Monday, September 22, 2008
The Secrets of Effective Communication beneath the Sea
An acoustic signal is sent horizontally through ocean waters from one point to another. Along the way the sound is bouncing off a “ceiling” of choppy, wind-whipped seas and seafloor that could be craggy rock or smooth sand.
If researchers can better understand how physical conditions like these distort sound as it travels through the ocean, they could send data underwater faster and with less power and could make it much easier for networks of sensors to talk to each other simultaneously. They could improve wireless communications from commonly used ocean instruments such as Doppler current profilers and potentially eliminate the need for vehicles and gliders to surface just to transmit modest amounts of data.
With these goals on the horizon, a science team led by Scripps Institution of Oceanography at UC San Diego researchers have completed a three-week study of waters west of the Hawaiian island of Kauai.
The research team inventoried the suite of conditions that can disrupt a signal as it travels between two underwater points. The team recorded wind speed and surface wave measurements to gauge the structure of the sea surface and temperature profiles to estimate sound speed (the colder the water, the slower sound travels), and measured the topography of the seafloor.
Principal investigator, Bill Hodgkiss, rated the experiment a major success and said its data could enhance computer models used to guide development of underwater acoustic modems-especially for use in places less accessible than Kauai.
"This experiment should improve prediction of the fluctuation characteristics in other environments that scientists don't necessarily have the resources to go and study," Hodgkiss said.
Further Reading: explorations
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If researchers can better understand how physical conditions like these distort sound as it travels through the ocean, they could send data underwater faster and with less power and could make it much easier for networks of sensors to talk to each other simultaneously. They could improve wireless communications from commonly used ocean instruments such as Doppler current profilers and potentially eliminate the need for vehicles and gliders to surface just to transmit modest amounts of data.
With these goals on the horizon, a science team led by Scripps Institution of Oceanography at UC San Diego researchers have completed a three-week study of waters west of the Hawaiian island of Kauai.
The research team inventoried the suite of conditions that can disrupt a signal as it travels between two underwater points. The team recorded wind speed and surface wave measurements to gauge the structure of the sea surface and temperature profiles to estimate sound speed (the colder the water, the slower sound travels), and measured the topography of the seafloor.
Principal investigator, Bill Hodgkiss, rated the experiment a major success and said its data could enhance computer models used to guide development of underwater acoustic modems-especially for use in places less accessible than Kauai.
"This experiment should improve prediction of the fluctuation characteristics in other environments that scientists don't necessarily have the resources to go and study," Hodgkiss said.
Further Reading: explorations
--
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Labels: research
Friday, September 19, 2008
Reef Search Finds Hundreds of New Species
Hundreds of new kinds of animal species surprised international researchers systematically exploring waters off two islands on the Great Barrier Reef and a reef off northwestern Australia - waters long familiar to divers.
The expeditions, affiliated with the global Census of Marine Life, help mark the International Year of the Reef and included the systematic scientific inventory of spectacular soft corals.
The discoveries were made at Lizard and Heron Islands (part of the Great Barrier Reef), and Ningaloo Reef in northwestern Australia. The found about 300 soft coral species, up to half of them thought to be new to science; dozens of small crustacean species -- and potentially one or more families of species – likewise thought unknown to science; The beautiful, rare Cassiopeia jellyfish, photographed upside down on the ocean
floor, tentacles waving in the water column -- a posture that enables symbiotic
algae living in its tentacles to capture sunlight for photosynthesis.
Preparing for future discoveries, the divers pegged several layered plastic structures – likened to empty doll houses – for marine life to colonize on the ocean floor at Lizard and Heron Islands. Creatures that move into these Autonomous Reef Monitoring Structures (ARMS), which provide shelter designed to appeal to a variety of sea life, will be collected over the next one to three years.
"Corals face threats ranging from ocean acidification, pollution, and warming to overfishing and starfish outbreaks," says Dr. Ian Poiner, Chief Executive Officer of the Australian Institute of Marine Science (AIMS), which led the research. "Only by establishing a baseline of biodiversity and following through with later censuses can people know the impact of those threats and find clues to mitigate them."
