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.

Tuesday, January 26, 2010

All About Algae

text and photos by Peter Vroom

Despite the nonflattering images of “pond scum” many people often associate with algae, marine algae (or macrophytes) have proven themselves to be among the most diverse, most ecologically important, most prevalent, and most beautiful organisms present in tropical reef systems. Their importance to the ecosystem is staggering: algae form the base of the food chain, occupy much of the available substrate, and help to oxygenate the water, allowing animal life to thrive. Additionally, without microscopic symbiotic algae living in healthy coral tissue, most corals would be unable to survive – a scenario that is becoming all too real as coral bleaching events (processes where stressed corals expel their algal symbionts) become more common.

Although large, fleshy algal forms are often the most recognizable floral components on reefs, tiny turf algae and crustose coralline red algae are also extremely prevalent and play significant roles in the ecosystem. Turf algae are the first to colonize vacant substrate and cover essentially every nonliving hard surface on the reef. Turf algae are also among the most important food source for herbivorous fish and invertebrates. Relatively fast growing crustose coralline red algae act as a glue that cements together loose components of the reef system, and serve as a settling surface for larval invertebrates and other algae. Without crustose algae holding everything together, much of the reef would be washed into deep water or onto shore during heavy winter storms.

Clearly, without algae there would be no tropical reef ecosystem, yet marine algae are among the least studied and least understood organisms on the reef. More research is sorely needed to catalog and quantify the species that are present on reef systems around the Pacific, and ecological studies are necessary to examine the role of these critical plants in reef ecosystems.

To accomplish these objectives, CRED is studying tropical reef algae to address the following questions:
  •  What is the best way to quantify algal functional groups (macroalgae, crustose coralline algae, turf algae) in tropical reef settings? 
  •  What species are present in each island ecosystem and in what quantity? 
  •  Do changes in algal populations serve as a good environmental indicator of reef heath? 
  •  How do algal diversity and abundance change over time? 
  •  Can biogeographical hypotheses be formulated about algal dispersal and evolution using qualitative and quantitative data from island groups around the Pacific? 
A modified Rapid Ecological Assessment technique that incorporates the use of digital cameras and photoquadrats is our primary field method, which we will be employing on this cruise.

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