Figure 1. Bathymetric map of the five Endeavour vent fields: Main Endeavour, Mothra, High Rise, Salty Dawg and Sasquatch. Image Source: Kristall et al, 2011.

Data Package 4 – Hydrothermal Vents

Background:

Hydrothermal vents form along ocean spreading centres and back-arc basins where seawater percolates through the thin ocean crust to form hydrothermal fluid. Seawater becomes enriched in sulfur and dissolved minerals (e.g. iron, zinc and copper) through reactions with superheated rock within fractures and permeable zones in the seafloor, near the magma chamber, and is released as superheated (250 – 400 °C) buoyant plumes of hydrothermal fluid. Once the vent effluent mixes with the cold seawater, minerals precipitate and form black metal sulfide deposits and tall chimneys. When the seawater does not penetrate deep enough into the ocean crust, chemical reactions are partial and the fluid is released as diffuse flow characterized by lower temperatures (20-50 °C). The mixing of hydrothermal fluid with seawater generates steep heat and chemical gradients, sometimes at the scale of a few centimetres.

Vents are home to an endemic faunal community independent of energy from sunlight and photosynthetic organisms. The vent food web fully relies on chemical fluxes as a source of energy. Vent organisms including limpets and snails graze upon dense mats of sulphur oxidizing bacteria, whereas suspension feeders (polychaetes and bivalves) feed on the sulphur bacteria suspended in the water column. A common method for vent dwelling organisms to obtain nutrients is through symbiosis with sulphur oxidizing bacteria (Lalli and Parsons, 2010).

Study Location:

1. EndeavourLocated 250 km offshore from southern Vancouver Island, the Endeavour segment of the Juan de Fuca mid-ocean ridge is a region of active seafloor spreading and hydrothermal venting. New oceanic crust is formed at Endeavour when magma emerges onto the seafloor as lava, 2250 m’s below the ocean surface. There are five known major vent fields at the Endeavour Segment – Main Endeavour, Mothra, High Rise, Salty Dawg and Sasquatch. Except for Sasquatch, all vent fields are designated as Marine Protected Areas under Canada’s Oceans Act (DFO, 2010).

2. NEPTUNE CanadaThe NEPTUNE Canada array is the offshore component of the Ocean Networks Canada Observatory. NEPTUNE Canada is an 812 km cabled underwater network in the northeastern Pacific Ocean off the west coast of

Vancouver Island. It consists of five primary locations whose instruments collect a variety of oceanographic data. This network extends from a depth of 20 meters at Folger Passage on the continental shelf, to a depth of 2660 meters at Cascadia Basin on the abyssal plain.

Figure 2. The Ocean Networks Canada observatory located off the coasts of Vancouver Island and British Columbia mainland. Image credit: Ocean Networks Canada

Data Analysis:

Undersea videos collected by the remotely operated vehicle (ROV) ROPOS and the TEMPO-mini camera. Environmental data from the Main Endeavour vent field are provided in this data package. Both the videos (TEMPO-mini and ROPOS) and the provided environmental data (BARS and RAS temperature; oxygen concentration, temperature and iron concentration from TEMPO-mini) cover the sample time period during Sept 29 – 30 2011. These data can be used to guide your research paper on hydrothermal vents. It is important to note that hydrothermal vent fields have extreme temperature gradients, so a temperature reading at one point is not representative of the entire area.

Questions:

What are the environmental conditions like at a hydrothermal vent field? (i.e. high temp, low oxygen, scales of variability)

What types of marine organisms live in these environments? How do they adapt to such an extreme environment?

Available Data: (note: to access the data you will need a log-in. Click dmas.uvic.ca/Registration to obtain one)

A. Part 1: Undersea Videos Collected by ROPOSTo view video segments of the hydrothermal vents at Endeavour, follow the instructions provided below. Note: You only need to watch the video segments indicated in Table 1. You may need to download the Marine Field Guide to identify the species at the vents, see bottom of this activity for download instructions.

Accessing the Data:1. Go to the Data Portal Log-in dmas.uvic.ca/SeaTube

2. Make sure the location is set to NEPTUNE Canada (this should be the default but if it isn’t follow this pathway: Click on the Tools tab -> navigate down to Network Preference -> Change the Network Preference by clicking Switch to NEPTUNE Canada).

3. On the left side of the SeaTube page, you will be able to find ROPOS dive videos. Click on the “NEPTUNE Maintenance Cruise Sept 2011”. A list of dive videos should now appear in your window.

