Project description:In the mid-1990s, yellow perch (Perca flavescens) and common loons (Gavia immer) from Kejimkujik National Park and National Historic Site (KNPNHS), Nova Scotia, Canada, had among the highest mercury (Hg) concentrations across North America. In 2006 and 2007, we re-examined 16 lakes to determine whether there have been changes in Hg in the loon's preferred prey, yellow perch. Total Hg concentrations were measured in up to nine perch in each of three size classes (5-10 cm, 10-15 cm, and 15-20 cm) consumed by loons. Between 1996/97 and 2006/07, polynomial regressions indicated that Hg in yellow perch increased an average of 29% in ten lakes, decreased an average of 21% in three, and were unchanged in the remaining three lakes. In 2006/07, perch in 75% of the study lakes had Hg concentrations (standardized to 12-cm fish length) equal to or above the concentration (0.21 μg·g(-1) ww) associated with a 50% reduction in maximum productivity of loons, compared with only 56% of these lakes in 1996/97. Mercury contamination currently poses a greater threat to loon health than a decade ago, and further reductions in anthropogenic emissions should be considered to reduce its impacts on ecosystem health.
Project description:The thermophilic Aquificales inhabit and play important biogeochemical roles in the geothermal environments globally. Although intensive studies on physiology, microbial ecology, biochemistry, metagenomics and metatranscriptomics of the Aquificales¬ species and Aquificales-containing environmental samples have been conducted, comprehensive understandings about their ecophysiology, especially in the natural niches have been limited. In the present study, an integrated suite of metagenomic, metatranscriptomic and metaproteomic analyses, for the first time, were conducted on a filamentous microbial community from the Apron and Channel Facies (ACF) of CaCO3 (travertine) deposition at Narrow Gauge, Mammoth Hot Springs, Yellowstone National Park.
Project description:The Nile perch (Lates niloticus L.) commercial fishery for Lake Victoria in East Africa is an important source of revenue and employment. We focused on shifts in food web structure and total mercury (THg) bioaccumulation and biomagnification in Nile perch, and lower food web items collected from Winam Gulf (Kenya) sampled 24 years apart (1998 and 2022). Stable isotope carbon (δ13C) values were higher in all species from 2022 compared to 1998. Stable nitrogen isotope (δ15N) values in baseline organisms were lower in 2022 compared to 1998. In Nile perch, δ15N values were correlated with total length, but the δ15N-length regressions were steeper in 1998 compared to 2022 except for one large (158 cm) Nile perch from 1998 with an uncharacteristically low δ15N value. Total Hg concentrations were lower in lower trophic species from 2022 compared to 1998. However, the THg bioaccumulation rate (as a function of fish length) in Nile perch was greater in 2022 compared to 1998 resulting in 24.2 % to 42.4 % higher wet weight dorsal THg concentrations in 2022 Nile perch for market slot size (50 to 85 cm) fish. The contrasting observations of increased THg bioaccumulation with size in 2022 against decreases in the rate of trophic increase with size and lower THg concentrations of lower food web items imply reduced fish growth and potential bioenergetic stressors on Winam Gulf Nile perch. All samples except 1 large Nile perch (139 cm total length collected in 2022) had THg concentrations below the European Union trade limit (500 ng/g wet weight). However, for more vulnerable individuals (women, children and frequent fish eaters), we recommend a decrease in maximum monthly meal consumption for 55-75 cm Nile perch from 16 meals per month calculated for 1998 to a limit of 8 meals per month calculated for 2022.
Project description:The thermophilic Aquificales inhabit and play important biogeochemical roles in the geothermal environments globally. Although intensive studies on physiology, microbial ecology, biochemistry, metagenomics and metatranscriptomics of the Aquificales¬ species and Aquificales-containing environmental samples have been conducted, comprehensive understandings about their ecophysiology, especially in the natural niches have been limited. In the present study, an integrated suite of metagenomic, metatranscriptomic and metaproteomic analyses, for the first time, were conducted on a filamentous microbial community from the Apron and Channel Facies (ACF) of CaCO3 (travertine) deposition at Narrow Gauge, Mammoth Hot Springs, Yellowstone National Park.
Project description:Paired end Illumina Mi-Seq sequencing of 16S rRNA gene amplicon was carried out to study the bacterial community in the soil of Murlen National Park located in Indo-Burman Biodiversity hotspot region. Metagenome consisted of 302,416 reads with 151.81 Mb data and G + C content of 56.48%. More than 85% sequence was having a Phred score >=Q30 and individual sequence length was 251 bp. Metagenome sequence data are available at NCBI under the Bioproject database with accession no. SRP057136. Community metagenomics revealed a total of 1802 species belonging to 29 different phyla dominated by Acidobacteria (39.45%), Proteobacteria (26.95%) and Planctomycetes (7.81%). Our data detected a wide group of bacterial community which will be useful in further isolating and characterizing the economic importance of bacteria from this region.
