8th july 2009 – august 13th 2009 principal scientist r ...· 8th july 2009 – august 13th 2009

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  • 1

    Cruise D341 Porcupine Abyssal Plain Time Series Site Process Study Oceans 2025 Cruise 8

    th July 2009 August 13

    th 2009

    Principal Scientist R Sanders NOCS

  • 2

    Table of contents Cruise D341 Porcupine Abyssal Plain Time Series Site Process Study..................................................1 Abstract ....................................................................................................................................................3 List of personnel .......................................................................................................................................4 Narrative Richard Sanders ....................................................................................................................5 Chronology of events D341......................................................................................................................8 Nitrogen cycling ......................................................................................................................................16 Microbial processes using high pressure sampling systems .................................................................17 Dinoflagellate Bioluminescence .............................................................................................................21 Chlorophyll-a ..........................................................................................................................................28 Sediment Coring.....................................................................................................................................30 CTD Survey 1 .........................................................................................................................................32 Sinking Marine Particles.........................................................................................................................39 CTD operations ......................................................................................................................................44 210

    Po-210

    Pb profiles .................................................................................................................................46 Ammonium .............................................................................................................................................48 D341 Doms Recovery ............................................................................................................................50 Microbial community abundance, structure and dynamics ....................................................................55 D341 Moorings Report ...........................................................................................................................61 PELAGRA - neutrally buoyant sediment traps (technical) .....................................................................65 234

    Th-238

    U profiles ...................................................................................................................................75 Organic Biogeochemistry .......................................................................................................................78 Lowered CTD Sampling, Processing and Calibration ............................................................................81 Vessell Mounted ADCP (VM-ADCP) and navigation data .....................................................................89 Giering net and ARIES samples.............................................................................................................94 PELAGRA neutrally buoyant sediment traps (scientific) .....................................................................98 Mooring Sensors ..................................................................................................................................101 Titanium CTD cast................................................................................................................................105 Trace-metal deployments of SAPS ......................................................................................................106 Oxygen consumption and evolution .....................................................................................................107

  • 3

    Abstract The Biological Carbon Pump (BCP) is a major feature of the global carbon transporting approximately 10GT C yr

    -1 from the ocean surface to the interior mainly via the sinking of particles with an organic

    component. The scale of the BCP requires good year-round measurements of its functioning. Moreover, the BCPs susceptibility to global change means that we need better information on how its climate sensitive elements function and how its poorly parameterised elements operate. These three requirements map directly onto the objectives of this cruise, which will be undertaken using Oceans 2025 funding at the Porcupine Abyssal Plain (PAP) site. The PAP site (47

    oN, 16.5

    oW) is the location of

    a time series of observations from surface to seafloor compiled by IOS, GDD and now NOCS over the last 20 years (Lampitt et al., 2001). A summary of these observations, together with descriptions of surface water biogeochemistry in the region from a cruise in 2005, is currently being published as a special issue of Deep-Sea Research II. The PAP site is close to the site of the JGOFS north Atlantic Bloom experiment and the French POMME programme and is a waypoint on the Atlantic Meridional Transect programme (SO1 in Oceans 2025). There is therefore a rich wealth of previous observations in which our 2009 observations can be grounded. Objectives: 1) To recover and redeploy the PAP site observatory (Theme 10 of Oceans 2025) 2) To compile a vertical carbon budget for the PAP site with particular focus on the process of remineralisation in the mesopelagic (100 1000 m) and on the mechanisms leading to export from the upper ocean (Themes 2, 5 of Oceans 2025) 3) To quantify climate sensitive elements of the BCP at the PAP site, particularly the physical processes responsible for introducing nutrients to the upper water column, which combine to set the maximum level of export (Theme 2 of Oceans 2025) Of these, 1) was partially successful, 2) was successful, 3) was unsuccessful.

  • 4

    List of personnel Peter Newton Master Richard Warner Chief Officer James Gwinnell Second Officer William McClintock Third Officer Chris Carey Chief Engineer Mark Coultas Second Engineer John Harnett Third Engineer Edin Silajdzic Third Engineer Robert Masters ETO David Hartshorne Purser Michael Drayton Chief Petty Officer - Deck Martin Harrison Chief Perry Offer - Scientific Stuart Cook Petty Officer Deck Gary Crabb Seaman 1A Ian Mills Seaman 1A Peter Smith Seaman 1A Nathaniel Gregory Seaman 1A Duncan Lawes Motorman John Haughton Chef Walter Link Chef Jeffrey Orsborn Steward Anne Robert LMGEM Charlotte Marcinko NOCS Christian Tamburini LMGEM Dominique Lefevre LMGEM Adrian Martin NOCS Athanasios Gritzalis-Papadopoulos NOCS Jennifer Riley NOCS John Allen NOCS Kostas Kiriakoulakis University of Liverpool Nina Rothe NOCS Stuart Painter NOCS Jim Hunter FRS Aberdeen Kevin Saw NOCS Maria Villa University of Seville, Spain Mehdi Boutrif LMGEM Chris Marsay NOCS Frederic Le Moigne NOCS Ian Brown Plymouth Marine Laboratory Mike Zubkov NOCS Peter Statham NOCS Richard Sanders NOCS Ross Holland NOCS Sarah Giering University of Aberdeen Sam Ward NOCS Terry Edwards NOCS Darren Young NOCS Peter Keen Keen Marine Martin Bridger NOCS LMGEM - Laboratoire de Microbiologie Gochimie et Ecologie marine, Marseille NOCS National Oceanography Centre, Southampton

  • 5

    Narrative Richard Sanders July 2009 9

    th Sailed from Govan at noon following the pickup of Sarah Giering and James Hunter from Glasgow

    station 10

    th On passage

    11

    th On Passage

    12

    th On Passage

    13

    th Work started with a CTD at the future French Mooring position for acoustic release test. The

    snowcatcher was deployed followed by another CTD. The weather blew up after the CTD was recovered and the rest of the day was lost. 14

    th Work resumed at 9.30. Nets, snowcatchers and Pelagras were deployed at the French mooring

    site then CTDs and finally SAPS 15

    th Biological work continued till dawn including the French CTD and the French drifter, then the

    IODA mooring was deployed. Unfortunately the line linking the release to the instruments parted and approx 700m parafil plus an acoustic release was lost. The remainder of the mooring was recovered. Subsequent tests showed that parafil is slightly negatively buoyant and hence the release can be fired safely some time towards the end of the cruise for recovery. 16

    th Aries was deployed around midnight, the French drifter recovered. More biological work ensued

    including Snowcatcher, CTD, SAPS. Finally Corer deployment 1 was undertaken which yielded 6 good cores. 17

    th More biological work was undertaken and then we embarked on Pelagra recoveries. All were

    rounded up in double quick time. The first three were found easily and the other two were slightly more problematic. We then returned to the core site for biological work and coring. 18

    th The corer was deployed, PAP 3 was deployed. The French drifter was recovered. The overnight

    Aries tow was abandoned due to CLAM problems which were fixed around 4am. Corer deployment 2 19

    th IODA was deployed again. This time the deployment was successful. 5 Pelagras were deployed

    at the cor