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February 2012 Issue

pH Sensors Reveal Unexpectedly High Ocean Acidification Levels
Using data gathered from pH sensors, researchers have found that some areas of the ocean are already experiencing daily acidification levels that scientists had predicted would not be reached until 2100. The study, conducted by 19 researchers from five research organizations, was published in PLoS One in December.

"These data represent a critical step in understanding the consequences of ocean change: The linkage of present-day pH exposures to organismal tolerance and how this translates into ecological change in marine ecosystems," the authors wrote.

Acidification leads to increasing amounts of carbonic acid in seawater and limits the amount of carbonate forms that are needed by marine invertebrates such as coral and shelled organisms to form their skeletons. Though many lab simulations of this effect have been performed, there have been few comparable field studies.

The researchers used SeaFET and SeapHOx sensors, which were developed by marine chemistry researcher Todd Martz, to survey 15 ocean regions ranging from coral reefs in the South Pacific Ocean to volcanic CO2 vent communities in the Mediterranean Sea. Capable of measuring pH and temperature in the top 70 meters of the ocean, the sensors are based on a modified Honeywell DuraFET ISFET pH sensor. SeapHOx contains additional integrated sensors: AADI's (Bergen, Norway) Oxygen Optode 3835 and Sea-Bird Electronics Inc.'s (Bellevue, Washington) SBE-37.

The researchers found that in some areas, such as Antarctica and the Line Islands in the central Pacific, the range of pH variance is more limited than in areas of the California coast subject to large vertical movements of water known as upwellings. Despite surveying 15 ocean regions, the authors noted that they only made observations on coastal surface oceans and that more study is needed in deeper ocean regions farther away from land.

"I am really excited about the prospect of adding these sensors to mobile autonomous platforms like profiling floats, gliders and drifters. ... I think you can expect to see a pH sensor sending back data from an Argo-type profiling float at some point in 2012," Martz said. For more information, visit www.plosone.org.

AUV Deployments Yield Discovery Of Species in Deep-Sea Vents
By deploying the Autosub6000 and HyBIS AUVs, scientists have discovered new species, including eyeless shrimp with a light-sensing organ on their back and snake-like fish, in deep-sea vents that are located 0.8 kilometers deeper than any explored before. These volcanic "black smoker" vents are located 5 kilometers deep in a rift in the Caribbean seafloor, a team of scientists from the National Oceanography Centre reported in Nature Communications in January.

During an expedition in April 2010 aboard the Royal Research Ship James Cook, scientists deployed the center's Autosub6000 and HyBIS, which was manufactured by Hydro-Lek (Berkshire, England).

Although scientists were unable to measure the temperature of the vents directly, the undersea vents may be hotter than 450° C. The vents are gushing hot fluids that are unusually rich in copper and shooting a jet of mineral-laden water four times higher into the ocean above than other deep-sea vents, the researchers said.

Despite these extreme conditions, the team found thousands of the eyeless shrimp with light-sensing organs on their backs in hordes of up to 2,000 shrimp per square meter. The team also saw hundreds of white-tentacled anemones lining cracks where warm water seeps from the seabed. For more information, visit www.noc.soton.ac.uk.

CSA Initiates Seabed Restoration Program
CSA International Inc. (Stuart, Florida) has begun developing a remediation methodology for use with marine sediments that have been subjected to excessive loading with organic compounds, especially in deepwater environments where biodegradation processes are slowed due to low temperatures, the company announced in January.

CSA has completed a concept design that incorporates proven subsea technologies modified to deploy specific tools developed by the program.

"By combining proven ROV tooling technology with the application of known biological compounds, we're able to positively effect the remediation of marine sediments, speeding up its natural recovery," said Kevin Peterson, president and CEO of CSA.

The second phase of development includes a pilot study that will evaluate the efficacy of a prototype in a lab. The third phase will build and test the full-size tooling required to be deployed by ROVs of opportunity, CSA said. For more information, visit www.csaintl.com.

Coral Reef Disease Hits Hawaii
Rice coral (Montipora capitata) in Kaneohe Bay in Oahu, Hawaii, have been affected with an outbreak of a coral reef disease called Montipora White Syndrome, the U.S. Geological Survey (USGS) reported in January.

The rice coral are important to Hawaii's marine ecosystems because they are one of the more abundant coral reef species in the region, USGS said. The loss of this coral can have negative effects on other reef-related organisms.

The University of Hawaii and USGS have been investigating the outbreak and collecting samples for laboratory analysis. The scientists are trying to determine the outbreak's extent, since coral diseases have the potential to be widespread. This particular disease, however, seems limited to south Kaneohe Bay, USGS said.

Montipora White Syndrome involves a loss of tissue from the rice coral until the underlying white skeleton is revealed or exposed, hence the name "white syndrome."

Based on surveys carried out since 2006 by the University of Hawaii and USGS, Montipora White Syndrome has historically been documented in coral reefs in Kaneohe Bay, albeit at low levels with scattered, isolated colonies affected.

Large-scale outbreaks involving multiple coral colonies over a larger geographic area have only been documented since March and this more recent event. For more information, visit www.usgs.gov.


2013:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC
2012:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY | AUG | SEPT | OCT | NOV | DEC

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