Silver Spring (Bernd F. Laeschke – 29.10.2010): The great Pacific garbage patch, a concentrated area of marine debris in the North Pacific Ocean, is the focus of the latest expedition led by the National Oceanic and Atmospheric Administration (NOAA). Scientists on board the Okeanos Explorer are collecting plankton samples and floating debris, mainly small bits of plastic, that collects in the calm center of this high pressure zone.
“There are some data gaps in our plankton sampling records between Guam and Hawaii and between Hawaii and the US 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.”
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.
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 near San Francisco. Taken together, the two plankton-sampling legs cover more than 5,100 nautical miles, making it the longest sampling of its kind.
Throughout the expedition, members of NOAA’s Office of Ocean Exploration and Research have also been taking water samples and collecting data from the ship’s multi-beam sonar to make 3-D maps of the seafloor.
“This cooperation helps meet a number and variety of needs important to NOAA and the nation,” said Craig McLean, NOAA’s acting assistant administrator for research. “Okeanos Explorer is the only federal ship on the planet assigned to systematically explore the ocean. With the objective of always exploring, the ship probes the ocean even during transits from one operating area to the next.”
The continuous plankton recorder is towed behind the ship to collect samples. While moving, water and plankton enter the nose of the device and drifting organisms are caught on a slowly advancing strip of silk mesh. The plankton in these samples will be carefully 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 debris 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 plastic particles - some as small as pollen that may be ingested by marine life including plankton.
Plastic particles from both collection methods will be counted at Scripps Institution of Oceanography at the University of California, San Diego. NOAA’s Fisheries Science Center in Seattle will perform several chemical analyzes to test the particles for PCBs, DDT, BPA and other toxins that might be on or in the particles. All these laboratory tests are designed to understand the impact micro-plastic debris may have on the marine ecosystem and ultimately on humans.