NOAA Ship Okeanos Explorer recently completed an exploration cruise across more than 2000 nautical miles of the Pacific Ocean, acquiring data from the air-sea interface to the seafloor along the way. During the October 19-29 cruise from Honolulu to San Francisco, the Okeanos Explorer program teamed up with NOAA’s National Marine Fisheries Service (NMFS) to conduct two “surveys of opportunity”: sampling plankton across the Pacific, and sampling for plastics to gain a greater understanding of the extent of the area commonly referred to as the Pacific “Garbage Patch” or “Plastic Gyre”.
Sampling for plastics and plankton are exploratory projects in nature, and were thus a great fit aboard Okeanos Explorer – the Nation’s first and only dedicated Ocean Exploration vessel with a federal mandate to systematically explore the world’s ocean. Some of the most basic questions about the “Garbage Patch” remain to be answered. Questions like: How large is it? How is it distributed? And how does it affect marine life? Sampling conducted during the October cruise sought to help answer some of these questions.
Sampling for plankton using an instrument called a Continuous Plankton Recorder (CPR) was a project continued from Okeanos Explorer’s previous cruise, when the CPR was towed from Guam to Honolulu. The CPR was again towed behind Okeanos Explorer from Honolulu to San Francisco, continuously collecting samples of plankton from about 10 meters beneath the sea surface. The combined samples represent nearly 5100 nautical miles of plankton data in two rarely sampled areas. After analysis, the sample data will help scientists begin to understand the nature of the plankton community – the base of the marine food web – in these regions. Combined with the plastics data, insights about the effect of plastics in the environment on the marine food web may be made.
Okeanos Explorer was on her way to the west coast following a major expedition in Indonesian waters, and her return route to the U.S. west coast transited directly through the “Eastern Garbage Patch”, and two regions rarely sampled for plankton – the base of the marine food web. Okeanos Explorer is always exploring and conducts “operational transits” – meaning that new data about the ocean continues to be collected. Since becoming operational in 2008, Okeanos Explorer has almost always collected bathymetric data of the seafloor while underway using the ships EM302 multibeam sonar. The sonar system uses sound to image the seafloor in greater detail than satellite bathymetry, revealing previously unknown features and creating a truer picture of what the seafloor actually looks like.
The voyage was what is traditionally referred to as a ‘transit’ cruise; these are truly exploration cruises and offer unique exploration opportunities such as the chance to examine oceanographic conditions over great distances or detect new seafloor features. As a dedicated Ocean Exploration vessel, Okeanos Explorer travels to and explores areas not typically visited by research vessels, providing the opportunity to partner with groups like NMFS to further explore the mostly unknown ocean, and learn more about relatively undescribed features like the “Garbage Patch”.
Kelley Elliott, Expedition Coordinator
NOAA Office of Ocean Exploration & Research