13 Zooplankton

Description: Annual time series of zooplankton abundance

Found in: State of the Ecosystem - Gulf of Maine & Georges Bank (2017+), State of the Ecosystem - Mid-Atlantic (2017+)

Indicator category: Database pull with analysis; Synthesis of published information; Extensive analysis, not yet published; Published methods

Contributor(s): Ryan Morse, Kevin Friedland

Data steward: Harvey Walsh, ; Mike Jones,

Point of contact: Ryan Morse, ; Harvey Walsh, ; Kevin Friedland,

Public availability statement: Source data through 2019 are publicly available here, and data through 2021 are available upon request from . Derived data can be found here.

13.1 Methods

13.1.1 Data sources

Zooplankton data are from the National Oceanographic and Atmospheric Administration Marine Resources Monitoring, Assessment and Prediction (MARMAP) program and Ecosystem Monitoring (EcoMon) cruises detailed extensively in Kane (2007), Kane (2011), and Morse et al. (2017).

13.1.2 Data extraction

Data are from the publicly available plankton dataset at NCEI Accession 0187513. The accession metadata has a list of excluded samples and cruises based on Kane (2007) and Kane (2011) in addition to other collection details.

13.1.3 Data analysis

13.1.3.1 Annual abundance anomalies

Data are processed similarly to Kane (2007) and Perretti et al. (2017a), where a mean annual abundance by date is computed by area for each species meeting inclusion metrics set in Morse et al. (2017). This is accomplished by binning all samples for a given species to bi-monthly collection dates based on median cruise date and taking the mean, then fitting a spline interpolation between mean bi-monthly abundance to give expected abundance on any given day of the year.

Code used for zooplankton data analysis can be found here.

13.1.3.2 Copepod

Abundance anomalies are computed from the expected abundance on the day of sample collection. Abundance anomaly time series are constructed for Centropages typicus, Pseudocalanus spp., Calanus finmarchicus, and total zooplankton biovolume. The small-large copepod size index is computed by averaging the individual abundance anomalies of Pseudocalanus spp., Centropages hamatus, Centropages typicus, and Temora longicornis, and subtracting the abundance anomaly of Calanus finmarchicus. This index tracks the overall dominance of the small bodied copepods relative to the largest copepod in the Northeast U.S. region, Calanus finmarchicus.

13.1.3.3 Euphausiids and Cnidarians

Stratified abundance of euphausiids and cnidarians were included in the 2020 State of the Ecosystem reports. These were calculated as the log of estimated absolute number of individuals.

13.1.3.4 Seasonal abundance

Time series of zooplankton abundance in the spring and fall months have been presented in the 2019 Mid-Atlantic State of the Ecosystem report. Raw abundance data were sourced from the EcoMon cruises referenced above, and ordinary kriging was used to estimate seasonal abundance over the Northeast Shelf. These data were then aggregated further into time series of mean abundance by Ecological Production Unit.

13.1.3.5 Zooplankton Diversity

Time series of zooplankton diversity (effective shannon) was calculated using 42 zooplankton classifications collected fromt the EcoMon cruises, referenced above.

13.1.4 Data processing

Zooplankton abundances indicators were formatted for inclusion in the ecodata R package using the code at these links, abundance anomaly and seasonal abundance.

catalog link https://noaa-edab.github.io/catalog/zoo_abundance_anom.html

References

Kane, Joseph. 2007. Zooplankton abundance trends on Georges Bank, 1977-2004.” ICES Journal of Marine Science 64 (5): 909–19. https://doi.org/10.1093/icesjms/fsm066.
———. 2011. Multiyear variability of phytoplankton abundance in the Gulf of Maine.” ICES Journal of Marine Science 68 (9): 1833–41. https://doi.org/10.1093/icesjms/fsr122.
Morse, R. E., K. D. Friedland, D. Tommasi, C. Stock, and J. Nye. 2017. Distinct zooplankton regime shift patterns across ecoregions of the U.S. Northeast continental shelf Large Marine Ecosystem.” Journal of Marine Systems 165: 77–91. https://doi.org/10.1016/j.jmarsys.2016.09.011.
———, et al. 2017a. Regime shifts in fish recruitment on the Northeast US Continental Shelf.” Marine Ecology Progress Series 574: 1–11. https://doi.org/10.3354/meps12183.