ScienceDaily (Feb. 26, 2012) — Not all that glitters is gold. Sometimes it is just bacteria trying to get ahead in life. Many sea creatures glow with a biologically produced light. This phenomenon, known as bioluminescence, is observed, among others, in some marine bacteria which emit a steady light once they have reached a certain level of concentration (a phenomenon called “quorum sensing”) on organic particles in ocean waters.
Though this was a known occurrence, the benefits of producing light remained unclear.
Now, in an article published recently in the Proceedings of the National Academy of Sciences (PNAS), researchers of the Hebrew University of Jerusalem have unraveled the mystery of why the marine bacteria glow. It has to do with what might be called “the survival of the brightest.”
James Lovelock’s “Gaia hypothesis” has challenged conventional thinking about the nature of the earth as an integrated system. Gaia proposes that the earth acts like a living organism — that life is part of a self-regulating system, manipulating the physical and chemical environment to maintain the planet as a suitable home for life itself. Lovelock has developed this idea in a series of books, from “Gaia: A new look at life on earth” (1979) through to “Revenge of Gaia” (2006) and “The Vanishing Face of Gaia” (2009). He argues that as changes in the physical earth system occur, living systems respond so as to mitigate such changes. Read the full article
This article is based on a lecture delivered in April 2009 as part of The University of Melbourne series of public lectures on Key Thinkers.
ScienceDaily (Feb. 17, 2012) — The Deepwater Horizon oil spill in the Gulf of Mexico in April 2010 will have a large economic impact on the U.S. Gulf fisheries. A new study published in the Canadian Journal of Fisheries and Aquatic Sciences (CJFAS) says that over 7 years this oil spill could have a $US8.7 billion impact on the economy of the Gulf of Mexico. This includes losses in revenue, profit, and wages, and close to 22 000 jobs could be lost.
“Unlike the visually obvious and immediate effects on birds and mammals, the effects of oil on fisheries can be more difficult to detect, though they are no less devastating,” says lead author U. Rashid Sumaila. “Oil and hydrocarbons are taken up by plankton and other surface-dwelling species that link to aquatic food chains.” This in turn affects the fishing industry. Read the full article at http://www.sciencedaily.com/releases/2012/02/120217115553.htm
By Stephen Lendman
February 19, 2012. Fogcityjournal.com
In November 2006, Washington Post writer Juliet Eilperin headlined, ” World’s Fish Supply Running Out, Researchers Warn,” saying International ecologists and economists believe “the world will run out of seafood by 2048″ if current fishing rates continue.
A journal Science study “conclude(d) that overfishing, pollution and other environmental factors are wiping out important species” globally. They’re also impeding world oceans’ ability to produce seafood, filter nutrients, and resist disease.
Marine biologist Boris Worm warned, “We really see the end of the line now. It’s within our lifetime. Our children will see a world without seafood if we don’t change things.”
Researchers studied fish populations, catch records, and ocean ecosystems for four years. By 2003, 29% of all species collapsed. It means they’re at least “90% below their historic maximum catch levels.” Read the full article at http://www.fogcityjournal.com/wordpress/3410/depleting-the-seas-of-fish/
by Underwatertimes.com News Service – February 2, 2012 17:41 EST
NEW YORK, New York — A recently published study by the Wildlife Conservation Society and others reveals that humpback whales on both sides of the southern Indian Ocean are singing different tunes, unusual since humpbacks in the same ocean basin usually all sing very similar songs.
The results of the study—conducted by researchers from WCS, Columbia University, and Australia —contradict previous humpback whale song comparisons. Generally, when song from populations in the same ocean basins are compared, researchers find that the songs contain similar parts or “themes.” The differences in song between the Indian Ocean humpback populations most likely indicate a limited exchange between the two regions and may shed new light on how whale culture spreads.
