NOAA Fisheries scientists onboard NOAA Ship Okeanos Explorer are collecting plankton samples from Hawaii to the U.S. West Coast and collecting floating plastic debris from the so-called “great Pacific garbage patch,” a concentrated area of marine debris in the North Pacific Ocean.
Marine debris, mainly small bits of plastic, collects in the calm center of this high pressure zone. Although plankton — small, drifting organisms — are at the base of the ocean food chain, the microscopic bits of plastic can also be ingested by fish and other animals.
“There are some data gaps in our plankton sampling records between Guam and Hawaii and between Hawaii and the U.S. West Coast,” said Michael Ford of NOAA Fisheries and chief scientist for the mission sampling operations. “We need samples in these areas to better describe the diversity and distribution of plankton, so we may detect changes and better understand the plankton communities’ response to features such as the Pacific garbage patch.”
Okeanos Explorer is returning from a joint ocean expedition with Indonesian partners in the biologically diverse but largely unexplored Sulawesi Sea in Malaysia, and the ship’s route back includes legs from Guam to Hawaii and then to Alameda, Calif., near San Francisco. Taken together, the two plankton-sampling legs measure more than 5,100 nautical miles, making it the longest sampling of its kind.
Plankton is collected on silk mesh as water flows through the Continuous Plankton Recorder, a small but sophisticated rocket-shaped vehicle with wings that help keep it just below the surface where plankton congregates, is towed behind the ship to collect plankton samples. While moving, water and plankton enter the nose of the device and the plankton are caught on a slowly advancing strip of silk mesh. The plankton in these samples will be identified and quantified on land to provide data to better describe plankton communities in this area and to help fill in the data gap.
Plastic is collected by a special net called a manta, which is also towed by the ship. It measures the volume of water passing through it and collects tiny plastic samples in its fine mesh. Filtered surface water samples allow scientists to analyze the smallest end of the size spectrum for plastic particles — some as small as pollen that may be ingested by marine life including plankton.
Samples of plastic particles from both collection methods, many too small to be seen by the eye, will be counted at Scripps Institution of Oceanography at the University of California, San Diego. NOAA Fisheries Northwest Fisheries Science Center in Seattle will perform several chemical analyses to test the particles for PCBs, DDT, BPA and other toxins that might be on or in the particles. All these laboratory analyses are designed to improve our understanding of the impact of microplastic marine debris on the marine ecosystem and ultimately on humans.
Plankton consists of drifting microscopic plants (phytoplankton), animals (zooplankton), bacteria (bacterioplankton) and viruses (virioplankton) that inhabit oceans, seas and bodies of fresh water. They are the most abundant form of life in the ocean, and all other marine life is ultimately dependent on plankton for food. Phytoplankton also absorbs large amounts of carbon, which would otherwise be released as carbon dioxide.