The Continuous Plankton Recorder Survey has been running for nearly 90 years, but scientists hope this new project will help shed light on the significant decline in population numbers of endangered North Atlantic right whales.

This autumn, ships in the Gulf of Maine will once again be towing Continuous Plankton Recorders (CPRs) thanks to a new four year project funded by the National Oceanic and Atmospheric Administration (NOAA) Northeast Fisheries Science Center, hosted by the Woods Hole Oceanographic Institution. Each month, CPRs will collect plankton samples from this region, identifying changes in plankton species and distribution. The resulting data will help provide valuable insights into the health of the marine environment and help inform effective management action.

Plankton form the base of the marine food chain, providing food for larger animals, and ultimately supporting almost all life on the planet, both above and below the ocean’s surface.

“Continuing a long-term time series like the Continuous Plankton Recorder Survey is essential to understanding the impact of climate change to marine ecosystems,” said Chris Melrose, a research oceanographer at the Northeast Fisheries Science Center’s laboratory in Narragansett, Rhode Island and NOAA representative on the agreement. “Many marine species are shifting their distributions as ocean waters warm," explained Melrose. “Because plankton are an important food source for many species, including the endangered North Atlantic right whale, knowing about changes in the plankton helps us to understand other changes we see in the ecosystem.”

Research has shown the North Atlantic right whale population has collapsed in recent years, with various factors at play including poor calving rates. Scientists believe these animals are having to follow their preferred plankton food source, Calanus, a large lipid rich copepod, north due to warming seas, and are entering areas of fishing and other potential hazards, which further contribute to high mortality rates. It is hoped by identifying the spread and abundance of these important plankton species, improved understanding of species movements can be developed which will help support improved management and conservation efforts.

The CPR Survey first began regular sampling in this area in 1961, supported by NOAA’s Northeast Fisheries Science Center. This programme ran until 2013, achieving 446 successful tows and earning the accolade of being the longest running plankton time-series in the northwest Atlantic. After funding for this research ended in 2013, the CPR Survey continued collecting samples until 2017, when tows had to be suspended. From this October, tows will resume in the Gulf of Maine, with funding secured until 2021. The CPR Survey, based in Plymouth will be responsible for all tows, analysis and sample storage, with data from the samples being available to all, in line with CPR Survey policy.

David Johns, Head of the CPR Survey explains “The value of sampling in an area accumulates each subsequent year, building a dataset of evidence and insight that we can use to investigate recent changes in the Gulf of Maine. We can compare our new dataset with the historical time series, and start to put these changes into context in a warming world”

The resumed Gulf of Maine survey will add to plankton samples collected on two other CPR Survey routes in the Northwest Atlantic. The first route runs across the Scotian Shelf off Nova Scotia to Cape May, New Jersey. The second, runs across the North Atlantic from Iceland to Newfoundland.

What is the CPR Survey?

Based at the Marine Biological Association (MBA) in Plymouth, the CPR Survey is the largest marine monitoring programme in the world. CPR transects have been conducted around the world, with the core monthly plankton sampling program focused on the northwest European shelf and in the Northeast and Northwest Atlantic. This year it celebrated reaching its 7 million nautical mile milestone, 89 years after the Survey’s first tow in 1931.

The Survey uses a mechanical plankton sampling device towed behind merchant vessels as they ply their usual trade. Measuring 1 meter in length, the torpedo shaped instrument contains two reels of fine silk mesh that gradually unwind, filtering the water and capturing the plankton. The silks are wound together, creating a plankton sandwich, before being preserved in-situ in formalin, to be analysed back at the lab in Plymouth. Methods of sampling and plankton analysis have not changed since 1958, resulting in an important baseline of data against which change can be measured. Every silk sample collected is stored in a large physical archive, so as new ways to analyse the samples develop, they can be applied to historic samples.

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Oct 16, 2020 By jenski