March 14, 2012
Coral communities are frequently associated with warm, shallow tropical waters. Yet corals survive and thrive in both deep and cold waters of regions such as the Gulf of Maine, the Arctic and the Antarctic. Just like tropical corals, cold-water corals play an important role in creating habitats that support thousands of species of ocean creatures.
Corals found in deep seas, however, are much less frequently studied than their shallow cousins because the depths needed to reach coral communities are often beyond the reach of traditional scuba gear. Just as tropical corals are being threatened, deep-sea corals are also vulnerable to environmental pressures and human impacts. It was discovered relatively recently that in a few high-latitude environments, deep-sea coral species can be found much shallower than usual, some even within the depths that scuba equipment can reach.
Rhian Waller, a University of Maine assistant research professor, has received grants to explore corals usually found in the deep sea but now living in shallower waters in the Gulf of Maine, Alaskan fjords and the Patagonian fjords in Chile.
Waller has received a $78,457 RAPID Grant from the National Science Foundation and the National Geographic Society has awarded her $30,064 to establish three long-term monitoring sites in Chile where she will monitor and take samples of usually deep-sea corals for reproductive ecology. Waller has also received another $9,000 from UMaine to explore Maine’s coastal areas for deepwater emergent coral habitat sites, and $48,000 from the National Oceanic and Atmospheric Association (NOAA) to continue a long-time series of Red Tree corals in Alaska.
“The discovery of deepwater emergent corals in areas such as Chile, Alaska and even here in the Gulf of Maine, make ecological research possible on species previously unobtainable in enough numbers and from enough times of year to say anything useful about their population processes,” Waller said.
More than 60 species of cold-water coral are known in the Gulf of Maine, but little is understood of their biogeography and diversity, primarily because it is thought that fisheries impacts may have been high in the past, and therefore pristine coral communities may be scare. However, anecdotal and other information gathered from fishermen indicate the distribution of coral communities may be wider than thought, particularly closer to shore and in areas not impacted by fisheries. Waller’s goals are to discover, characterize and map areas of gorgonian corals, also known as sea fans or sea whips, along the Maine coast at depths of 150 feet.
She intends to register the new locations and depth ranges in the U.S. Geological Survey Cold Water Coral Geographic Database and also hopes to discover a scuba-accessible site from which to launch future studies of deep-sea, cold-water coral ecology and physiology.
In Chile, Waller will launch her research from the Huinay Scientific Field Station and work in the waters of the northern Patagonian fjords, which are influenced by strong tides, large volumes of freshwater runoff, upwelling of deep ocean waters and steep climatic gradients from north to south. Species found in these fjords can more usually be found at depth of up to 3,000 meters, yet in these locations they can now be collected by scuba at just 10 meters. This presents researchers such as Waller with a unique opportunity to form baseline data on ecological and population processes – a sort of window into a deep-sea ecosystem.
Corals in the northern Patagonian fjords are facing pressures from activity such as intense salmon farming and logging, which is why there is an urgent need to document and understand the coral systems in this region. Quantifying reproduction is important because it is the fundamental ecological process that every species on the planet needs to undergo in order to survive through time. Measurements of reproduction provide information to understand recruitment, recolonization, population connectivity and recovery from damage.
In Alaska, Waller will continue a time series on deepwater emergent Red Tree corals in the Alaskan fjords. These corals form essential habitat in this region for rockfish and crustacean species. In 2010, Waller and NOAA collaborators established a site of 40 corals, which have since been sampled every three months for reproductive analysis. This site has provided the best time-series reproductive data on any deep-water coral species to date. Waller will return to investigate fertilization and larval dynamics in this species and continue the reproductive timeline to assess when and how much this species reproduces, with the goal of providing essential management information.