<< Previous

Next >>

Increased exposure to solar UV radiation and elevated water temperatures are believed to play a role in the bleaching of corals. To provide additional tools for evaluating the role of UV radiation, we have examined UV-specific effects in coral and have characterized factors that ...

Recent studies have indicated that solar LTV radiation is a significant stressor of coral assemblages in tropical and subtropical marine environments. Here evidence is presented that UV exposure of coral reefs in the Florida Keys near Key West is controlled by the colored compone...

Review of the the book &quot;Ecological Indicators for the Nation&quot;. This book is the report of the Committee to Evaluate Indicators for Monitoring Aquatic and Terrestrial Environments, which was established at the behest of the U.S. Environmental Protection Agency. The boo...

Several important optical terms such as "absorbance" and "absorption coefficient" are frequently used ambiguously in the current peer-reviewed literature. Since they are important terms that are required to derive other quantities such as the "apparent quantum yield" of photoprod...

There is no abstract available for this product. If further information is requested, please refer to the bibliographic citation and contact the person listed under Contact field.

Terrestrially derived dissolved organic matter (DOM) impacts the optical properties of coastal seawater and affects carbon cycling on a global scale. We studied sequential long-term photochemical and biological degradation of estuarine dissolved organic matter from the<br>Satilla...

Concentrations of CO2, CO, and CH4 were measured in beaver pond and lake ice in April 1996 near Thompson, Manitoba to derive information on possible impacts of ice melting on corresponding atmospheric trace gas concentrations. CH4 concentrations in beaver pond and lake ice ranged...

We have investigated the importance of leaf litter from red mangroves (Rhizophora mangle) and living Sargassum plants as sources of chromophoric dissolved organic matter (CDOM) to the coastal ocean waters and coral reef system of the Florida Keys. The magnitude of UVB exposure t...

Chromophoric dissolved organic matter (CDOM) in the Mississippi plume region may have several distinct sources: riverine (terrestrial soils), wetland (terrestrial plants), biological production (phytoplankton, zooplankton, microbial), and sediments. Complex mixing, photodegradati...

Slide presentation presented at Clemson University, March 13, 2007.

Quantum yield spectra for the photochemical formation of biologically labile photoproducts from dissolved organic matter (DOM) have not been available previously, although they would greatly facilitate attempts to model photoproduct formation rates across latitudinal, seasonal, a...

Fluorescence-based observations provide useful, sensitive information concerning the nature and distribution of colored dissolved organic matter (CDOM) in coastal and freshwater environments. The excitation-emission matrix (EEM) technique has become widely used for evaluating sou...

Increase in agricultural practices in the Cerrado (tropical savannah) and Amazon regions in Brazil is causing drastic changes in the nutrient and carbon cycling of native areas. Because microorganisms play a key role in biogeochemical cycling, monitoring the shifts in the microb...

The combination of compound specific stable isotopic analysis with phospholipid fatty acid (PLFAS) analysis is useful in determining the source of organic carbon used by groups of a microbial community. Determination of the effect of certain environmental parameters is important ...

Pasture plots included unharvested, hayed, light and heavy cattle grazing pressure, fertilized with either inorganic N-P-K or broiler litter. Total phospholipid fatty acids (PLFAs) followed a seasonal trend and were higher in grazed plots than hayed & unharvested plots. Fungi a...

Corals and coral reefs of the Caribbean and through the world are deteriorating at an accelerated rate. Several stressors are believed to contrbute to this decline, including global changes in atmospheric gases and land use patterns. In particular, warmer water temperatures and...

Savanna ecosystems are controlled by the interactions between water and nutrient availability. The savannas of Central Brazil (Cerrado) are the second most extensive plant formation in tropical South America with two million km2 of area. The Cerrado landscape contains different ...

A study examined the effect of sunlight-initiated photo-degradation of dissolved organic matter (DOM) on its carboxyl content, and the role of oxygen and iron in this process. Solar-simulated irradiations were performed on 0.2-mm filtered water samples collected from the highly c...

The soil microbial community plays an important role in tropical ecosystem functioning because of its importance in the soil organic matter (SOM) cycle. We have measured the stable carbon isotopic ratio (delta13C) of individual phospholipid fatty acids (PLFAs) in a variety of tr...

The Brazilian cerrado is experiencing rapid land use changes that are often accompanied by fire. Here we report initial studies of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the ...

Pioneering studies by Don Crosby and co-workers demonstrated that the sunlight-induced dissipation of agrochemicals in water often is strongly affected by natural constituents in the water such as nitrate and dissolved organic matter. In this presentation, the focus is on the rol...

Land use changes accompanied by fire frequently occur in the Brazilian cerrado. Here we report measurements in the cerrado of the effects of fire and land use change on the composition and persistence of litter and soil organic carbon and nitrogen and related changes in the soil-...

Solar radiation provides the primary driving force for the biogeochemical cycles upon which life and climate depend. Recent studies have demonstrated that the absorption of solar radiation, especially 'm the ultraviolet spectral region, results in photochemical reactions that can...

The effects of ozone depletion on global biogeochemical cycles, via increased UV-B radiation at the Earth's surface, have continued to be documented over the past 4 years. In this report we also document various effects of UV-B that interact with global climate change because the...

Estuaries are very dynamic ecosystems with regard to the transport and transformation of organic matter. Detrital organic matter is abundant in most estuaries, however, the dynamics of detritus utilization is not well understood. Two questions that remain unanswered are the sou...