by Playfuls Staff |
2nd November 2006
Marine species loss is
accelerating and threatening human well-being, according to a report published
in the 3 November issue of the journal Science published by AAAS, the nonprofit
science society. "Species have been disappearing from ocean ecosystems and
this trend [more] has recently been accelerating," said lead author Boris
Worm. "Now we begin to see some of the consequences. For example, if the
long-term trend continues, all fish and seafood species are projected to
collapse within my lifetime -- by 2048." Worm is an assistant professor of
marine conservation biology at
Dalhousie
University,
Halifax, Canada.
In the paper "Impact of
Biodiversity Loss on Ocean Ecosystem Services," an international team of
ecologists and economists studied the role marine biodiversity plays in
maintaining ecosystem services, which are those goods and functions that are
essential for the growing human population.
"Worm and colleagues have
provided the first comprehensive assessment of thestate of ecosystem services
provided by the biodiversity of the world's oceans to humanity," said
Science International Managing Editor Andrew Sugden. "The news is both bad
and good.
"The strength of this paper
lies in the breadth of the array of information the authors used for their
analysis; they not only used new experimental data and recent data, they also
delved into historical archives to assess the impact of humans on marine
ecosystem overdecades and centuries," Sugden said.
"At this point," Worm
said, "29 percent of fish and seafood species have collapsed -- that is
their catch has declined by 90 percent. It is a very clear trend, and it is
accelerating. We don't have to use models to understand this trend; it is based
on all the available data."
Researchers also determined that
the problem is much greater than losing a key source of food. Damage to the
oceans impact not only fisheries, but the ocean ecosystem's overall
productivity and stability. Specific services that have declined involve the
maintenance of water quality by biological filtering, the provision of nursery
habitats and the protection of shorelines by marine species. The loss of marine
diversity also appeared to increase the risks of beach closures, harmful algal
blooms (red tide, for example), oxygen depletion, fish kills and coastal
flooding.
"The good news is that it is
not too late to turn things around," Worm said. The scientists studied 48
areas worldwide that have been protected to improve marine biodiversity.
"We see that diversity of species recovered dramatically, and with it the
ecosystem's productivity and stability."
Researchers studied a variety of
information in four meta-analyses, progressing from local to regional and
global scales.
First, they analyzed 32 marine
experiments that manipulated species diversity on small, local scales, and
monitored the effects. Second, researchers tracked the 1,000-year-long history
of change in species diversity and associated services across 12 coastal
regions around the world. These included Chesapeake, Delaware, Massachusetts,
Galveston, San Francisco Bay and Pamlico Sound (all U.S.), The Bay of Fundy and
Gulf of St. Lawrence (Canada), The Adriatic, Baltic and North Seas (Europe), as
well as Moreton Bay (Australia). Sources included archives, fishery records,
sediment cores and archeological data.
Then, the team compiled global
fisheries catch data from 64 large marine ecosystems to test for the effects of
large-scale species loss on fisheries-related services. They used the fisheries
database compiled by the United Nations Food and Agriculture Organization and
the Sea Around Us Project at the Fisheries Centre, University of British
Columbia. Finally, the scientists investigated
how recovery of biodiversity in 48 marine protected areas -- reserves and
fishery closures -- affected the recovery of services.
The researchers were surprised to
find very similar relationships between biodiversity change and ecosystem
services at scales ranging from small square-meter plots to entire ocean
basins, Worm said. "This suggests that small-scale experiments can be used
to predict large-scale ocean change.
"Through this research, it
became clear to me that we hardly appreciate living on a blue planet,"
Worm said. "The oceans define our planet, and their fate may to a large
extent determine our fate, now and in the future."
