODP Hole 1026B measured temperature of the ocean crust in 2010 (Figure 32).

Figure 32. Temperature measured by the

ODP 1026B CORK between June and July, 2010 at various

depths in metres below the seafloor (mbsf). Note that the

temperature increases in a downward direction on the y-axis. The general increase

in temperature reflects the geothermal gradient. The peak in temperature

was due to a team using a submersible to sample fluids

from the borehole, causing warm water to rise inside

the borehole. After sampling the temperature disturbance

decays slowly.


3.5 Endeavour

Setting

Endeavour, located in water depths ranging from 2200 to 2400 m, is part of the complex mid-ocean ridge system along the boundary between the Juan de Fuca and Pacific plates. The seafloor is an elaborate network of fissures, trenches, dykes, pillow lava deposits, rocky outcrops, sediment beds, and sulphide towers (see Box 7 on page 45). Because this is an area of active geothermal venting, local temperatures are highly variable throughout the ridge system. The hydrothermal vent fluid is extremely hot and cools very quickly as it mixes with the surrounding cold sea water. Temperature sensors from the benthic and resistivity sensor (Figure 33), the remote-access water sampler, and a CTD on the regional circulation mooring northeast (see section 3.5 Instruments and Platforms) show the high variability of thermal conditions in this environment (Figure 34).

Figure 33. The benthic and resistivity sensor (BARS) probe was placed in Grotto vent black smoker at a depth of 2190 m. This probe is able to measure the extremely high temperatures (~350 oC) of the effluent.


ADCPs on the regional circulation mooring (Figure 35) show that during the October-December time period, current flow direction higher in the water column (1627 m) trended to the southwest while deeper in the water column, as measured by the deepest ADCP (1907 m), the currents trended to the northeast.

Figure 34. Temperatures recorded by the remote-access water sampler

(RAS; sea water surrounding vent) and benthic and resistivity sensor

(BARS; vent effluent) show how hot the vent effluent can be compared

to surrounding water (top). The regional circulation mooring

northeast is equipped with several CTDs that recorded the temperature

between October and December 2010 at 5 mab (bottom).

Figure 35. Progressive vector diagram at

regional circulation mooring northeast at Endeavour between

October and December 2010. The ADCP at 250 mab (1904 m) indicates

current flow in the southwest direction. The lowest depth measured

by the ADCP (1907 m) indicates flow in the northeast direction.

Insets: data availability bar (top) and magnitude frequency plot (right).


Organisms Observed at Endeavour

While most of the deep sea depends on photosynthetic surface productivity, vent communities are independent from the surface and sunlight. Bacteria are able to use reduced compounds from vent effluent as an energy source to produce organic matter through a process called chemosynthesis (see Box 8 on page 48). Those bacteria, free-living or symbiotic, are at the base of the vent food chain and support local dense biological communities where 90% of the species are endemic to this special environment. At Endeavour, the tubeworm Ridgeia piscesae grow in large colonies in diffuse venting areas, supported by symbiotic chemosynthetic bacteria developing in their cells. These worms are unique

Beneath the oceans there are large mountain chains called mid-ocean ridges formed as a result of plate tectonics. Where two plates meet at a divergent boundary (each side moving away from the other), convection currents in the mantle rise up as magma, emerge through rifts as lava, and crystallise as rocks (basalt and gabbro). These processes continually create new ocean crust. Hydrothermal vents, which typically form along these mid-ocean ridges, are fissures from which geothermally heated water flows. The water that flows out of the vents is mostly seawater drawn into the system through faults, porous sediments, and

volcanic rocks. As the cool seawater moves through the sediment and rock toward the hot magma, the water becomes superheated (300-400 oC) and rich in dissolved mineral elements (such as sulphur, iron, zinc and copper) from the ocean crust. When the hot effluent encounters the cold, ambient seawater (~2 oC) minerals precipitate from the element-rich vent water. At some vent sites, black smokers form; these are found in areas where the effluent is very hot (~350 oC precipitating iron sulphides, giving it a dark colour, and forming sulphide-mineral deposits.

