equilibrates with carbonate sediments, but over a
much longer time, about 6000 years. Technical
means could also be used to bypass this timescale,
thereby increasing the effectiveness and diminishing
the environmental impacts of intentional storage of
carbon dioxide in the ocean. For example, CO 2
reacts with carbonate sediments to form bicarbonate
ions (HCO 3
À ) as indicated by eqn [2]. Power plant
CO 2 could be dissolved in seawater, then reacted
with crushed limestone, either at the power plant or
at the point of release, thus minimizing changes in
plume pH. Or an emulsion of liquid CO 2 -in-water
could be stabilized by fine particles of pulverized
limestone; the emulsion would be sufficiently dense
to form a sinking plume, whose pH change would be
buffered by the limestone. Drawbacks of these approaches include the cost to mine and transport large
quantities of carbonate minerals.
Local Environmental Impacts and
Public Perception
Environmental impacts may be the most significant
factor determining the acceptability of ocean storage,
since the strategy is predicated on the notion that
impacts to the ocean will be significantly less than the
avoided impacts of continued emission to the atmosphere. Earlier, environmental impacts were discussed from the global viewpoint. Here, we examine
the environmental impacts near the injection point.
A number of studies have summarized potential
impacts to different types of organisms, including
adult fish, developmental fish, zooplankton, and
benthic fauna. While earlier studies focused mainly
on lethal impacts to coastal fauna exposed to strong
acids, recent data have focused on deep-water organisms exposed to CO 2 , and have included sublethal effects. Impacts include respiratory stress
(reduced pH limits oxygen binding and transport of
respiratory proteins), acidosis (reduced pH disrupts
an organism’s acid/basis balance), and metabolic
depression (elevated CO 2 causes some animals to
reach a state of torpor).
Data generally show that CO 2 causes greater stress
than an equivalent change in pH caused by a different
acid, that there are strong differences in tolerance
among different species and among different life stages
of the same species, and that the duration of stress, as
well as the level of stress, are important. While some
studies imply that deep organisms would be less tolerant than surface organisms, other studies have found
the opposite. Likewise, some animals are able to avoid
regions of high CO 2 concentration, while others appear less able to. Results generally suggest that lethal
effects can be avoided by achieving high near-field
dilution. However, more research is needed to resolve
impacts, especially at the community level (e.g., reduced lifespan and reproduction effects).
The viability of ocean storage as a greenhouse gas
mitigation option hinges on social, political, and
regulatory considerations. In view of public precaution toward the ocean, the strategy will require
that all parties (private, public, nongovernmental
organizations) be included in ongoing research and
debate. But the difficulty in this approach is highlighted by the recent experience of an international
research team working on ocean carbon sequestration research. A major part of their collaboration
was to have included a field experiment involving
release of 5 t of CO 2 off the coast of Norway. Researchers would have monitored the physical,
chemical, and biological effects of the injected CO 2
over a period of about a week. However, lobbying
from environmental groups caused the Norwegian
Minister of Environment to rescind the group’s permit that had previously been granted. Such actions
are unfortunate, because field experiments of this
type are what is needed to produce data that would
help policymakers decide if full-scale implementation
would be prudent.
See also
Air–Sea Transfer: Dimethyl Sulfide, COS, CS 2 , NH 4 ,
Non-Methane Hydrocarbons, Organo-Halogens.
Air–Sea Transfer: N 2 O, NO, CH 4 , CO. Carbon
Cycle. Carbon Dioxide (CO 2 ) Cycle. Ocean Carbon
System, Modeling of.
Further Reading
Alendal G and Drange H (2001) Two-phase, near field
modeling of purposefully released CO 2 in the ocean.
Journal of Geophysical Research 106(C1): 1085--1096.
Brewer PG, Peltzer E, Aya I, et al. (2004) Small scale field
study of an ocean CO 2 plume. Journal of Oceanography 60(4): 751--758.
Caldeira K and Rau GH (2000) Accelerating carbonate
dissolution to sequester carbon dioxide in the ocean:
Geochemical implications. Geophysical Research
Letters 27(2): 225--228.
Caldeira K and Wickett ME (2003) Anthropogenic carbon
and ocean pH. Nature 425: 365.
Giles J (2002) Norway sinks ocean carbon study. Nature
419: 6.
