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Ocean Research


December 2013 Issue

Wind Turbine Configuration Combines Two Approaches
Staggering and spacing out turbines in an offshore wind farm can improve performance up to 33 percent, according to the University of Delaware's Atmosphere and Energy Research Group.

The researchers used a wind farm offshore Sweden and compared its tightly packed grid layout to six other configurations.

Computer-intensive simulations took into account the impact of downwind eddies created by wind turbines on surrounding turbines. The most efficient arrangement turned out to be spacing the turbines farther apart and staggering the rows, which decreased losses caused by eddies and improved overall performance by one-third.

The best configuration had the rows facing the prevailing wind direction, which typically changes from season to season in most locations. Considering these various factors could help in planning the location and configuration of future offshore wind farms.

Scientists Study Effect Of Data Tags on Dolphins
Researchers from Woods Hole Oceanographic Institution (WHOI) and Texas A&M University-Corpus Christi are working with dolphins and their trainers at Dolphin Quest at The Kahala Hotel and Resort in Oahu to determine the effect of data-logging tags on marine mammals.

'This research at Dolphin Quest gave us a unique opportunity to evaluate the metabolic cost of marine mammal suction cup data tags in a controlled environment,' said Michael Moore, director of the Marine Mammal Center at WHOI. 'The dolphins work with the humans who care for them to generate data that are impossible to obtain from animals in the wild.'

Marine animals have a low-drag body shape, close to the optimal hydrodynamic design. Attaching data tags to the animals could cause them to use more energy for ordinary activities, such as diving and feeding. To test the drag created by the tags, Dolphin Quest trainers taught the dolphins to follow a remote-controlled boat with a sensor on it that tracks each dolphin's speed and duration of the session. The dolphins perform the task with and without a tag.

The dolphins' breaths are measured before they begin to determine each individual's resting oxygen consumption and breathing rate. After swimming, each session ends with the dolphin greeting its trainer and giving a series of voluntary breath samples into a custom-made device that measures respiratory flow rates, oxygen and carbon dioxide levels of the expired gas.

The data collected will provide baseline values for healthy dolphins, which can then be used for early detection of disease both in captive and wild animals.

Results from this research will help scientists better interpret data in field studies with wild dolphins and other marine mammals, and could lead to the development of even better data tags.

In addition, the study could help shed new light on the impacts of drag on marine mammals created from entanglements in fishing gear.

OceanGate Completes Rigs to Reefs Dives
OceanGate Inc. (OGI), based in Woodinville, Washington, has completed a series of dives in the Gulf of Mexico to observe the ecological impact of decommissioned oil platforms on ocean life using the five-person manned submersible Antipodes. This expedition was part of an initial study related to the 'Rigs to Reefs' program.

Known as 'idle iron,' retired platforms in many sites across the Gulf of Mexico have evolved into the perfect hosts for a complex and diverse set of species that are thriving and reestablishing underwater footprints, much as they do around artificial reefs.

OGI's crew took coral expert Dr. Paul W. Sammarco and CBS news reporter Chip Reid to South Timbalier 185 B, owned by Black Elk Energy Offshore Operations LLC (Houston, Texas). Black Elk Energy CEO John Hoffman was also onboard.

Antipodes's 180-degree hemispherical viewport offered a broad perspective on the plants and animals present, including, corals, soft corals, algae, bottom fish, and open-water organisms such as dolphins, cobia and sharks.

Deep-Sea Animals Survive Off Organic Feasts
Animals living on the abyssal plain do not usually get much to eat. Their main source of food is 'marine snow'—a slow drift of mucus, fecal pellets and body parts—that sinks down from surface waters. Researchers have long been puzzled that the steady fall of marine snow cannot account for all the food consumed by these animals.

Monterey Bay Aquarium Research Institute (MBARI) researcher Ken Smith and his colleagues discovered that population booms of algae or animals near the sea surface can sometimes result in huge pulses of organic material sinking to the deep seafloor. In a few weeks, such deep-sea 'feasts' can deliver as much food to deep-sea animals as would normally arrive over years or even decades of typical marine snow.

For more than 20 years, the researchers have studied animals living at Station M about 220 kilometers off the Central California coast. The muddy seafloor 4,000 meters below the surface is home to a variety of deep-sea animals, from sea cucumbers and sea urchins to grenadier fish. Smaller animals and microbes live buried in the mud.

Conical sediment traps suspended above the seafloor collected and measured the amount of marine snow falling. Automated camera systems took time-lapse photographs of the seafloor to track the behavior, numbers and sizes of larger deep-sea animals. A seafloor-crawling robot, the Benthic Rover, measured the oxygen being consumed by animals and microbes in the sediment, which enabled estimation of food consumption.

Excess food was rapidly consumed by deep-sea animals and seafloor microbes, which used it to grow and reproduce. Some of the organic carbon from the food was released into the surrounding seawater by respiration. Most of the rest was incorporated into the deep-sea sediments, where it could be recycled by animals and microbes that feed on the mud. In this way, large, intermittent pulses of food could help sustain life in the deep for years or even decades.


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