Tag Archives: marine ecosystems

North Atlantic doubles carbon intake

The North Atlantic is gulping down twice as much human-caused carbon and becoming increasingly acidic, intensifying alarm for marine creatures.

LONDON, 12 February, 2016  – The North Atlantic Ocean is responding rapidly to climate change: it has absorbed 50% more carbon from human activities in the last 10 years,than in the previous decade, a new study shows.

In effect, it has become both a sink for the byproduct of the fossil fuel combustion that is driving global warming, and at the same time an index of the impact humans are now having on the ocean and atmosphere.

Scientists from the University of Miami’s school of marine and atmospheric science established the Atlantic’s hunger for carbon dioxide by simply looking at data samples taken a decade apart.

They report in the journal Global Biogeochemical Cycles that the data were collected in two international ship-based studies. One was CLIVAR, short for Climate Variability CO2 Repeat Hydrography, the other GO-SHIP, or the Global Ocean Ship-based Hydrographic Investigations Program’

Unprecedented rate

The extra CO2 absorbed means a change in ocean chemistry: the oceans are becoming increasingly acidic at an unprecedented rate, with unknown consequences for corals, shellfish and juvenile fish.

“This study shows the impact all of us are having on the environment and that our use of fossil fuels isn’t only causing climate to change, but also affects the oceans by decreasing the pH,” said Ryan Woosley, of the University of Miami, one of the authors.

But that is not the only change in the region. Jon Hawkings, of the University of Bristol, UK,  and colleagues report in the same journal that they spent three months in 2012 and 2013 sampling the flow of water from two glaciers in Greenland and calculated that the overall melt from the northern hemisphere’s biggest ice sheet is now delivering the nutrient phosphorus into the Arctic at about the same level as the Mississippi, or the Amazon.

“It could stimulate growth of plankton at the base of the food web, which could impact birds, fish and marine mammals higher up the food chain”

Since, once again, the Greenland ice sheet is melting as a response to global warming, humans are as a consequence altering ocean productivity. By how much is less certain: the researchers still have to establish how much of the nutrient crushed from the rocks by the moving glaciers is getting to the open ocean.

“It could stimulate growth of plankton at the base of the food web, which could impact birds, fish and marine mammals higher up the food chain,” said Dr Hawkings. “The research also suggests ice sheet-derived phosphorus could eventually reach the northern Pacific and Atlantic Oceans, which are connected to the Arctic Ocean.”

Underestimated consequences

Both studies indicate a warming ocean. And research by German scientists now suggests that humans have underestimated one important consequence of this rate of warming; the rise in global sea levels.

They report in the Proceedings of the National Academy of Sciences that the expansion of the oceans as a consequence of raised temperature could lift sea levels by an average of 1.4mm a year. Until now, oceanographers have assumed that the calculated expansion would add up to perhaps 0.7mm a year. The new study doubles that estimate.

“This height difference corresponds to roughly twice the volume from the melting ice sheets of Greenland,” said one of the authors, Roelof Rietbroek of the University of Bonn. – Climate News Network

The North Atlantic is gulping down twice as much human-caused carbon and becoming increasingly acidic, intensifying alarm for marine creatures.

LONDON, 12 February, 2016  – The North Atlantic Ocean is responding rapidly to climate change: it has absorbed 50% more carbon from human activities in the last 10 years,than in the previous decade, a new study shows.

In effect, it has become both a sink for the byproduct of the fossil fuel combustion that is driving global warming, and at the same time an index of the impact humans are now having on the ocean and atmosphere.

Scientists from the University of Miami’s school of marine and atmospheric science established the Atlantic’s hunger for carbon dioxide by simply looking at data samples taken a decade apart.

They report in the journal Global Biogeochemical Cycles that the data were collected in two international ship-based studies. One was CLIVAR, short for Climate Variability CO2 Repeat Hydrography, the other GO-SHIP, or the Global Ocean Ship-based Hydrographic Investigations Program’

Unprecedented rate

The extra CO2 absorbed means a change in ocean chemistry: the oceans are becoming increasingly acidic at an unprecedented rate, with unknown consequences for corals, shellfish and juvenile fish.

