Microbial Communities Associated With Passive Acidic Abandoned Coal Mine Remediation

Abstract

Acid mine drainage (AMD) is an environmental issue that can be characterized by either acidic or circumneutral pH and high dissolved metal content in contaminated waters. It is estimated to affect roughly 3000 miles of waterways within the state of Pennsylvania, with half being acidic and half being circumneutral. To negate the harmful effects of AMD, ∼300 passive remediation systems have been constructed within the state of Pennsylvania. In this study, we evaluated the microbial community structure and functional capability associated with Middle Branch passive remediation system in central PA. Sediment and water samples were collected from each area within the passive remediation system and its receiving stream. Environmental parameters associated with the remediation system were found to explain a significant amount of variation in microbial community structure. This study revealed shifts in microbial community structure from acidophilic bacteria in raw AMD discharge to a more metabolically diverse set of taxa (i.e., Acidimicrobiales, Rhizobiales, Chthoniobacteraceae ) toward the end of the system. Vertical flow ponds and the aerobic wetland showed strong metabolic capability for sulfur redox environments. These findings are integral to the understanding of designing effective passive remediation systems because it provides insight as to how certain bacteria [sulfate reducing bacteria (SRBs) and sulfur oxidizing bacteria (SOBs)] are potentially contributing to a microbially mediated AMD remediation process. This study further supports previous investigations that demonstrated the effectiveness of SRBs in the process of removing sulfate and heavy metals from contaminated water.

Passive Treatment for Acid Mine Drainage Partially Restores Microbial Community Structure in Different Stream Habitats

“…The richness and alpha diversity of the microbial communities in this study were generally not useful metrics for distinguishing the habitat type or the effects of AMD treatment. This contrasts with Ly et al [16], who found less diverse microbial communities at sites with raw AMD. However, our beta diversity trends corresponded to the findings of Ly et al [16] in that the similarity of communities among different habitats increased with AMD impact.…”

“…Streams remediated using passive treatment for AMD have shown varying degrees of biological recovery in benthic algal and macroinvertebrate communities relative to reference streams [12][13][14]. The role of microbes in contributing to AMD has been examined [2,15]; however, the effects of AMD and remediation methods on stream bacterial communities have received less attention, especially compared to eukaryotes [16]. Nutrient cycling and organic matter processing by benthic and aqueous microbial communities are critical to stream ecosystems [17], and AMD runoff has been shown to significantly impair these processes [18][19][20].…”

“…Our objectives were (1) to determine the impact AMD has on microbial community structure in the three different types of stream habitats, (2) to ascertain the degree to which those communities are restored by passive treatment, and (3) to assess whether the similarity among the three types of communities (beta diversity) was altered by AMD and treatment. To the best of our knowledge, only one study has previously examined microbial community structure in relation to the passive treatment of AMD [16]. Our study differs by including samples from a reference stream to determine the degree of recovery and examining the microbial communities on leaves in addition to those in sediment and aqueous habitats.…”

Insights into the Metabolism and Evolution of the Genus Acidiphilium , a Typical Acidophile in Acid Mine Drainage

“…For example, the coincided acquisitions of the photosystem II-type photosynthetic reaction center (RC), Calvin cycle enzymes, and carbon monoxide dehydrogenases might have conferred adaptive benefits to Acidiphilium by taking advantage of the high CO levels (∼50 ppm) in mining areas as an energy source ( 47 , 71 ) and the increasing solar luminosity for enhanced CO 2 assimilation and/or energy production ( 72 ). The methane (CH 4 ), metal sulfides, hydrogen (H 2 ), and hydrogen sulfide (H 2 S) that are present in mining areas ( 47 , 73 ) are also potential energy sources for Acidiphilium . Hydrogen (H 2 ) might be formed in AMD areas through the acid dissolution of metals and minerals, and Ni/Fe hydrogenases might exploit this as an electron donor to support chemolithotrophic growth ( 74 ).…”

Zinc removal from highly acidic and sulfate-rich wastewater in horizontal sub-surface constructed wetland

“…Other additional phyla identified (,1%) were Bacteroidetes (0.51%), Chlamydiae (0.36%), Verrucomicrobia (0.22%), Spirochaetes (0.19%), Nitrospirae (0.18%) and Chlorobi (0.13%). Many authors have also revealed the presence of similar bacterial groups in AMD-impacted streams and sediments (Fan et al 2016;Ly et al 2019). The most abundant classes detected were Clostridia (20%), Bacili (16%), Alphaproteobacteria (9.3%), Planctomycetia (7.0%), Actinobacteria (6.4%) and Deltaproteobacteria (5%), while some less detected classes (,5%) were Methanobacteria (3.4%), Miscellaneous Crenarchaeota Group (2.9%), Anaerolineae (2.2%), TG3 (1.5%) and Acidimicrobiia (1.4%).…”