Project description:Several recent investigations into montane regions have reported on excess mercury accumulation in high-altitude forest ecosystems. This study explored the Singalila National Park, located on the Singalila ridge of the Eastern Himalayas, revealing substantial mercury contamination. Particular focus was on Sandakphu (3636 m), the highest peak in West Bengal, India. It harboured 6.77 ± 0.01 mg/kg of total mercury in its topsoil. Further evidence was provided by accumulation in leaves (0.040 ± 0.01 mg/kg), and roots (0.150 ± 0.008 mg/kg) of local vegetation, litterfall (0.234 ± 0.019 mg/kg), mosses (0.367 ± 0.043 mg/kg), surface water from local lakes and waterbodies (0.010 ± 0.005 mg/l), fresh snow (0.014 ± 0.004 mg/l), and sleet (0.019 ± 0.009 mg/l). Samples from other points of varying elevation in the park also demonstrated contamination. The soil displayed a range of 0.068-5.28 mg/kg, while the mean concentration in leaves was 0.153 ± 0.105 mg/kg, roots was 0.106 ± 0.054 mg/kg, and leaf litter was 0.240 ± 0.112 mg/kg. Additionally, the microbial consortia isolated from the contaminated soil displayed a high tolerance to mercuric chloride, presumably gained through repeated and consistent exposure. Four high tolerance bacterial strains, MTS2C, MTS3A, MTS4B and MTS6A, were further characterized for potential use in bioremediation strategies. Their mercury removal capacities were determined to be 82.35%, 75.21%, 61.95%, and 37.47%, respectively. Overall, the findings presented provide evidence for a highly contaminated environment in the Singalila National Park, that poses significant ecological risk to the flora, fauna and local inhabitants of this biodiversity hotspot. This research also highlights the need for further exploration and monitoring of the Eastern Himalayas for its role as a sink for atmospheric mercury.
Project description:Historical records of trace elements in lake sediments provide source-to-sink information about potentially toxic pollutants across space and time. We investigated two lakes located at different elevations in the Ecuadorian Andes to understand how trace element fluxes are related to (i) geology, (ii) erosion in the watersheds, and (iii) local point sources and atmospheric loads. In remote Lake Fondococha (4150 m a.s.l.), total Hg fluxes stay constant between ca. 1760 and 1950 and show an approximately 4.4-fold increase between pre-1950 and post-1950 values. The post-1950 increase in fluxes of other trace elements (V, Cr, Co, Ni, Cu, Zn, As, Cd, and Pb) is lower (2.1-3.0-fold) than for Hg. Mostly lithogenic sources and enhanced soil erosion contribute to their post-1950 increase (lithogenic contribution: > 85%, Hg: ~ 58%). Average post-1950 Hg fluxes are approximately 4.3 times higher in peri-urban Lake Llaviucu (3150 m a.s.l.) than in the remote Lake Fondococha. Post-1950 fluxes of the other trace elements showed larger differences between Lakes Fondococha and Llaviucu (5.2 < 25-29.5-fold increase; Ni < Pb-Cd). The comparison of the post-1950 average trace element fluxes that are derived from point and airborne sources revealed 5-687 (Hg-Pb) times higher values in Lake Llaviucu than in Lake Fondococha suggesting that Lake Llaviucu's proximity to the city of Cuenca strongly influences its deposition record (industrial emissions, traffic, caged fishery). Both lakes responded with temporary drops in trace element accumulations to park regulations in the 1970s and 1990s, but show again increasing trends in recent times, most likely caused by increase in vehicular traffic and openings of copper and gold mines around Cajas National Park.
Project description:Protected areas require long-term monitoring to understand the influence and extent of ecosystem stress to inform management and conservation decisions. As long-term data are not always available, paleolimnological methods offer a way of extending our knowledge of past environmental conditions necessary to use as context for remediation. Here, we examine four sediment cores and additional surface sediments from 14 ponds located on Sable Island National Park Reserve Canada (SINPR), where long-term ecological changes and vulnerability to disturbance are not well defined. We develop a paleolimnological approach to assessing environmental vulnerability through the use of biological indicators (Diptera: Chironomidae), where shifts in the environment are inferred by shifts in chironomid assemblages over time. Analysis of surface sediments show four distinct assemblage types reflecting four different habitat conditions; primarily represented by the presence of Glyptotendipes, Chironomus, Microtendipes, and Dicrotendipes. Differences in habitat conditions through time based on these results are then compared to biostratigraphic analysis of sediment cores from four of the ponds. We found that two ponds had large shifts in chironomids assemblages that were associated with changes in habitat over time, while two others that were not as exposed to the influence of erosion and influx of sand dunes did not. Our findings established a baseline of historical change in SINPR, broadening the scope of long-term monitoring, which is essential for defining goals for management and conservation of the ecological integrity of Sable Island.