Golomb D, Pennell S, Ryan D, Barry E, and Swett P (2007)
Ocean sequestration of carbon dioxide: Modeling the
deep ocean release of a dense emulsion of liquid
CO 2 -in-water stabilized by pulverized limestone
320 CARBON SEQUESTRATION VIA DIRECT INJECTION INTO THE OCEAN
much longer time, about 6000 years. Technical
means could also be used to bypass this timescale,
thereby increasing the effectiveness and diminishing
the environmental impacts of intentional storage of
carbon dioxide in the ocean. For example, CO 2
reacts with carbonate sediments to form bicarbonate
ions (HCO 3
À ) as indicated by eqn [2]. Power plant
CO 2 could be dissolved in seawater, then reacted
with crushed limestone, either at the power plant or
at the point of release, thus minimizing changes in
plume pH. Or an emulsion of liquid CO 2 -in-water
could be stabilized by fine particles of pulverized
limestone; the emulsion would be sufficiently dense
to form a sinking plume, whose pH change would be
buffered by the limestone. Drawbacks of these approaches include the cost to mine and transport large
quantities of carbonate minerals.
Local Environmental Impacts and
Public Perception
Environmental impacts may be the most significant
factor determining the acceptability of ocean storage,
since the strategy is predicated on the notion that
impacts to the ocean will be significantly less than the
avoided impacts of continued emission to the atmosphere. Earlier, environmental impacts were discussed from the global viewpoint. Here, we examine
the environmental impacts near the injection point.
A number of studies have summarized potential
impacts to different types of organisms, including
adult fish, developmental fish, zooplankton, and
benthic fauna. While earlier studies focused mainly
on lethal impacts to coastal fauna exposed to strong
acids, recent data have focused on deep-water organisms exposed to CO 2 , and have included sublethal effects. Impacts include respiratory stress
(reduced pH limits oxygen binding and transport of
respiratory proteins), acidosis (reduced pH disrupts
an organism’s acid/basis balance), and metabolic
depression (elevated CO 2 causes some animals to
reach a state of torpor).
Data generally show that CO 2 causes greater stress
than an equivalent change in pH caused by a different
acid, that there are strong differences in tolerance
among different species and among different life stages
of the same species, and that the duration of stress, as
well as the level of stress, are important. While some
studies imply that deep organisms would be less tolerant than surface organisms, other studies have found
the opposite. Likewise, some animals are able to avoid
regions of high CO 2 concentration, while others appear less able to. Results generally suggest that lethal
effects can be avoided by achieving high near-field
dilution. However, more research is needed to resolve
impacts, especially at the community level (e.g., reduced lifespan and reproduction effects).
The viability of ocean storage as a greenhouse gas
mitigation option hinges on social, political, and
regulatory considerations. In view of public precaution toward the ocean, the strategy will require
that all parties (private, public, nongovernmental
organizations) be included in ongoing research and
debate. But the difficulty in this approach is highlighted by the recent experience of an international
research team working on ocean carbon sequestration research. A major part of their collaboration
was to have included a field experiment involving
release of 5 t of CO 2 off the coast of Norway. Researchers would have monitored the physical,
chemical, and biological effects of the injected CO 2
over a period of about a week. However, lobbying
from environmental groups caused the Norwegian
Minister of Environment to rescind the group’s permit that had previously been granted. Such actions
are unfortunate, because field experiments of this
type are what is needed to produce data that would
help policymakers decide if full-scale implementation
would be prudent.
See also
Air–Sea Transfer: Dimethyl Sulfide, COS, CS 2 , NH 4 ,
Non-Methane Hydrocarbons, Organo-Halogens.
Air–Sea Transfer: N 2 O, NO, CH 4 , CO. Carbon
Cycle. Carbon Dioxide (CO 2 ) Cycle. Ocean Carbon
System, Modeling of.
Further Reading
Alendal G and Drange H (2001) Two-phase, near field
modeling of purposefully released CO 2 in the ocean.
Journal of Geophysical Research 106(C1): 1085--1096.
Brewer PG, Peltzer E, Aya I, et al. (2004) Small scale field
study of an ocean CO 2 plume. Journal of Oceanography 60(4): 751--758.
Caldeira K and Rau GH (2000) Accelerating carbonate
dissolution to sequester carbon dioxide in the ocean:
Geochemical implications. Geophysical Research
Letters 27(2): 225--228.
Caldeira K and Wickett ME (2003) Anthropogenic carbon
and ocean pH. Nature 425: 365.
Giles J (2002) Norway sinks ocean carbon study. Nature
419: 6.
Golomb D, Pennell S, Ryan D, Barry E, and Swett P (2007)
Ocean sequestration of carbon dioxide: Modeling the
deep ocean release of a dense emulsion of liquid
CO 2 -in-water stabilized by pulverized limestone
320 CARBON SEQUESTRATION VIA DIRECT INJECTION INTO THE OCEAN