Pacific islands on equator may become refuge for corals in a warming climate due to changes in ocean currents

Pacific islands on equator may become refuge for corals in a warming climate due to changes in ocean currents

The Future: Global climate models predict a sea surface temperature rise of nearly 3 degrees C (5.4 degrees F) by the end of the century. According to Karnauskas’s and Cohen’s fine-scale model, equatorial trade winds will weaken, causing a weakening of the surface current. In turn, the frictional drag on the EUC will lessen, and the EUC will strengthen, carrying more cool, nutrient-enriched water to the surface around the Gilbert Islands. The result will be enhanced productivity close to the islands, and slower warming during the coming century than neighboring islands not in the EUC’s path. The slower warming may allow corals to adapt and survive, making the Gilberts a refuge for coral reef ecosystems. (Credit: Illustration by Amy Caracappa_Qubeck, Woods Hole Oceanographic Institution

ScienceDaily (Apr. 29, 2012) — Scientists have predicted that ocean temperatures will rise in the equatorial Pacific by the end of the century, wreaking havoc on coral reef ecosystems. But a new study shows that climate change could cause ocean currents to operate in a surprising way and mitigate the warming near a handful of islands right on the equator. As a result these Pacific islands may become isolated refuges for corals and fish.

Under climate change, winners and losers on the coral reef

Under climate change, winners and losers on the coral reef

Coral on the Great Barrier Reef, Australia. (Credit: © StrangerView / Fotolia)

ScienceDaily (Apr. 12, 2012) — As ocean temperatures rise, some species of corals are likely to succeed at the expense of others, according to a report published online on April 12 in the Cell Press journal Current Biology that details the first large-scale investigation of climate effects on corals.

"The good news is that, rather than experiencing wholesale destruction, many coral reefs will survive climate change by changing the mix of coral species as the ocean warms and becomes more acidic," said Terry Hughes of James Cook University in Australia. "That's important for people who rely on the rich and beautiful coral reefs of today for food, tourism, and other livelihoods."

In an attempt to understand the sorts of changes that may take place as the world's oceans warm, the researchers examined the coral composition of reefs along the entire length of Australia's Great Barrier Reef. Earlier studies of climate change and corals have been done on a much smaller geographical scale, with a primary focus on total coral cover or counts of species as rather crude indicators of reef health.

"We chose the iconic Great Barrier Reef as our natural laboratory because water temperature varies by 8 to 9 degrees Celsius along its full length from summer to winter, and because there are wide local variations in pH," Hughes explained. "Its regional-scale natural gradients encompass the sorts of conditions that will apply several decades from now under business-as-usual greenhouse gas emissions."

In total, the researchers identified and measured more than 35,000 coral colonies on 33 reefs. Their survey revealed surprising flexibility in the assembly of corals. As they saw one species decline in abundance, some other species would tend to rise. The waxing or waning of any given coral species the researchers observed as they moved along the coastline occurred independently of changes to other coral species.

Hughes concludes that corals' response to climate change is likely to be more complicated than many had thought. Although he now believes that rising temperatures are unlikely to mean the end of the coral reef, critical issues remain.

"If susceptible table and branching species are replaced by mound-shaped corals, it would leave fewer nooks and crannies where fish shelter and feed," he said. "Coral reefs are also threatened by much more local impacts, especially by pollution and overfishing. We need to address all of the threats, including climate change, to give coral reefs a fighting chance for the future."

Evolution at sea: Long-term experiments indicate phytoplankton can adapt to ocean acidification

Emiliania huxleyi cells in an electro-microscopic picture. (Credit: Lennart Bach, GEOMAR)

Evolution at sea: Long-term experiments indicate phytoplankton can adapt to ocean acidification

ScienceDaily (Apr. 8, 2012) — Fossil fuel derived carbon dioxide has a serious impact on global climate but also a disturbing effect on the oceans, know as the other CO₂ problem. When CO₂ dissolves in seawater it forms carbonic acid and results in a drop in pH, the oceans acidify. A wealth of short-term experiments has shown that calcifying organisms, such as corals, clams and snails, but also micron size phytoplankton are affected by ocean acidification. The potential for organisms to cope with acidified oceanic conditions via evolutionary adaptations has so far been unresolved.

New Comparison of Ocean Temperatures Reveals Rise Over the Last Century

Argo's 3,500 ocean-profiling robots blanket the world's oceans. 

(Credit: Image courtesy of Scripps Institute of Oceanography)

ScienceDaily (Apr. 1, 2012) — A new study contrasting ocean temperature readings of the 1870s with temperatures of the modern seas reveals an upward trend of global ocean warming spanning at least 100 years.

The research led by Scripps Institution of Oceanography at UC San Diego physical oceanographer Dean Roemmich shows a .33-degree Celsius (.59-degree Fahrenheit) average increase in the upper portions of the ocean to 700 meters (2,300 feet) depth. The increase was largest at the ocean surface, .59-degree Celsius (1.1-degree Fahrenheit), decreasing to .12-degree Celsius (.22-degree Fahrenheit) at 900 meters (2,950 feet) depth

Carbon dioxide was hidden in the ocean during last Ice Age

Example of an icecore from 2590 metres depth, which is more than 150 000 years old. It is divided into pieces of one metre each for further analysis in the laboratory. Diametre of the icecore: 10 cm. (Credit: Hans Oerter, Alfred Wegener Institute)

Carbon dioxide was hidden in the ocean during last Ice Age

http://www.sciencedaily.com/releases/2012/03/120329142020.htm

Um documentário sobre o processo de acidificação dos oceanos.

 
Its all about where all  the PLASTIC goes in our daily lives !
Well made and won the 2010 Blue Ocean film festival.