The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Climate change 2014 - Mitigation of climate change

Transactions of the Institute of British Geographers

Dissolved organic matter (DOM) in soils plays an important role in the biogeochemistry of carbon, nitrogen, and phosphorus, in pedogenesis, and in the transport of pollutants in soils. The aim of this review is to summarize the recent literature about controls on DOM concentrations and fluxes in soi

Controls on the dynamics of dissolved organic matter in soils: a review.

Several hypotheses have been proposed to explain recent, widespread increases in concentrations of dissolved organic carbon (DOC) in the surface waters of glaciated landscapes across eastern North America and northern and central Europe. Some invoke anthropogenic forcing through mechanisms related to climate change, nitrogen deposition or changes in land use, and by implication suggest that current concentrations and fluxes are without precedent. All of these hypotheses imply that DOC levels will continue to rise, with unpredictable consequences for the global carbon cycle. Alternatively, it has been proposed that DOC concentrations are returning toward pre-industrial levels as a result of a gradual decline in the sulphate content of atmospheric deposition. Here we show, through the assessment of time series data from 522 remote lakes and streams in North America and northern Europe, that rising trends in DOC between 1990 and 2004 can be concisely explained by a simple model based solely on changes in deposition chemistry and catchment acid-sensitivity. We demonstrate that DOC concentrations have increased in proportion to the rates at which atmospherically deposited anthropogenic sulphur and sea salt have declined. We conclude that acid deposition to these ecosystems has been partially buffered by changes in organic acidity and that the rise in DOC is integral to recovery from acidification. Over recent decades, deposition-driven increases in organic matter solubility may have increased the export of DOC to the oceans, a potentially important component of regional carbon balances. The increase in DOC concentrations in these regions appears unrelated to other climatic factors.

Dissolved organic carbon trends resulting from changes in atmospheric deposition chemistry.

A positive temperature coefficient is the term which has been used to indicate that an increase in solubility occurs as the temperature is raised, whereas a negative coefficient indicates a decrease in solubility with rise in temperature.

Effect of Temperature

Sociopolitical influences on cropland area change in Iraq, 2001–2012

Surface coal mining impacts on water resources in the Appalachian region, USA, are widely studied. Total dissolved solids (TDS), which are estimated in situ by the proxy variable specific conductance (SC), are of interest due to potential aquatic macroinvertebrate effects. Prior studies have documented the hydrochemical impacts of surface mining on streams, but research on the relationships between SC and discharge is limited. SC–Stage relationships can help infer potential hydrologic flow paths, as well as source water TDS concentrations in mining-influenced watersheds. The objectives of this study were to compare baseflow and stormflow hydrochemistry and determine SC–Stage relationships in valley fill (VF) streams. Five VF streams of varying ages in Virginia were equipped with continuous SC and stage data loggers for up to 12 months (December 2013–November 2014). Data analyses included baseflow and stormflow hydrochemistry, and SC–Stage regressions and storm hysteresis patterns. Data were analyzed seasonally. Stages were generally highest in winter and lowest in summer, while SCs were generally highest in summer and lowest in winter. All SC–Stage regressions indicated SC dilution during stormflow, but significance differed seasonally. Storm SC–Stage hysteresis patterns varied with storm precipitation amounts, season, and vegetative period, implying climatic controls on VF stream storm responses. Counterclockwise storm hysteresis likely occurred in response to high rainfall amounts exceeding the mine soil infiltration capacity. Clockwise storm hysteresis likely resulted from precipitation dissolving salts brought to the surface by evapotranspiration, but may have also resulted from rapid flow through pseudokarst features within the VF.

Specific conductance–stage relationships in Appalachian valley fill streams

Virginia Cooperative Extension programs and employment are open to all, regardless of race, color, national origin, sex, religion, age, disability, political beliefs, sexual orientation, or marital or family status. An equal opportunity/affirmative action employer. Issued in furtherance of Cooperative Extension work, Virginia Polytechnic Institute and State University, Virginia State University, and the U.S. Department of Agriculture cooperating. Rick D. Rudd, Interim Director, Virginia Cooperative Extension, Virginia Tech, Blacksburg; Wondi Mersie, Interim Administrator, 1890 Extension Program, Virginia State, Petersburg. PUBLICATION 460-138

