Table of Contents

• Coverage
• Dataset Description
  • Methods & Sampling
  • Data Processing Description
• Data Files
• Supplemental Files
• Related Publications
• Parameters
• Instruments
• Deployments
• Project Information
• Funding

Abundance (number per square meter) of copepod species captured with a 200-um mesh vertical net at the Wilkinson Basin Time Series Station, Gulf of Maine from 2005 to 2016.

Sampling at the Wilkinson Basin Time Series (WBTS) station followed as a guideline the protocols established by the Atlantic Zone Monitoring Program (AZMP) established by Fisheries and Oceans Canada (Mitchell et al. 2002).

Sampling and analytical procedures:

Environmental data. The R/V Gulf Challenger system comprised a Sea-Bird Electronics (SBE) 25Plus CTD, an SBE-55 Sampling Rosette with six four-liter Niskin bottles, a dedicated Hawboldt Industries SPR 1424/S Science winch, and a SBE-33 real-time monitoring and sampling deck unit. The system provided high-resolution vertical profiling of hydrographic properties (e.g. conductivity, salinity, temperature), physiochemical properties (e.g. Photosynthetically Active Radiation (PAR)), and surrogates for biological and geological processes (e.g. dissolved oxygen, chlorophyll-a fluorescence, and beam transmittance). The raw CTD data and bottle trips were acquired by SBE Seasave on a Windows 7 workstation and were processed from hex files to .cnv files. Post cruise data processing was completed on a Windows 7 machine running SEABIRD SBE DATA Processing version 7.22.5 At most stations, Niskin bottles were used to capture water samples at depths of 2, 10, 20 and 40 meters. To measure chlorophyll a concentration at discrete depths, duplicate, 100 mL or 500-550 mL subsamples were collected from Niskin bottles at the surface, 10, 20 and 40 meters. Water was filtered immediately on the vessel using glass fiber filters (GF/F) and polycarbonate membrane filters with pore sizes of 0.7 µm and 0.1µm. Chlorophyll-a concentrations were calculated were using equations in Strickland and Parsons (1972). Prior to 2014, IOP profilers calibrated annually were used to measure water column stimulated fluorescence. After 2014, the nominal chlorophyll-a readings from stimulated fluorescence measured with a Wetlabs Wetstar Chlorophyll Fluorometer S/N WSS-164 were corrected with chlorophyll concentrations measured from bottle samples.

Copepod data: To measure zooplankton abundance and biomass, two net two casts were made using a 0.75 meter diameter single ring or a SEA-GEAR Model 9600 twin-ring 200µm mesh net, The nets were towed vertically at approx.. 40m/min from within 5 meters of the bottom. The samples were preserved in 4% buffered formaldehyde. For the dual ring casts, a third sample was preserved in 95%, denatured ethanol and on many occasions, the fourth sample was kept live, diluted with sea water and distributed into 3.7 L plastic containers, and placed in a cooler until they could be transported back to the lab for live image analysis.

The zooplankton samples fixed in formalin were further processed for identification and enumeration of species. Samples were diluted in seawater and subsamples were taken until 200 copepods and at least 75 Calanus were identified.

Data processing:
Zooplankton analysis: All samples were preserved in a 4% seawater-buffered formaldehyde solution. In the laboratory, samples were split using a Folsom plankton splitter. Half of the sample was archived for identification and enumeration of zooplankton species. The archived split was diluted and a 5- to 10-mL subsample taken to obtain a target number of 200 organisms. An additional subsample of 75–200 individuals was analyzed to enumerate stages of Calanus finmarchicus, copepod. The counts were normalized to number/m2, taking into account the subsample dilution factor and split factors. Volume sampled was determined geometrically as the area of the net multiplied by the station depth. This was found to be more consistently reliable than the volume calculated from flowmeter readings. Note that the depth of water sampled by the net was typically within 5 m of the station depth.

BCO-DMO Processing Notes:
- added conventional header with dataset name, PI name, version date
- modified parameter names to conform with BCO-DMO naming conventions
- re-formatted date from m/d/yyyy to yyyy-mm-dd
- rounded some Sample_examined_for_zoo and sample_examined_for_Cfin from 16 to 5 decimal places

Description from NSF award abstract:
In the Gulf of Maine region, rapid warming of the ocean surface in recent years has raised concern in the research and resource management communities, fishing industry and the general public about effects on the coastal marine ecosystem. This interdisciplinary, collaborative project will improve understanding of the physical and biological processes controlling the abundance of a planktonic animal that is particularly important in the food web of the northeast coastal ocean. About the size of a grain of rice, the marine copepod Calanus finmarchicus is the primary prey for herring and other forage fish, as well as for the endangered northern right whale. This study will examine whether transport of C. finmarchicus into the Gulf of Maine from cold Canadian waters, in combination with growth and reproduction in the relatively cold Maine Coastal Current, is sufficient to supply the region with the numbers needed to attract and nourish the fish, seabirds and mammals that rely on its energy rich life stages, despite recent ocean warming. The research team will develop a computer model that links extensive understanding of the species' life history with ocean currents and temperature. Results from the model will be tested against field collections at two locations. This study will also contribute to the new Integrated Sentinel Monitoring Network, a joint effort planned by federal and state agencies with academic research participation to monitor future ecosystem change on the northeastern coastal shelf. It will train a graduate student and postdoctoral scientist in interdisciplinary research and also provide support for an early-career investigator.

The project will take a process modeling approach that takes into account regional and mesoscale interaction between life history and bathymetry and circulation to improve understanding of planktonic species distribution shifts. It will combine two decades of research on Calanus finmarchicus life history, including diapause, with a high resolution regional circulation model into an innovative application of a three dimensional, physical-biological model. The modeling approach represents an advancement of climate forecasts of species ranges by coupling a Lagrangian perspective with local processes to better resolve complex range boundaries. It will use Lagrangian parameters such as finite-scale or finite-time Lyapunov exponents, translating particle trajectories into scalar fields that represent the structure of the advective regime. The model will be informed by and tested with measurements of vital rates and demographic data collected on a research vessel at two time series stations. It will be used in backward-in-time and forward-in-time modes to test hypotheses about sources and destinations of C. finmarchicus in the Gulf of Maine, effects of match/mismatch in phenologies, and exploration effects of climate forced scenarios on advective pathways.