183 research outputs found

    Results of Cultural Resources Survey for the Spring Lake Section 206 Aquatic Ecosystem Restoration Project, Texas State University-San Marcos, Hays County, Texas

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    The Center for Archaeological Studies (CAS) at Texas State University-San Marcos conducted intensive archaeological survey and subsurface testing investigations of the Area of Potential Effect (APE) of the Spring Lake Section 206 Aquatic Ecosystem Restoration Project (SLAERP). The SLAERP proposes to restore the aquatic ecosystem components of Spring Lake and riparian corridor/grassland habitat located directly adjacent to the lake to a more natural condition within the constraints of existing land uses. This work will be conducted under Section 206 of the Water Resources Development Act of 1996, which provides authority for the United States Army Corps of Engineers (USACE) to restore aquatic ecosystems. A Memorandum of Agreement (MOA) between the USACE, Texas State University-San Marcos (TxState), and the Texas Historical Commission (THC) regarding the Spring Lake Aquatic Restoration Project required CAS to develop and implement a subsurface testing program to determine the extent of intact cultural deposits within the project area. A testing program was developed and implemented by CAS that included both terrestrial and underwater investigations. Terrestrial investigations consisted of pedestrian survey, shovel test excavation, test unit excavation, auger pit excavation and backhoe trench excavation. Underwater investigations included limited reconnaissance survey, test unit excavation and the extraction of sediment cores. Investigations were conducted within or adjacent to State Archaeological Landmarks 41HY160 and 41HY165. Neither site was adequately delineated prior to this undertaking, and the work reported here results in modified site boundaries within the APE. New site boundaries demonstrate nearly continuous deposits across the APE, confirming that these sites actually represent a single extensive complex of archaeological deposits associated with the freshwater springs that presently form Spring Lake. Based on pending impacts as indicated in the 65 percent project design documents together with the results of the survey, six areas were identified as “Archaeologically Sensitive,” as they contained or possess a high probability to contain cultural deposits that would be negatively impacted by proposed demolition, modifications, and construction. Each of these archaeologically sensitive areas is linked with either 41HY160 or 41HY165, although, given the continuous nature of deposits in the APE, CAS concludes that distinctions between these trinomials are less meaningful than previously believed. CAS recommended the development of mitigation efforts to offset the loss of important information from these areas

    Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom

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    © The Author(s), 2020. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Bhatnagar, S., Cowley, E. S., Kopf, S. H., Pérez Castro, S., Kearney, S., Dawson, S. C., Hanselmann, K., & Ruff, S. E. Microbial community dynamics and coexistence in a sulfide-driven phototrophic bloom. Environmental Microbiome, 15(1),(2020): 3, doi:10.1186/s40793-019-0348-0.Background: Lagoons are common along coastlines worldwide and are important for biogeochemical element cycling, coastal biodiversity, coastal erosion protection and blue carbon sequestration. These ecosystems are frequently disturbed by weather, tides, and human activities. Here, we investigated a shallow lagoon in New England. The brackish ecosystem releases hydrogen sulfide particularly upon physical disturbance, causing blooms of anoxygenic sulfur-oxidizing phototrophs. To study the habitat, microbial community structure, assembly and function we carried out in situ experiments investigating the bloom dynamics over time. Results: Phototrophic microbial mats and permanently or seasonally stratified water columns commonly contain multiple phototrophic lineages that coexist based on their light, oxygen and nutrient preferences. We describe similar coexistence patterns and ecological niches in estuarine planktonic blooms of phototrophs. The water column showed steep gradients of oxygen, pH, sulfate, sulfide, and salinity. The upper part of the bloom was dominated by aerobic phototrophic Cyanobacteria, the middle and lower parts by anoxygenic purple sulfur bacteria (Chromatiales) and green sulfur bacteria (Chlorobiales), respectively. We show stable coexistence of phototrophic lineages from five bacterial phyla and present metagenome-assembled genomes (MAGs) of two uncultured Chlorobaculum and Prosthecochloris species. In addition to genes involved in sulfur oxidation and photopigment biosynthesis the MAGs contained complete operons encoding for terminal oxidases. The metagenomes also contained numerous contigs affiliating with Microviridae viruses, potentially affecting Chlorobi. Our data suggest a short sulfur cycle within the bloom in which elemental sulfur produced by sulfide-oxidizing phototrophs is most likely reduced back to sulfide by Desulfuromonas sp. Conclusions: The release of sulfide creates a habitat selecting for anoxygenic sulfur-oxidizing phototrophs, which in turn create a niche for sulfur reducers. Strong syntrophism between these guilds apparently drives a short sulfur cycle that may explain the rapid development of the bloom. The fast growth and high biomass yield of Chlorobi-affiliated organisms implies that the studied lineages of green sulfur bacteria can thrive in hypoxic habitats. This oxygen tolerance is corroborated by oxidases found in MAGs of uncultured Chlorobi. The findings improve our understanding of the ecology and ecophysiology of anoxygenic phototrophs and their impact on the coupled biogeochemical cycles of sulfur and carbon.This work was carried out at the Microbial Diversity summer course at the Marine Biological Laboratory in Woods Hole, MA. The course was supported by grants from National Aeronautics and Space Administration, the US Department of Energy, the Simons Foundation, the Beckman Foundation, and the Agouron Institute. Additional funding for SER was provided by the Marine Biological Laboratory