Box 7

Mid-Ocean Ridges and Black Smokers

Black smoker at Grotto hydrothermal vent in the Endeavour Segment rift valley (October, 2010).


in that they lack both a mouth and anus; they take sulphur and oxygen from the environment and transport them to the intracellular bacteria.

Other dominant macrofaunal species include limpets (molluscs), worms, fish, and a species of arthropod known as a sea spider (Ammothea verenae). In diffuse venting areas, the limpet Lepetodrilus fucensis hosts symbiotic chemoautotrophic bacteria associated with its gills, but is also able to graze on bacterial mats developing in the environment, resulting in great colonization success. Indeed, this species can reach a density of 400,000 individuals/m2 (Warén et al., 2006). Often observed crawling amongst R. piscesae and L. fucensis are the worms Paralvinella pandorae, P. palmiformis, and the scale worm Branchinotogluma tunnicliffae. The sulfide worm (P. sulfincola) grows in high temperature areas around smokers where only thermophilic (heat-loving) bacteria can develop.

ROPOS dives enabled observations of non-vent organisms living on the ridge crest, on abyssal plains away from the ridge, and in the open ocean water column. Fish, such as deep sea skates, Pacific flatnose, and rough-scaled grenadiers, have been noted near the sea bottom while Pacific herring and ocean sunfish have been encountered in the water column. Octopus are seen on the sea floor and squid in the water column. On the ridge crest, sessile (fixed) organisms, including echinoderms (crinoids), various cnidarians (corals, gorgonians, sea pens, anemones), and many sponges (e.g. leather bag sponge, sharp lipped boot sponge, round lipped boot sponge), as well as motile organisms like brittle stars (echinoderms) occur. Sea cucumbers and urchins are more common on the soft bottom abyssal plain. Jellyfish have been observed in the water column.

Figure 36. Tubeworms (Ridegeia piscesae)

and palm worms (Paralvinella palmiformis), scale worms

(Branchinotogluma tunnicliffae), and limpets (Lepetodrilus

fucensis) on Grotto vent (2189 m), 4 October 2010.


Figure 37. Ocean sunfish (Mola mola) in water column near Endeavour.

Figure 38. Octopus (Muusoctopus canthylus) in Mothra vent field at Endeavour.


Life is usually thought to be driven by energy from the sun. The deep ocean is devoid of sunlight, yet life persists. While most of the abyss relies on photosynthetic surface productivity, hydrothermal vent communities use a different energy pathway, relying on a process called chemosynthesis. Specialized chemoautotrophic bacteria oxidize inorganic molecules contained in hydrothermal vent effluent and use the released energy to produce organic matter (carbohydrates) from dissolved CO2. At these vents, bacteria oxidize hydrogen sulphide, a compound that is toxic to most forms of life. These bacteria, free-living or symbiotic, support an abundant and dense faunal community of mostly endemic species, by providing food for grazers,

suspension- and deposit-feeders, or living in association with macrofaunal species as symbionts.

One example of this association is the tubeworm Ridgeia piscesae, a keystone species that provides habitat for other members of this unique ecosystem. These worms have no gut and cannot feed on bacteria directly. Instead, chemotrophic bacteria live within the cells of a specialized part of the tubeworm’s body called the trophosome. The red gill plumes of the tubeworms are the result of their blood being very rich in haemoglobin, which absorbs and transfers oxygen and hydrogen sulphide that are dissolved in seawater to the bacteria in the trophosome.

Box 8

Vent Fauna and Chemosynthetic Bacteria

Tubeworms (Ridgeia piscesae) and worms (Paralvinella palmiformis) on Godzilla edifice, High Rise vent field, Endeavour (July 2011).



In September 2010, two sites at Endeavour were connected to the NEPTUNE Canada network: the main Endeavour field (in 2192 m water depth) and the northeast regional circulation mooring (in 2154 m water depth). Main Endeavour field supports four instruments at the grotto hydrothermal vent site: the cabled observatory vent imaging sonar (COVIS) which acoustically images vent plumes, the benthic and resistivity sensor instrument measuring the temperature and resistivity of high temperature vent effluent, a short-period seismometer, and the remote-access water sampler for sampling the sea water above the vent.

Figure 39. Endeavour site map with instruments installed as of October 2010 and planned 2011 installations.


