74 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, harvey.walsh@noaa.gov; Mike Jones, michael.jones@noaa.gov
Point of contact: Ryan Morse, ryan.morse@noaa.gov; Harvey Walsh, harvey.walsh@noaa.gov; Kevin Friedland, kevin.friedland@noaa.gov
Public availability statement: Source data through 2019 are publicly available here, and data through 2021 are available upon request from harvey.walsh@noaa.gov. Derived data can be found here.
74.1 Methods
74.1.1 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).
74.1.2 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.
74.1.3 Data analysis
74.1.3.1 Annual abundance anomalies
Data are processed similarly to Kane (2007) and Perretti et al. (2017b), 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.
74.1.3.2 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.
74.1.3.3 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.
74.1.3.4 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.
74.1.4 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