    Optimal Parametric Density Estimation by Minimizing an Analytic Distance Measure

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    In this paper, we present a novel approach to parametric density estimation from given samples. The samples are treated as a parametric density function by means of a Dirac mixture, which allows for applying analytic optimization techniques. The method is based on minimizing a distance measure between the integral of the approximation function and the empirical cumulative distribution function (EDF) of the given samples, where the EDF is represented by the integral of the Dirac mixture. Since this minimization problem cannot be solved directly in general, a progression technique is applied. Increased performance of the approach in comparison to iterative maximum likelihood approaches is shown in simulations

    A Reservoir Species for the Emerging Amphibian Pathogen Batrachochytrium dendrobatidis Thrives in a Landscape Decimated by Disease

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    Chytridiomycosis, a disease caused by the fungal pathogen Batrachochytrium dendrobatidis (Bd), is driving amphibian declines and extinctions in protected areas globally. The introduction of invasive reservoir species has been implicated in the spread of Bd but does not explain the appearance of the pathogen in remote protected areas. In the high elevation (>1500 m) Sierra Nevada of California, the native Pacific chorus frog, Pseudacris regilla, appears unaffected by chytridiomycosis while sympatric species experience catastrophic declines. We investigated whether P. regilla is a reservoir of Bd by comparing habitat occupancy before and after a major Bd outbreak and measuring infection in P. regilla in the field, monitoring susceptibility of P. regilla to Bd in the laboratory, examining tissues with histology to determine patterns of infection, and using an innovative soak technique to determine individual output of Bd zoospores in water. Pseudacris regilla persists at 100% of sites where a sympatric species has been extirpated from 72% in synchrony with a wave of Bd. In the laboratory, P. regilla carried loads of Bd as much as an order of magnitude higher than loads found lethal to sympatric species. Histology shows heavy Bd infection in patchy areas next to normal skin, a possible mechanism for tolerance. The soak technique was 77.8% effective at detecting Bd in water and showed an average output of 68 zoospores per minute per individual. The results of this study suggest P. regilla should act as a Bd reservoir and provide evidence of a tolerance mechanism in a reservoir species

    Complete Genome Sequence of Streptomyces sp. Strain CCM_MD2014, Isolated from Topsoil in Woods Hole, Massachusetts

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    Here, we present the complete genome sequence of Streptomyces sp. strain CCM_MD2014 (phylum Actinobacteria), isolated from surface soil in Woods Hole, MA. Its single linear chromosome of 8,274,043 bp in length has a 72.13% G+C content and contains 6,948 coding sequences

    Multiple Statistical Analysis Techniques Corroborate Intratumor Heterogeneity in Imaging Mass Spectrometry Datasets of Myxofibrosarcoma

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    MALDI mass spectrometry can generate profiles that contain hundreds of biomolecular ions directly from tissue. Spatially-correlated analysis, MALDI imaging MS, can simultaneously reveal how each of these biomolecular ions varies in clinical tissue samples. The use of statistical data analysis tools to identify regions containing correlated mass spectrometry profiles is referred to as imaging MS-based molecular histology because of its ability to annotate tissues solely on the basis of the imaging MS data. Several reports have indicated that imaging MS-based molecular histology may be able to complement established histological and histochemical techniques by distinguishing between pathologies with overlapping/identical morphologies and revealing biomolecular intratumor heterogeneity. A data analysis pipeline that identifies regions of imaging MS datasets with correlated mass spectrometry profiles could lead to the development of novel methods for improved diagnosis (differentiating subgroups within distinct histological groups) and annotating the spatio-chemical makeup of tumors. Here it is demonstrated that highlighting the regions within imaging MS datasets whose mass spectrometry profiles were found to be correlated by five independent multivariate methods provides a consistently accurate summary of the spatio-chemical heterogeneity. The corroboration provided by using multiple multivariate methods, efficiently applied in an automated routine, provides assurance that the identified regions are indeed characterized by distinct mass spectrometry profiles, a crucial requirement for its development as a complementary histological tool. When simultaneously applied to imaging MS datasets from multiple patient samples of intermediate-grade myxofibrosarcoma, a heterogeneous soft tissue sarcoma, nodules with mass spectrometry profiles found to be distinct by five different multivariate methods were detected within morphologically identical regions of all patient tissue samples. To aid the further development of imaging MS based molecular histology as a complementary histological tool the Matlab code of the agreement analysis, instructions and a reduced dataset are included as supporting information
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