The 267 m tall regional circulation mooring helps scientists estimate ocean currents within the axial rift valley and gauge the effects of hydrothermal venting on those currents. This mooring is the first of four planned for the site, which will eventually provide a comprehensive picture of circulation in the area. The uppermost instrument on the mooring at 250 metres above bottom (mab) is an ADCP; below this are four instrument pairs distributed along the length of the mooring (200 mab, 125 mab, 50 mab, and 5 mab). Each pair includes a CTD and a current meter. A float at the top of the mooring keeps the instrument array in a vertical orientation. Nearby is a BPR, which is used in conjunction with the mooring’s current meters to establish the overall structure of the circulation dynamics. CTD temperature data and other data can be used (Figure 40) to monitor physical properties throughout the water column over various time periods. When all four moorings are deployed, the data will be used to develop 3D models and visualizations of circulation in the region.

2010 Experiments at EndeavourAt the Endeavour ridge segment research is focused on hydrothermal vent systems, plate tectonics along with seismic and volcanic activities, vent ecology, and fluid chemistry.

The COVIS project is customized a sonar system, connected to the NEPTUNE Canada cabled observatory at the main Endeavour field on the Juan de Fuca Ridge (September 2010), that is providing a first-ever time series of acoustically imaged and measured hydrothermal change at the study site. The images are of the plumes that buoyantly rise from high-temperature black smoker vents and lower-temperature diffuse flow discharging from the surrounding seafloor. Measurements comprise flow rate and volume flux of the plumes and the area of diffuse

Figure 40. Regional circulation mooring

northeast temperature profile time series, recorded using CTDs located 5-200 mab (metres above bottom) or 1954-2149 m below the surface,

October – December 2010.


flow to determine how these flows change. Time scales are of oceanic (hours, related to tides) and geologic (longer time periods related to earthquake and volcanic activity) processes. This information is essential to understanding how hydrothermal flow impacts chemical and physical processes and the distribution of life in the ocean. The COVIS project is a collaborative initiative of Rutgers University and the Applied Physics Laboratory of the University of Washington supported by the U.S. National Science Foundation.

Network-Wide ObservationsFive NEPTUNE Canada nodes are currently connected to one or more instrument platforms, which are, in turn, equipped with different types of devices and sensors used to monitor variables across many locations within the network. These variables can be used both to track the propagation of individual events across the network and to monitor temporal trends. Several network-wide arrays are established, and as more instruments are added, these networks may grow and new ones may be created.

Figure 41. Acoustic image built using COVIS looking south showing black smoker plumes and areas of diffuse flow layered over bathymetry of the Grotto vent cluster in the Main Endeavour field, Juan de Fuca Ridge. The image was created from data collected on 11 October 2010, 06:00 UTC, near slack tide when tidal currents were minimal. See Rona and Light (2011) for more details.


4.1 Seismograph Network - Led by Garry Rogers (Geological Survey of Canada)

Seismometers are located at all but the Folger Passage node (which is too noisy) comprising the seismograph network (Table 4). Data from the seismometers are directed to the Incorporated Research Institutions for Seismology and the Geological Survey of Canada’s National Seismograph Network where they are used, together with data from land-based instruments, to locate global seismicity and regional events around the Juan de Fuca plate. The data also allow for detailed studies to be conducted in locations where the instruments are installed. At Endeavour, the instruments provide the basis for interdisciplinary collaboration in the analyses of earthquake-related events at a mid-ocean ridge. At ODP 889, the seismometer data are used to monitor temporal variability of gas hydrates in the subseafloor.

A selection of major earthquakes of 2009 and 2010 recorded by NEPTUNE Canada instruments are listed in Table 5. The 2010 Chilean earthquake is shown in Figure 3 as detected by an ocean-bottom broadband seismometer as part of the seismograph network experiment.

Location Environment Instruments

Barkley Canyon Continental slope • Broadband seismometer

ODP 889 Continental slope • Broadband seismometer

ODP 1027 Mid-plate, abyss • Broadband seismometer

Endeavour Spreading ridge • Two short period seismometers• One broadband and two additional

short-period seismometers are planned.

Table 4. Locations, environments, and instruments belonging to the

seismograph network.

