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2014 NETCARE AMUNDSEN CRUISE
Ocean-Atmosphere Interactions
Michel Gosselin
University of Quebec at Rimouski
Maurice Levasseur
Laval University
Highly qualified personnel:
Collaborators:
Joannie Charette, MSc student, UQAR
Yves Gratton, INRS-ETE
Marjolaine Blais, Research assistant, UQAR
Jean-Éric Tremblay, U. Laval
Margaux Gourdal, PhD student, U. Laval
Martine Lizotte, Research assistant, U. Laval
Main research question
What are the sources of DMS at the ice edge in
spring and summer and what is controlling the
strength of these sources?
Simplified Arctic ice-edge ecosystem
Light
Melt pond algae
Algal aggregates
Bottom ice algae Sub-ice algae
Under-ice phytoplankton
Phytoplankton
Mixed Layer Depth
Simplified Arctic ice-edge ecosystem
Light
DMSair
DOM
Algae
(DMSP)
DMSaq
Bacteria
Recycling
MLD
Simplified Arctic ice-edge ecosystem
Light
DMSair
DOM
Algae
(DMSP)
DMSaq
Bacteria
Sinking
MLD
Nutrients
Who are the key players in DMS production?
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Open water phytoplankton and bacteria
Ice-edge phytoplankton and bacteria
Under-ice phytoplankton and bacteria
Melt pond algae and bacteria
Marine aggregates at the sea surface (e.g. the centric diatom Melosira sp.)
Specific questions concerning the algal community
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Who are they? To which algal group they belong?
How much are they? What are their abundance and biomass?
Are they active? What are their production rates?
Are they light or nutrient stressed?
What are their residence times in the surface mixed layer?
WATER SAMPLING
• Water column sampling with 24 12-L Niskin-type water bottles
attached to a CTD-rosette system
• Melt pond sampling with a slurp-gun (large syringe of 4 L) and
a 12 V electric pump (Cyclone)
SEA ICE SAMPLING
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Snow depth
Ice thickness
Depth of melt ponds
Extent of melt ponds
Light transmission
Temperature
Salinity
MEASUREMENTS
Light
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Incident photosynthetically active radiation (PAR, 400-700 nm, LI-COR sensor)
MEASUREMENTS
Light
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Incident photosynthetically active radiation (PAR, 400-700 nm, LI-COR sensor)
Vertical structure of the water column (Sea-Bird CTD with additional sensors)
(Yves Gratton’s team)
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Water temperature
Salinity
PAR
Transmissivity (proxy of particle number)
Oxygen
Nitrate (Satlantic sensor)
In vivo fluorescence (proxy of algal biomass)
MEASUREMENTS
Light
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Incident photosynthetically active radiation (PAR, 400-700 nm, LI-COR sensor)
Vertical structure of the water column (Sea-Bird CTD with additional sensors)
(Yves Gratton’s team)
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Water temperature
Salinity
PAR
Transmissivity (proxy of particle number)
Oxygen
Nitrate (Satlantic sensor)
In vivo fluorescence (proxy of algal biomass)
Nutrients (Bran-Luebbe 3 autoanalyzer) (Jean-Éric Tremblay’s team)
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Nitrate plus nitrite
Nitrite
Phosphate
Silicic acid
Ammonium (Fluorometric method)
MEASUREMENTS
DMS dynamics (Maurice Levasseur’s team)
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Particulate DMSP and DMSO (Gas chromatography)
Dissolved DMSP, DMS (Gas chromatography)
Microbial DMSP uptake and metabolism (35S-DMSP method)
MEASUREMENTS
DMS dynamics (Maurice Levasseur’s team)
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Particulate DMSP and DMSO (Gas chromatography)
Dissolved DMSP, DMS (Gas chromatography)
Microbial DMSP uptake and metabolism (35S-DMSP method)
Biology (Michel Gosselin’s team)
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Chlorophyll a (3 size fractions: 0.7-5 µm; 5-20 µm; > 20 µm) (Fluorometric method)
Cell abundance
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Bacteria (Flow cytometry)
Picoalgae (0.2-2 µm) (Flow cytometry)
Nanoalgae (2-20 µm) (Flow cytometry)
Microalgae (> 20 µm) (Light microscopy)
Identification of cells > 2 µm (Light microscopy)
Identification of cells < 2 µm (HPLC pigment signature)
Particulate algal production rate (2 size fractions: 0.7-5 µm; > 5µm: 14C-assimilation
method)
Release rate of dissolved organic carbon (DOC) by algae (14C-assimilation method)
Potential export rate of algae (Model of Tremblay & Legendre (1994) based on the
production of large cells)
MEASUREMENTS
Organic material (Michel Gosselin’s team)
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Total particulate carbon (TOC) (CHN analyzer)
– Particulate organic carbon (POC)
– Particulate inorganic carbon (PIC)
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Particulate organic nitrogen (PON) (CHN analyzer)
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Total dissolved carbon (TOC) (Shimadzu TOC-VCPN analyzer)
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Dissolved organic carbon (DOC) (Shimadzu TOC-VCPN analyzer)
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Total dissolved nitrogen (TDN) (Shimadzu TOC-VCPN analyzer)
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Transparent exopolymer particles (TEP) (Alcian blue method?; Oliver Wulf)
These data will permit us to determine the vertical
and horizontal gradients of environmental and
biological variables across the ice-edge zone
See you onboard!
Specific objective
• To identify processes favoring DMS production at the ice edge zone.
• Specific research questions
• What are the abundance, biomass and production rate of the algae
at the ice edge zone?
• What are the environmental conditions favoring the growth and
accumulation of DMSP containing algae?
• What is the role of light, nutrient flux and water column
stratification/mixing on the DMSP containing algae?