2023 Northeast Summer Ecosystem Monitoring Cruise Completed

Overview

Our Ecosystem Monitoring Surveys help researchers understand and predict changes in the Northeast shelf ecosystem and its fisheries. Our core sampling provides data that help us understand ocean acidification as well as changes in:

• Distribution and abundance of zooplankton and larval fish
• Temperature
• Salinity

Researchers also record observations of seabirds, marine mammals, and sea turtles. Egg data collected are important for managing Atlantic mackerel in U.S. and Canadian waters.

We sampled 209 stations from August 8 to 25, 2023. We completed 100 percent of our planned research activities and collected supplemental data, thanks to 18 sea days and efficient crew and command. 

The plankton we gather provide information about the food chain supporting fisheries and marine mammals. Scientists use our larval fish and egg samples to learn more about fish stock spawning and help estimate stock abundance. By measuring physical and chemical conditions like temperature and salinity, we can describe:

• Ecosystem productivity
• Fish spawning
• Larval recruitment
• Species distribution

Core Sampling Summary

Plankton Collection

During this survey, we conducted “bongo” net tows at 163 different stations. We attached fine-mesh nets to adjoined aluminum rings, creating a sampling device that resembles bongo drums when deployed. Bongo net tows collect zooplankton, larval fish, and fish eggs. 

We conducted supplemental at fixed plankton stations in wind energy lease areas near Nantucket Shoals. Data will directly help the science center's efforts to understand the impacts of wind energy development in the region.

Conductivity, Temperature, and Depth Profiles

The crew deployed instruments that can measure conductivity, temperature, and depth at all 209 stations on this survey. Seawater conducts electricity. Conductivity varies with the amount of dissolved salts in the ocean, and scientists use it to estimate the salinity of seawater. The combination of temperature and salinity at various depths helps define marine habitat boundaries, track ocean circulation, and monitor changes in climate. This can help explain changes in marine species distribution and productivity.

Ocean Acidification Monitoring

To monitor marine carbon cycling and ocean acidification, scientists collected water samples at 36 stations and measured:

• Dissolved inorganic carbon
• Total alkalinity
• pH
• Nutrient concentrations

Increases in dissolved carbon dioxide can increase the acidity of the water, which can affect shellfish and other sensitive organisms. The NOAA Ocean Acidification Program funded this work. We conducted it in partnership with NOAA’s Atlantic Oceanographic and Meteorological Laboratory in Miami, Florida.

The crew also collected pteropods—tiny planktonic snails—from the water column. Researchers will examine the condition of the pteropod shells to measure the biological effects of ocean acidification. We expanded our plankton net tows to include the chemistry stations in the Mid-Atlantic Bight to facilitate pteropod sampling alongside carbonate chemistry measurements. We also took supplemental surface carbonate chemistry samples at any plankton station where we saw pteropods.

We conduct pteropod measurements in partnership with the Bermuda Institute of Ocean Science, using a measurement technique developed by Dr. Amy Maas.

Special Collection Summary

We collaborate with other agencies and institutions that support research which enhances our core sampling.

Visual Sighting

One trained observer watched for and recorded data on seabirds, marine mammals, and sea turtles we encountered along the cruise track. This is part of the Atlantic Marine Assessment Program for Protected Species.

Phytoplankton Monitoring

We deployed an imaging flow cytobot to image and count phytoplankton cells from surface waters throughout the ship’s transit. This work is part of a National Science Foundation project led by Woods Hole Oceanographic Institution in collaboration with NOAA Fisheries. The imaging flow cytobot was especially useful in documenting a large dinoflagellate bloom that was occurring in the Gulf of Maine. 

Satellite Imagery and Water Column Radiometry

On days when skies were clear, we lowered a submersible light sensor into the water to measure subsurface light levels while a satellite was passing over in the middle of the day. These measurements will provide verified data for scientists to evaluate the algorithms used by satellites to determine sea-surface chlorophyll estimates. 

Community and Primary Production

A researcher from our Narragansett Laboratory took subsamples of plankton to determine their energy content. These samples will help determine if different preservation methods—storing in formaldehyde or drying—can affect the energy determination analyses. 

Outreach

We hosted two college students on this cruise, one from Maine Maritime Academy and one from the University of Rhode Island. The students participated in all aspects of the data and sample collection.