Table 5. Selected major earthquakes

detected by the NEPTUNE Canada seismograph network including

magnitude (Mw) and the significance to British Columbia’s

coast. Data collected from United States Geological Survey and

Natural Resources Canada websites.

Date Earthquake Location Magnitude Significance to BC Coast

27 Feb. 2010 Offshore Maule, Chile (epicenter 06:34:14 UTC)

8.8 Wave heights of 40-100 cm seen at 23:00:00 UTC

29 Sep. 2009 Samoa Island Region (epicenter at 17:48:10 UTC)

8.1 Seen on NEPTUNE Canada tsunami array at 11 hrs (ODP 1027) and 16 hrs (ODP 889) after the initial seismic event. Wave heights of 18 cm recorded in Port Alberni

17 Nov. 2009 Queen Charlotte City (epicenter at 15:30:00 UTC)

6.5 Ground shaking felt, no damage reported


4.2 West Coast Tsunami-Meter - Led by Richard Thompson (Fisheries and Oceans Canada, Institute of Ocean Sciences)

The west coast tsunami-meter will enhance scientific knowledge and predictive capability for long waves (tsunamis and other large-scale sea level disturbances in the ocean) by studying wave generation, propagation, transformation, run-up, and dissipation. The evolution of a wave can be tracked from its source region, through the deep ocean, across the shelf, and onto shore. These data are then used in numerical models to determine the spatial and temporal structure of sea level disturbances. The tsunami-meter comprises four different locations (Table 6) using BPRs. At ODP 1027, the 3-BPR array will allow for precise determination of tsunami amplitude, direction of propagation, and speed of the wave.

Table 6. Locations, environments and corresponding instruments within the west coast tsunami-meter experiment.

Location Environment Instruments

Folger Passage Shelf 1 BPR

Barkley Canyon Continental slope 1 BPR

ODP 889 Continental slope 1 BPR

ODP 1027 Mid-plate, abyss 3 BPRs

Endeavour Spreading ridge 1 BPR

Figure 42. The Samoan tsunami recorded by BPRs at ODP 1027, ODP 889, Barkley Canyon and Folger Passage in the NEPTUNE Canada array (red) overlaid with output from Institute of Ocean Sciences regional tsunami numerical model (blue) (Thomson et al., 2011). The primary arrival of the tsunami consisted of approximately 4-5 cm waves with decreasing intervals between wave crests of 12 min 50 s, 10 min 54 s and 9 min 54 s; amplitude of following waves is 2-3 cm.


4.3. Water Properties

The subsea network provides data on primary water properties, such as temperature and salinity, in near real-time and at fine-scale temporal resolution. The spatial extent enables characterisation of water property variability in the northeast Pacific as well as coastal BC waters. These data, combined with data from other network-hosted interdisciplinary projects, traditional ship-borne surveys, and remote sensing will enhance understanding of the complex interactions in the Pacific Ocean. Scientists can monitor the link between global climate variations such as El Niño/La Niña Pacific Decadal Oscillations with conditions in the northeast Pacific. Understanding this co-variability helps in the prediction of, for example, the abundance of phytoplankton, returning/timing of sockeye salmon in the Fraser River and, in general, the variability of ecological systems.

Figure 43. Daily averaged time series of

temperature (red) and salinity (green) from various locations

across the NEPTUNE Canada subsea network between January

and December 2010. The blue lines in all panels show the Nino3.4

index, a measure of El Niño/La Niña amplitude. The Nino3.4

index is defined as the sea surface temperature anomalies averaged

between 120oW-170oW and 5oN-5oS. The data gaps in panel c prior to May

2010 are due to a problem with the connection port. ODP 889 (panel d) shows data from BPR and the right

axis (blue) shows the Nino3.4 index.


