U.S. Rivers and Streams Saturated With Carbon

Science Daily  — Rivers and streams in the United States are releasing substantially more carbon dioxide into the atmosphere than previously thought, according to researchers publishing their results in the current issue of the journal Nature Geoscience.

Their findings could change the way scientists model the movement of carbon among land, water and the atmosphere.

"Direct measurements of carbon dioxide concentrations and fluxes in streams and rivers are still extremely rare," said Henry Gholz, program director in the National Science Foundation's (NSF) Division of Environmental Biology, which funded the research.

"This study demonstrates that both are much higher than assumed. The research should enable more predictive and precise models of carbon cycling at regional to global scales."

The researchers found that a significant amount of carbon contained in land, which first is absorbed by plants and forests through the air, is leaking into streams and rivers and then released into the atmosphere before reaching coastal waterways.

"What we are able to show is that there is a source of atmospheric carbon dioxide from streams and rivers, and that it is significant enough for terrestrial modelers to take note of it," said David Butman, a co-author of the paper and scientist at the Yale University School of Forestry & Environmental Studies.

He and his co-author, ecologist Peter Raymond also of Yale, analyzed data from samples of more than 4,000 rivers and streams throughout the United States, and incorporated detailed geospatial data to model the flux of carbon dioxide from water.

This release is equal to a car burning 40 billion gallons of gasoline, enough to drive back and forth to the moon 3.4 million times.

"These rivers breathe a lot of carbon," said Butman. "They are a source of carbon dioxide, just like we breathe out carbon dioxide and like smokestacks emit carbon dioxide.

"This has never been systematically estimated from a region as large as the United States."

The paper, titled "Significant Efflux of Carbon Dioxide from Streams and Rivers in the United States," also indicates that as the climate heats up there will be more rain and snow, and that an increase in precipitation will result in even more terrestrial carbon flowing into rivers and streams and being released into the atmosphere.

Any accurate estimate of carbon uptake vs. carbon released must include the carbon in streams and rivers, Butman said.

The researchers note that currently it's difficult to determine how to include this flux in regional carbon budgets, because the influence of human activity on the release of carbon dioxide into streams and rivers is still unknown.

The research was also funded by a NASA Earth and Space Science Fellowship, a NASA Carbon & Ecosystems Program grant, and the Yale School of Forestry & Environmental Studies.

Bioluminescence: Explanation for Glowing Seas Suggested

Science Daily  — It has long been known that distinctive blue flashes- a type of bioluminescence- visible at night in some marine environments are caused by tiny, unicellular plankton known as dinoflagellates. However, a new study has, for the first time, detailed the potential mechanism for this bioluminesence.

A key aspect of the potential mechanism for bioluminescence in dinoflagellates proposed in the PNAS study involves voltage-gated proton channels--channels in membranes that can be opened or closed by chemical or electrical events.The study, which was partially funded by the National Science Foundation, is reported by Susan Smith of Emory School of Medicine, Thomas DeCoursey of Rush University Medical Center and colleagues in the Oct. 17, 2011 issue of the Proceedings of the National Academy of Sciences(PNAS).

J. Woodland Hastings, a Smith and DeCoursey research team member and an author of the PNAS article, suggested the presence of voltage-gated proton channels in dinoflagellates almost forty years ago. But the Smith and Decoursey team only recently confirmed them by the identification and subsequent testing of dinoflagellate genes that are similar to genes for voltage-gated proton channels that had previously been identified in humans, mice and sea squirts.

According to the study, here is how the light-generating process in dinoflagellates may work: As dinoflagellates float, mechanical stimulation generated by the movement of surrounding water sends electrical impulses around an internal compartment within the organism, called a vacuole--which holds an abundance of protons. These electrical impulses open so-called voltage-sensitive proton channels that connect the vacuole to tiny pockets dotting the vacuole membrane, known as scintillons.

Once opened, the voltage-sensitive proton channels may funnel protons from the vacuole into the scintillons. Protons entering the scintillons then activate luciferase--a protein, which produces flashes of light, that is stored in scintillons. Flashes of light produced by resulting luciferase activation would be most visible during blooms of dinoflagellates.

This research illuminates the novel mechanisms underlying a beautiful natural phenomenon in our oceans, and enhances our understanding of dinoflagellates--some of which can produce toxins that are harmful to the environment.

First-Ever Pics of a Star Cluster on the Far Side of the Galactic Center

By Clay Dillow

ESO's New VISTA Shots Looking Through the Galactic Center ESO/D. Minniti/VVV Team

The European Southern Observatory’s VISTA survey telescope has turned its eyes inward to the center of our galaxy, and for the first time has looked straight through it. VISTA’s latest batch of infrared images have discovered two new globular clusters here in the Milky Way that had never been seen before, but more importantly they are the first star clusters that we’ve been able to image beyond the dusty and gaseous core of our galaxy.

That’s because the galactic center is extremely difficult for us to see through. Anything beyond the dense and swirling clouds of interstellar dust and other gases is impossible to see in the invisible spectrum, but VISTA’s infrared eyes can peer deep into areas impermeable with visible range telescopes.

The two new clusters--titled VVV CL001 and VVV CL002 (catchy, no?)--appear faint but visible in the new VISTA images. The beautiful panorama above is dominated by the bright globular cluster UKS 1 on the right hand side of the image, but if you look toward the upper left quadrant of the image you can see VVV CL001 as the faint bright spot that looks like a concentration of stars and gas. VVV CL002 is more visible in the detail below, where it rests squarely in the center of the image.

Closeup of VVV CL002:  ESO/D. Minniti/VVV Team

Download the ginormized, wallpaper-quality pic via ESO.

[ESO]