A Better Understanding of Coral Reef Ecosystems

Pelagic predators such as these barracuda, Sphyraena qenie, are part of the coral reef ecosystem in the U.S. Line Islands (NOAA Photo by Kevin Lino).
A team of scientists have embarked from Hawai'i on a three-month survey of coral reef ecosystems at Johnston Atoll, the U.S. Phoenix Islands, the islands of American Samoa, and the U.S. Line Islands in the tropical Pacific Ocean. The overarching objective is to better understand the coral reef ecosystems of these areas, many of which are seldom explored. The research expedition is part of a regular monitoring program, conducted by the Coral Reef Ecosystem Division (CRED), headquartered in Honolulu, Hawai'i. The expedition is supported by NOAA's Coral Reef Conservation Program and involves extensive cooperation among NOAA scientists and research partners, including the University of Hawaii Joint Institute for Marine and Atmospheric Research (JIMAR), the U.S. Fish and Wildlife Service, San Diego State University, and the Papahānaumaokuākea Marine National Monument.

The research expedition will be carried out from February 27 to May 24, 2012 aboard the NOAA ship Hi'ialakai. Under the leadership of Chief Scientists Dr. Jill Zamzow, Dr. Bernardo Vargas-Angél, and Jamison Gove, a diverse team of researchers will be conducting multidisciplinary coral reef ecosystem surveys, assessing the status of fishes, corals, algae, marine invertebrates, and the oceanographic conditions in which these organisms exist. The scientific data collected during the three-month research expedition will enable informed and effective implementation of ecosystem-based management and conservation strategies for coral reef ecosystems, helping to ensure their protection for generations to come.

Sunday, October 17, 2010

Coral Reef Oceanography: The CTD

The bow of the Rubber Duck plowed through the frothy white cap of another wave and drenched us with sheets of salty water as we motored closer to the southern-most point of land in the United States; South Point on the island of Hawaii. The two 90 horse-power motors pushed us doggedly upwind toward our next survey site. With a trusty oceanographic instrument known as a CTD onboard, we were ready to collect some valuable data about the water column.
The view from below as a CTD is lowered over the side of the Rubber Duck by Oceanographer Oliver Vetter.  NOAA Photo by N. Pomeroy
CTD — an acronym for Conductivity, Temperature, and Depth — is a tool for measuring a variety of physical properties of sea water. Although a large version of this instrument can be found on our research ship, the Hi’ialakai, we make use of a smaller version of this classic oceanographic instrument when conducting operations from our small boat, the Rubber Duck. When we arrive at a survey site in our small boat, we lower a handheld CTD over the side of the boat to collect data about the water column. The protective steal cage of the CTD houses a variety of instruments that collect data continuously as the device descends through the water column. This data includes a detailed account of water temperature, salinity, dissolved oxygen, and turbidity. This information helps us to better understand how ocean water characteristics are distributed across space and time around the islands we visit. Shallow water CTD data, coupled with results of actual water samples that are collected at CTD survey sites, helps paint a picture of major influences on reef life, such as transport of warm or cold water, nutrients, and possibly organisms from one region to another.
With our CTD full of detailed oceanographic data, we secured it to the console of the Rubber Duck and began our transit to the next survey site.

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