Scientists and staff in charge of maintaining the Flower Garden Banks National Marine Sanctuary 100 miles off Galveston Island are busy preparing for their 2019 treks to the banks, starting in May.
“We’re getting our vessel ready for a variety of research and monitoring projects we’ll be conducting this summer,” said G.P. Schmahl, superintendent of the sanctuary under the National Oceanic and Atmospheric Administration of the U.S. Department of Commerce. The sanctuary’s offices are on Galveston Island in the old Fort Crockett complex occupied by the administration on Avenue U.
The best-known part of the 56 square miles of protected underwater sanctuary are the tip-tops of the banks, the living coral caps covering what are essentially small, underwater mountains.
East Flower Garden Banks, West Garden Banks and Stetson Bank, comprising just 1 percent of the total area of the sanctuary, are at the northern geographic limit for coral reef development and are remote enough that they remain protected from environmental hazards that have threatened and damaged coral reefs in recent decades in Florida, the Caribbean and around the world.
“The banks are fairly remote and inaccessible to most people,” Schmahl said. “They’re a little outside the range of coastal runoff impact, and they’ve benefited from their isolation and from being relatively deep.”
The shallowest point of the reef is about 60-feet deep, creating a buffer for the banks against ocean warming, especially high surface water temperatures that can damage coral reefs.
“Historically, we’ve not had a lot of major issues related to disease, sedimentation or human-caused degradation,” Schmahl said.
In 2016, however, the banks experienced a large bleaching event in which corals expelled symbiotic algae that live on them, a phenomenon related to warming waters.
When the symbiotic algae that live in coral tissue are stressed, they produce proteins toxic to coral and the coral expel them, said Emma Hickerson, research coordinator at the marine sanctuary. The algae give coral their vivid colors, so the coral turns white as a result of the expulsion and loses as much as two-thirds of its nutritional intake, provided by the algae. Coral can starve to death if they don’t recover quickly enough. In addition, weakened reefs are more vulnerable to disease.
“It was a bad year for bleaching around the globe,” Hickerson said. “Luckily for us, of the bleaching that occurred at the banks in 2016, the corals recovered.” The banks staff has studied that recovery and recently submitted a paper about it that has been accepted for publication.
One part of the study monitored surface temperatures of the water at the site of the bleaching, and found that using a standard sea temperature of 30 degrees centigrade, the east bank experienced 30 days between June and October when water temperatures were higher than 30, and the West Garden Bank experienced 18 days over 30. The East Garden Bank bleached more than the west, confirming the role of water temperature in the event.
Monitoring the health of the reef is one aspect of the annual expeditions to the flower garden banks, keeping tabs on the reef condition, health of the corals and other organisms living on the reef, and measuring fish populations, temperature, water salinity, turbidity, nutrient content and other environmental factors in the water as well as monitoring invasive species.
“We’re also doing quite a bit of work exploring the area surrounding the banks, deeper areas out of range of scuba diving,” Schmahl said. “We use Remotely Operated Vehicles or ROVs that go down and collect things in the lower-light or mesophotic zone. Sometimes it’s referred to as the twilight zone.”
The group travels in an 83-foot research vessel, a catamaran that sleeps 14 people, including four crew, and goes out usually for two to five days. In general, it takes six to eight hours to sail to the banks.
Some of the research projects scheduled for this season include a study of underwater acoustics, monitoring the waters around the banks for human-made sounds that can be damaging to marine mammals. Other studies will explore ocean acidification and genetic connectivity of ocean organisms through sampling DNA.
The sanctuary for the past several years has been working on an expansion plan, under the guidance of an advisory board that includes representatives from the fishing and oil and gas industries. A final plan that could claim other reefs and banks along the Texas and Louisiana coast as part of the sanctuary program will be completed soon, Schmahl said.