Coastal Pacific Canadian waters were warmer and fresher than normal in the first four months of 2010 due to the presence of El Niño (see blue lines in Figure 43; Crawford and Irvine, 2011). El Niño weather along the west coast combined with strong southerly winds brought warm, fresh ocean waters to the BC coast. Upper ocean stations at Folger Deep and Barkley Upper Slope (Figure 43 a,b), reflected these changes until May, when La Niña set in. With La Niña, winds weakened and by summer blew much more strongly than normal from the north, resulting in the upwelling of cool and salty waters. This upwelling is seen in both Folger Deep and Barkley Upper Slope data until November 2010. La Niña conditions prevailed until early 2011 with strong westerly winds in the Pacific and relatively cooler water along BC coast. Although linked to the El Niño Southern Oscillation (ENSO) variability, deep ocean stations Barkley Canyon, ODP 889, and ODP 1027 (Figure 43 c,d,e) do not show a direct association with the upwelling/downwelling dynamics as in the upper ocean (shallower waters). Both Barkley Canyon and ODP 1027 stations show a small increase in temperature during the La Niña period. More investigation is needed to understand the link between ENSO variability and changes at NEPTUNE node locations as the length of the time series and amount of data collected increases.

Both temperature and salinity show much less variability in the deep ocean (note y-axis scale in Figure 43 c,d,e) than at the upper ocean stations (Figure 43 a,b). While Folger Deep salinity varies noticeably over the year, the deeper sites remain much more consistent and show only small-scale salinity changes. Temperature varies throughout the year quite noticeably in the shallower sites (Folger Deep and Barkley Upper Slope). But as water depth increases, temperature variability decreases. Deep ocean temperature values are not directly affected by solar heating, run-off or wind forcing, but are controlled primarily by mixing and other processes at much longer time-scales. Temperature (Figure 44) and salinity (Figure 45) trends between October 2009 and December 2010 remain almost constant at greater depths; at shallower locations both temperature and salinity fluctuate more significantly.

In the future, core instruments at each node location will be installed so that scientists can compare fundamental parameters like temperature, salinity, and oxygen consistently across the entire network.


Figure 45. Averaged hourly salinity for various locations across the

NEPTUNE Canada subsea network between October 2009

and December 2010. Endeavour data were only collected during

October 2010 – December 2010. The gaps in Pod 4 data prior to

May 2010 are due to a problem with the connection port.

Figure 44. Hourly average temperature

for various locations across the NEPTUNE Canada subsea

network between October 2009 and December 2010. Endeavour data were only collected during

October 2010 – December 2010. The data gaps in Pod 4 prior to

May 2010 are due to a problem with the connection port.


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AppendixInstrument Listings by Site

This appendix lists the instruments present at each location, Sept 2009 - Dec 2010. Further information about all instruments can be obtained via our Device Search page (login required, http://dmas.uvic.ca/DeviceSearch).

Location Folger Passage

Barkley Canyon

ODP 889

ODP 1027

Endeavour

Audio x x

Backscatter x x x

Chlorophyll x x

CO2x

Conductivity x x x x

Currents - Single Point

x x x x x

Currents - Water Column

x x x

Density x x x x

Eh x x

Gravity x

Irradiance - Radiometer

x x

Irradiance - Biospherical

x

Methane x

Nitrate x

Oxygen x

Pressure x x x x x

Salinity x x x x

Seismic x x x x

Sigma-t x x x x x

Sound Velocity x x x x x

Temperature x x x x x

Turbidity x

Video x

Table A1. Variables measured by instruments within the

NEPTUNE Canada subsea network,

September 2009 - December 2010.


Table A2. Instruments present at locations within the NEPTUNE Canada subsea network, September 2009 - December 2010. Black Xs indicate instruments that were operational and collected useable data; red Xs indicate instruments that did not collect scientifically useable data. Total number of instruments at each location is included at the base of the table.

Location Folger Passage

Barkley Canyon

ODP 889

ODP 1027

Endeavour

ACM x x x x x

ADCP x x x

BARS x

BPR x x x

Camera System x

CO2 Sensor x

CORK x

Crawler x

CSEM x

CTD x x x x

DPG x

Echosounder x

Fluorometer x x

Gravimeter x

Hydrophone x x

Light Sensor x

Methane Sensor x

Microbial Sensor x

Nitrate Sensor x

Oxygen Sensor x

Plankton Pump x

Radiometer x

RAS x

Sediment Trap x

Seismometer x x x

Sonars x x x

Turbidity Meter x

VPS x

Number of Instruments

14 59 8 10 18

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