Assessing impacts of coral bleaching: NOAA scientists embark on a three-month survey of coral reef ecosystems in the Hawaiian Archipelago

by Drs. Bernardo Vargas-Ángel and Rusty Brainard
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French Frigate Shoals in the Northwestern Hawaiian Islands (NOAA Photo)

Today, scientists from the NOAA Pacific Islands Fisheries Science Center’s Coral Reef Ecosystem Program boarded the NOAA Ship Hi‘ialakai to begin a 75-day Hawaiian Archipelago Reef Assessment and Monitoring Program (HARAMP) research mission. The goal of this mission is to document the status and trends of the coral reef ecosystems of the populated main Hawaiian Islands and the remote Papahānaumokuākea Marine National Monument in the uninhabited Northwestern Hawaiian Islands.

As part of the National Coral Reef Monitoring Program of NOAA’s Coral Reef Conservation Program, this HARAMP expedition will conduct the first statewide surveys to assess the overall impacts of two back-to-back mass coral bleaching events, which occurred in 2014 and 2015 and were caused by unusually warm water temperatures. When water temperatures reach 1°C warmer than their usual summertime maximum, many corals begin to lose the symbiotic algae living in their tissues, making them look white — that is, they become “bleached.”

This expedition will be the 6th monitoring cruise in the main Hawaiian Islands and the 10th monitoring cruise in the Northwestern Hawaiian Islands led by the PIFSC Coral Reef Ecosystem Program and partner agencies since 2000. It’s designed to provide an ongoing, consistent flow of information to document the status and long-term trends of the coral reefs and changing environmental conditions.

These statewide monitoring surveys will complement the local and site-specific coral reef monitoring efforts led by our partner agencies and institutions. Partners participating in this mission include scientists from the State of Hawai‘i Division of Aquatic ResourcesThe Nature ConservancyHawai‘i Institute of Marine Biology, and San Diego State University, among others.

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Autonomous Reef Monitoring Structure installed on left, calcification accretion unit on right (NOAA Photo)

Scientists will survey the coral reefs around each of the main Hawaiian Islands, including Ni‘ihau, Kaua‘i, O‘ahu, Molokai, Lāna‘i, Maui, Kaho‘olawe, and Hawai‘i Islands, and the coral reefs at French Frigate Shoals, Lisianski/Neva Shoals, Pearl and Hermes Atoll, and Kure Atoll in the Northwestern Hawaiian Islands. Each day, they will deploy 4–5 small boats with a team of scientific divers from the Hi`ialakai to conduct in-water surveys of the different reef zones, such as forereef, backreef, and lagoons around the different sides of each island or atoll ecosystem. We often find that the coral reefs and associated organisms vary greatly between leeward and windward sides of islands that are exposed to different environmental conditions, such as waves and currents.

Coral Reef

Under the direction of Chief Scientists Drs. Bernardo Vargas-Ángel in the main Hawaiian Islands and Brett Schumacher in the Northwestern Hawaiian Islands, the different dive teams will conduct underwater surveys of reef fishes, corals, other invertebrates, algae, and microbes. They will deploy and retrieve Autonomous Reef Monitoring Structures, or ARMS, to assess the biodiversity of ‘cryptic’ coral reef species that live within the reef (small crabs, shrimp, snails, etc.).

Autonomous Reef Monitoring Structures (ARMS) installed at Pearl and Hermes Atoll, NWHI (NOAA Photo)

Autonomous Reef Monitoring Structures (ARMS) installed at Pearl and Hermes Atoll, NWHI (NOAA Photo)

Close-up of ARMS unit at Pearl and Hermes Atoll, NWHI (NOAA Photo)

Close-up of ARMS unit at Pearl and Hermes Atoll, NWHI (NOAA Photo)

Calcification accretion unit installed at French Frigate Shoals, NWHI (NOAA Photo)

Calcification accretion unit installed at French Frigate Shoals, NWHI (NOAA Photo)

 

 

 

 

 

 

Additionally, oceanographers aboard the Hi`ialakai will collect data on water temperature, salinity, carbonate chemistry, and other physical characteristics of the coral reef environment with an assortment of oceanographic monitoring instruments. Among other things, they’re monitoring the ecological impacts of ocean acidification by determining the rates of reef growth and reef removal using tools called calcification accretion units and bioerosion monitoring units, respectively, which are deployed on the reef substrate for three years.

Data collected by the scientific staff of this cruise are pivotal to long-term biological and oceanographic monitoring of coral reef ecosystems in the Hawaiian Archipelago. This 2016 HARAMP expedition will help inform scientists, resource managers, and policy makers about changes that have occurred compared with similar surveys conducted in 2000, 2001, 2002, 2003, 2004, 2005 (main Hawaiian Islands only), 2006, 2008, 2010, and 2013.

Hawaiian Archipelago Reef Assessment and Monitoring Program Cruise 2016 Timeline

In particular, data on the abundance and spatial distribution of reef fishes and benthic organisms will allow scientists to evaluate potential changes in the condition and integrity of coral reef ecosystems across the Hawaiian Archipelago. It will also enable federal and state resource managers to more effectively manage and conserve reef-associated animal and plant life in the region. This year’s surveys are particularly important since many of the coral reefs experienced mass coral bleaching in both 2014 and 2015, and these surveys will provide an opportunity to assess the net change in coral cover for each of the islands across the archipelago.

 

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