ScienceDaily (Jan. 26, 2012) — Over dinner on R.V. Calypso while anchored on the lee side of Glover’s Reef in Belize, Jacques Cousteau told Phil Dustan that he suspected humans were having a negative impact on coral reefs. Dustan — a young ocean ecologist who had worked in the lush coral reefs of the Caribbean and Sinai Peninsula — found this difficult to believe. It was December 1974.
But Cousteau was right. During the following three-plus decades, Dustan, an ocean ecologist and biology professor at the University of Charleston in South Carolina, has witnessed widespread coral reef degradation and bleaching from up close. In the late 1970s Dustan helped build a handheld spectrometer, a tool to measure light given off by the coral. Using his spectrometer, Dustan could look at light reflected and made by the different organisms that comprised the living reefs. Since then, he has watched reefs deteriorate at an alarming rate. Recently he has found that Landsat offers a way to evaluate these changes globally. Using an innovative way to map how coral reefs are changing over time, Dustan now can find ‘hotspots’ where conservation efforts should be focused to protect these delicate communities.
A Role for Remote Sensing
Situated in shallow clear water, most coral reefs are visible to satellites that use passive remote sensing to observe Earth’s surface. But coral reefs are complex ecosystems with coincident coral species, sand, and water all reflecting light. Dustan found that currently orbiting satellites do not offer the spatial or spectral resolution needed to distinguish between them and specifically classify coral reef composition. So instead of attempting to classify the inherently complex coral ecosystem to monitor their health, Dustan has instead started to look for change — how overall reflectance for a geographic location varies over time.
Dustan uses a time series of Landsat data to calculate something called temporal texture¬ — basically a map showing where change has occurred based on statistical analysis of reflectance information. While Dustan cannot diagnosis the type of change with temporal texture he can establish where serious changes have occurred. Coral communities have seasonal rhythms and periodicities, but larger, significant changes show up as statistical outliers in temporal texture maps and often correlate with reef decline.
A Case Study
Carysfort reef — named for the HMS Carysfort, an eighteenth century British warship that ran aground on the reef in 1770 — is considered the most ecologically diverse on the Florida Keys National Marine Sanctuary’s northern seaward edge, but today it is in a state of ecological collapse.
Dustan and colleagues conducted the first quantitative field study of coral health at Carysfort in 1974. After a quarter century their studies showed that coral had declined 92 percent. The coral had succumbed to an array of stressors culminating with deadly diseases.
Using the well-characterized Carysfort reef as his control, Dustan calculated the temporal texture for the reef using a series of 20 Landsat images collected between 1982 and 1996. The resulting temporal texture maps correlated with the known areas of significant coral loss (where coral communities have turned into algal-dominated substrates) and they correctly showed that the seaward shallow regions have had the most detrimental change.
This novel approach to change detection is only possible because the long-term calibration of Landsat data assures that data from year-to-year is consistent. Dustin needs at least 6 to 8 Landsat images to create a reliable temporal texture map, but the more data that is available, the finer the results.
Dustan tested this work in the U.S. because he had a robust study site and because prior to 1999 coverage of reefs outside of the U.S. was spotty. With the Landsat 7 launch in 1999 a new global data acquisition strategy was established and for the first time the planet’s coral reefs were systematically and regularly imaged, greatly increasing our knowledge of reefs. The Landsat archive enabled the completing of the first exhaustive global survey of reefs (Millennium Global Coral Reef Mapping Project, http://landsat.gsfc.nasa.gov/news/news-archive/news_0031.html). Efforts are currently underway to receive and ingest Landsat data collected and housed by international ground-receiving stations. International partners often downlink Landsat scenes of their countries that the U.S. does not, so it is very likely that historic reef images will be added the U.S. Landsat archive during this process.
Carrying on Outside of Carysfort
Temporal texture gives scientists an entirely new way to look at coral reefs. A worldwide study could help managers locate change ‘hotspots’ and could better inform conservation efforts.
Ideally, after more testing, Dustan would like to see an automatic change detection system implemented to follow major worldwide reef systems. “There is no reason that a form of temporal texture monitoring could not be implemented with current satellites in orbit,” Dustan says.
