 Climate Change Mitigation Strategies Ignore Carbon Cycling Processes Of Inland Waters, Scientists Say
ScienceDaily (Sep. 1, 2009) — In a paper titled "The Boundless Carbon Cycle," published in the September issue of Nature Geoscience, scientists from the University of Vienna, Uppsala University in Sweden, University of Antwerp, and the U.S. based Stroud™ Water Research Center argue that current international strategies to mitigate manmade carbon emissions and address climate change have overlooked a critical player - inland waters. Streams, rivers, lakes, reservoirs, and wetlands play an important role in the carbon cycle that is unaccounted for in conventional carbon cycling models. The commentary comes just months before COP15, the December 2009 UN Climate
Change Conference in Copenhagen where representatives from 192 countries will
gather to decide upon a 2012 climate agreement that will succeed the "Kyoto
protocol."
Dr. Tom J. Battin of the department of Freshwater Ecology at the University
of Vienna and lead author of the paper states that "While inland waters
represent only 1% of the Earth's surface, their contribution to the carbon cycle
is disproportionately large, underestimated, and not recognized within the models
on which the Kyoto protocol was based."
The team of scientists points out that all current global carbon models consider
inland waters static conduits that transfer carbon from the continents to the
oceans. In reality, inland waters are dynamic ecosystems with the potential
to alter the fates of terrestrial carbon delivered to them including: burial
in sediments leading to long-term storage or sequestration; and metabolism in
rivers and subsequent outgassing of respired carbon dioxide to the atmosphere.
"Twenty percent of the continental carbon sequestration actually occurs
as burial in inland water sediments," said Dr. Lars Tranvik, Professor
of Limnology at Uppsala University in Sweden.
"River outgassing of respired carbon, contributes carbon to the atmosphere
in an amount equivalent to 13% of annual fossil fuel burning," said Dr.
Anthony K. Aufdenkampe, a scientist at the Stroud Water Research Center. Because
the amount of atmospheric carbon is well known and conservation of matter requires
a balanced global carbon budget, this previously unaccounted for source of carbon
to the atmosphere implies the existence of an additional continental carbon
sink such as higher rates of biomass accrual in forests. "A larger accumulation
of carbon in forest ecosystems that could offset the outgassing from rivers
would be more consistent with current independently-derived estimates of carbon
sequestration on the continents," said Dr. Sebastian Luyssaert of the department
of Biology at University of Antwerp in Belgium.
The authors feel that a Boundless Carbon Cycle – that accounts for carbon
transfers between the land-freshwater boundary, the freshwater-atmosphere boundary,
and regional boundaries within continents – presents opportunities and
challenges for scientists and policy makers alike. They stress the need for
collaborative scientific investigations augmented by new observatories and experimental
platforms for long-term research to improve insights into carbon cycles across
terrestrial and aquatic ecosystems. For policy makers, the authors note that
riverine transport presents a book keeping challenge as carbon in rivers that
escapes burial or outgassing flows downstream, traversing geographic regions
and political boundaries, and thus altering regionally based carbon accounts.
Source: ScienceDaily
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