Breaking Waves: Ocean News

07/08/2016 - 09:58
Two predatory species are added to IUCN Red List of endangered species as pressure from fishing sees their populations fall by half in the last 75 years Whale sharks and winghead sharks have moved one step closer to extinction, after the International Union for the Conservation of Nature (IUCN) redefined them both as endangered species on the group’s ‘Red List’. The two predatory species have fallen foul of increased pressure from human activity, especially the fishing industry, with populations of whale sharks – the world’s largest living fish – halving in the last 75 years. Continue reading...
07/08/2016 - 08:34
Ocean Leadership ~ (Click to enlarge) Sea Snail (Credit: Kerri Bartup / Flickr) The lowly sea snail, a slow-moving denizen of tide pools up and down the California coast, could be in big trouble as greenhouse gases change the world’s climate and increase the acidity of the oceans. (From The San Francisco Chronicle / by David Perlman)– The snails are the favorite prey of the voracious purple sea stars. In any natural tide pool, they will quickly flee from their predator to a nearby dry rock, because the starfish rarely leave the water. Now a young biologist at the Bodega Marine Laboratory in Bodega Bay has discovered that the increasing pace of ocean acidification can deeply alter the relationship between prey and predator — to the sea snail’s disadvantage. Her experiments may well foreshadow major changes in the life of the open oceans everywhere. For the past four years, Brittany Jellison, 27, has been studying the relationship between the black turban sea snail and the purple sea star, its dominant predator, as they thrive in the rocky tide pools of Bodega Bay. In the lab, she has used chemical traces of the starfish bodies to observe the snails’ reactions and chart their escape routes as they flee from the starfish they perceive is looming. Jellison has measured the snails’ pathways and their speeds as they crawl up the slopes of their tanks. “Those snails can move faster than you’d think when they feel they’re at risk of being eaten,” Jellison said. Read the full article here: The post Ocean Acidification Tips Predator-Prey Balance appeared on Consortium for Ocean Leadership.
07/08/2016 - 08:28
The week’s top environment news stories and green events. If you are not already receiving this roundup, sign up here to get the briefing delivered to your inbox Continue reading...
07/08/2016 - 08:00
A bald eagle, drought-hit alligators, and a feeding leopard are among this week’s pick of images from the natural world Continue reading...
07/08/2016 - 07:42
Ocean Leadership ~ (Click to enlarge) Invasive and venomous lionfish (Pterois miles) (Credit: Wikipedia Commons) Venomous lionfish are striking to look at, with bold stripes and flowing, sail-like fins. However, scientists are paying especially close attention to the fish not for their beauty, but for their ability to invade ecosystems where they have no natural predators. The fish also tend to multiply in numbers that upset the balance of native biodiversity. (From Scientific American / by Mindy Weisberger)– A new study shows that the first wave of a lionfish invasion has struck in the Mediterranean Sea, a region where these fish had not been established before. Researchers gathered reports of lionfish sightings from fishermen and divers, discovering that in just one year, lionfish have colonized nearly all of Cyprus’ southeastern coast, and that the animals’ numbers are expected to grow. As ocean temperatures warm, numerous non-native fish have invaded Mediterranean waters—about 130 species since 2001, according to the study authors. The common lionfish (Pterois miles) recently detected in the Mediterranean is a close relative of the red lionfish (Pterois volitans). This notorious invasive species threatens reef ecosystems in coastal waters around the southeastern U.S. and in the Caribbean Sea. According to study lead author Demetris Kletou, director of the Marine and Environmental Research Lab in Cypress, lionfish were first spotted in the Mediterranean in the 1990s. But sightings were few and far between, and there was no evidence suggesting that the animals were breeding successfully in the area, Kletou told Live Science in an email. In fact, it was suspected that the Mediterranean might not be a suitable habitat for dispersing lionfish larvae, the researchers reported in the study. But recent observations suggest otherwise. Kletou and his colleagues compiled 24 new sightings of at least 19 individual fish, including mating pairs, which were seen in Mediterranean waters for the first time. That may not sound like much of an invasion, but lionfish can spawn every four days year-round, and can produce more than 2 million eggs per year. And with venomous spines to protect them, these opportunistic predators can quickly come to dominate a reef environment. Read the full article here: The post Invasive Lionfish Arrive In The Mediterranean appeared on Consortium for Ocean Leadership.
07/08/2016 - 05:06
Ocean Leadership ~ (Click to enlarge) Starfish in the surf (Credit: Our Breathing Planet OBP / Flickr) Ocean acidification makes it harder for sea snails to escape from their sea star predators, according to a study from the University of California, Davis. (From Science Daily)– The findings, published in the journal Proceedings of The Royal Society B, suggest that by disturbing predator-prey interactions, ocean acidification could spur cascading consequences for food web systems in shoreline ecosystems. For instance, black turban snails graze on algae. If more snails are eaten by predators, algae densities could increase. “Ocean acidification can affect individual marine organisms along the Pacific coast, by changing the chemistry of the seawater,” said lead author Brittany Jellison, a Ph.D. student studying marine ecology at the UC Davis Bodega Marine Laboratory. “But it can also alter how species interact, such as by impairing the ability of prey to avoid predators,” she said. Jellison and colleagues from the UC Davis Bodega Marine Laboratory collected ochre sea stars and black turban snails — two common species along the Pacific coastline — from tide pools on the Bodega Marine Reserve. In lab tanks, they explored interactions between the sea stars and snails under 16 different levels of seawater pH, or acidity, ranging from present levels to those expected for rocky intertidal pools by the year 2100. The scientists found that lower pH levels, which indicate higher acidity, did not slow the snails’ movements or reduce their ability to sense the predatory sea stars. However, the more acidic waters did impair the snails’ escape response. Usually, when a black turban snail senses an ochre sea star, it quickly crawls up and out of the tide pool to avoid it, as sea stars rarely leave the water to eat. But when pH levels fell to 7.1 or below, the snails failed to fully implement their escape response. Neither did the snails recover their escape response when the water’s acidity fluctuated between normal and more acidic levels. The pH levels that spur these behavioral changes already occur in tide pools and are expected to become more frequent in coming decades. More research is needed to understand why the snails show a degraded escape response, or if they may adapt to more acidic ocean conditions in the future. Read the full article here: The post Ocean Acidification Affects Predator-Prey Response appeared on Consortium for Ocean Leadership.
