Change in land cover type from 1990 to 2010 near South Padre, Texas.

<p>Change in land cover type from 1990 to 2010 near South Padre, Texas.</p

Confusion matrices depicting the accuracy of coastal Texas land cover classification in 2010 and 1990.

<p>Confusion matrices depicting the accuracy of coastal Texas land cover classification in 2010 and 1990.</p

Net change in (a) salt marsh and (b) mangrove area.

<p>Changes are broken down by land cover type and are summed across the entire Texas coast from 1990 to 2010.</p

Generalized Two-Dimensional Perturbation Correlation Infrared Spectroscopy Reveals Mechanisms for the Development of Surface Charge and Recalcitrance in Plant-Derived Biochars

Fundamental knowledge of how biochars develop surface-charge and resistance to environmental degradation is crucial to their production for customized applications or understanding their functions in the environment. Two-dimensional perturbation-based correlation infrared spectroscopy (2D-PCIS) was used to study the biochar formation process in three taxonomically different plant biomass, under oxygen-limited conditions along a heat-treatment-temperature gradient (HTT; 200–650 °C). Results from 2D-PCIS pointed to the systematic, HTT-induced defragmenting of lignocellulose H-bonding network and demethylenation/demethylation, oxidation, or dehydroxylation/dehydrogenation of lignocellulose fragments as the primary reactions controlling biochar properties along the HTT gradient. The cleavage of OH^...O-type H-bonds, oxidation of free primary hydroxyls to carboxyls (carboxylation; HTT ≤ 500 °C), and their subsequent dehydrogenation/dehydroxylation (HTT > 500 °C) controlled surface charge on the biochars; while the dehydrogenation of methylene groups, which yielded increasingly condensed structures (R–CH₂–R →RCH–R →RCR), controlled biochar recalcitrance. Variations in biochar properties across plant biomass type were attributable to taxa-specific transformations. For example, apparent inefficiencies in the cleavage of wood-specific H-bonds, and their subsequent oxidation to carboxyls, lead to lower surface charge in wood biochars (compared to grass biochars). Both nontaxa and taxa-specific transformations highlighted by 2D-PCIS could have significant implications for biochar functioning in fire-impacted or biochar-amended systems

Coastal Zone Management study area and Landsat 5 TM footprints.

<p>Coastal Zone Management study area and Landsat 5 TM footprints.</p

Landsat 5 TM image locations, acquisition dates, and water level at time of image acquisition (select stations).

<p>NA indicates that water level data were not available for that date.</p><p>Landsat 5 TM image locations, acquisition dates, and water level at time of image acquisition (select stations).</p

Difference in the number of pre-imagery days with minimum temperatures below 0°C from November—February.

<p>Positive values (blue) indicate more freeze days in 2010 compared to 1990 (cooling trend). Negative values (red) indicate more freeze days in 1990 compared to 2010 (warming trend).</p

Change in land cover type from 1990 to 2010 near Port O’Connor, Texas.

<p>Change in land cover type from 1990 to 2010 near Port O’Connor, Texas.</p

The minimum recorded temperature (°C) at weather stations along the Texas coast, with the number of days with minimum temperatures below -6.7°C in parentheses.

<p>- indicates that data were not available. Weather data were obtained from the NOAA National Climatic Data Center (<a href="http://www.ncdc.noaa.gov/" target="_blank">http://www.ncdc.noaa.gov/</a>).</p><p>The minimum recorded temperature (°C) at weather stations along the Texas coast, with the number of days with minimum temperatures below -6.7°C in parentheses.</p

Average annual rates of change in relative sea level at stations on the Texas coast, listed from south to north.

<p>Rates are calculated from 1965 (or earlier) through 2006. Data are from <a href="http://tidesandcurrents.noaa.gov/sltrends/sltrends.html" target="_blank">http://tidesandcurrents.noaa.gov/sltrends/sltrends.html</a>.</p><p>Average annual rates of change in relative sea level at stations on the Texas coast, listed from south to north.</p