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Climate change is warming Welsh streams and rivers, affecting the number and variety of some of their smallest animals, a major Cardiff University study has found.

Rivers and streams are key ecosystems for many aquatic species and form important links with surrounding habitats, yet little emphasis has been given so far to the ecological effects of climate change on these running-waters.

Now a twenty-five year study at Llyn Brianne in central Wales, led by Professor Steve Ormerod and Dr Isabelle Durance of the Cardiff School of Biosciences, has examined for the first time the effects of climate change on stream species.

The study looked at the effects of climate change on stream macroinvertebrates – animals that can be seen with the naked eye such as crustaceans, snails and larval insects including stoneflies or mayflies.

Professor Ormerod, said: “Streams and rivers are likely to be highly sensitive to climate and yet long-term evidence of effects is scarce globally. Our study shows a clear climate-change signal over the last 25 years, with temperatures warming faster than could be explained by background variations. An ecological response to warming has also been clear.”

The study predicts that at the present rate the springtime abundance of macroinvertebrates in streams could decline by as much as 21 per cent for every 1 degree Celsius rise in temperature.

Dr Durance added “The numbers of species in the streams we examined might also fall by 12-25 per cent if trends continue as expected over the next 50 years”.

Carbon dioxide consumed before it sinks in deep ocean may re-enter atmosphere as greenhouse gas

 

Mike Tidwell comments -This article and many others supoort the idea that the deep ocean is a sink for atmospheric carbon as was once hoped. Actually, carbon dioxide levels have been much higher in the deep past, in some instances as much 4,000 ppmv versus the current level of 385 ppmv. There is no easy way out–the natural removal of CO2 from the atmosphere is on the order of hundreds of years, and because of negative feedbacks in the system, possibly much longer.

A major study sheds new light on the role of carbon dioxide once it’s transported to the oceans’ depths. The research indicates that instead of sinking, carbon dioxide is often consumed by animals and bacteria and recycled in the “twilight zone,” a dimly lit area 100 to 1,000 meters below the surface. Because the carbon often never reaches the deep ocean, where it can be stored and prevented from re-entering the atmosphere as a green-house gas, the oceans may have little impact on changes in the atmosphere or climate.
The research is the result of two international expeditions to the Pacific Ocean, and is published in the April 27, 2007, issue of Science.
“These results are particularly important to our efforts today to improve the predictive capacity of numerical models that relate ocean carbon to global climate change on different time scales,” said Don Rice, director of NSF’s chemical oceanography program.
It also adds a new wrinkle to proposals to mitigate climate change by fertilizing the oceans with iron–to promote blooms of photosynthetic marine plants and transfer more carbon dioxide from the air to the deep ocean.
“The twilight zone is a critical link between the surface and the deep ocean,” said Ken Buesseler, a biogeochemist at Woods Hole Oceanographic Institution and lead author of the new study, which is co-authored by 17 other scientists. “We’re interested in what happens in the twilight zone, what sinks into it and what actually sinks out of it. Unless the carbon goes all the way down into the deep ocean and is stored there, the oceans will have little impact on climate change.”
Buesseler was the leader of a project funded by the National Science Foundation (NSF) called VERTIGO (Vertical Transport In the Global Ocean).
The twilight zone acts as a gate that allows more sinking particles through in some regions and fewer in others, complicating scientists’ ability to predict the ocean’s role in offsetting the impacts of greenhouse gases.
Using new technology, the researchers found that only 20 percent of the total carbon in the ocean surface made it through the twilight zone off Hawaii, while 50 percent did in the northwest Pacific near Japan.
These sinking particles, often called “marine snow,” supply food to organisms deeper down, including bacteria that decompose the particles. In the process, carbon is converted back into dissolved organic and inorganic forms that are re-circulated and reused in the twilight zone and that can make their way to the surface and back into the atmosphere.
The problem, say scientists, is that particles sink slowly, perhaps 10 to a few hundred meters per day, but they are swept sideways by ocean currents traveling many thousands of meters per day. To collect sinking particles, oceanographers use cones or tubes that hang beneath buoys or float up from sea floor. That, Buesseler said, “is like putting out a rain gauge in a hurricane.”
While many studies have investigated the surface of the ocean, little research has been conducted on the carbon cycle below. The VERTIGO team examined a variety of processes to open a new window into the difficult-to-explore twilight zone. They successfully used a wide array of new tools, including an experimental device that overcame a longstanding problem of how to collect marine snow falling into the twilight zone.
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Other scientists involved in VERTIGO are David Karl of the University of Hawaii; Makio Honda of the Japan Agency for Marine-Earth Science and Technology; Deborah Steinberg of the Virginia Institute of Marine Sciences; Mary Silver of the University of California at Santa Cruz; David Siegel of the University of California at Santa Barbara; James Bishop of the University of California at Berkeley; Thomas Trull of the University of Tasmania, Australia; Philip Boyd of the University of Dunedin, New Zealand; and Frank Dehairs of Free University of Brussels, Belgium.
More than 40 biologists, chemists, physical oceanographers, and engineers from 14 institutions and seven countries participated in the two VERTIGO oceanographic research cruises in 2004 and 2005 to investigate how marine plants die and sink, or are eaten by animals and converted into sinking fecal pellets.