Restoring the Value of Forests on Reclaimed Mined Land

Benthic macroinvertebrate communities in headwater streams influenced by Appalachian coal mining often differ from communities in minimally disturbed streams. Elevated levels of total dissolved solids (TDS) associated with mining have been suggested as stressors to these communities. In studies of such streams conducted to date, both non-TDS stressors and elevated TDS have been present as potential influences on biota. In the study reported here the association between dissolved salts and benthic macroinvertebrate community structure was examined using a familylevel multimetric index and genus-level taxa sensitivity distributions. Test sites were selected along a gradient of elevated TDS, with non-TDS factors of reference quality. Virginia Stream Condition Index (VASCI) scores were regressed against log-transformed measures of TDS, specific conductance, and sulfate (SO4) using ordinary least squares and quantile regression techniques. Biological effects, as defined by VASCI scores <60 indicating stressed or severely stressed conditions, were observed with increasing probability from 0% at ≤ 190 mg/L TDS to 100% at ≥ 1,108 mg/L TDS, with 50% probability of effects observed at 422 mg/L TDS. Associations between water quality measures and biological condition were variable, with approximately 48% of the variance explained by TDS. Genus-level analysis using a field sensitivity distribution approach indicated 95% of reference genera were observed at sites with TDS ≤ 281 mg/L, and 80% of genera were observed at sites with TDS ≤ 411 mg/L. This is evidence that TDS, specific conductance, or SO4can be used to establish dissolved solids levels for streams influenced by Appalachian coal mining above which aquatic life effects are increasingly probable. A preliminary report of results was published as Timpano et al. (2010), and a final report as Timpano et al. (2011). The final report was derived directly from Timpano (2011). This research was supported by Virginia Department of Environmental Quality, Virginia Department of Mines, Minerals, and Energy, and Powell River Project. The authors thank property owners and mine permittees for providing access to study sites, as well as the industry and consultant personnel that provided site orientation. Finding and accessing high-quality study sites was made possible with assistance from numerous mine operators and their consultants, as well as private landowners. They are: Eddie Clapp and Roger Jones, Red River Coal Company; Mark Sproles, Dickenson-Russell Coal Company; Tad Nunley, United Coal Company; Phil Mullins, Skelly & Loy, Inc.; Keith Mohn, Arch Coal, Inc.; Chris Stanley and Dean Childress, Clintwood-Elkhorn Mining Company; Craig Kaderavek, The Forestland Group, LLC; Marty Large, Marty Corp. We thank also the Virginia Tech students that assisted with site selection, data collection, sample processing, and sample analysis: Autumn Timpano, Jackie Carl, Robert Northington, Trip Krenz, Mindy Forsyth, and Caleb Parks.

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Levels of Dissolved Solids Associated with Aquatic Life Effects in Headwater Streams of Virginia's Central Appalachian Coalfield Region

The Clinch River of southwestern Virginia and northeastern Tennessee is arguably the most important river for freshwater mussel conservation in the United States. This featured collection presents investigations of mussel population status and habitat quality in the Clinch River. Analyses of historic water- and sediment-quality data suggest that water column ammonia and water column and sediment metals, including Cu and Zn, may have contributed historically to declining densities and extirpations of mussels in the river's Virginia sections. These studies also reveal increasing temporal trends for dissolved solids concentrations throughout much of the river's extent. Current mussel abundance patterns do not correspond spatially with physical habitat quality, but they do correspond with specific conductance, dissolved major ions, and water column metals, suggesting these and/or associated constituents as factors contributing to mussel declines. Mussels are sensitive to metals. Native mussels and hatchery-raised mussels held in cages in situ accumulated metals in their body tissues in river sections where mussels are declining. Organic compound and bed-sediment contaminant analyses did not reveal spatial correspondences with mussel status metrics, although potentially toxic levels were found. Collectively, these studies identify major ions and metals as water- and sediment-quality concerns for mussel conservation in the Clinch River.

Carl E. Zipper

Papers

Sociopolitical influences on cropland area change in Iraq, 2001–2012

Specific conductance–stage relationships in Appalachian valley fill streams

Restoring the Value of Forests on Reclaimed Mined Land

Levels of Dissolved Solids Associated with Aquatic Life Effects in Headwater Streams of Virginia's Central Appalachian Coalfield Region

Freshwater Mussel Population Status and Habitat Quality in the Clinch River, Virginia and Tennessee, USA: A Featured Collection