15 December 2000
Geophysical Union Fall Meeting
Media Contact: Debbie Meyer, AGU press room, Dec. 15-19,
(415) 905-1007 or
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Scientists study the effects of carbon dioxide
sequestration on deep-sea animals
SAN FRANCISCO, California—Scientists at the Monterey Bay Aquarium
Research Institute (MBARI) have recently begun a series of novel
experiments to address the potential biological impacts of deep-sea carbon
dioxide sequestration. Initial results of these studies will be presented
by MBARI scientist Mario Tamburri at the Fall 2000 meeting of the American
Geophysical Union in San Francisco.
As international political interest increases for disposing of
human-generated excess carbon dioxide in the ocean, scientists play a
critical role for decision-makers in providing the necessary experimental
data on its impacts. Previously, only theoretical models and shallow water
studies have been available for estimating the possible effects of carbon
dioxide storage on deep-sea biota. Tamburri and his colleagues have
devised new field experiments, using MBARI's remotely operated vehicles,
to make the first empirical observations.
The first field experiments were conducted in the summer of 1998 on the
Monterey Canyon seafloor at a depth of 625 meters. MBARI's ROV Ventana
was instrumented with a pH sensor and a special odor/carbon dioxide
release rig that were used to test the responses of mobile animals to
dissolving carbon dioxide hydrates—an ice-like form of the gas that
occurs naturally at low temperatures and high pressures. The researchers
created these hydrates by injecting liquid CO2 into a beaker.
The ROV released an odor solution to attract mobile deep-sea animals to
the beaker and its dissolving hydrates. The interactions of animals—sablefish,
hagfish, dover sole, urchin, and snail—were recorded on video and
analyzed in the laboratory. The tests revealed some surprises.
"Previous work assumed that animals encountering the carbon
dioxide-rich waters would avoid the solution due to the correspondingly
low pH of the water," said Tamburri. "Instead, the animals
continued to be attracted by the odor solution."
Testing another possible carbon dioxide disposal scenario, the
scientists repeated similar experiments at a depth of 250 meters using a
carbon dioxide-saturated solution. An instrument on Ventana
released a fish odor solution into the water to attract fish. In this
study, the animals would come in brief contact with the CO2-saturated
odor solution, back away, then return.
To address questions about the effects of carbon dioxide disposal on
deep-sea benthic communities, MBARI scientists began new experiments last
spring using ROV Tiburon at a depth of 2,995 meters. Their
preliminary tests have helped them develop the tools that will be used for
follow-on studies next year.
While many of the initial results in these experiments were unexpected,
the biological impacts of carbon dioxide disposal on the deep sea may be
relatively benign, according to Tamburri, particularly when compared to
other human impacts on the ocean. But clearly there is much more work to
"Our initial work has established the methodologies needed to
examine questions about the ecological effects of deep sea carbon dioxide
disposal options. We've gained important new insight into the factors that
must be considered before the feasibility of ocean CO2 disposal
can be evaluated completely," said Tamburri.
Related sessions at AGU 2000 Fall Meeting
B11D-07, Monday 10:20, MC 103
Brewer, et al. Progress in direct experiments on the ocean
disposal of fossil fuel CO2.
B22C-08, Tuesday 15:45, MC 103
Tamburri, et al. Determining the effects of carbon dioxide ocean
disposal on deep-sea organisms.
Tamburri, et al. A field study of the effects of CO2
ocean disposal on mobile deep-sea animals. Marine Chemistry 72 (2000)
Brewer, et al. Direct Experiments on the Ocean Disposal of Fossil Fuel
CO2. Science, 7 May 1999, 284: 943-945.