Sarah is an aquatic ecologist, with a focus of expertise in algae, including diatoms and harmful algae.
Sarah's research interests cover the application of taxonomy, paleoecology, and biogeography to environmental assessment. Most recently, Sarah worked on regional river surveys, using diatoms, eDNA, and algal metrics to assess the impacts of a variety of stresses on freshwater organisms. For several years, Sarah has managed the USGS BioData Algal Taxonomy section, keeping algal nomenclature up to date and in accordance with the International Code of Algae, Fungi, and Plants (INA). She is passionate about sharing algal taxonomy and ecology with scientists, students, and the public. Sarah currently serves as the Chair of the Editorial Review Board for the collaborative (USGS, EPA & University of Colorado), electronic, peer-reviewed flora, Diatoms of North America (diatoms.org).
Sarah's published research covers a wide range of topics including atmospheric deposition of nitrogen, aquatic invasive species, environmental DNA sequencing, harmful algal blooms, paleolimnology, automated identification of organisms, development of new assessment methods, and modeling algal species response.
Science and Products
Water Resources Trend Assessments: State of the Science, Challenges, and Opportunities for Advancement
Natural and anthropogenic influences on benthic cyanobacteria in streams of the northeastern United States
Diatoms.org: Supporting taxonomists, connecting communities
A web-based tool for assessing the condition of benthic diatom assemblages in streams and rivers of the conterminous United States
Nutrients and warming interact to force mountain lakes into unprecedented ecological state
Characterizing benthic macroinvertebrate and algal biological condition gradient models for California wadeable Streams, USA
Reduction of taxonomic bias in diatom species data
Diatom enumeration method influences biological assessments of southeastern USA streams
Taxonomic harmonization may reveal a stronger association between diatom assemblages and total phosphorus in large datasets
Perspectives on the paleolimnology of the late Eocene Florissant lake from diatom and sedimentary evidence at Clare’s Quarry, Teller County, Colorado, USA
A diatom voucher flora from selected southeast rivers (USA)
Paleolimnological records of nitrogen deposition in shallow, high-elevation lakes of Grand Teton National Park, Wyoming, USA
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Water Resources Trend Assessments: State of the Science, Challenges, and Opportunities for Advancement
Water is vital to human life and healthy ecosystems. Here we outline the current state of national-scale water resources trend assessments, identify key gaps, and suggest advancements to better address critical issues related to changes in water resources that may threaten human development or the environment. Questions like, “Do we have less suitable drinking water now than we had 20 years ago?”AuthorsSarah M. Stackpoole, Gretchen P. Oelsner, Edward G. Stets, Jory Seth Hecht, Zachary Johnson, Anthony J. Tesoriero, Michelle A. Walvoord, Jeffrey G. Chanat, Krista A. Dunne, Phillip J. Goodling, Bruce D. Lindsey, Michael Meador, Sarah SpauldingNatural and anthropogenic influences on benthic cyanobacteria in streams of the northeastern United States
Benthic cyanobacteria are widespread in streams and rivers and have the potential to release toxins. In large numbers, these microorganisms and their toxins present a risk to human health. Cyanobacterial abundance in stream biofilms is typically related to single or a limited set of environmental factors, mainly light availability, water temperature, and nutrient concentrations. However, these facAuthorsNicholas O. Schulte, Daren M. Carlisle, Sarah SpauldingDiatoms.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. Firstly, literature is often inaccessible because oAuthorsSarah Spaulding, Marina Potapova, Ian W. Bishop, Sylvia S. Lee, Tim Gasperak, Elena Jovanoska, Paula C. Furey, Mark B. EdlundA web-based tool for assessing the condition of benthic diatom assemblages in streams and rivers of the conterminous United States
Benthic diatom assemblages are known to be indicative of water quality but have yet to be widely adopted in biological assessments in the United States due to several limitations. Our goal was to address some of these limitations by developing regional multi-metric indices (MMIs) that are robust to inter-laboratory taxonomic inconsistency, adjusted for natural covariates, and sensitive to a wide rAuthorsDaren Carlisle, Sarah Spaulding, Meredith Tyree, Nicholas O. Schulte, Sylvia S Lee, Richard M. Mitchell, Amina A. PollardNutrients and warming interact to force mountain lakes into unprecedented ecological state