Article here;

http://www.ucar.edu/news/releases/2007/seaice.shtml

arctic_sea_ice_extent5-small.jpg

Mike Tidwell comments – That plants emit a diverse number compounds, including a very small amount of hydrocarbons, is well documented. But keep in mind that even if plants were emitting a great deal of methane into the atmosphere, this still would not constitute a source of climate change. All carbon emitted by plants originated from the atmosphere. In the long view, the great majority of carbon held by plants is returned to the atmosphere as they die and decompose. Only deep-earth atoms moved from below ground to the atmosphere are a true addition of greenhouse gases to our atmosphere. There is a tendency to blame other earth processes for climate change, but the reality is that the blame rests squarely on our shoulders. It is we who are moving carbon-based molecules, safely locked up underground, into our atmosphere on a massive scale.

Scientists disprove a recent study that suggests plants emit the potent greenhouse gas methane

 

A recent study in Nature1 suggested that terrestrial plants may be a global source of the potent greenhouse gas methane, making plants substantial contributors to the annual global methane budget. This controversial finding and the resulting commotion triggered a consortium2 of Dutch scientists to re-examine this in an independent study. Reporting in New Phytologist, Tom Dueck and colleagues present their results and conclude that methane emissions from plants are negligible and do not contribute to global climate change.

 

The consortium brings together a unique combination of expertise and facilities enabling the design and execution of a novel experiment. Plants were grown in a facility containing atmospheric carbon dioxide almost exclusively with a heavy form of carbon (13C). This makes the carbon released from the plants relatively easy to detect. Thus, if plants are able to emit methane, it will contain the heavy carbon isotope and can be detected against the background of lighter carbon molecules in the air.

 

Six plant species were grown in a 13C-carbon dioxide atmosphere, saturating the plants with heavy carbon. 13C-Methane emission was measured under controlled, but natural conditions with a photo-acoustic laser technique. This technique is so sensitive that the scientists are able to measure the carbon dioxide in the breath of small insects like ants. Even with this state-of-the-art technique, the measured emission rates were so close to the detection limit that they did not statistically differ from zero. To our knowledge this is the first independent test which has been published since the controversy last year.

 

Conscious of the fact that a small amount of plant material might only result in small amounts of methane, the researchers sampled the ‘heavy’ methane in the air in which a large amount of plants were growing. Again, the measured methane emissions were neglible. Thus these plant specialists conclude that there is no reason to reassess the mitigation potential of plants. The researchers stress that questions still remain and that the gap in the global methane budget needs to be properly addressed.

 

1’Methane emissons from terrestrial plants under aerobic conditions’ by Keppler F, Hamilton JTG, Braβ M, Rockmann T. Nature 439: 187–191

 

2The Dutch consortium includes scientists from Plant Research International, IsoLife and Plant Dynamics in Wageningen, Utrecht University, and the Radboud University in Nijmegen.

 

ENDS

Notes to Editors

1. The article referred to is available Online Only via Blackwell Synergy:
’No evidence for substantial aerobic methane emission by terrestrial plants: A 13C-labelling approach’ Tom A. Dueck, Ries de Visser, Hendrik Poorter, Stefan Persijn, Antonie Gorissen, Willem de Visser, Ad Schapendonk, Jan Verhagen, Jan Snel, Frans J. M. Harren, Anthony K. Y. Ngai, Francel Verstappen, Harro Bouwmeester, Laurentius A. C. J. Voesenek and Adrie van der Werf

New Phytologist. Article published online: 27-April-2007.

2. For further information, please contact Lucy Mansfield, email: lucy.mansfield@oxon.blackwellpublishing.com or telephone: +44 (0) 1865 476241

 

3. New Phytologist is an international journal offering rapid publication of high quality original research in plant science. Owned by a not-for-profit organisation, the New Phytologist Trust is dedicated to the promotion of plant science.

Mike Tidwell comments -Modern satelite data has not only ended long-standing controveries about ice and climate, but it has also spurred new ones such as the waves mentioned in this article. I do not have a comment on the influence of long waves on our environment at the present time. This is an new idea for me and something I want to think about before commenting.

Read article here;

http://www.esa.int/esaEO/SEMRLH12Z0F_planet_0.html

Mike Tidwell comments — This article is good example of a change in the environment, but which is difficult to say with certainty what caused it.  

Changes in growth rates in some coastal and long-lived deep-ocean fish species in the south west Pacific are consistent with shifts in wind systems and water temperatures, according to new Australian research published in the United States this week.

27 April 2007

“We have drawn correlations between the growth of fish species related to their environmental conditions – faster growth in waters above a depth of 250 metres and slower rates of growth below 1,000 metres,” says lead author, Dr Ron Thresher.

“These observations suggest that global climate change has enhanced some elements of productivity of shallow-water stocks but at the same time reduced the productivity and possibly the resilience of deep water stocks,” he says.