“This study shows the impact all of us are having on the environment and that our use of fossil fuels isn’t only causing climate to change, but also affects the oceans by decreasing the pH,” said Ryan Woosley, of the University of Miami, one of the authors.

But that is not the only change in the region. Jon Hawkings, of the University of Bristol, UK,  and colleagues report in the same journal that they spent three months in 2012 and 2013 sampling the flow of water from two glaciers in Greenland and calculated that the overall melt from the northern hemisphere’s biggest ice sheet is now delivering the nutrient phosphorus into the Arctic at about the same level as the Mississippi, or the Amazon.

“It could stimulate growth of plankton at the base of the food web, which could impact birds, fish and marine mammals higher up the food chain”

Since, once again, the Greenland ice sheet is melting as a response to global warming, humans are as a consequence altering ocean productivity. By how much is less certain: the researchers still have to establish how much of the nutrient crushed from the rocks by the moving glaciers is getting to the open ocean.

“It could stimulate growth of plankton at the base of the food web, which could impact birds, fish and marine mammals higher up the food chain,” said Dr Hawkings. “The research also suggests ice sheet-derived phosphorus could eventually reach the northern Pacific and Atlantic Oceans, which are connected to the Arctic Ocean.”

Underestimated consequences

Both studies indicate a warming ocean. And research by German scientists now suggests that humans have underestimated one important consequence of this rate of warming; the rise in global sea levels.

They report in the Proceedings of the National Academy of Sciences that the expansion of the oceans as a consequence of raised temperature could lift sea levels by an average of 1.4mm a year. Until now, oceanographers have assumed that the calculated expansion would add up to perhaps 0.7mm a year. The new study doubles that estimate.

“This height difference corresponds to roughly twice the volume from the melting ice sheets of Greenland,” said one of the authors, Roelof Rietbroek of the University of Bonn. – Climate News Network

Offshore turbines get approval of seals

Researchers tracking the movements of seals in the North Sea reveal that “artificial reefs” created by wind farms and pipelines are becoming attractive as foraging grounds on fishing expeditions. LONDON, 25 July, 2014 − Environmental campaigners and countryside conservators aren’t the only fans of those great arrays of turbines, generating renewable energy from the winds at sea. Grey and harbour seals in the North Sea are beginning to show a preference for offshore wind farms as well. Deborah Russell, research fellow at the University of St Andrews, Scotland, and colleagues tracked the movements of both the harbour seal (Phoca vitulina) and the grey seal (Halichoerus grypus). There are an estimated 56,000 harbour seals in the North Sea and around 65,000 of the greys haul out on the British coast on the North Sea alone. Tagged specimens, with their movements tracked by GPS satellite systems as they surface to breathe, reveal a lot about the ecology of each species and their response to environmental change.

Distinct preference

The researchers report in the journal Current Biology that some of their tagged animals seemed to show a distinct preference for offshore wind farms and associated pipelines. Eleven harbour seals headed for two wind farms: one was Alpha Ventus, off northern Germany, and the other was Sheringham Shoal, off the North Norfolk coast, England. Some individuals regularly cruised the sites, and some even revealed a pattern of grid-like movements as they appeared to forage at individual turbines. Two seals in the Netherlands were tracked along sections of submarine pipeline, on fishing expeditions that lasted 10 days at a time.

A harbour seal with a GPS phone tag used to track movements Image: Current Biology, Russell et al
A harbour seal with a GPS phone tag Image: Current Biology, Russell et al

The guess is that the seals regarded the offshore structures as artificial reefs where crustaceans settle and fish congregate. Turbine blades can swirl at speeds of up to 280 kilometres an hour, and represent a danger to  birds and bats − one estimate is that such structures in the US account for 600,000 bat deaths a year. But marine creatures far below the circling blades seem to value a touch of freshly-planted, three-dimensional shelter in the muddy basin of a shallow sea. “I was shocked when I first saw the stunning grid pattern of a seal track around Sheringham Shoal,” Dr Russell said. “You could see that the individual appeared to travel in straight lines between turbines, as if he was checking them out for potential prey, and then stopping to forage at certain ones.”

