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Phytoplankton growth and microzooplankton grazing rates were measured from incubation experiments using the dilution method in the framework of the Northeast U.S. Shelf Long-Term Ecological Research project. The data set includes plankton population dynamics rates obtained during 12 cruises from winter 2018 (EN608) to summer 2022 (EN687) along a north/south transect from Martha’s Vineyard to the shelf-break. Phytoplankton growth and microzooplankton grazing rates were measured for the total phytoplankton community (chl-a concentrations) and for size fractions (chl-a size fractionation) less than and greater than 10 µm. Phytoplankton growth and microzooplankton grazing rates, the first trophic interaction between primary producers and higher trophic levels, are essential parameters to assess the cycling and export of carbon in the ocean and to better understand marine food webs.
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Phytoplankton response to a warming ocean
Phytoplankton, a diverse group of small photosynthetic algae inhabiting the sunlit region near the ocean surface, form the base of marine trophic webs ( 1 ). Whereas phytoplankton have evolved in tandem with the climate system for hundreds of millions of years ( 2 ), cumulative greenhouse gas emissions are causing rising ocean temperature, acidification, and oxygen loss at increasing rates ( 3 ). How phytoplankton will respond and adapt to these multistressors in the future ( 4 ), and how this will in turn threaten marine trophic webs and food supply for humans, remain important questions in oceanography. On page 1487 of this issue, Holm et al. ( 5 ) show that a physiological adaptation of phytoplankton to a warming world will lead to a reduction in their nutritional value, with negative consequences for marine ecosystems.
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- Award ID(s):
- 2047057
- PAR ID:
- 10346368
- Date Published:
- Journal Name:
- Science
- Volume:
- 376
- Issue:
- 6600
- ISSN:
- 0036-8075
- Page Range / eLocation ID:
- 1378 to 1379
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Marine snow, formed through the aggregation of phytoplankton and other organic matter, can be consumed by various types of zooplankton, affecting both planktonic trophic dynamics and the export of carbon to depth. This study focuses on how two factors—phytoplankton growth phase and species—affect copepod feeding on marine snow. To do this, we conducted a series of grazing experiments using gut pigment and stable isotope methods to quantify the ingestion of the copepod, Calanus pacificus, on both marine snow aggregates and individual phytoplankton. Results demonstrate that marine snow can represent a substantial food source for copepods, comparable to rates on individual phytoplankton. Moreover, we found that both the overall ingestion and the relative ingestion of aggregates vs. individual phytoplankton depended on phytoplankton growth phase for experiments conducted with the diatom Thalassiosira weissflogii. Although copepods consumed aggregates composed of Skeletonema marinoi at similar rates as those composed of T. weissflogii, no effect of growth phase was observed for S. marinoi. These findings suggest that marine snow can be an important source of nutrition for copepods, but that its role in planktonic food webs may differ depending on the phytoplankton community composition and the stage of phytoplankton blooms.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1126/science.abo5235
