Scientists on the NOAA Ship Hi'ialakai are Surveying Coral Reef Ecosystems in the Remote Northwestern Hawaiian Islands
Scientists from the NOAA Pacific Islands Fisheries Science Center are on a 26-day expedition to study coral reef biota and habitats in the remote Northwestern Hawaiian Islands (NWHI). The research is part the Pacific Reef Assessment and Monitoring Program (Pacific RAMP) conducted by the PIFSC Coral Reef Ecosystem Division (CRED). Joining PIFSC scientists on the NOAA Ship Hi'ialakai are research colleagues from the University of Hawaii Joint Institute for Marine and Atmospheric Research, Ocean Associates, San Diego State University, and the Papahānaumokuākea Marine National Monument. Chief Scientist for the expedition is CRED researcher Peter Vroom.
Under Vroom's direction, teams of scientists will monitor a variety of reef and oceanographic parameters, continuing biennial studies that began in 2000. As with previous Pacific RAMP cruises in the NWHI, the research team will visit established, long-term Rapid Ecological Assessment (REA) sites at French Frigate Shoals, Lisianski Island, Pearl and Hermes Atoll, and Kure Atoll to survey populations of corals, algae, and targeted invertebrate fauna, and investigate diseases of coral and algae. In addition, at several REA sites chosen using a stratified random sampling design, researchers will conduct species-level surveys of fish and genus-level surveys of benthic organisms. To fill in gaps in information collected at the fixed long-term and randomly sampled REA sites, towed-diver teams will survey fishes, specifically large fishes longer than 50 cm in total length, as well as benthic biota. In these operations, divers will be towed over the seafloor behind a small boat, covering wide swaths of bottom habitat around each island.
The CRED's oceanography team will retrieve and deploy a suite of scientific instruments, conduct hydrographic surveys, and collect water samples to better understand spatial and temporal variations of oceanographic and water-quality parameters. Data will be collected on sea-surface temperature, currents, and nutrient concentrations. In addition, ecological acoustic recorders (EARs) will be deployed to gain a sense of what reefs sound like under healthy and possibly stressed conditions. Calcification acidification unit (CAU) plates will be deployed to establish a baseline of information on crustose coralline algae and scleractinian coral in the NWHI, information necessary to understand expected changes in these critical reef-building organisms, including their growth rates, as oceans become more acidic. Autonomous reef monitoring structures (ARMS) will be collected and deployed to gain a better grasp of cryptic invertebrate populations that are difficult to study using other survey methods. Finally, the role of microbes in NWHI coral reef communities will be studied by a microbial biologist from San Diego State University.
This year, an alert has been issued for possible coral bleaching in the NWHI. CRED scientists, who observed and reported massive bleaching events in the NWHI during the past decade, will continue to record bleaching event parameters to improve understanding of the response of coral reef ecosystems to elevated sea-surface temperatures. They will assess and record the susceptibility of different coral species to bleaching, the percentage of colonies bleached, and the geographic areas around each island where the majority of bleaching occurs.
Summer blooms of native green macroalgae, first recorded at Pearl and Hermes Atoll, Midway Atoll, and Kure Atoll in 2008 and 2009 have appeared again. Towed-diver and REA surveys will used to determine the extent of blooms and whether they are posing a risk to live coral communities. Voucher specimens of algae from REA sites will be collected and identified to ascertain whether any alien species are responsible for bloom conditions.
The Hi'ialakai expedition will also provide support for other partner agencies working in the NWHI. Supplies and equipment will be transported for the U.S. Fish and Wildlife Service, which maintains a station at Tern Island, French Frigate Shoals. Scientists will also be testing out a new data management system for the Papahānaumokuākea Marine National Monument.