Yuan Liu and Christopher Taylor processing water samples in the NOAA ship Gordon Gunter’s laboratory. Courtesy of NOAA Fisheries.
HYANNIS – NOAA Fisheries has wrapped up its 2019 Northeast fall ecosystem monitoring survey.
Researchers aboard the NOAA vessel Gordon Gunter sampled 117 stations along the U.S. East Coast.
Data collected during the cruise helps researchers understand and predict seasonal and yearly changes in the Northwest Atlantic Ocean ecosystem and its fisheries.
Due to weather conditions about 75 percent of the cruise objectives were accomplished, including complete coverage of the Mid-Atlantic and Southern New England regions, and 97 percent of Georges Bank.
There was reduced coverage in the northern survey area, including just 22 percent in the Gulf of Maine and no coverage of the Scotian Shelf.
Long-term sampling on the cruise includes the use of “bongo” net tows. The fine-mesh nets are attached to side-by-side aluminum rings. The nets get their name for resembling bongo drums when deployed.
The bongo net tows were conducted at 100 different stations during the cruise.
The samples collected included fish larvae, fish eggs, sub-adult squid, and zooplankton, which are tiny animals, mainly crustaceans, and very young stages of some larger animals.
Zooplankton provide information about the food chain supporting fisheries and marine mammals. Scientists use larval fish and egg samples to learn more about fish stock abundance.
Seawater conducts electricity and the conductivity is used to estimate seawater salinity.
The crew deployed an instrument that measures conductivity, temperature and depth at all 117 stations surveyed.
The temperature and salinity at various depths help to define marine habitat boundaries, track ocean circulation, and monitor changes in climate. The data can help to explain changes in the distribution and productivity of marine species.
Researchers also collected water samples and measured dissolved inorganic carbon, total alkalinity, pH and nutrients at two dozen stations to monitor marine carbon cycling and ocean acidification.
Increases in dissolved carbon dioxide can increase water acidity. Changes in acidity can impact shellfish and other sensitive organisms.
This portion of the work was funded by NOAA’s Ocean Acidification Program which was conducted in partnership with NOAA’s Atlantic Oceanographic and Meteorological Laboratory in Miami.
Several other special collection research projects were conducted during the cruise.
Water samples were collected to look for genetic material shed into the environment by marine organisms. The DNA can identify which species are present in a specific location.
The work was conducted by the NEFSC Population Biology Branch with help from the NEFSC Ecosystem and Aquaculture Division.
Seawater was filtered to measure methyl mercury concentrations in the environment for a researcher from the University of Connecticut, who was on the crew.
Ring nets were deployed next to the standard bongo nets during tows at two collection stations to compare the samples collected.
The ring nets are used for plankton sampling by the Department of Fisheries and Oceans Canada’s Atlantic Zone Monitoring program.
The experiment is part of studies to find ways of combining data collected by each country in the Gulf of Maine and Georges Bank.
Researchers also took optical measurements for a University of Rhode Island project that uses ocean color measurements in satellite images to identify sizes and types of phytoplankton.
This work was funded by NOAA’s Joint Polar Satellite System Proving Ground and Risk Reduction Program. Partners include researchers from NOAA and the Woods Hole Oceanographic Institution.
Seabirds, marine mammals and sea turtles spotted along the trip were monitored by two observers. This work was part of the Atlantic Marine Assessment Program for Protected Species.
The program is a partnership of researchers from NOAA, the U.S. Fish and Wildlife Service, the Bureau of Ocean Energy Management and the U.S. Navy.
An underwater microscope, or imaging flow cytobot, was used to image and count phytoplankton cells continuously from surface waters during the voyage.
The work is part of a National Science Foundation project led by WHOI in collaboration with the UMass Dartmouth, URI, Wellesley College and NOAA Fisheries.
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