Twenty-five miles southwest of Hawaii and five degrees north of the equator, it is located in the federal state of Kusaiai Island, the easternmost of the four states of Micronesia. The 42 square kilometer island is surrounded by an abundance of coral reefs, recognized as one of the most pristine in the Western Pacific. Since 1996, a group of island stakeholders, including government branch representatives and private ecotourism operators, has partnered with OceanEarth, Inc., a California 501(c)3 nonprofit organization, to support long-term monitoring efforts to track coral reef systems health.
In the first two years of the project, more than 55 mooring buoys were installed on the island and helped provide local fishermen with an alternative to dropping anchors in delicate reef structures to protect the reef. At the same time, 15 mooring sites were selected to be permanent environmental monitoring locations.
Since then, on at least an annual basis, scientists and lay volunteer divers have been added to inventory and assess the extent and health of coral cover around the islands. At the same time, population stocks are taken of fish targeted for food and aquarium trade as well as invertebrate species commonly used locally and for export.
As part of the annual survey, various environmental measurements are taken such as weather and water conditions, visibility, temperature, salinity and pH. In earlier projects, it was accepted that single-point measurements of water temperature had information from visibility measurements, but had relatively limited research value in predicting or understanding changes in coral reefs.
In late 2008, the first set of four HOBO® Prendent temperature/light compact loggers UA-002-64, UA-002-08 temperature/light loggers were installed at various key points around the island, evidence of coral bleaching events previously Observed. These water temperature data loggers are attached to rebar driven into the reef substrate at a depth of approximately 30 feet and placed for up to nine months, UA-002-64, UA-002-08 temperature/light loggers, every 15 minutes. The first set of three of the four compact data loggers was successfully recovered in mid-2009 and the data was downloaded, providing the first ever look at long-term temperature cycles on the reef or any of the Commonwealth states of Micronesia.
The collected data are expected to help distinguish temperature effects from other environmental and anthropogenic stressors. In addition, it is hoped that insolation data will be useful in predicting the occurrence of coral spawning events.
After data recovery, the data logger was given a battery replacement on site and returned to the monitoring site for one year service. Efforts to improve the layout and data loggers will result in all four being recovered and reinstalled in October 2010. The data loggers are well dated, providing researchers with a continuous stream of valuable water temperature information. The ease, speed, and maintenance of data recovery, battery replacement, and maintenance can allow rapid deployment in the limited time available to researchers in the field. Future plans include the deployment of additional HOBO data loggers at other locations around the island, where changes in water temperature are believed to affect coral growth and survival.
