A Voucher Flora of Diatoms from Fens in the Tanana River Floodplain, Alaska.

Climate change and human activities may alter the structure and function of boreal peatlands by warming waters and changing their hydrology. Diatoms can be used to assess or track these changes. However, effective biomonitoring requires consistent, reliable identification. To address this need, this study developed a diatom voucher flora of species found across a boreal fen gradient (e.g., vegetation) in interior Alaskan peatlands. Composite diatom samples were collected bi-weekly from three peatland complexes over the 2017 summer. The morphological range of each taxon was imaged. The fens contained 184 taxa across 38 genera. Eunotia (45), Gomphonema (23), and Pinnularia (20) commonly occurred in each peatland. Tabellaria was common in the rich and moderate fen but sparse in the poor fen. Eunotia showed the opposite trend. Approximately 11% of species are potentially novel and 25% percent matched those at risk or declining in status on the diatom Red List (developed in Germany), highlighting the conservation value of boreal wetlands. This voucher flora expands knowledge of regional diatom biodiversity and provides updated, verifiable taxonomic information for inland Alaskan diatoms, building on Foged's 1981 treatment. This flora strengthens the potential to effectively track changes in boreal waterways sensitive to climate change and anthropogenic stressors.

Diatoms.org: supporting taxonomists, connecting communities.

Consistent identification of diatoms is a prerequisite for studying their ecology, biogeography, and successful application as environmental indicators. However, taxonomic consistency among observers has been difficult to achieve, because taxonomic information is scattered across numerous literature sources, presenting challenges to the diatomist. First, literature is often inaccessible because of cost, or its location in journals that are not widely circulated. Second, taxonomic revisions of diatoms are taking place faster than floras can be updated. Finally, taxonomic information is often contradictory across literature sources. These issues can be addressed by developing a content creation community dedicated to making taxonomic, ecological, and image-based data freely available for diatom researchers. Diatoms.org represents such a content curation community, providing open, online access to a vast amount of recent and historical information on North American diatom taxonomy and ecology. The content curation community aggregates existing taxonomic information, creates new content, and provides feedback in the form of corrections and notice of literature with nomenclatural changes. The website not only addresses the needs of experienced diatom scientists for consistent identification, but is also designed to meet users at their level of expertise, including engaging the lay public in the importance of diatom science. The website now contains over 1000 species pages contributed by over 100 content contributors, from students to established scientists. The project began with the intent to provide accurate information on diatom identification, ecology, and distribution using an approach that incorporates engaging design, user feedback, and advanced data access technology. In retrospect, the project that began as an "extended electronic book" has emerged not only as a means to support taxonomists, but for practitioners to communicate and collaborate, expanding the size of and benefits to the content curation community. In this paper, we outline the development of diatoms.org, document key elements of the project, examine ongoing challenges, and consider the unexpected emergent properties, including the value of diatoms.org as a source of data. Ultimately, if the field of diatom taxonomy, ecology, and biodiversity is to be relevant, a new generation of taxonomists needs to be trained and employed using new tools. We propose that diatoms.org is in a key position to serve as a hub of training and continuity for the study of diatom biodiversity and aquatic conditions.

Substratum-associated microbiota.

Highlights of new, interesting, and emerging research findings on substratum-associated microbiota covered from a survey of 2019 literature from primarily freshwaters provide insight into research trends of interest to the Water Environment Federation and others interested in benthic, aquatic environments. Coverage of topics on bottom-associated or attached algae and cyanobacteria, though not comprehensive, includes new methods, taxa new-to-science, nutrient dynamics, auto- and heterotrophic interactions, grazers, bioassessment, herbicides and other pollutants, metal contaminants, and nuisance, and bloom-forming and harmful algae. Coverage of bacteria, also not comprehensive, focuses on the ecology of benthic biofilms and microbial communities, along with the ecology of microbes like Caulobacter crescentus, Rhodobacter, and other freshwater microbial species. Bacterial topics covered also include metagenomics and metatranscriptomics, toxins and pollutants, bacterial pathogens and bacteriophages, and bacterial physiology. Readers may use this literature review to learn about or renew their interest in the recent advances and discoveries regarding substratum-associated microbiota. PRACTITIONER POINTS: This review of literature from 2019 on substratum-associated microbiota presents highlights of findings on algae, cyanobacteria, and bacteria from primarily freshwaters. Coverage of algae and cyanobacteria includes findings on new methods, taxa new to science, nutrient dynamics, auto- and heterotrophic interactions, grazers, bioassessment, herbicides and other pollutants, metal contaminants, and nuisance, bloom-forming and harmful algae. Coverage of bacteria includes findings on ecology of benthic biofilms and microbial communities, the ecology of microbes, metagenomics and metatranscriptomics, toxins and pollutants, bacterial pathogens and bacteriophages, and bacterial physiology. Highlights of new, noteworthy and emerging topics build on those from 2018 and will be of relevance to the Water Environment Federation and others interested in benthic, aquatic environments.

Substratum-associated microbiota.

