Guam ocean waters heating up; mass coral bleaching on the rise

The resolution calls for a pause to the designation of critical coral habitats all around Guam. (file photo)

According to the National Oceanic and Atmospheric Administration (NOAA), Guam’s ocean waters are heating up and NOAA’s Coral Reef Watch recently changed Guam to alert level one, which means chances of mass coral bleaching increased for 2019.

Guam’s reefs are expected to reach bleaching alert level one within one to four weeks and alert level two within five to eight weeks, according to the latest outlook report released by the (NOAA).

At alert level one, coral bleaching is likely to occur, and at alert level two – the highest level – coral death is likely, NOAA warned.

In addition, when coral reefs experience very warm water and calm, hot weather, corals become stressed and eject the tiny plants that live inside them.

Normally, these plants – called algae – provide corals with most of the energy they need to grow. However, when temperatures rise, NOAA said the algae become toxic to the corals. Corals that have lost their algae appear “bleached” because the algae give healthy corals their bright colors.

If temperatures remain very high, many corals may die, NOAA warned, and climate change, the cause of ocean warming, is expected to increase the frequency of coral bleaching events in the future.

According to the NOAA report, Guam experienced coral bleaching in 2013, 2014, and 2016. Between 2013 and 2017, Guam lost approximately one-third of all shallow corals around the island.

Members of Guam’s Coral Reef Response Team, including staff from local and federal agencies and the University of Guam, are now surveying Guam’s reefs to measure bleaching and determine which coral species and reef areas are most vulnerable – and which are likely to survive.

Eyes of the Reef

Residents can help protect Guam’s coral reefs by becoming the “eyes of the reef” and reporting impacts, including coral bleaching.

Natural resource managers are asking for the community’s help with tracking these impacts. Eyes of the Reef Marianas ( is hosting a training session on Thursday, July 25, from 6:30 to 7:30 p.m. at the Marianas Yacht Club.

During the training, which is free and open to the public, participants will learn how to identify reef impacts such as bleaching and report their sightings online. These reports help managers identify reef areas that are in trouble and need to be protected.