Ningaloo Reef appears to be the least biodiverse of the three sites studied, which may be related to its comparative isolation from other reef systems.
Understanding these biodiversity gradients and the influence of connectivity will help scientists predict reef biodiversity worldwide.
Expeditions to the same three sites will be repeated annually over the next three years to continue their inventory and measure impacts of climate change and other processes over time.
The addition of perhaps as many as 150 new species to the global inventory of soft corals is a major addition to the knowledge of this group which, despite its high distribution worldwide, remains one of the most poorly understood groups.
The scientists' studies also included seaweeds, urchins, and lace corals. More formally known as Bryozoans, lace coral colonies consist of asexually budded (and therefore genetically identical) individuals. Colonies form large intricate structures which bear no resemblance to the structure of the individual.
The Census of Marine Life (www.coml.org) is a global network of researchers in more than 80 nations engaged in a 10-year initiative to assess and explain the diversity, distribution, and abundance of marine life in the oceans – past, present, and future. The network will release the first Census of Marine Life in 2010.
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The expeditions, affiliated with the global Census of Marine Life, help mark the International Year of the Reef and included the systematic scientific inventory of spectacular soft corals.
The discoveries were made at Lizard and Heron Islands (part of the Great Barrier Reef), and Ningaloo Reef in northwestern Australia. The found about 300 soft coral species, up to half of them thought to be new to science; dozens of small crustacean species -- and potentially one or more families of species – likewise thought unknown to science; The beautiful, rare Cassiopeia jellyfish, photographed upside down on the ocean
floor, tentacles waving in the water column -- a posture that enables symbiotic
algae living in its tentacles to capture sunlight for photosynthesis.
Preparing for future discoveries, the divers pegged several layered plastic structures – likened to empty doll houses – for marine life to colonize on the ocean floor at Lizard and Heron Islands. Creatures that move into these Autonomous Reef Monitoring Structures (ARMS), which provide shelter designed to appeal to a variety of sea life, will be collected over the next one to three years.
"Corals face threats ranging from ocean acidification, pollution, and warming to overfishing and starfish outbreaks," says Dr. Ian Poiner, Chief Executive Officer of the Australian Institute of Marine Science (AIMS), which led the research. "Only by establishing a baseline of biodiversity and following through with later censuses can people know the impact of those threats and find clues to mitigate them."
Ningaloo Reef appears to be the least biodiverse of the three sites studied, which may be related to its comparative isolation from other reef systems.
Understanding these biodiversity gradients and the influence of connectivity will help scientists predict reef biodiversity worldwide.
Expeditions to the same three sites will be repeated annually over the next three years to continue their inventory and measure impacts of climate change and other processes over time.
The addition of perhaps as many as 150 new species to the global inventory of soft corals is a major addition to the knowledge of this group which, despite its high distribution worldwide, remains one of the most poorly understood groups.
The scientists' studies also included seaweeds, urchins, and lace corals. More formally known as Bryozoans, lace coral colonies consist of asexually budded (and therefore genetically identical) individuals. Colonies form large intricate structures which bear no resemblance to the structure of the individual.
The Census of Marine Life (www.coml.org) is a global network of researchers in more than 80 nations engaged in a 10-year initiative to assess and explain the diversity, distribution, and abundance of marine life in the oceans – past, present, and future. The network will release the first Census of Marine Life in 2010.
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Monday, September 15, 2008
Aqua Lung Recalls Scuba Regulators and Adaptors
Aqua Lung USA are recalling Titan DIN 1st Stage Scuba Regulators and Titan/Conshelf DIN Scuba Adaptors.
Over-tightening of the DIN retainer by a technician during installation can result in the retainer breaking under pressure, a rapid escape of air from the scuba cylinder, and the regulator detaching from the cylinder. This poses a drowning hazard to divers.
Aqua Lung asks all the owners of TITAN DIN regulators whose serial number is lower than 6062501 or TITAN/CONSHELF DIN adaptors that are marked 300 BAR MAX to return their regulator to their Aqua Lung authorized retailer for an upgrade.
