A Spotlight on the Enigmatic Atlantic Canyons
Gathering together a few hundred people devoted to studying coral in the darker, inaccessible regions of the oceans, can lead to some illuminating moments. USGS “gene-hunter” Katharine Coykendall discussed her unexpected genetic results she called “bananas” during a break at the 6th International Symposium on Deep-Sea Corals. Coykendall uses forensic science techniques to determine how closely related the same coral species are between deepwater canyons in the Atlantic Ocean; how far do the juveniles migrate from the parent corals? What she discovered in her informal conversation with a colleague was that the species of Paragorgia coral (commonly known as the bubblegum coral) she tested from a canyon off Ireland was in fact not the same species from those tested in other canyons! When Coykendall presented her talk the next day, she garnered many chuckles as she wryly slid in her new discovery about why such genetic outliers occur.
“Keep your friends close, but keep your taxonomists and geneticists closer!” joked USGS microbiologist Christina Kellogg during her own presentation.
Kellogg and Coykendall were two of the six USGS scientists presenting at the conference, along with Amanda Demopoulos, Cheryl Morrison, Jill Bourque, and Nancy Prouty. This all-female force hailed from USGS centers in West Virginia, California, and Florida.
This symposium occurs every four years, and less than 200 attendees gathered this time in Boston—with about half from outside the U.S. With no concurrent talks, one could easily spot common trends and identify possible partnerships. Geneticists, chemists, ecologists, and microbiologists received the entire deep-sea picture of new results, which covered such issues as the Gulf of Mexico oil spill, trawling effects, toxic plumes from deep-sea mining, ocean acidification and climate change, plus the challenges to protecting deep-sea coral. Amassing these experts from all corners of the globe can increase the spread of knowledge faster than publishing a scientific paper, as it gave researchers a chance to pose questions to the collective coral brain: what do these results mean, have you seen this aberration, how do you approach this problem, and where can one find more samples? Case in point, five researchers offered Coykendall new samples.
USGS science covered the gamut of topics. Morrison spoke about a contentious issue in the deep-sea coral world: should the coral poster child for the deep-sea—Lophelia, a colonial reef-building coral—merge with Desmophyllum, a solitary coral, now that genetics indicates they are similar? Morrison questioned combining these genera because the key-defining characteristic for corals divides those living alone from those living in a colony. Many also worry that the confusion generated by merging the genera may hamper conservation efforts for Lophelia.
Demopoulos studied deepwater canyons situated just 70 nautical miles apart, but found that their seafloor communities differed greatly. After assembling a small army to analyze the 2,000 samples, she discovered that a canyon’s shape influenced access to food, and thus the structure of the deep-sea community residing there.
Bourque dove into seafloor sediments to explain why a completely different community of animals inhabits the sediment next to Lophelia compared with other corals. Apparently Lophelia’s complex shape creates a physically different habitat, right down to the size of sediment grains. This coral also has more food available to support the animals. She emphasized that deep-sea corals actually have an influence beyond the reef; they foster a higher diversity of microscopic critters in the surrounding seafloor.
Kellogg focused in even closer: the microbes residing within these deep corals. The bacterial community in most corals was completely unknown. These microbes help cycle nutrients, and can both protect against and indicate disease; they are one way a coral adapts to its environment. She found only one bacterial group shared by all of them, and that the coral itself controlled which bacteria lived there. Having this basic knowledge is critical in the face of change during a climate change, or an oil spill.
Prouty looked within the coral matrix to show that its iodine levels could reveal the age of one of the oldest organisms on earth: the long-lived black coral (see “Gulf’s Mysterious Black Corals Are 2,000 Years Old”). This coral may live up to 4,000 years; iodine makes up about a quarter of its skeleton (see “Deep sea corals may be oldest living marine organism”). It’s a novel and inexpensive approach to carbon dating, which can be miscalculated for deepwater corals. That’s because corals may be influenced by seawater that has flowed deep below the surface for some time, and not reset its carbon clock to reflect the current carbon-dioxide levels at the surface.
The growing volume of knowledge used to conserve and manage these deeper ocean realms comes from many at this symposium. It was thus, an apt and rewarding surprise that the last day began with the announcement that President Obama decided to protect a patch of deep sea in the Atlantic—a first for this ocean (see “Presidential Proclamation -- Northeast Canyons and Seamounts Marine National Monument”). Many in the room had contributed the scientific support during the past 20 years for this “monumental” decision, which created the Northeast Canyons and Seamounts Marine National Monument. It would prohibit fishing and any other activities extracting the region’s resources. The announcement seemed to get at the heart of the week’s presentations by the USGS: the diversity of life in the Atlantic Ocean canyons provides a record of how our climate has been changing, and warrants protection (see “Obama Creates Atlantic Ocean’s First Marine Monument”).
The USGS co-sponsored the symposium with the Bureau of Ocean Energy Management (BOEM), the National Oceanic and Atmospheric Administration (NOAA), Woods Hole Oceanographic Institution (WHOI), and Temple University College of Science and Technology. Some of those sponsors have worked jointly on prior deep-sea coral projects. NOAA, USGS, and BOEM and other non-federal partners won three awards (see “Deepwater Canyon Study Among Projects Given Prestigious DOI Partners in Conservation Award”) recognizing their collaboration in Lophelia II (see “‘Atlantic Canyons’ Interagency Study Team Receives Excellence in Partnering Award” and “Pathways to the Abyss”). This federal trio and their partners will likely be in the running for yet another award for their new study in the Atlantic Ocean that began with a cruise to look at deep-sea environments off the coast of Virginia and the Carolinas in the fall of 2016 (see “Exploring Carolina Canyons: Mission Plan”).The backdrop for the next symposium in 2019 will be tropical Cartagena, Columbia, which won out over Scotland. Considering the environmental hurdles facing deepwater corals, and that impacts to them extend beyond just the reef, that conference promises to showcase a melting pot of revelations.
in this issue:
International Symposium on Deep-Sea Corals