No abstract

No abstract

In order to determine the influence of geologic patterns and coal mining on benthic algal assemblages, 56 stream sites throughout the unglaciated Western Allegany Plateau were investigated. These sites were categorized based upon catchment mining/reclamation history. At each site, select environmental parameters such as pH, temperature, dissolved oxygen, specific conductance, metallic salts concentration, turbidity, maximum wetted width, and average thalweg depth were measured. Periphyton from riffle areas and macroscopic algal taxa from a 20 m segment were collected. Relative importance values were developed and calculated for both the periphyton and macroalgal communities. Canonical correspondence analyses of the periphyton and macroalgal data set each showed five major groups of stream reaches that were defined by specific algal taxa and environmental characteristics. Two of the groups were dominated by variables associated with acid mine drainage (AMD) and had taxa known from very acidic waters. One group was entirely composed of sites receiving treated waters from active coal mines. Another group was dominated by sites classified as alkaline mine drainage (AkMD) and the last group was primarily reference sites with a few reclaimed reaches. The AMD impacted groups had a significantly lower species richness and diversity than the other three groups. Species-based models for inferring the level of critical environmental parameters related to mining showed the periphyton-based inference model for pH was highly predictable and may be quite useful for evaluation of coal mine remediation. Other promising periphyton-and macroalgalbased models, yielded poor r 2 and root mean square error (RMSE) after cross-validation. Comparison of the relative importance values with more traditional assessments of community structure showed similar results with the diatoms and chlorophytes dominating the periphyton and macroalgae, respectively.

One of the primary goals of forensic pathology is the determination of time of death. In aquatic systems, one method to do this is to analyze the colonization of a corpse by algae. Algal communities typically follow a serial colonization pattern, therefore the taxa present at any given time may provide clues about post-mortem submersion time. This study was undertaken to examine the algal colonization on rat carcasses in a medium-order woodland stream. Two habitats were studied: a low flow pool and a high flow riffle, with rats being removed from each site every 3 to 6 days over 31 days. The diversity of colonizing taxa increased at both sites as the study progressed, and after 17 days similar taxa were present (Sorensen's similarity index >60%) in each site. Some taxa, such as desmids (Chlorophyta), tended to increase in diversity throughout the study, making them possible indicators of submersion time. Diatoms were the most abundant taxa found in each site and accounted for 63 of the 92 total taxa identified. Due to their ubiquitous presence in nearly all streams, we suggest that diatoms may be the key organisms for the study of postmortem submersion in lotic systems.

Fifteen stream segments in an acid mine drainage (AMD) impacted basin were sampled for periphyton, measured for water chemistry and evaluated for physical habitat in June, August and October in order to assess stream quality. Periphyton index of biotic integrity (PIBI) scores for individual stream segments varied among sampling dates, with the June and October scores being significantly different (~4. 0 5). The PIBI scores were correlated with six water chemistry variables in August and with at least one variable indicative of AMD in June and October. However, the PIBI scores and the individual metrics were generally not correlated to the measures of physical habitat. Non-metric multi-dimensional scaling (NMS) of water chemistry data identified four groups of streamsreference streams, heavily impacted streams, and two groups of moderately impacted streams. The same groupings were not evident in the NMS biplots of the PIBI scores, but the heavily impacted stream and reference stream groups were distinguished for the June and August data. When the PIBI scores were recalculated using only the correlated six water chemistry variables, the NMS biplot for the August data distinguished the four groups from the water chemistry data.