Who’s eating whom in the planktonic food web of the Northeast Shelf?

Posted by mmaheigan 
· Wednesday, May 5th, 2021 

It is critical to quantify the amount of phytoplankton that microzooplankton consume to better understand the flow of carbon toward higher trophic levels in the ocean. The Northeast US Shelf (NES) sustains intense fisheries with huge economical importance, but the links between the planktonic food web and the fish stocks are poorly constrained.

A recent study, which is part of the NES-LTER site (NES Long-Term Ecological Research, est. 2017), quantified phytoplankton growth rates and microzooplankton grazing rates across the NES during one summer and two winter cruises. The strong seasonal differences of physical and biogeochemical properties, associated with their intense spatial heterogeneity along the shelf, provided a unique opportunity to investigate the planktonic food web dynamics across contrasting environmental conditions.

Seasonal (winter vs. summer) and spatial (coastal vs. offshore) variability of the phytoplankton community structure, phytoplankton growth rates and microzooplankton grazing rates in the Northeast US Shelf.

During both winter and summer, coastal waters, which originate in the Arctic, were colder and fresher, and hosted greater phytoplankton biomass compared to the offshore warm slope-sea waters of the Gulf Stream (Figure 1). In winter the phytoplankton community was dominated by large cells (>10 µm), and most of the primary production was directly consumed by microzooplankton, allowing direct and efficient transfer of carbon to higher trophic levels (Figure 1). In contrast, small phytoplankton cells dominated in summer, when fast growing phytoplankton were not preyed upon by microzooplankton grazers, limiting their role conducting organic matter, yet the lack of phytoplankton accumulation during summer suggests some unidentified loss processes and more complex trophic interactions (e.g., trophic cascades, mixotrophy).

The ongoing NES-LTER project is an outstanding opportunity to investigate the flow of carbon amongst the planktonic food web for a predictive understanding of ecosystem productivity in a changing coastal ocean.

 

Authors:
Pierre Marrec, Heather McNair, Gayantonia Franzè (present address: Institute of Marine Research, Norway), Françoise Morison, Jacob P. Strock and Susanne Menden-Deuer
(All authors: Graduate School of Oceanography, University of Rhode Island)

 

Filter by Keyword

abundance acidification africa air-sea interactions algae alkalinity allometry ammonium AMOC anoxic Antarctic anthro impacts anthropogenic carbon aquaculture aquatic continuum aragonite saturation arctic Argo argon arsenic artificial seawater Atlantic atmospheric CO2 atmospheric nitrogen deposition authigenic carbonates autonomous platforms bacteria bathypelagic BATS BCG Argo benthic bgc argo bio-go-ship bio-optical bioavailability biogeochemical cycles biogeochemical models biogeochemistry Biological Essential Ocean Variables biological pump biophysics bloom blue carbon bottom water boundary layer buffer capacity C14 CaCO3 calcification calcite carbon carbon-climate feedback carbon-sulfur coupling carbon budget carbon cycle carbon dioxide carbon export carbon sequestration carbon storage Caribbean CCA CCS changing marine ecosystems changing marine environments changing ocean chemistry chemical oceanographic data chemical speciation chemoautotroph chesapeake bay chl a chlorophyll circulation climate change climate variability CO2 coastal darkening coastal ocean cobalt Coccolithophores commercial community composition conservation cooling effect copepod coral reefs CTD currents cyclone daily cycles data data access data assimilation data management data product Data standards DCM dead zone decadal trends decomposers decomposition deep convection deep ocean deep sea coral deoxygenation depth diatoms DIC diel migration diffusion dimethylsulfide dinoflagellate discrete measurements DOC DOM domoic acid dust DVM ecology ecosystem management ecosystems eddy Education Ekman transport emissions ENSO enzyme equatorial regions ESM estuarine and coastal carbon fluxes estuary euphotic zone eutrophication evolution export export fluxes export production EXPORTS extreme events faecal pellets fecal pellets filter feeders filtration rates fire fish Fish carbon fisheries fishing floats fluid dynamics fluorescence food webs forage fish forams freshening freshwater frontal zone functional role future oceans geochemistry geoengineering geologic time GEOTRACES glaciers gliders global carbon budget global ocean global warming go-ship grazing greenhouse gas Greenland ground truthing groundwater Gulf of Maine Gulf of Mexico Gulf Stream gyre harmful algal bloom high latitude human food human impact human well-being hurricane hydrogen hydrothermal hypoxia ice age ice cores ice cover industrial onset inland waters in situ inverse circulation ions iron iron fertilization isotopes jellies katabatic winds kelvin waves krill kuroshio lab vs field land-ocean continuum larvaceans lateral transport LGM lidar ligands light light attenuation lipids machine learning mangroves marine carbon cycle marine heatwave marine particles marine snowfall marshes Mediterranean meltwater mesopelagic mesoscale metagenome metals methane methods microbes microlayer microorganisms microscale microzooplankton midwater mixed layer mixed layers mixing mixotrophy model modeling model validation mode water molecular diffusion MPT multi-decade n2o NAAMES NASA NCP nearshore net community production net primary productivity new ocean state new technology Niskin bottle nitrate nitrogen nitrogen cycle nitrogen fixation nitrous oxide north atlantic north pacific nuclear war nutricline nutrient budget nutrient cycling nutrient limitation nutrients OA ocean-atmosphere ocean acidification ocean acidification data ocean carbon uptake and storage ocean color ocean modeling ocean observatories ocean warming ODZ oligotrophic omics OMZ open ocean optics organic particles oscillation overturning circulation oxygen pacific paleoceanography parameter optimization particle flux partnerships pCO2 PDO peat pelagic PETM pH phenology phosphorus photosynthesis physical processes physiology phytoplankton PIC piezophilic piezotolerant plankton POC polar regions policy pollutants precipitation predation prediction pressure primary productivity Prochlorococcus prokaryotes proteins pteropods pycnocline radioisotopes remineralization remote sensing repeat hydrography residence time resource management respiration resuspension rivers rocky shore Rossby waves Ross Sea ROV salinity salt marsh satellite scale seafloor seagrass sea ice sea level rise seasonal patterns seasonal trends sea spray seawater collection seaweed secchi sediments sensors shelf ocean shelf system shells ship-based observations shorelines silicate silicon cycle sinking particles size SOCCOM soil carbon southern ocean south pacific spatial covariations speciation SST state estimation stoichiometry subduction submesoscale subpolar subtropical sulfate surf surface surface ocean Synechococcus technology teleconnections temperate temperature temporal covariations thermocline thermodynamics thermohaline thorium tidal time-series time of emergence titration top predators total alkalinity trace elements trace metals trait-based transfer efficiency transient features Tris trophic transfer tropical turbulence twilight zone upper ocean upper water column upwelling US CLIVAR validation velocity gradient ventilation vertical flux vertical migration vertical transport volcano warming water clarity water mass water quality waves western boundary currents wetlands winter mixing zooplankton

Copyright © 2023 - OCB Project Office, Woods Hole Oceanographic Institution, 266 Woods Hole Rd, MS #25, Woods Hole, MA 02543 USA Phone: 508-289-2838  •  Fax: 508-457-2193  •  Email: ocb_news@us-ocb.org

link to nsflink to noaalink to WHOI

Funding for the Ocean Carbon & Biogeochemistry Project Office is provided by the National Science Foundation (NSF) and the National Aeronautics and Space Administration (NASA). The OCB Project Office is housed at the Woods Hole Oceanographic Institution.