This survey of 2018 literature on substratum-associated microbiota presents brief highlights on research findings from primarily freshwaters, but includes those from a variety of aquatic ecosystems. Coverage of topics associated with benthic algae and cyanobacteria, though not comprehensive, includes new methods, taxa new to science, nutrient dynamics, trophic interactions, herbicides and other pollutants, metal contaminants, nuisance, bloom-forming and harmful algae, bioassessment, and bioremediation. Coverage of bacteria, also not comprehensive, focused on methylation of mercury, metal contamination, toxins, and other environmental pollutants, including oil, as well as the use of benthic bacteria as bioindicators, in bioassessment tools and in biomonitoring. Additionally, we cover trends in recent and emerging topics on substratum-associated microbiota of relevance to the Water Environment Federation. PRACTITIONER POINTS: This review of literature from 2018 on substratum-associated microbiota presents highlights of findings on algae, cyanobacteria, and bacteria from primarily freshwaters. Topics covered that focus on algae and cyanobacteria include findings on new methods, taxa new to science, nutrient dynamics, trophic interactions, herbicides and other pollutants, metal contaminants, nuisance, bloomforming and harmful algae, bioassessment, and bioremediation. Topics covered that focus on bacteria include findings on methylation of mercury, metal contamination, toxins and other environmental pollutants, including oil, as well as the us e of benthic bacteria as bioindicators, in bioassessment tools and in biomonitoring. A brief presentation of new, noteworthy and emerging topics on substratum-associated microbiota, build on those from 2017, to highlight those of particular relevance to the Water Environment Federation.

Changes in feeding selectivity of freshwater invertebrates across a natural thermal gradient.

Environmental warming places physiological constraints on organisms, which may be mitigated by their feeding behavior. Theory predicts that consumers should increase their feeding selectivity for more energetically valuable resources in warmer environments to offset the disproportionate increase in metabolic demand relative to ingestion rate. This may also result in a change in feeding strategy or a shift towards a more specialist diet. This study used a natural warming experiment to investigate temperature effects on the feeding selectivity of three freshwater invertebrate grazers: the snail Radix balthica, the blackfly larva Simulium aureum, and the midgefly larva Eukiefferiella minor. Chesson's Selectivity Index was used to compare the proportional abundance of diatom species in the guts of each invertebrate species with corresponding rock biofilms sampled from streams of different temperature. The snails became more selective in warmer streams, choosing high profile epilithic diatoms over other guilds and feeding on a lower diversity of diatom species. The blackfly larvae appeared to switch from active collector gathering of sessile high profile diatoms to more passive filter feeding of motile diatoms in warmer streams. No changes in selectivity were observed for the midgefly larvae, whose diet was representative of resource availability in the environment. These results suggest that key primary consumers in freshwater streams, which constitute a major portion of invertebrate biomass, can change their feeding behavior in warmer waters in a range of different ways. These patterns could potentially lead to fundamental changes in the flow of energy through freshwater food webs.

Substratum-Associated Microbiota.

This review briefly highlights findings from a survey of 2017 literature on substratum-associated microbiota from a variety of aquatic environments, but primarily freshwaters. Centered on algae, cyanobacteria, and bacteria, topics covered include those of relevance to the Water Environment Federation, along with those of recent and emerging interest such as new or updated methods, new and interesting taxa, general ecology, trophic interactions, biogeochemical cycling, aquatic pollutants like herbicides and heavy metals, and nuisance, bloom-forming, or harmful algae. Additional coverage includes studies on bioremediation, bioassessment, biomonitoring and quantification of benthic microbiota.

Substratum-Associated Microbiota.

This survey of literature on substratumassociated microbiota from 2016 includes highlights of research findings associated with algae, cyanobacteria, and bacteria from a variety of aquatic environments, but primarily freshwaters. It covers topics of relevance to the Water Environment Federation along with those of emerging or recent interest such as nuisance, bloom forming and harmful algae, fossil fuel related contamination, and other environmental pollutants like nanoparticles. Additional interesting findings reported on include general ecology, method development, multistressor interactions, nutrient cycling, taxonomy and systematics, trophic interactions, and biomonitoring, bioassessment, and bioremediation.

Substratum-Associated Microbiota.

This survey of literature on substratum associated microbiota from 2015 highlights research findings associated with benthic algae and bacteria from a variety of aquatic environments, but primarily freshwaters. It focuses on topics of interest to the Water Environment Federation along with those of current emerging interest such as global change, oil spills, and environmental contaminants like pharmaceutical compounds, microplastics, nanoparticles and organic pollutants. Other interesting findings briefly covered include areas of general ecology, nutrient cycling, trophic interactions, water quality, nuisance and invasive species, bioindicators, and bioremediation.

Substratum-Associated Microbiota.

This review of literature on substratumassociated microbiota from 2014 highlights topics on benthic algae and bacteria from a range of aquatic environments, but focuses on freshwater habitats. Advances in pollution and toxin detection, assessment methods, and applications of new technologies are highlighted as are updates in taxonomy and systematics. Aspects of general ecology, water quality, nutrient cycling, trophic interactions, land use changes, biofuels, biofouling, and environmental challenges such as climate change, pollutants, tar sands and fracking, oil spills and nuisance blooms are presented.