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Ocean Research

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July 2016 Issue

Acoustic Devices
Track Equipment

Attempting to relocate underwater objects in open ocean or a low-visibility environment can be a difficult and time consuming task. Acoustic pingers and transponders solve this problem. These acoustic devices are being employed by many marine scientists and researchers to keep track of expensive oceanographic equipment, enabling instruments to be quickly relocated and retrieved.

Examples include recent research by Scripps Institution of Oceanography (SIO) in the Cayman Islands on the spawning behavior of the Nassau grouper using an array of hydrophones whose position was marked with a JW Fishers SFP-1 acoustic pinger.

The Prince William Sound Science Center in Cordova, Alaska, also ensures their oceanographic instruments can be safely recovered if lost by using an SFP-1.

In addition, the Naval Engineering and Test Establishment (NETE) in Lasalle, Quebec, the Royal Canadian Navy’s principal test and evaluation center, is using several of Fishers’ MLFP-1 low-frequency pingers to deploy mobile equipment in the open ocean.


Europa Could Have
Right Conditions for Life

A new study finds the ocean of Jupiter’s moon Europa could have the necessary balance of chemical energy for life, even if the moon lacks volcanic hydrothermal activity, the American Geophysical Union reported.

Europa is strongly believed to hide a deep ocean of salty liquid water beneath its icy shell. Whether it has the raw materials and chemical energy in the right proportions to support biology is a topic of intense scientific interest.

The study compared Europa’s potential for producing hydrogen and oxygen with that of Earth, through processes that do not directly involve volcanism. The balance of these two elements is a key indicator of the energy available for life. The study found that the amounts would be comparable in scale; on both worlds, oxygen production is about 10 times higher than hydrogen production.

NASA is currently formulating a mission to explore Europa and investigate the moon’s potential habitability.


Drones Detect Sharks
Along the Coast

Researchers from Duke University and UNC-Chapel Hill are testing the ability of drones to detect sharks in coastal waterways. In a collaborative study funded by North Carolina Aquariums, the researchers are examining whether drones can effectively pinpoint bonnethead sharks in different habitats and water conditions.

Over the past year, researchers have conducted experiments using decoy sharks and found that the drones have been able to reliably detect the decoys.

Researchers plan to expand their detection surveys into other types of habitats to see how well the drones perform. Ultimately they’d like to set up a framework that would allow other researchers to use drones to detect any type of shark in any coastal area.

The drone-detection method could eventually help alert swimmers to the presence of a shark.


Healy Heads Out
For Arctic Research

The crew of Coast Guard Cutter Healy departed for a four-month deployment to the Arctic Ocean to carry out scientific research. The crew will primarily conduct three missions focusing on the biology, chemistry, geology and physics of the Arctic Ocean and its ecosystems, as well as perform multibeam sonar mapping of the Extended Continental Shelf (ECS).

For the first mission, the crew will work with 46 researchers from NOAA and University of Alaska-Anchorage. The mission will employ the ROV Global Explorer, net trawls, bottom cores and conductivity, temperature and depth casts to assess the biological diversity of the Chukchi Sea. The team of scientists will use cutting-edge technology to identify and document the species living in this poorly understood and rapidly changing region.

The crew will also deploy an array of acoustic bottom moorings in support of researchers from Scripps Institution of Oceanography and the Office of Naval Research. The moorings will collect data on how climate change and decreased ice coverage is affecting the Arctic Ocean.

The final mission is funded by NOAA in support of the State Department and the White House Office of Science and Technology. Researchers from the University of New Hampshire will use multibeam sonar mapping and bottom dredging in the Bering Sea and Arctic Ocean to further support the demarcation of the ECS.

This work will directly support the United States’ claim for natural resources found on or beneath the ocean floor.


Parrotfish Deadly to
Stressed Coral Reefs

In a three-year effort to understand the effects of known stressors such as overfishing and nutrient pollution on coral reefs, scientists made a totally unexpected finding: a normally healthy interaction between fish and coral had turned deadly.

In typical conditions, parrotfish—like many other species—are essential to the health of coral reefs, nibbling at them to remove algae while causing no permanent damage. However, a new study conducted by UC Santa Barbara field ecologist Deron Burkepile and colleagues in the Florida Keys found that 62 percent of corals weakened by nitrogen and phosphorus pollution died when parrotfish bit them.

The researchers found that multiple local stressors combined with warming ocean temperatures weaken corals to such an extent that opportunistic pathogens build to deadly levels.

Their three-year experiment simulated both overfishing and nutrient pollution on a coral reef. They built exclosures to keep herbivorous fishes away from corals; in some reef areas, they added nutrients to mimic nutrient pollution in order to understand the relative roles of each scenario.

The findings make it clear that in the face of rising ocean temperatures, some of the best opportunities to protect coral reefs lie in careful management of fishing and protection of water quality.



2016:  JAN | FEB | MARCH | APRIL | MAY | JUNE | JULY
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Sea Technology is read worldwide in more than 110 countries by management, engineers, scientists and technical personnel working in industry, government and educational research institutions. Readers are involved with oceanographic research, fisheries management, offshore oil and gas exploration and production, undersea defense including antisubmarine warfare, ocean mining and commercial diving.