While deposition of reactive nitrogen (N) in the 20th century has been strongly linked to changes in diatom assemblages in high-elevation lakes, pronounced and contemporaneous changes in other algal groups suggest additional drivers. We explored the origin and magnitude of changes in two mountain lakes from the end of the Little Ice Age at ca. 1850, to ca. 2010, using lake sediments. We found dramAuthorsIsabella A. Oleksy, Jill S. Baron, Peter Leavitt, Sarah SpauldingCharacterizing 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., peAuthorsMichael J. Paul, Ben Jessup, Larry R. Brown, James Carter, Marco Cantonati, Donald F. Charles, Jeroen Gerritsen, Dave Herbst, Rosalina Stancheva, Jeanette K. Howard, Bill Isham, Rex Lowe, Raphael D Mazor, Patina K. Mendez, Peter R Ode, Alison O'Dowd, Yangdong Pan, Andrew C. Rehn, Sarah A. Spaulding, Martha Sutula, Susanna TherouxReduction of taxonomic bias in diatom species data
Inconsistency in taxonomic identification and analyst bias impede the effective use of diatom data in regional and national stream and lake surveys. In this study, we evaluated the effect of existing protocols and a revised protocol on the precision of diatom species counts. The revised protocol adjusts four elements of sample preparation, taxon identification and enumeration, and quality controlAuthorsMeredith Tyree, Ian W. Bishop, Charles P. Hawkins, Richard M. Mitchell, Sarah A. SpauldingDiatom enumeration method influences biological assessments of southeastern USA streams
Current fixed-count enumeration methods for benthic diatoms are likely inadequate for most research and monitoring objectives. These methods underestimate taxa richness and may fail to detect losses of species caused by human impacts. Consequently, the full potential of diatoms is not realized in current assessments of biological integrity or species diversity. In this study, we hypothesize that aAuthorsMeredith Tyree, Daren M. Carlisle, Sarah SpauldingTaxonomic harmonization may reveal a stronger association between diatom assemblages and total phosphorus in large datasets
Diatom data have been collected in large-scale biological assessments in the United States, such as the U.S. Environmental Protection Agency’s National Rivers and Streams Assessment (NRSA). However, the effectiveness of diatoms as indicators may suffer if inconsistent taxon identifications across different analysts obscure the relationships between assemblage composition and environmental variableAuthorsSylvia S Lee, Ian W. Bishop, Sarah A. Spaulding, Richard M. Mitchell, Lester YuanPerspectives on the paleolimnology of the late Eocene Florissant lake from diatom and sedimentary evidence at Clare’s Quarry, Teller County, Colorado, USA
The late Eocene Florissant Formation in central Colorado is a rich and diverse continental Lagerstätte yielding well-preserved fossil assemblages from lacustrine and fluvial facies. This investigation focused on the lacustrine facies at Clare’s Quarry and used biotic and abiotic evidence to characterize aspects of the lake and processes that resulted in the accumulation and preservation of the hosAuthorsMary Ellen Benson, Dena M. Smith, Sarah A. SpauldingA diatom voucher flora from selected southeast rivers (USA)
This flora is intended to serve as an image voucher for samples analyzed for the U.S. Geological Survey Southeast Stream Quality Assessment (SESQA). The SESQA study included measurement of watershed and water quality parameters to determine the factors that have the greatest potential to alter biotic condition. Algal samples were collected at 108 sites in 2014, from streams representing gradientsAuthorsIan W. Bishop, Rhea R.M. Esposito, Meredith Tyree, Sarah A. SpauldingPaleolimnological records of nitrogen deposition in shallow, high-elevation lakes of Grand Teton National Park, Wyoming, USA
Reactive nitrogen (Nr) from anthropogenic sources has been altering ecosystem function in lakes of the Rocky Mountains, other regions of western North America, and the Arctic over recent decades. The response of biota in shallow lakes to atmospheric deposition of Nr, however, has not been considered. Benthic algae are dominant in shallow, high-elevation lakes and are less sensitive to nutrient inpAuthorsSarah A. Spaulding, Megan K. Otu, Alexander P. Wolfe, Jill Baron