Search for: All records

Diatoms are a group of phytoplankton that contribute disproportionately to global primary production. Traditional paradigms that suggest diatoms are consumed primarily by larger zooplankton are challenged by sporadic parasitic “epidemics” within diatom populations. However, our understanding of diatom parasitism is limited by difficulties in quantifying these interactions. Here, we observe the dynamics of Cryothecomonas aestivalis (a protist) infection of an important diatom on the Northeast U.S. Shelf (NES), Guinardia delicatula , with a combination of automated imaging-in-flow cytometry and a convolutional neural network image classifier. Application of the classifier to >1 billion images from a nearshore time series and >20 survey cruises across the broader NES reveals the spatiotemporal gradients and temperature dependence of G. delicatula abundance and infection dynamics. Suppression of parasitoid infection at temperatures <4 °C drives annual cycles in both G. delicatula infection and abundance, with an annual maximum in infection observed in the fall-winter preceding an annual maximum in host abundance in the winter-spring. This annual cycle likely varies spatially across the NES in response to variable annual cycles in water temperature. We show that infection remains suppressed for ~2 mo following cold periods, possibly due to temperature-induced local extinctions of the C. aestivalis strain(s) that infect G. delicatula . These findings have implications for predicting impacts of a warming NES surface ocean on G. delicatula abundance and infection dynamics and demonstrate the potential of automated plankton imaging and classification to quantify phytoplankton parasitism in nature across unprecedented spatiotemporal scales. 

Particulate organic carbon and nitrogen are measured from discrete bottle samples collected during CTD-rosette casts on Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) Transect cruises (ongoing since 2017). Sampling frequency is approximately seasonal. Samples were filtered and collected on combusted glass fiber filters, pelletized using ultra clean tin disks, and combusted using a Flash EA1112 CHN analyzer to calculate concentrations of particulate organic carbon and particulate organic nitrogen in micromoles per liter. Values are also reported as concentrations in micrograms per liter and carbon to nitrogen molar ratio. 

These data represent the abundance, biovolume, and biomass of prokaryotic and eukaryotic picoplankton and nanoplankton sampled continuously underway during Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER) Transect cruises, ongoing since 2018. Samples were obtained with an Attune NxT Flow Cytometer sampling at approximately 2-min intervals from the underway science seawater. Cells were identified and enumerated from the flow cytometry data files based on their scattering, phycoerythrin (575 nm) and chlorophyll (680 nm) fluorescence signals. 

This package provides a table of day cruises to the Martha's Vineyard Coastal Observatory for Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER). Sampling frequency is approximately monthly, with NES-LTER sampling ongoing since 2017. Cruises involve collection of water column bottle samples, surface bucket samples, and zooplankton net tow samples, as well as ship provided data. The event number for each cruise is provided, along with date, vessel name, cruise identifier where applicable, link to data location (for CTD, ADCP, and other underway data), and checklist of six data types. 

These data include abundances of the diatom, Guinardia delicatula (= Rhizosolenia delicatula), on the Northeast U.S. Shelf from 2006 to 2022 as part of Long-Term Ecological Research (NES-LTER). Abundances are determined from Imaging FlowCytobot (IFCB) deployed in-situ at ~4m depth at the nearshore Martha’s Vineyard Coastal Observatory (MVCO) from 2006 to 2022 and in underway mode (sampling near-surface seawater) on 24 NOAA EcoMon survey cruises from 2013 to 2022. Abundances based on both human and machine learning image classification are provided. Total G. delicatula abundances are divided into two categories based on whether G. delicatula exhibited current or recent infection by the protistan parasitoid, Cryothecomonas aestivalis. Four data tables are provided with abundance values separated by sampling scheme (time series or survey cruise) and image classification approach (human or machine learning). 

This package provides a concatenated table of events recorded on seasonal Transect cruises for Northeast U.S. Shelf Long-Term Ecological Research (NES-LTER). Events were recorded onboard with Rolling Deck to Repository (R2R) event logger (elog) software. Event listings include date, time, ship’s position, instrument, and action for use in physical sample cataloging and post-cruise data integration. Cruises include winter and summer cruises dedicated to NES-LTER, spring and fall cruises in collaboration with the Ocean Observatories Initiative (OOI), and additional fall cruises.