A biological oceanographer with CSIRO’s Wealth from Oceans Research Flagship, Dr Thresher said the research – published in the latest edition of the US science journal, Proceedings of the National Academy of Sciences – is based on the examination of fish earbones, or otoliths, which show similar characteristics to the growth rings used to date the age of trees.  The work was done in collaboration with the Victorian Marine and Aquatic Fisheries Research Institute, which has specialist skills in analysing otoliths.

Water temperatures have been obtained from a 60-year-long record at Maria Island on the Tasmanian east coast, and using 400-year-old deep-ocean corals to measure temperate at depth.

Dr Thresher said populations of large marine species are widely subject to two major stressors – commercial fishing and climate change. Heavy exploitation increases the sensitivity of species to environmental effects and could be magnifying the effects of long-term climate change and short-term climate variability on the viability of some species.

“Dr Thresher said slower growth in fishes has been correlated with a variety of life history traits – from higher mortality to reduced food availability and increased age or smaller size at sexual maturity.”

He said correlations for long-lived shallow and deep-water species suggest that water temperatures have been a primary factor in determining juvenile growth rates in the species examined – banded morwong, redfish, jackass morwong, spiky, black, smooth and warty oreo and orange roughy.  Because of the pervasive effect of temperature on the physiology and growth of marine animals, it was likely that similar effects would be seen in many other species.

The science team examined 555 specimens ranging in age from two to 128 years, with birth years from 1861 to 1993.

Growth rates of a coastal species, juvenile morwong, in the 1990s were 28.5 per cent faster than at the beginning of the period under assessment in the mid-1950s.  By comparison, juvenile oreos, a species found at depths of around 1,000 metres, were growing 27.9 per cent slower than in the 1860s. There was no or little change in the growth rates of species found between 500 and 1,000 metres.

Growth rates of the juveniles of the deep-water species all began decreasing well before the onset of commercial fishing.

Dr Thresher said slower growth in fishes has been correlated with a variety of life history traits – from higher mortality to reduced food availability and increased age or smaller size at sexual maturity.

He said comparisons of historical and modern oceanographic data indicate temperature trends very similar to the apparent changes in growth rates.  In the south west Pacific east of Tasmania sea surface temperatures have risen nearly two degrees, based on the results of a monitoring program at Maria Island.  Coinciding with this has been a southward shift in South Pacific zonal winds which has strengthened the warm, poleward-flowing East Australian Current.

“Modelling suggests that, with increasing global warming, temperatures at intermediate depths are likely to rise near-globally,” Dr Thresher said. “This could mean that over the course of time, the decrease in growth rates for the deep-water species could slow or even be reversed,” Dr Thresher said.

The paper: Depth-mediated reversal of the effects of climate change on long-term growth rates of exploited marine fish, was authored by Dr Thresher, Dr Tony Koslow, now of the Scripps Institute of Oceanography, Dr A.K. Morison, now at the Bureau of Resource Sciences,  and Dr David Smith, now of CSIRO.

University of Colorado at Boulder researchers are forecasting a one in three chance that the 2007 minimum extent of sea ice across the Arctic region will set an all-time record low.

The researchers at CU-Boulder’s Colorado Center for Astrodynamics Research also say there is a 57 percent chance the 2007 sea-ice minimum will be lower than the 2006 minimum of 2.27 million square miles, now the second lowest on record. There is a 70 percent chance the 2007 sea-ice minimum will rank within the lowest five years on record, according to Research Associate Sheldon Drobot of CCAR’s Arctic Regional Ice Forecasting System group in CU-Boulder’s aerospace engineering sciences department.

Sea-ice extent is the area of an ocean covered by at least 15 percent ice. Declining sea ice in the Arctic is believed by researchers to be caused by higher winter temperatures due to greenhouse warming, said Drobot. Arctic sea ice has been declining since the late 1970s.

Researchers pay particular attention to September and March because they generally mark the annual minimum and maximum sea-ice extents respectively, said Drobot. On April 4, researchers from CU-Boulder’s National Snow and Ice Data Center reported the maximum extent of this year’s March Arctic sea ice, 5.7 million square miles, was the second-lowest maximum on satellite record.

While regional sea ice declines were sharpest in the western Arctic over the past few years, large declines also occurred last year in much of the eastern Arctic, according to Drobot. Such regional variation is of interest to the maritime industry, including government agencies, international shipping companies, energy exploration corporations and tourism cruise lines active in the far North, he said.

“The practical offshoot here is that people operating ships in Arctic waters can use these forecasts to try to plan activities several months in advance,” said Drobot. The sea ice research by the CCAR group — the only research group in the world currently making seasonal Arctic sea ice forecasts based on probability — is funded by the National Science Foundation and NASA, he said.

The CCAR researchers used satellite data from the U.S. Department of Defense and temperature records from the National Oceanic and Atmospheric Administration for the forecasts, which they have been producing for five years, said Drobot. Updated forecasts will be provided throughout the spring and summer, he said.

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