07/08/2016 - 03:25
Manmade climate change increased the risk of heat-related deaths by about 70% in Paris and 20% in London in 2003, research shows Hundreds of deaths in the searing European heatwave of 2003 can be attributed to manmade climate change, say scientists. Researchers calculated that 506 out of 735 heat-related deaths recorded that summer in Paris – the hottest city – were due to global warming. Continue reading...
07/07/2016 - 23:30
Langstone, Hampshire Parting the ivy I discovered a buff-tailed bumblebee ensnared in an orb web A frantic buzz emanated from behind the curtain of ivy covering the fence, rising in pitch like an accelerating Vespa scooter. Parting the glossy leaves I discovered a buff-tailed bumblebee ensnared in an orb web. Researchers have discovered that bees generate a positive electrostatic charge as they fly. This helps pollen grains stick to their bodies as they forage, but has the unfortunate side effect of increasing the likelihood that they will be caught in a web. Spider silk tends to be neutral or negatively charged, which causes an attractive interaction between insect and web. Continue reading...
07/07/2016 - 18:48
Ocean Leadership ~ (Click to enlarge) Calm over the North Atlantic (Credit: tearbringer / Flickr) There was a period during the last ice age when temperatures in the Northern Hemisphere went on a rollercoaster ride, plummeting and then rising again every 1,500 years or so. Those abrupt climate changes wreaked havoc on ecosystems, but their cause has been something of a mystery. New evidence published this week in the leading journal Science shows for the first time that the ocean’s overturning circulation slowed during every one of those temperature plunges — at times almost stopping. (From Science Daily)– “People have long supposed this link between overturning circulation and these abrupt climate events. This evidence implicates the ocean,” said L. Gene Henry, the lead author of the study and a graduate student at Columbia University’s Lamont-Doherty Earth Observatory. The impact of changes in the ocean overturning circulation on climate has become a hot topic today as global temperatures rise and melting sea ice and glaciers add freshwater to the North Atlantic. A 2015 study suggested that cooling in the North Atlantic may be due to a reduction in the overturning circulation, while a 2016 study suggested there had not been enough freshwater to have an effect. The new study explores what happened to ocean circulation when Earth went through a series of abrupt climate changes in the past during a time when ice covered part of North America and temperatures were much colder than today. It looks at the Atlantic meridional overturning circulation, which distributes heat as it moves warmer surface water from the tropics toward Greenland and the high northern latitudes and carries colder, deeper water from the North Atlantic southward. Using chemical tracers in sediment that builds up on the sea floor over time, Henry and his coauthors were able to document the relative speed of the Atlantic meridional overturning circulation during each abrupt climate change during the last ice age. The chemical tracers show that the speed of the ocean overturning circulation changed first, and that sea surface temperature changed a while later. That suggests that cooling may start with changes in the ocean circulation, influencing the northern sea surface and atmosphere, said co-author Jerry McManus, a professor at Lamont-Doherty Earth Observatory. Evidence from ice cores and deep-sea sediment has shown that the northern climate also cooled before the southern climate during these abrupt changes, creating a “bipolar seesaw,” with the north cool while the south was warm, and the south cooling as the north warmed. The scientists stress that more work is needed to determine whether changes in ocean circulation initiated the abrupt climate changes or were an intermediary effect initially triggered by something else. “Our study supports the view that changes in ocean circulation were at least in part responsible for causing abrupt climate changes. However, what in turn caused those changes in circulation remains a mystery,” Henry said. Read the full article here: The post Ocean Circulation Implicated In Past Abrupt Climate Changes appeared on Consortium for Ocean Leadership.
07/07/2016 - 18:13
Ocean Leadership ~ (Click to enlarge) A closeup view of a cuttlefish eye. (Credit: iStockphoto/Dan Schmitt) Animals like cuttlefish and octopuses can rapidly change color to blend into the background and dazzle prospective mates. But there’s only one problem: As far as we know, they can’t see in color. (From Science Magazine / by Patrick Monahan)– Unlike our eyes, the eyes of cephalopods—cuttlefish, octopuses, and their relatives—contain just one kind of color-sensitive protein, apparently restricting them to a black and white view of the world. But a new study shows how they might make do. By rapidly focusing their eyes at different depths, cephalopods could be taking advantage of a lensing property called “chromatic blur.” Each color of light has a different wavelength—and because lenses bend some wavelengths more than others, one color of light shining through a lens can be in focus while another is still blurry. So with the right kind of eye, a quick sweep of focus would let the viewer figure out the actual color of an object based on when it blurs. The off-center pupils of many cephalopods—including the w-shaped pupils of cuttlefish (above)—make this blurring effect more extreme, according to a study published this week in the Proceedings of the National Academy of Sciences. In that study, scientists built a computer model of an octopus eye and showed that—for an object at least one body length away—it could determine the object’s color just by changing focus. Because this is all still theoretical, the next step is testing whether live cephalopods actually see color this way—and whether any other “colorblind” animals might, too.  Read the full article here: The post How ‘Colorblind’ Cuttlefish May See In Living Color appeared on Consortium for Ocean Leadership.