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Forest fragmentation alters global carbon cycle

Careful measurements show how roads and other disturbances affect moisture and the ability of fungi and bacteria to break down dead wood


Forest fragmentation has a big impact on the carbon cycle. bberwyn photo.

By Summit Voice

FRISCO —Logging roads, clearcuts and other disturbances that fragment forests can slow the decay of dead wood and significantly alter the cycling of carbon and nutrients in woodland ecosystems, according to a new study.

Scientists with Earthwatch and the University of Exeter (UK) took a hard look at global forest fragmentation, starting the well-known fact that the edge effect influences temperature, moisture and other elements of forest microclimates. But the effect on the carbon cycle is less understood, so the researchers used on-the-ground experiments combined with modeling to try and fill the gaps. Continue reading

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Oceans: Study shows whales are ecosystem engineers

A North Atlantic right whale and calf. PHOTO COURTESY NOAA.

A North Atlantic right whale and calf. PHOTO COURTESY NOAA.

Healthy whale populations could buffer oceans from some global warming impacts

Staff Report

FRISCO — Whales may play a much bigger role in ocean ecosystems than previously thought, according to a University of Vermont researcher who studied how the great cetaceans recycle and move nutrients from one region to another.

“For a long time, whales have been considered too rare to make much of a difference in the oceans,” notes University of Vermont conservation biologist Joe Roman.

That was a mistake, he said, explaining how his research shows that whales  have a powerful and positive influence on the function of oceans, global carbon storage, and the health of commercial fisheries. Continue reading

Climate: Does the Southern Ocean hold the ice age key?

Abysmal waters play huge role in global carbon cycles

The water in the Antarctic Sound can be smooth as glass, and sometimes look thick and oily, probably because it's so cold. Click on the photo to learn about some of the environmental issues in Antarctica.

The water in the Antarctic Sound can be smooth as glass. bberwyn photo.

By Summit Voice

FRISCO — The remote Southern Ocean, encircling Antarctica, may be a key driver of the carbon cycle, inhaling and exhaling enough carbon to help shift the global climate in and out of ice ages.

For decades, scientists have been trying to figure out what exactly, along with the known wobbles in Earth’s journey around the sun, may cause the huge shifts that lead to vast ice sheets covering many of the planet’s land masses. Continue reading

Climate: Arid lands also help sequester carbon

The Grand Canyon, bberwyn photo.

The Grand Canyon, bberwyn photo.

Researchers surprised by findings from Mojave desert

Staff Report

FRISCO — The world’s arid regions may be able to take up more carbon than previously thought, according to a new study based on detailed soil and carbon measurements from the Mojave Desert.

The research, led by a Washington State University biologist, will help develop a more accurate global carbon budget — how much carbon remains in the atmosphere as CO2, contributing to global warming, and how much gets stored in the land or ocean in other carbon-containing forms. Continue reading

Old trees key to forest carbon cycles


Giant California redwood tree.

Study makes case for maintaining old-growth forests

By Summit Voice

FRISCO — Giant old trees play a key role in forest carbon cycles, researcher said this week, dispelling long-held misconceptions about the growth rate of trees.

In fact, trees never stop growing — as they age, their growth accelerates, even after they’ve reached massive sizes. This means that older trees play a substantial and disproportionate role in the Earth’s carbon cycle, one of the cycles that makes Earth capable of sustaining life.

The study, published in the journal Nature, was co-authored by University of Nebraska-Lincoln biologist Sabrina Russo. To reach their findings, the scientists analyzed biomass growth measurements of 673,046 trees belonging to 403 species from various temperate and tropical regions across six continents. Continue reading

Study: Fungi play key role in global carbon cycle


The role of fungi must be considered in carbon models.

Interaction between plants, fungi and bacteria determine how much carbon is stored in soils

By Summit Voice

FRISCO — Certain types of fungi that live symbiotically with plants play a crucial role in the global carbon cycle by regulating how much carbon is stored by soils.

According to a new study by scientists with the University of Texas at Austin, Boston University and the Smithsonian Tropical Research Institute, the fungi have a bigger effect that most other factors, including including the amount of plant growth, temperature and rainfall.

Another recent study from Sweden also showed that mycorrhizal fungi are trapping the carbon deep in the ground as part of the process of nutrient exchange between the fungi and plant species. Continue reading

Climate study shows nuances in Arctic carbon cycle

Warmer seas don’t always take up more carbon

West Antarctic ice sheets

How will melting sea ice affect global carbon cycles? bberwyn photo.

By Summit Voice

FRISCO — As sea ice inexorably declines, the Arctic Ocean has started to absorb more carbon — by some as estimates, as much as one additional megaton each each, thanks to increased biological productivity.

But those effects are not spread evenly across the region, according to a new study that paints a nuanced picture of how global warming is changing the carbon cycle in the Arctic. The MIT research team modeled changes in Arctic sea ice, temperatures, currents, and flow of carbon from 1996 to 2007, and found that the amount of carbon taken up by the Arctic increased by 1 megaton each year.

But their detailed analysis found that some areas of the Arctic where temperatures have warmed the most are actually storing less carbon. Instead, these regions — including the Barents Sea, near Greenland — have become a carbon source, emitting carbon dioxide to the atmosphere. Continue reading

Extreme weather spurs classic climate feeback loop


Climate feedback loops could have significant implications for agricultural production. bberwyn photo.

Extreme weather events alter carbon uptake by plants

By Summit Voice

FRISCO — Scientists often think about climate change in terms of how larger, ongoing atmosphere changes affect ecosystems on land and in the ocean, but a new study by German researchers shows that it works both ways.

In a classic climate feedback loop, the researchers determined that extreme weather events like like storms, heavy precipitation, as well as droughts and heat waves, prevent the uptake of 3 gigatons of carbon by global vegetation. Continue reading

Global warming: Earth is breathing more deeply these days


Careful atmospheric measurement shows the annual carbon-dioxide cycle is amplifying.

‘A clear signal of widespread changes in northern ecosystems’

By Summit Voice

FRISCO — The Earth breathes in seasonal cycles, exhaling and inhaling great gulps of carbon dioxide as plant life goes through its annual cycle of growth.

And lately, those breaths have become up to 50 percent deeper, as more carbon dioxide is emitted from burning fossil fuels and other human activities, according to a study led by scientists at the Scripps Institution of Oceanography. Continue reading

Study challenges forest carbon cycle assumptions


Forests alone won’t be able to soak up all the excess heat-trapping carbon dioxide in the atmosphere. bberwyn photo.

‘Nature cannot self-correct entirely against climate change …’

By Summit Voice

FRISCO — Massive reforestation efforts may help soak up a small part of the carbon dioxide generated by fossil fuel combustion, but it’s not a panacea for increasing concentrations of heat-trapping greenhouse gases.

Most widely accepted climate models have probably been over-estimating the ability of forests to absorb carbon from the atmosphere because the models do not represent the responses of soil microorganisms correctly, according to scientists with Northern Arizona University.

Their 11-year study showed that, contrary to expectations, high CO2 levels didn’t significantly increase carbon uptake. Plants did contain more carbon when CO2 levels were increased, but the soil actually lost carbon due to microbial decomposition; both factors essentially balanced one another out. Continue reading


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