More OCEAN EXPLORATION and UNDERSEA RESEARCH
and Undersea Research
NOAA, through its Fisheries, Ocean, and Research offices has recently
ramped up a major program on deep-sea coral research. This research has
a foundation spanning more than a century ago with the author Jules Verne
who described an underwater forest "composed of large treelike plants....with
branches of a shape I have never seen before" in his book 20,000 Leagues
Under the Sea. For at least 200 years people who have fished have
reported lines becoming entangled in deep-sea trees. These so called trees
are thickets of corals that provide essential fish habitat for fish and
other marine life. Unlike the shallow tropical coral reefs these corals
are found in dark frigid waters often beyond the continental shelf break
in many of the world's oceans.
Why are deep-sea corals important?
Only in the past two decades has there been an increase in the concern
and study of these corals because their importance was not generally recognized
nationally and internationally. These deep-sea trees of the seas can be
thousands of years old and have been found at depths ranging from 150
to 3,000 feet although some species range to 20,000 feet. These corals,
unlike the shallow water species, do not require symbiotic organisms and
sunlight to provide their energy needs. In contrast, these deep-sea corals
actively feed upon materials and nutrients in the water column. Deep-sea
corals basically come in two types—hard or stony corals—which are similar
to those found on tropical coral reefs and soft corals, which can be small
and delicate or very large (up to 9 feet) and tree-like. Specifically,
deep-sea corals are important for several reasons:
- Deep-sea corals have a critical ecological role in that much like
ancient forests they serve as habitat for a diversity of other organisms
including fish and invertebrate communities, including commercially
important fisheries species.
- They may serve as important indicators of past climates. Like terrestrial
trees, deep-sea corals add annual rings. While they are slow growing,
some specimens have been estimated to be nearly 2,000 years old. Non-living
corals have been carbon dated to be greater than 40,000 years old. In
addition, corals have a much better time resolution than sediment cores
and are unaffected by bioturbation.
- Deep-sea coral ecosystems provide a rich biodiversity and as such
are looked upon as a potential future source of novel bio-compounds
for development by the pharmaceutical and biotechnology industries.
NOAA should build on recent deep-sea coral meetings and workshops held
over the past year. These have included the Deep-Sea Corals Collaboration
Planning Meeting (11-2003 Tampa, FL), the Deep-Sea Corals Workshop (1-2003
Galway, Ireland), and the 2nd International Symposium on Deep-Sea Corals
(9-2003 Erlangen, Germany).
Critical information needs and research themes have emerged
from these sessions:
- Locating and mapping these corals, with a priority on U.S. deep-sea
coral habitats, which have been largely unmapped when compared to European
and Canadian coral habitats.
- A more comprehensive understanding of the biology and ecology of
deep-sea corals by conducting a species inventory, growth and reproductive
studies, and food web and species interaction studies.
- Understanding the uses of specific deep-sea species of corals as indicators
of climatic change.
Exploration and research of deep-sea corals are key to increasing
our understanding and improving the effective management of these unique
organisms. These studies should be multidisciplinary and utilize the unique
technologies and capabilities available to the research community.
Deep sea paragorgia
coral covered in zoanthids and a sea star, demonstrating the
beauty and diversity of life on the New England Seamounts.
This single colony of slow-growing Lophelia
pertusa coral was photographed during an OE-sponsored expedition
to the Gulf of Mexico in 2003. Lophelia requires a hard substrate
for attachment and growth, and this large boulder provided the necessary
This image of Callogorgia
coral with a solitary cup coral is from video footage of the
last ROV dive at Mississippi Canyon in the OE-sponsored cruise to
the Gulf of Mexico in 2003.
This large pink sea fan belongs to the genus Paragorgia.
This specimen is nearly two meters tall and is held in place by
a "holdfast" nearly 12 cm in diameter. It holds within its branches
a thriving community of brittle stars, crabs, and shrimp - giving
it the appearance of a well-decorated Christmas tree. This image
was taken during the OE-sponsored expedition to explore Gulf of
Alaska seamounts in 2002.