Tens of thousands of stream kilometers worldwide are degraded by a legacy of acid loads, high metal concentrations, and altered habitat caused by acid mine drainage (AMD) from abandoned underground and surface mines. As the primary production base in streams, the condition of algal-dominated periphyton communities is particularly important to nutrient cycling, energy flow, and higher trophic levels. Here, we synthesize current knowledge regarding how AMD-associated stressors affect (i) algal communities and their use as ecological indicators, (ii) their functional roles in stream ecosystems, and (iii) how these findings inform management decisions and evaluation of restoration effectiveness. A growing body of research has found ecosystem simplification caused by AMD stressors. Species diversity declines, productivity decreases, and less efficient nutrient uptake and retention occur as AMD severity increases. New monitoring approaches, indices of biological condition, and attributes of algal community structure and function effectively assess AMD severity and effectiveness of management practices. Measures of ecosystem processes, such as nutrient uptake rates, extracellular enzyme activities, and metabolism, are increasingly being used as assessment tools, but remain in their infancy relative to traditional community structure-based approaches. The continued development, testing, and implementation of functional measures and their use alongside community structure metrics will further advance assessments, inform management decisions, and foster progress toward restoration goals. Algal assessments will have important roles in making progress toward improving and sustaining the water quality, ecological condition, and ecosystem services of streams in regions affected by the legacy of unregulated coal mining.
The assessment of lotic ecosystem quality plays an essential role to help determine the extent of environmental stress and the effectiveness of restoration activities. Methods that incorporate biological properties are considered ideal because they provide direct assessment of the end goal of a vigorous biological community. Our primary objective was to use biofilm lipids to develop an accurate biomonitoring tool that requires little expertise and time to facilitate assessment. A model was created of fatty acid biomarkers most associated with predetermined stream quality classification, exceptional warm water habitat (EWH), warm water habitat (WWH), and limited resource (LR-AMD), and validated along a gradient of known stream qualities. The fatty acid fingerprint of the biofilm community was statistically different (P = 0.03) and was generally unique to recognized stream quality. One striking difference was essential fatty acids (DHA, EPA, and ARA) were absent from LR-AMD and only recovered from WWH and EWH, 45 % more in EWH than WWH. Independently testing the model along a stream quality gradient, this model correctly categorized six of the seven sites, with no match due to low sample biomass. These results provide compelling evidence that biofilm fatty acid analysis can be a sensitive, accurate, and cost-effective biomonitoring tool. We conceive of future studies expanding this research to more in-depth studies of remediation efforts, determining the applicable geographic area for the method and the addition of multiple stressors with the possibility of distinguishing among stressors.
Pre-regulation coal mining and subsequent acid mine drainage (AMD) have drastically altered stream quality in the Appalachian region of the USA. Streams impaired by AMD often times demonstrate lowered pH, increases in specific conductance, and increase in dissolved metal concentrations. These changes in the chemical environment are reflected in the biotic community with drastic reductions in diversity and biomass. Recently, there has been an increase in applying traditional measures of food quality to understand how the biofilm community is altered by environmental condition and use for stream quality monitoring. The purpose of this study was two-fold: (1) to use fatty acid profiles to distinguish between biofilm communities in AMD impaired and unimpaired streams and (2) to determine the consistency of biofilm fatty acid profiles throughout the summer sampling period. Impaired streams showed significantly lower pH and increased specific conductance. Biofilm samples from the AMD impaired streams had lower fatty acid content with a decreased proportion of polyunsaturated fatty acids. Fatty acid profiles easily and rapidly separated biofilm communities into their respective categories, either as being impaired by AMD or unimpaired by AMD, using multivariate statistical approaches. Fatty acid profiles were similar within stream type throughout the summer sampling season, and the profiles were correlated to pH and specific conductance. The results of this study suggest that fatty acid profiles can rapidly and accurately categorize the biofilm community responses to environmental impairment.
Abstract:The freshwater red algal species, Batrachospermum gelatinosum, is common in temperate/boreal regions North America and Europe. In southeast Ohio, gametophytes of this taxon were observed to have two different phenologies; in one stream the gametophytes were present only during the spring months and in another stream they were present year-round. Therefore, the purpose of this study was to determine environmental parameters associated with occurrence, peak vegetative growth and reproduction for B. gelatinosum gametophytes in these two streams. Field sampling was conducted for 18 months with both streams being sampled every three to four weeks, when possible. Physical and chemical parameters of stream depth, current velocity, pH, conductivity and nutrients were measured each sampling date. Algal thalli were measured for changes in both vegetative and reproductive characters. In both streams, algal reproductive structures were positively correlated with stream depth (7-52 cm), but there was no correlation of vegetative characteristics with environmental variables measured. Algal cover (0-50%) in each stream was positively correlated with stream depth (7-52 cm), current velocity (BDL-1.08 m.s ) and day length (10.3-15.1 hrs). The site with the least canopy cover and greatest water depth had the highest algal cover and gametophytes present year-round; whereas the site with lower water depth had lower algal cover and gametophyte present only during spring and early summer. This result suggests that stream size and amount of riparian vegetation may play a role in determining phenologies observed. Contrasting phenologies have been reported for B. gelatinosum from sites that are geographically distant, but this study has found that local physical factors may produce differing phenologies in streams only a few kilometers apart.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.