4. Select dive number R1488. This video is of the Endeavour hydrothermal vents and was recorded by ROPOS during Sept 29, 2011.

5. Notice on the screen: The video player is in the centre, the map of the site is on the right, the dives are listed on the left and the Dive Log Entries are on the bottom. The dive log entries describe what is going on in the dive video.

Table 1. Important video segments for the dive video R1488 of the Endeavour hydrothermal vents.

Start Date (UTC) End Date (UTC) Comments

03:18:21 03:19:43 Active vent with tubeworms03:22:23 03:28:20 Active vent with tubeworms03:42:22 03:44:19 Active vent05:14:02 05:15:23 BARS sensor wand in hydrothermal

vent (~325 °C)08:54:56 08:56:53 View of TEMPO-mini with

hydrothermal vent plume10:21:09 10:25:11 Great view of vent life at TEMPO –

mini site10:35:51 10:36:03 TEMPO-mini with hydrothermal vent

plume

6. To select the appropriate video segments, start and end dates (UTC) that are listed in Table 1 from the dive log entries

B. Part 2: Close up video clips from TEMPO-mini, located at Endeavour To observe the hydrothermal vent marine life, the instrument TEMPO-mini records close up video clips in addition to a variety of environmental data. To locate these videos:1. Navagiate to the left where the dives are listed2. Click on the heading “Location”3. Click on “Endeavour”, click on “Main Endeavour Field” 4. Click on TEMPO-mini5. Click on 20116. Observe the close up shots on September 29th and/or 30th. There are many short clips here, choose any to watch

7. Use Figure 3 to help you identify the vent organisms. For each organism consult the confidence levels in the Marine Life Field Guide. If the confidence levels are low, do not record the species name.

The Marine Life Field guide can be downloaded here: http://www.oceannetworks.ca/science/publications/general-interest/marine-life-field-guide

Figure 3. Marine creatures viewable from TEMPO-mini, located at the Main Endeavour vent field at Endeavour. Image credit: Ocean Networks Canada

Environmental Data

Provided are supplemental environmental data from the same time that the video was taken. Notice the temperature, oxygen level and iron concentration. Explore the relationship between the environmental data and the video data.

Figure 1. Temperature (°C) recorded by the remote access water sampler (RAS) at the Main Endeavour Field during Sept. 29-30, 2011.

Figure 2. Temperature (°C) recorded by the benthic and resistivity sensor (BARS) probe at the Main Endeavour Field during Sept. 29-30 2011.

Figure 3. Oxygen concentration [ml/l] measured from the oxygen sensor on TEMPO-mini deployed at the Main Endeavour Field during Sept 29 – 30 2011.

Figure 3. Iron concentration [µmol/l] measured from the TEMPO-mini deployed at the Main Endeavour Vent field during Sept 30, 2011.

References:

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

Lalli, C. M., & Parsons, T. R. (2010). Biological Oceanography: An Introduction. (2nd ed.). Burlington, MA: Elsevier Ltd.

DFO, 2010-2015.Endeavour Hydrothermal vents marine protected area management plan. Retrieved from: http://www.pac.dfo-mpo.gc.ca/consultation/oceans/endeavour/docs/EHV-CHE-mgmtplan-gestion-eng.pdf.

Kristall, B., Nielsen, D., Hannington, M.D., Kelley, D.S., Delaney, J.R. 2011. Chemical microenvironments within sulfide structures from the Mothra Hydrothermal Field: Evidence from high-resolution zoning of trace elements. 290(1-2). Pages: 12-30.

Further Reading:

Kelley, D.S., Carbotte S.M., Caress, D.W., Clague, D.A., Delaney, J.R., Gill, J.B., Hadaway, H., Holden, J.F., Hooft, E.E.E., Kellogg, J.P., Lilley, M.D., Stoermer, M., Toomey, D., Weekly, R., Wilcock, W.S.D . 2012. Endeavour Segment of the Juan de Fuca Ridge, One of the most remarkable places on earth. Oceanography. 25(1). Pages: 44-61.

Tunnicliffe, V., 1992. Hydrothermal-Vent Communities of the Deep-Sea. American Scientist. 80 (4). Pages: 336-349.

Tunnicliffe, V., Tsurumi, M. 2003. Tubeworm-associated communities at hydrothermal vents on the Juan de Fuca Ridge, northeast Pacific. Deep Sea Research. 50 (5). 611-629

Fowler, C.M.R., Tunnicliffe, V. 1997. Hydrothermal vent communities and plate tectonics. 21(4). 164-168.