Sea Technology

JUL 2013

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

Issue link:

Contents of this Issue


Page 58 of 71

marineresources Rapid Adaptation to Combat Ocean Acidifcation In the race against climate change and ocean acidifcation, some sea urchins may still have a few tricks up their spiny sleeves, suggesting that adaptation will likely play a large role for the sea creatures as the carbon content of the ocean increases. Identifed by their spherical symmetry and prickly barbs, sea urchins are found on the seafoor all over the world. They are considered a keystone species, meaning their population has an important impact on the rest of the undersea ecosystem. If too many sea urchins and their habitats become barren, other algae-eating species will disappear. Predators, including sea mammals, seabirds and fsh, could lose an important food source. Due to rising carbon dioxide in the Earth's atmosphere, the oceans of the future are projected to absorb more carbon dioxide, leading to increased acidifcation of the water. The change in ocean chemistry is expected to negatively impact the way urchins and other calcifying creatures create and maintain their shells and exoskeletons. To observe the potential effects of increased levels of carbon dioxide in ocean water, the researchers bred generations of purple sea urchins in conditions mimicking the projected environment of the ocean at the end of the century. While the larvae reared under the future carbon dioxide levels were smaller on average, the researchers also noted a wide variation in size. This indicated that some of the larvae—the ones that remained the same size as they would have under today's conditions—had inherited a tolerance for higher CO2 levels. OceanGate Investigates Invasive Lionfsh The Invasive Lionfsh Expedition headed to the southeast Florida coast in June to study lionfsh aboard OceanGate's (Woodinville, Washington) manned submersible Antipodes. The venture sought to raise public awareness of lionfsh as an invasive species, improve understanding of lionfsh distributions and behaviors, and test and evaluate methods for lionfsh remediation. In January 2012, OceanGate began a year-long expedition to Miami, Florida, the primary focus of which was to conduct research in conjunction with the Miami-Dade Artifcial Reefs Program. The nine sites visited by Antipodes and her crew included several wrecks. While marine researchers were aware that the lionfsh was an increasingly invasive species in south Florida waters, the extensive prevalence of the fsh noted during the dives, even at depths as great as 70 meters, pointed to the need for an ongoing investigation of the species and its effects on the local marine habitat. Researchers Unravel Reasons for Success of Calcifed Alga Researchers at the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research have sequenced the genome of the calcifed alga Emiliania huxleyi and have found an explanation for the adaptive potential and global distribution of the unicellular alga. The researchers reported in an online prepublication of Nature that the microalga's trick is genetic diversity. It has a large pan-genome, which means that the unicellular alga shares a set of common genetic information present in all strains. The remaining gene pool depends on the geographic location and the living conditions of the algae. The calcifed E. huxleyi is the frst alga that scientists have been able to detect with this characteristic. It is fve thousandths of a millimeter in size, and the shape of its shield is made of thin calcifed platelets. Scientists from the U.S., Germany, Canada, France, the U.K., Belgium and Chile participated in the project to sequence the genome. During their work, the researchers identifed groups of genes that permit the calcifed alga to prosper in water with a low phosphorous iron or nitrogen content. NOAA Proposal Would Extend Rule Reducing Whale Ship Strikes NOAA Fisheries is seeking comments on its proposal to make permanent its rules to reduce the number of collisions between ships and North Atlantic right whales. The rules were introduced fve years ago. Right whales are an endangered species highly vulnerable to ship collisions. The current rules are scheduled to expire in December 2013. NOAA's proposal to make them permanent, which includes a 60-day public comment period, was fled at the Federal Register. NOAA's rules, which reduce a vessel's speed to 10 knots or less during certain times and locations along the U.S. East Coast, have reduced the number of whales struck by ships since 2008, when the speed limits began. No right whale ship strike deaths have occurred in seasonal management areas since the rules went into place. Modeling studies indicate the measures have lessened the probability of fatal ship strikes of right whales by 80 to 90 percent. The rule proposes to continue existing speed restrictions during migration periods along regions of the East Coast. These measures are implemented during the time of year when right whales are present in each area. Speed restrictions apply to vessels that are 65 feet or more in length, except federal agency vessels. Fishermen Struggle with Effects of Radiation After the 2011 Japan tsunami and the subsequent nuclear reactor meltdown, the government shut down commercial fshing operations in the waters northeast of Tokyo, leaving fshermen out of work, reported Reuters. Many fshermen have turned to the only way left to make a living, checking fsh for radiation in the waters near the reactors. The Fukushima Dai-ichi nuclear plant has been trying to fnd a solution for the disposal of the water used to cool the reactor. Fishermen are at odds with the company that owns the plant as it proposed a plan to fush the water under the reactor and into the ocean. The fshermen are concerned that the water from the plant will contribute to the contamination of fsh, the resource their livelihoods depends on. Much of the fsh in the region test below radiation limits, however, fsh living near the ocean bottom have unsafe levels of contamination. n July 2013 / st 59

Articles in this issue

Links on this page

Archives of this issue

view archives of Sea Technology - JUL 2013