Time series of phytoplankton net primary production reveals intense interannual variability and size‐dependent chlorophyll‐specific productivity on a continental shelf
Year: 2024
Type: article
Abstract: Phytoplankton community size structure influences the production and fate of organic carbon in marine food webs and can undergo strong seasonal shifts in temperate regions. As part of the Northeast US Shelf (NES) Long‐Term Ecological Research program, we measured net primary production (NPP) rates and chlorophyll a (Chl a ) concentrations in three phytoplankton size classes (< 5, 5–20, and > 20 μ m) during winter and summer for 3 yr along a coastal‐to‐offshore transect. Mean depth‐integrated NPP was 37% higher in summer than winter, with limited cross‐shelf differences because of significant interannual variability. When averaged across the shelf, depth‐integrated NPP was dominated by the > 20 μ m size class in winter and generated equally by the three size fractions in summer because of substantial contributions from cells > 20 μ m at the Chl a maximum depth. Furthermore, the relationship between Chl a and NPP, in terms of relative contributions, varied by size class. Variations in this relationship have implications for models of primary productivity on the NES and beyond. In comparison to historical NPP data, we identified equivalent levels of winter NPP but observed a 25% decrease in summer NPP, suggesting a potential reduction in the seasonality of NPP on the NES. Together, our results highlight seasonal shifts in NPP rates of different phytoplankton size classes, with implications for food web structure and export production. These data emphasize the importance of quantifying size‐fractionated NPP over time to constrain its variability and better predict the fate of organic carbon in coastal systems under environmental change.
Source: Limnology and Oceanography
DOI: 10.1002/lno.12749
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,360
Funder: National Science Foundation
Awards: RII Track-1: Rhode Island Consortium for Coastal Ecology Assessment, Innovation, and Modeling, RAPID: Collaborative Research: Autumn transition in plankton ecology during an ocean heatwave on the Northeast U.S. Shelf, LTER: Scales of Variability in Ecosystem Dynamics and Production on the Changing Northeast U.S. Shelf (NES II), RAPID: Collaborative Research: Autumn transition in plankton ecology during an ocean heatwave on the Northeast U.S. Shelf, LTER: Linking Pelagic Community Structure with Ecosystem Dynamics and Production Regimes on the Changing Northeast US Shelf
OpenAlex ID: W4405025399