Open questions

Only a small proportion of the tracked animals showed a preference for wind farms, and such structures still cover only a trifling area of the available coast. But the research leaves open a number of questions. One is whether, as wind farms add to the available habitat in the North Sea, they will increase the available fish and crustacean populations, or whether they simply attract the prey and make life easier for innovative predators. As offshore investment grows, such studies may help engineers to design farms that help both the consumer and the wild things in the offshore waters. The researchers say: “In this period of unprecedented development of the marine renewables industry, the number of apex predators encountering such structures is likely to increase. The ecological consequences may be dependent on whether such reefs constitute an increase or just a concentration of prey.” – Climate News Network

Researchers tracking the movements of seals in the North Sea reveal that “artificial reefs” created by wind farms and pipelines are becoming attractive as foraging grounds on fishing expeditions. LONDON, 25 July, 2014 − Environmental campaigners and countryside conservators aren’t the only fans of those great arrays of turbines, generating renewable energy from the winds at sea. Grey and harbour seals in the North Sea are beginning to show a preference for offshore wind farms as well. Deborah Russell, research fellow at the University of St Andrews, Scotland, and colleagues tracked the movements of both the harbour seal (Phoca vitulina) and the grey seal (Halichoerus grypus). There are an estimated 56,000 harbour seals in the North Sea and around 65,000 of the greys haul out on the British coast on the North Sea alone. Tagged specimens, with their movements tracked by GPS satellite systems as they surface to breathe, reveal a lot about the ecology of each species and their response to environmental change.

Distinct preference

The researchers report in the journal Current Biology that some of their tagged animals seemed to show a distinct preference for offshore wind farms and associated pipelines. Eleven harbour seals headed for two wind farms: one was Alpha Ventus, off northern Germany, and the other was Sheringham Shoal, off the North Norfolk coast, England. Some individuals regularly cruised the sites, and some even revealed a pattern of grid-like movements as they appeared to forage at individual turbines. Two seals in the Netherlands were tracked along sections of submarine pipeline, on fishing expeditions that lasted 10 days at a time.

A harbour seal with a GPS phone tag used to track movements Image: Current Biology, Russell et al
A harbour seal with a GPS phone tag Image: Current Biology, Russell et al

The guess is that the seals regarded the offshore structures as artificial reefs where crustaceans settle and fish congregate. Turbine blades can swirl at speeds of up to 280 kilometres an hour, and represent a danger to  birds and bats − one estimate is that such structures in the US account for 600,000 bat deaths a year. But marine creatures far below the circling blades seem to value a touch of freshly-planted, three-dimensional shelter in the muddy basin of a shallow sea. “I was shocked when I first saw the stunning grid pattern of a seal track around Sheringham Shoal,” Dr Russell said. “You could see that the individual appeared to travel in straight lines between turbines, as if he was checking them out for potential prey, and then stopping to forage at certain ones.”

Open questions

Only a small proportion of the tracked animals showed a preference for wind farms, and such structures still cover only a trifling area of the available coast. But the research leaves open a number of questions. One is whether, as wind farms add to the available habitat in the North Sea, they will increase the available fish and crustacean populations, or whether they simply attract the prey and make life easier for innovative predators. As offshore investment grows, such studies may help engineers to design farms that help both the consumer and the wild things in the offshore waters. The researchers say: “In this period of unprecedented development of the marine renewables industry, the number of apex predators encountering such structures is likely to increase. The ecological consequences may be dependent on whether such reefs constitute an increase or just a concentration of prey.” – Climate News Network