All the TITAN DIN regulators whose serial number are above 6062501 and/or whose DIN handwheel retainer is marked 300 BAR MAXI are assembled with a stainless steel DIN handwheel retainer and are not affected by this recall.
For additional information, visit www.aqualung.com.
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Over-tightening of the DIN retainer by a technician during installation can result in the retainer breaking under pressure, a rapid escape of air from the scuba cylinder, and the regulator detaching from the cylinder. This poses a drowning hazard to divers.
Aqua Lung asks all the owners of TITAN DIN regulators whose serial number is lower than 6062501 or TITAN/CONSHELF DIN adaptors that are marked 300 BAR MAX to return their regulator to their Aqua Lung authorized retailer for an upgrade.
All the TITAN DIN regulators whose serial number are above 6062501 and/or whose DIN handwheel retainer is marked 300 BAR MAXI are assembled with a stainless steel DIN handwheel retainer and are not affected by this recall.
For additional information, visit www.aqualung.com.
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Labels: equipment
Thursday, September 11, 2008
Mediterranean tuna management an "international disgrace"
According to environmental groups, an independent review panel of international fisheries experts has branded the management of the Mediterranean bluefin tuna fishery an "international disgrace" in its conclusions, published this week.The body responsible for the conservation of tunas and tuna-like species in the Atlantic Ocean and adjacent seas is the International Commission for the Conservation of Atlantic Tunas (ICCAT). The independent panel was commissioned by this very organisation to review its performance following concerns raised by the international community about the management of tuna fisheries resources.
In a very strong and direct recommendation, the Panel asks for "the suspension of fishing of bluefin tuna in the eastern Atlantic and Mediterranean until countries fully comply with ICCAT's recommendations on bluefin". Such a closure is seen by the Panel as "the only way to stop the continuation of what is seen by observers and by other contracting party countries as a travesty in fisheries management".
The Panel found that the management of the Mediterranean bluefin tuna fisheries was "unacceptable and not consistent with the objectives of ICCAT", such as the objective of guaranteeing that fish populations do not dwindle to unsustainable levels.
In addition to immediate suspension of the fishery, the Panel also recommended the immediate closure of all known bluefin tuna spawning grounds, at least during known spawning periods. This is in line with Greenpeace demands for the closure of the fishery and the creation of no-take marine reserves to protect crucial breeding areas in the Mediterranean Sea. Also needed are minimum size limits to allow the species to breed before being caught, fishing and farming capacities scaled back to sustainable quota levels, and the elimination of pirate fishing.
The Panel attributed the failure of ICCAT management largely due to the lack of implementation of existing regulations by its contracting party countries. However, some problems lie deeper than enforcement of rules. The review drew attention not only to the illegal catch, but also to the fact that the quota set by ICCAT was 29,500 tonnes - almost twice the 15,000 limit recommended by its own scientific committee. As the Panel put it, "it is difficult to describe this as responsible fisheries management and it reflects negatively not only on ICCAT but on all tuna RFMOs"(3).
In November, ICCAT members will review the current bluefin tuna management plan. Pressure groups Greenpeace and the WWF are demanding that they follow the recommendations of the Panel and close the fishery until capacity is decreased, spawning grounds protected and compliance guaranteed.
“Such staggering conclusions from independent experts only reinforce what WWF has been saying for years – this is a fishery grossly out of control, and if the fishery is not closed now pending radical management overhaul, this majestic species may be confined to the history books,” says Dr Sergi Tudela, Head of Fisheries at WWF Mediterranean.
"Fisheries Ministers are failing to protect single species, let alone marine ecosystems. What kind of management organisation ignores the advice of its own scientists and set quotas that condemn the very species it is responsible for??" asked Sebastian Losada, Greenpeace Spain oceans campaigner. "This report signals that it is time for ICCAT members to take responsibility for the fishery that has brought tuna to near-collapse or be relieved of its management altogether.
