DISCOVRE: Diversity, Systematics and Connectivity of Vulnerable Reef Ecosystems

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DISCOVRE (DIversity, Systematics and COnnectivity of Vulnerable Reef Ecosystems) is an integrated, multidisciplinary, international effort investigating the unique and fragile deep-sea coral environments from the microscopic level to the ecosystem level. 

The Deep Sea

The deep sea refers to anything below 200 m depth in the ocean; beyond this depth, little to no sunlight reaches, temperatures drop, and pressure increases. Yet, life persists. Diverse environments, such as trenches, canyons, volcanoes, and seamounts, scattered over the seafloor are home to a diversity of fishes, crustaceans, anemones, sea stars, and corals.

Deep-sea corals are as colorful and diverse as their shallow-water counterparts, however, because of the lack of sunlight, deepwater corals obtain energy by using their tentacles to capture prey rather than through photosynthesis. Deep-sea coral reefs provide food and shelter for marine life, including commercially and recreationally important species, and play a critical role in the aquatic food web. 

To better understand these little explored yet vital deep-sea coral reef ecosystems, USGS scientists from around the Nation contribute their expertise to the DISCOVRE effort. The multi-disciplinary approach examines components of microbiology, population genetics, paleoecology, food webs, taxonomy, community ecology, physical oceanography, seafloor characteristics, and submarine hazards. DISCOVRE relies on a network of partners from around the country and world, including the Bureau of Ocean Energy Management, National Oceanic and Atmospheric Administration (NOAA), and academic institutions. Using innovative tools and technologies, USGS scientists implement a multi-faceted research program that weaves together expertise in a variety of disciplines to investigate deepwater reefs.

 

Image shows a push core in the ocean sediment

The ROV SuBastian inserts a push core into the seafloor sediments of Astoria Canyon off the coast of Oregon. (Credit: Shelton Du Preez, Schmidt Ocean Institute)

Benthic Ecology

Benthic ecology is the term scientists use to describe the study of the animals living in or on the bottom of a water body. As part of the DISCOVRE project, the Benthic Ecology Group conducts research to understand community structure, biodiversity, trophic structure, and habitat connectivity of marine benthic ecosystems. The work involves examining the animals living in and on the seafloor in a variety of natural and artificial marine habitats:

  • deep-sea and shallow-water corals,
  • chemosynthetic seeps,
  • shipwrecks,
  • marine canyons, and
  • wetland communities.

 

processing sidescan data

USGS geologist Jason Chaytor processes sidescan data from an AUV Sentry dive. (Image courtesy of DEEP SEARCH 2017, NOAA-OER/BOEM/USGS)

 

Marine Geology and Geophysics

Geology and geophysics refer to the study of physical structure and associated processes occurring on the planet. The USGS marine geology and geophysics team maps seafloor morphology and images the shallow sub-seafloor structure of the canyons, plateaus, and other components of the deep-sea landscape to better understand the processes that form and shape these features. Sampling sediment and rocks allows scientists to ground truth geophysical and visual observations, while providing valuable information about the composition and age of these underwater geologic environments.

 

bacterial mat at Pea Island B site

AUV Sentry captured this image of an extensive bacterial mat (white areas). The bacteria thrive off of gases that seep up through the seafloor.

(Credit: AUV Sentry. Image courtesy of DEEP SEARCH 2017, NOAA-OER/BOEM/USGS)

 

Microbial Ecology

Microbial ecology is the study of microbes (bacteria, archaea, fungi, viruses), how they interact with each other, their host (if they are living on/in a plant or animal), and their environment.

Microbes are responsible for important ecosystem services, including biogeochemical cycling, nutrient availability, and structuring ecosystems by providing settlement cues to some invertebrates. Microbial associates have been shown to be key players in coral biology, serving functions such as fixing nitrogen, chelating iron, cycling waste products, and producing antibiotics to keep unwanted microbes from infecting the coral.

USGS identifies, characterizes, and enumerates environmental microbial communities, which are critical components of healthy marine ecosystems such as coral reefs, chemosynthetic seeps, and submarine canyons, with focus on coral microbiomes (both shallow and deep-sea), ecosystem metagenomics, and biodiversity.

Characterizing the microbial communities associated with deep-sea corals in these environments will increase the knowledge of the biodiversity in these ecosystems and provide insight into the variability or uniqueness of the corals between deep-sea environments.

 

 

Image: Black Coral Growth Rings

Scanning Electron Microscope photograph of growth rings in black coral from the Gulf of Mexico.

Paleoclimatology

Paleoclimatology is the study of past climates using evidence found in a variety of the Earth's surfaces. USGS scientists are using long-lived black corals as archives to determine the climate and ocean chemistry over hundreds to thousands of years. Deep-sea corals are extremely useful in determining past climates, and recent developments in coral sampling techniques, as well as the ability to study corals in a wide variety of geographic areas, has increased the value of using deep-sea corals for climate change studies. Coral skeletons have rings, similar to trees, that help scientists determine environmental cycles and ocean variability.

 

Lophelia pertusa coral

Lophelia pertusa coral

 

Population Genetics

Population genetics is the study of genetic variation within and between populations. Understanding how the biodiversity of corals and other invertebrates is distributed throughout the deep-sea environment can help guide management of sensitive species, especially in areas of interest to oil and gas exploration. USGS uses genetic tools to characterize biodiversity and local and regional patterns of genetic connectivity among deep-sea coral habitats.

 

 

 

For more information:

CSA Ocean Sciences Inc. Ross S, Brooke S, Baird E, Coykendall E, Davies A, Demopoulos A, France S, Kellogg C, Mather R, Mienis F, Morrison C, Prouty N, Roark B, Robertson C. 2017. Exploration and Research of Mid-Atlantic Deepwater Hard Bottom Habitats and Shipwrecks with Emphasis on Canyons and Coral Communities: Atlantic Deepwater Canyons Study. Draft Report. Sterling (VA): U.S. Dept. of the Interior, Bureau of Ocean Energy Management, Atlantic OCS Region. OCS Study BOEM 2017-060. 1,000 p. + apps.