Massive Bloom Of Pickle-Shaped Sea Creatures Fills The Pacific
"Millions of tubular sea creatures called pyrosomes have taken over the Pacific Ocean in an unprecedented bloom that has scientists baffled.
These bumpy, translucent organisms look like sea cucumbers that range in size from six inches to more than two feet long. But they’re actually made up of hundreds of tiny animals knit together with tissue into a filter-feeding cylinder. [...]
No one knows what the effects of the bloom will be, but scientists worry that if all the creatures die off at once they could sink to the seafloor and suck up all the oxygen as they’re decomposing, creating a dead zone for marine life."
NOAA, USGS and partners predict third largest Gulf of Mexico summer ‘dead zone’ ever
"Larger-than-average low and no oxygen area may affect the region’s shrimp fisheries
Federal scientists forecast that this summer’s Gulf of Mexico dead zone – an area of low to no oxygen that can kill fish and other marine life – will be approximately 8,185 square miles, or about the size of New Jersey.
This would be the third largest dead zone recorded since monitoring began 32 years ago – the average Gulf dead zone since then has been 5,309 square miles.
The Gulf’s hypoxic or low-oxygen zones are caused by excess nutrient pollution, primarily from human activities such as agriculture and wastewater treatment. The excess nutrients stimulate an overgrowth of algae, which then sinks and decomposes in the water. The resulting low oxygen levels are insufficient to support most marine life and habitats in near-bottom waters, threatening the Gulf’s fisheries. [...]"
Source: National Oceanic and Atmospheric Administration (NOAA)
NOAA, USGS and partners predict larger summer ‘dead zone’ for the Chesapeake Bay
"Scientists expect this year’s summer Chesapeake Bay hypoxic or “dead zone” — an area of low to no oxygen that can kill fish and aquatic life — will be larger than average, approximately 1.89 cubic miles, or nearly the volume of 3.2 million Olympic-size swimming pools.
Measurements for the Bay’s dead zone go back to 1950, and the 30-year mean maximum dead zone volume is 1.74 cubic miles. [...]"
Source: U.S. Geological Survey
Stormy waters: the salmon farmer trying to limit fishing and save the ocean
In the 1980s, protests over the proposed Franklin River hydroelectric dam threw the Apple Isle’s conservation plight onto the national stage. This time, it is the state’s salmon farming industry that is under a cloud. The relatively young industry is worth over $700m a year and now outpaces all other farming activities on the island but environmental campaigners are worried about its impact on the region’s pristine waters. [...]"
Source: The Guardian
Spreading Dead Zones and Consequences for Marine Ecosystems
"Dead zones in the coastal oceans have spread exponentially since the 1960s and have serious consequences for ecosystem functioning. The formation of dead zones has been exacerbated by the increase in primary production and consequent worldwide coastal eutrophication fueled by riverine runoff of fertilizers and the burning of fossil fuels. Enhanced primary production results in an accumulation of particulate organic matter, which encourages microbial activity and the consumption of dissolved oxygen in bottom waters. Dead zones have now been reported from more than 400 systems, affecting a total area of more than 245,000 square kilometers, and are probably a key stressor on marine ecosystems."
Source: Science Magazine (2008)
Authors: Robert J. Diaz, Rutger Rosenberg
Big Storms Pump Mediterranean Water Far into the Black Sea
"For the first time, scientists provide a sea-wide view of what happens to Mediterranean waters that flow into the Black Sea through the Bosporus Strait.
Below a depth of about 150 meters, the Black Sea is devoid of oxygen. Only certain microbes can survive in this “dead zone,” which reaches depths of over 2000 meters. Warm, salty water flowing from the Mediterranean Sea into the Black Sea ventilates the middepth water column of the sea, trapping anoxic water below and maintaining the sea’s distinctive structure. However, the precise fate of inflowing Mediterranean waters has remained something of a mystery to scientists. [...]"
Author: Sarah Stanley
Tropical dead zones and mass mortalities on coral reefs
"Oxygen-starved coastal waters are rapidly increasing in prevalence worldwide. However, little is known about the impacts of these “dead zones” in tropical ecosystems or their potential threat to coral reefs. We document the deleterious effects of such an anoxic event on coral habitat and biodiversity, and show that the risk of dead-zone events to reefs worldwide likely has been seriously underestimated. Awareness of, and research on, reef hypoxia is needed to address the threat posed by dead zones to coral reefs."
Source: Proceedings of the National Academy of Sciences of the United Stated of America (PNAS)
Authors: Andrew H. Altieri et al.
NCCOS: Price of Shrimp Impacted by Gulf of Mexico “Dead Zone”
The low oxygen conditions slow shrimp growth, leading to fewer and more expensive large shrimp.
The Guardian: Bay of Bengal: depleted fish stocks and huge dead zone signal tipping point
"Long treated as a bottomless resource pit, over-exploitation of the ocean, pollution and rising sea levels are having a catastrophic impact on life in the bay."