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Labels: environment, Mediterranean
Wednesday, September 10, 2008
SCUBA News Celebrates 100th Issue with a Prize Draw
SCUBA Travel, the guide to diving around the world, is celebrating the 100th issue of its newsletter SCUBA News (ISSN 1476-8011) with a free prize draw. Any subscriber to SCUBA News can participate, and subscription is free at http://www.scubatravel.co.uk/news.html. The free stuff on offer includes SCUBA Travel merchandise like pens, fridge magnets and caps, plus diving books. Elsewhere in the 100th issue is a newly updated list of the top 100 dive sites of the world, as voted for at the SCUBA Travel web site. Top of this list is the wreck of the Yongala in Australia, closely followed by Blue Corner Wall in Micronesia and the Thistlegorm in the Red Sea.
The publishers of SCUBA News would like to thank all their subscribers, especially the many who have sent contributions, questions and comments since the newsletter was launched eight years ago.
The Editor of the newsletter, Jill Studholme, says "I am very pleased to be editing SCUBA News as it reaches its 100th issue. Eight years is a considerable time for an independent e-mail publication and much of the success of SCUBA News is owed to the enthusiasm of our readers. They send us both criticism and praise, both of which help us progressively improve the newsletter."
Over the years SCUBA News has changed from being a purely text-based newsletter, to offering the choice of an HTML issue with colour and photographs. The main focus is still on content though, with not just the diving news from around the world but articles on diving areas, marine life, ocean facts and everything you need to know before visiting a new diving destination.
To read the 100th issue of SCUBA News visit http://www.scubatravel.co.uk/scubanews100.html
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Labels: competition
Monday, September 08, 2008
Solar Powered Ship Reduces CO2 Emissions
As part of corporate efforts to reduce CO2 emissions from ocean-going vessels, Nippon Yusen KK and Nippon Oil are developing a system to partially use solar power to propel ships.
This full-scale installation of a solar power generator is a world-first, and will produce as much as 40 kilowatts of power (gross), which is expected to supplement existing power production on large vessels.
In order to work toward the mutual goal of fighting climate change, NYK and Nippon Oil have decided to establish a joint eco-project starting with a new car carrier planned to be completed on December 19, 2008.
The installation of solar power generators onto ships has until now been limited to use within crews’ onboard living areas due to the harsh shipboard environment, which is subject to salt-water damage and constant vibrations. However, this new project will begin testing the 40-kilowatt solar generation system by installing it onto the car-carrier and connecting it to the onboard 440V electrical network.
In addition, as a part of its corporate strategy to reduce environmental burdens caused by the life cycle of automobiles, Toyota Motor Corporation has agreed to support the initiative as a shipper in order to reduce CO2 emissions from the ocean transportation of finished cars.
The solar panels would help conserve up to 6.5% of the fuel used in powering the diesel engines that generate electricity aboard the ships.
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This full-scale installation of a solar power generator is a world-first, and will produce as much as 40 kilowatts of power (gross), which is expected to supplement existing power production on large vessels.
In order to work toward the mutual goal of fighting climate change, NYK and Nippon Oil have decided to establish a joint eco-project starting with a new car carrier planned to be completed on December 19, 2008.
The installation of solar power generators onto ships has until now been limited to use within crews’ onboard living areas due to the harsh shipboard environment, which is subject to salt-water damage and constant vibrations. However, this new project will begin testing the 40-kilowatt solar generation system by installing it onto the car-carrier and connecting it to the onboard 440V electrical network.
In addition, as a part of its corporate strategy to reduce environmental burdens caused by the life cycle of automobiles, Toyota Motor Corporation has agreed to support the initiative as a shipper in order to reduce CO2 emissions from the ocean transportation of finished cars.
The solar panels would help conserve up to 6.5% of the fuel used in powering the diesel engines that generate electricity aboard the ships.
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Subscribe to SCUBA News (ISSN 1476-8011) for more free news, articles, diving reports and marine life descriptions - http://www.scubatravel.co.uk/news.html
Labels: environment
