PERU fishing with guts to report…
A new study suggests global warming may increase the upward movement of deep waters (upwelling) in current systems of various oceans around the world later this century, especially at high latitudes, and cause major changes in the marine biodiversity.
As the upwelling of cold, nutrient-rich waters is a driving force in marine productivity, the possibility exists to help improve some of the most important fisheries in the world.
However, the solar heating due to the greenhouse effect may also increase the persistence of “stratification”Or the horizontal stratification of ocean water of different temperatures. The result could be the formation of a warm layer near the surface and deeper cold layer.
If this occurs to a significant degree, could increase overall low oxygen-hypoxia-events, disengage the outcrop of water rich in nutrients and raise an important global role of Fisheries and Marine Ecosystems threat.
In other words, the expected increase in upwelling seems clear and definitive. But researchers say their biological impact is much less evident, which represents a considerable concern.
These systems upwelling cover less than 2% of the ocean surface, but contributes 7% of global marine primary production and 20% of the world catch of fish.
“Our model indicates that outcrops that are usually weaker towards the polar extremes of the Regions will be strengthened dominated by outcrops”Explains Bruce Menge, Professor of Marine Biology, Faculty of Sciences, Oregon State University and co-authored paper published Thursday in the journal Nature.
“Usually, one would expect an increase in the outcrops involve an increase in coastal marine productivity, and this could happen”, Agrega amount.
“However, later, an upper thicker and warmer and more stratified ocean waters may put cold water rich in nutrients too deep for them to climb, and reduce the ability of upwelling to boost food chain coastal ocean”Says the researcher. “This could have a very negative impact on production and marine fisheries.”
These findings were made by researchers at OSU and Northeastern University, as part of a work supported by the university and the National Science Foundation.
The study authors suggest that another possibility is that changes in the frequency or severity of the appearance of areas with low oxygen concentrations or hypoxic events such as those that have plagued the Pacific Northwest in the last decade occur. Depending on where the layers of hot and cold finished, and local underwater terrain and currents, hypoxia events could be much less frequent and more severe. At these events, phytoplankton blooms consume available oxygen, causing hypoxia and often lead to death of fish and other marine organisms.
Some key findings include:
-The Change in the outcrops may be more pronounced in the southern hemisphere, due to local influences of land masses, coasts, water depth and other issues.
-The Main current systems will be affected off the west coast of North America, South America, Africa and parts of Europe.
-The Overall increase in outcrops will be led by a strengthening winds along the coast due to a difference between global warming and ocean.
-In High latitudes, but not in the low season outcrops start earlier, last longer and be more intense.
-In Tropical and subtropical latitudes, outcrops become a phenomenon to be observed for most of the year.
-The Results are consistent with several studies showing that coastal upwelling have intensified in the last 60 years.
He expected impacts on the California Current are less pronounced due to the effect of other climatic, such as the Pacific Decadal Oscillation, the El Niño-Southern Oscillation and the North Pacific Gyre Oscillation forces.
The researchers argue that understanding these “hotspots” the outcrops driven by climate, and how they will change in the future, could help better manage productive fisheries and coastal ecosystems worldwide.
SOURCE: Fis.com