Because reefs are underwater it is difficult to grasp the extensive devastation being exacted upon them. Global temporal texture mapping could bring the ravages into focus.
The Landsat Program is a series of Earth observing satellite missions jointly managed by NASA and the U.S. Geological Survey. Landsat satellites have been consistently gathering data about our planet since 1972. They continue to improve and expand this unparalleled record of Earth’s changing landscapes for the benefit of all.
ScienceDaily (Jan. 24, 2012) — Scientists at USC have uncovered evidence that even when hydrothermal sea vents go dormant and their blistering warmth turns to frigid cold, life goes on.
Or rather, it is replaced.
A team led by USC microbiologist Katrina Edwards found that the microbes that thrive on hot fluid methane and sulfur spewed by active hydrothermal vents are supplanted, once the vents go cold, by microbes that feed on the solid iron and sulfur that make up the vents themselves.
The parrotfish Sparisoma viride often grazes live coral from edges undermined by the Caribbean encrusting and excavating sponge Cliona tenuis. To test whether parrotfish biting action has an effect on the dynamics of the sponge–coral interaction, we manipulated access of parrotfishes to the sponge–coral border in two species of massive corals. When parrotfish had access to the border, C. tenuis advanced significantly more slowly into the coral Siderastrea siderea than into the coral Diploria strigosa. When fish bites were prevented, sponge spread into S. siderea was further slowed down but remained the same for D. strigosa. Additionally, a thinner layer of the outer coral skeleton was removed by bioerosion when fish were excluded, a condition more pronounced in D. strigosa than in S. siderea. Thus, the speed of sponge-spread and the extent of bioerosion by parrotfish was coral species-dependent. It is hypothesized that coral skeleton architecture is the main variable associated with such dependency. Cliona tenuis spread is slow when undermining live S. siderea owing to the coral’s compact skeleton. The coral’s smooth and hard surface promotes a wide and shallow parrotfish bite morphology, which allows the sponge to overgrow the denuded area and thus advance slightly faster. On the less compact skeleton of the brain coral, D. strigosa, sponge spread is more rapid. This coral’s rather uneven surface sustains narrower and deeper parrotfish bites which do not facilitate the already fast sponge progress. Parrotfish corallivory thus acts synergistically with C. tenuis to further harm corals whose skeletal architecture slows sponge lateral spread. In addition, C. tenuis also appears to mediate the predator–prey fish–coral interaction by attracting parrotfish biting.
Read the full article: Parrotfish mediation in coral mortality and bioerosion by the encrusting, excavating sponge Cliona tenuis. Juan Carlos Márquez, Sven Zea .23 JAN 2012 DOI: 10.1111/j.1439-0485.2011.00506.x
ScienceDaily (Jan. 23, 2012) — Lessons from tens of millions of years ago are pointing to new ways to save and protect today’s coral reefs and their myriad of beautiful and many-hued fishes at a time of huge change in the Earth’s systems.
The complex relationship we see today between fishes and corals developed relatively recently in geological terms – and is a major factor in shielding reef species from extinction, says Professor David Bellwood of the ARC Centre of Excellence for Coral Reef Studies and James Cook University.
ScienceDaily (Jan. 6, 2012) — In March 2010 an outbreak of a disease called acute Montipora White Syndrome (MWS) was discovered affecting coral reefs in Kaneohe Bay, Oahu. Follow-up surveys found that the disease left trails of rubble in its wake. It was estimated that over 100 colonies of rice coral (Montipora capitata) died during that initial outbreak. The disease has reappeared and is killing corals in Kaneohe Bay. The current outbreak has already affected 198 colonies and a rapid response team led by Dr. Greta Aeby (HIMB) has been activated to document the outbreak.
Members of the investigative team include scientists from the University of Hawaii, Hawaii Institute of Marine Biology (HIMB), and USGS National Wildlife Health Center. Members of the Eyes of the Reef Network (EOR), a program that trains community members to identify threats to Hawaii’s reefs, are also being asked to report on any signs of disease from other reefs.