Comparative Molecular Microbial Ecology of the Spring Haptophyte Bloom in a Greenland Arctic Oligosaline Lake

The Arctic is highly sensitive to increasing global temperatures and is projected to experience dramatic ecological shifts in the next few decades. Oligosaline lakes are common in arctic regions where evaporation surpasses precipitation, however these extreme microbial communities are poorly characterized. Many oligosaline lakes, in contrast to freshwater ones, experience annual blooms of haptophyte algae that generate valuable alkenone biomarker records that can be used for paleoclimate reconstruction. These haptophyte algae are globally important, and globally distributed, aquatic phototrophs yet their presence in microbial molecular surveys is scarce. To target haptophytes in a molecular survey, we compared microbial community structure during two haptophyte bloom events in an arctic oligosaline lake, Lake BrayaSø in southwestern Greenland, using high-throughput pyrotag sequencing. Our comparison of two annual bloom events yielded surprisingly low taxon overlap, only 13% for bacterial and 26% for eukaryotic communities, which indicates significant annual variation in the underlying microbial populations. Both the bacterial and eukaryotic communities strongly resembled high-altitude and high latitude freshwater environments. In spite of high alkenone concentrations in the water column, and corresponding high haptophyte rRNA gene copy numbers, haptophyte pyrotag sequences were not the most abundant eukaryotic tag, suggesting that sequencing biases obscured relative abundance data. With over 170 haptophyte tag sequences, we observed only one haptophyte algal Operational Taxonomic Unit, a prerequisite for accurate paleoclimate reconstruction from the lake sediments. Our study is the first to examine microbial diversity in a Greenland lake using next generation sequencing and the first to target an extreme haptophyte bloom event. Our results provide a context for future explorations of aquatic ecology in the warming arctic

Production and temperature sensitivity of long chain alkenones in the cultured haptophyte Pseudoisochrysis paradoxa

The alkenone unsaturation index (U<sub>37</sub><sup>K</sup> or U<sub>37</sub><sup>K′</sup>) serves as a critical tool for reconstructing temperature in marine environments. Lacustrine haptophyte algae are genetically distinct from their ubiquitous and well studied marine counterparts, and the unknown species-specific genetic imprints on long chain alkenone production by lacustrine species have hindered the widespread application of the U37<sup>K</sup> temperature proxy to lake sediment records. The haptophyte Pseudoisochrysis paradoxa produces alkenones but its U37<sup>K</sup> calibration has never been determined. It has an alkenone fingerprint abundant in tetraunsaturated alkenones, a hallmark of lacustrine environments. We present here the first calibration of the U37<sup>K</sup> index to temperature for a culture of P. paradoxa. We found that the U37<sup>K</sup> index accurately captured the alkenone response to temperature whereas the U37<sup>K′</sup> index failed to do so, with U37<sup>K′</sup> values below 0.08 projecting to two different temperature values. Our results add a fifth species-specific U37<sup>K</sup> calibration and provide another line of evidence that different haptophyte species require different U37<sup>K</sup> calibrations. The findings also highlight the necessary inclusion of the C<sub>37:4</sub> alkenone when reconstructing temperatures from P. paradoxa-derived alkenone records

Culturing of the first 37:4 predominant lacustrine haptophyte : geochemical, biochemical, and genetic implications

Author Posting. © The Author(s), 2011. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Geochimica et Cosmochimica Acta 78 (2012): 51–64, doi:10.1016/j.gca.2011.11.024.Long chain alkenones (LCAs) are potential biomarkers for quantitative paleotemperature reconstructions from lacustrine environments. However, progress in this area has been severely hindered by the lack of culture studies of haptophytes responsible for alkenone distributions in lake sediments: the predominance of C37:4 LCA. Here we report the first enrichment culturing of a novel haptophyte phylotype (Hap-A) from Lake George, ND that produces predominantly C37:4-LCA. Hap-A was enriched from its resting phase collected from deep sediments rather than from water column samples. In contrast, enrichments from near surface water yielded a different haptophyte phylotype (Hap-B), closely related to Chrysotila lamellosa and Pseudoisochrysis paradoxa, which does not display C37:4-LCA predominance (similar enrichments have been reported previously). The LCA profile in sediments resembles that of Hap-A enrichments, suggesting that Hap-A is the dominant alkenone producer of the sedimentary LCAs. In enrichments, excess lighting appeared to be crucial for triggering blooms of Hap-A. Both and indices show a linear relationship with temperature for Hap-A in enrichments, but the relationship appears to be dependent on the growth stage. Based on 18S rRNA gene analyses, several lakes from the Northern Great Plains, as well as Pyramid Lake, NV and Tso Ur, Tibetan Plateau, China contain the same two haptophyte phylotypes. The Great Plains lakes show the Hap-A-type LCA distribution, whereas Pyramid and Tso Ur show the Hap-B type distribution. Waters of the Great Plain lakes are dominated by sulfate, whereas those Pyramid and Tso Ur are dominated by carbonate, suggesting that the sulfate to carbonate ratio may be a determining factor for the competitiveness of the Hap-A and Hap-B phylotypes in natural settings.This work was supported by a grant from the National Science Foundation to Y. Huang (EAR06-02325) and a Brown University Graduate School Dissertation Fellowship to J. L. Toney

Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA

The Biological Condition Gradient (BCG) is a conceptual model that describes changes in aquatic communities under increasing levels of anthropogenic stress. The BCG helps decision-makers connect narrative water quality goals (e.g., maintenance of natural structure and function) to quantitative measures of ecological condition by linking index thresholds based on statistical distributions (e.g., percentiles of reference distributions) to expert descriptions of changes in biological condition along disturbance gradients. As a result, the BCG may be more meaningful to managers and the public than indices alone. To develop a BCG model, biological response to stress is divided into 6 levels of condition, represented as changes in biological structure (abundance and diversity of pollution sensitive versus tolerant taxa) and function. We developed benthic macroinvertebrate (BMI) and algal BCG models for California perennial wadeable streams to support interpretation of percentiles of reference-based thresholds for bioassessment indices (i.e., the California Stream Condition Index [CSCI] for BMI and the Algal Stream Condition Index [ASCI] for diatoms and soft-bodied algae). Two panels (one of BMI ecologists and the other of algal ecologists) each calibrated a general BCG model to California wadeable streams by first assigning taxa to specific tolerance and sensitivity attributes, and then independently assigning test samples (264 BMI and 248 algae samples) to BCG Levels 1–6. Consensus on the assignments was developed within each assemblage panel using a modified Delphi method. Panels then developed detailed narratives of changes in BMI and algal taxa that correspond to the 6 BCG levels. Consensus among experts was high, with 81% and 82% expert agreement within 0.5 units of assigned BCG level for BMIs and algae, respectively. According to both BCG models, the 10th percentiles index scores at reference sites corresponded to a BCG Level 3, suggesting that this type of threshold would protect against moderate changes in structure and function while allowing loss of some sensitive taxa. The BCG provides a framework to interpret changes in aquatic biological condition along a gradient of stress. The resulting relationship between index scores and BCG levels and narratives can help decision-makers select thresholds and communicate how these values protect aquatic life use goals

The α1-adrenergic receptors: diversity of signaling networks and regulation

The α1-adrenergic receptor (AR) subtypes (α1a, α1b, and α1d) mediate several physiological effects of epinephrineand norepinephrine. Despite several studies in recombinant systems and insightfrom genetically modified mice, our understanding of the physiological relevance and specificity of the α1-AR subtypes is still limited. Constitutive activity and receptor oligomerization have emerged as potential features regulating receptor function. Another recent paradigm is that βarrestins and G protein-coupled receptors themselves can act as scaffolds binding a variety of proteins and this can result in growing complexity of the receptor-mediated cellular effects. The aim of this review is to summarize our current knowledge on some recently identified functional paradigms and signaling networks that might help to elucidate the functional diversity of the α1-AR subtypes in various organs

Microbial diversity in restored wetlands of San Francisco Bay

Wetland ecosystems may serve as either a source or a sink for atmospheric carbon andgreenhouse gases. This delicate carbon balance is influenced by the activity of belowgroundmicrobial communities that return carbon dioxide and methane to theatmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may helpto reverse land subsidence and possibly increase carbon storage in soils. However, theeffects of wetland restoration on microbial communities, which mediate soil metabolicactivity and carbon cycling, are poorly studied. In an effort to better understand theunderlying factors which shape the balance of carbon flux in wetland soils, we targetedthe microbial communities in a suite of restored and historic wetlands in the SanFrancisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhousegas monitoring, we profiled the diversity and metabolic potential of the wetland soilmicrobial communities along biogeochemical and wetland age gradients. Our resultsshow relationships among geochemical gradients, availability of electron acceptors, andmicrobial community composition. Our study provides the first genomic glimpse intomicrobial populations in natural and restored wetlands of the San Francisco Bay-Deltaregion and provides a valuable benchmark for future studies

Microbial diversity in restored wetlands of San Francisco Bay

Wetland ecosystems may serve as either a source or a sink for atmospheric carbon andgreenhouse gases. This delicate carbon balance is influenced by the activity of belowgroundmicrobial communities that return carbon dioxide and methane to theatmosphere. Wetland restoration efforts in the San Francisco Bay-Delta region may helpto reverse land subsidence and possibly increase carbon storage in soils. However, theeffects of wetland restoration on microbial communities, which mediate soil metabolicactivity and carbon cycling, are poorly studied. In an effort to better understand theunderlying factors which shape the balance of carbon flux in wetland soils, we targetedthe microbial communities in a suite of restored and historic wetlands in the SanFrancisco Bay-Delta region. Using DNA and RNA sequencing, coupled with greenhousegas monitoring, we profiled the diversity and metabolic potential of the wetland soilmicrobial communities along biogeochemical and wetland age gradients. Our resultsshow relationships among geochemical gradients, availability of electron acceptors, andmicrobial community composition. Our study provides the first genomic glimpse intomicrobial populations in natural and restored wetlands of the San Francisco Bay-Deltaregion and provides a valuable benchmark for future studies

The Second National Workshop on Marine eDNA: A workshop to accelerate the incorporation of eDNA science into environmental management applications

Abstract The Second National Workshop on Environmental DNA was held on September 12–15, 2022, at the Southern California Coastal Water Research Project (SCCWRP) in Southern California and was focused on transitioning eDNA from research to management applications. The Workshop was attended by 150 people in‐person and an additional 200 more online. Workshop attendees represented a broad cross‐section of disciplines and backgrounds, including research scientists, state, and federal agencies, and those in the environmental management sector. This diverse collection of attendees assembled with the goal of achieving cross‐sector collaboration and working together to identify the necessary next steps to move eDNA methods into the management application mainstream. The Workshop structure included a Training Day oriented towards environmental managers and those new to eDNA science, to facilitate a common ground for discussions on subsequent days. The Plenary Day focused on case studies about eDNA applications and culminated with a roundtable panel discussion with local, state, and federal agency representatives on eDNA method readiness and the road to method adoption. Among the key takeaways from the Workshop was bridging the communication gap between researchers and managers because scientists often focus on technical details and the unknowns, giving the impression that eDNA science is not yet mature, whereas managers want to hear consensus statements about readiness and a roadmap for method adoption, including standard operating procedures, lab accreditation, and unified sequence libraries. This outcome was a clear directive for many scientists in attendance that it is time to stop letting perfect be the enemy of good and to focus future efforts on method harmonization and a national strategy towards method adoption. The Workshop concluded with a working session of invited participants to identify key priorities and needs to achieve the goals highlighted in the Workshop discussions

Microbial diversity and carbon cycling in San Francisco Bay wetlands

Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangeredspecies and provide an effective carbon storage solution, reversing land subsidencecaused by a century of industrial and agricultural development. However, the benefits ofcarbon sequestration may be negated by increased methane production in newlyconstructed wetlands, making these wetlands net greenhouse gas (GHG) sources to theatmosphere. We investigated the effects of wetland restoration on below-ground microbialcommunities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species

Microbial diversity and carbon cycling in San Francisco Bay wetlands

Wetland restoration efforts in San Francisco Bay aim to rebuild habitat for endangeredspecies and provide an effective carbon storage solution, reversing land subsidencecaused by a century of industrial and agricultural development. However, the benefits ofcarbon sequestration may be negated by increased methane production in newlyconstructed wetlands, making these wetlands net greenhouse gas (GHG) sources to theatmosphere. We investigated the effects of wetland restoration on below-ground microbialcommunities responsible for GHG cycling in a suite of historic and restored wetlands in SF Bay. Using DNA and RNA sequencing, coupled with real-time GHG monitoring, we profiled the diversity and metabolic potential of wetland soil microbial communities. The wetland soils harbor diverse communities of bacteria and archaea whose membership varies with sampling location, proximity to plant roots and sampling depth. Our results also highlight the dramatic differences in GHG production between historic and restored wetlands and allow us to link microbial community composition and GHG cycling with key environmental variables including salinity, soil carbon and plant species