SFS Annual Meeting

5/23/2018  |   09:00 - 09:15   |  330 B

Asynchronous changes in trophic status of a lake and its watershed inferred from sedimentary diatoms of different habitats Paleolimnology is one important approach for setting realistic goals for restoration and management decisions for lakes. Both other lines of evidence, which is evaluated by a form of causal criteria analysis–Eco Evidence, and evidence from Muskegon Lake itself, were analyzed to evaluate whether TP is causal factor for diatom species composition change in Muskegon Lake. Both evidence supported the cause-effect linkage between TP and diatom species composition change. Our data analysis showed benthic and planktonic diatoms responded to changes in phosphorus conditions at two spatial scales. When inferring TP based on species composition of all diatoms, relationships to geochemical proxies and land use were poor. However, when inferring TP using benthic and planktonic diatoms, benthic diatom inferred TP was related most to in-lake conditions and planktonic diatom inferred TP was related most to changes in the Muskegon River, upstream from the lake. Only benthic diatom inferred TP correlated well with geochemical proxies in the lake. With a 23 d residence time of water in Muskegon Lake, species composition of planktonic diatoms in the core was likely more regulated by exogenous environmental factors and processes, Muskegon River, than benthic diatoms.

Bo Liu (Primary Presenter/Author), Hebei University, liubo3@msu.edu;


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5/23/2018  |   09:15 - 09:30   |  330 B

A STOCHASTIC MODEL OF EPILITHIC ALGAL SUCCESSION AND PATCH DYNAMICS IN STREAMS Spatiotemporal distribution of epilithic periphyton succession is described using a stochastic model based on continuous-time, Markovian processes. Periphyton within a reach is viewed as a mosaic of habitat patches undergoing different successional trajectories. Spatiotemporal, allogenic-conditions that define patches constrain autogenic factors within them. Each patch can contain 1 of 8 community types defined by algal growth forms. Ninety-two successional data sets were used to determine transition probabilities among communities as a function of light, nutrients and current. In the absence of disturbance and grazing, succession within a patch reaches a stationary, “climax”, state. Preliminary simulations indicate high light and nutrients increase transition probabilities toward communities containing a mat of motile diatoms with emergent filamentous Chlorophytes. Low light and nutrients result in communities with prostrate taxa and/or erect, araphid diatoms. Current has less of an effect on transitions. Data from the literature will be used to determine the probability and degree to which succession within patch is reset by disturbance or grazing. The dynamic distribution of patch types then can be described based on the frequency and severity of these resetting events.

Dean DeNicola (Primary Presenter/Author), Slippery Rock University, dean.denicola@sru.edu;


James McNair (Co-Presenter/Co-Author), Robert B. Annis Water Resources Institute, mcnairja@gvsu.edu;


Jiyeon Suh (Co-Presenter/Co-Author), Grand Valley State University, suhj@gvsu.edu;


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5/23/2018  |   09:30 - 09:45   |  330 B

THIAMINE LIMITATION OF PERIPHYTON IN ADIRONDACK STREAMS Nutrient enrichment experiments were conducted in four Adirondack streams using nutrient diffusing substrates to evaluate the potential influence of thiamine (vitamin B1) on chlorophyll a accumulation by stream periphyton. This work was prompted by recent observations in marine ecosystems showing that the presence of thiamine regulates primary production. However, the specific role of thiamine was not explored in freshwaters. Contrasting treatments in our study included nutrient additions of thiamine (C12H17ClN4OS•HCl), nitrogen (NH4Cl), and phosphorus (NaH2PO4). Thiamine limitation was observed in 12 of 14 experiments conducted from June through October in 2015, 2016, and 2017. Nitrogen limitation was observed in eight experiments and phosphorus limitation in one experiment. Thiamine limitation did not change seasonally from spring through the fall, while N limitation appeared in spring and summer but not in the fall. The periphyton community structure was also influenced by nutritional availability. Among the periphyton communities growing on the substrates, the portion of Chlorophyta increased with the addition of thiamine and ammonium, especially for Scenedesmus and Ankistrodesmus, and the portion of Bacillariophyta increased with the addition of ammonium, especially for Synedra.

Binbin Wang (Primary Presenter/Author), Cornell University, bw424@cornell.edu;


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5/23/2018  |   09:45 - 10:00   |  330 B

BOTTOM-UP AND TOP-DOWN FACTORS INFLUENCING PERIPHYTON COMMUNITY STRUCTURE ACROSS A STREAM CURRENT VELOCITY GRADIENT Stream current velocity is a master variable that can modify bottom-up and top-down factors influencing periphyton production and community structure. Current velocity impacts nutrient uptake and invertebrate consumption rates, but field experiments have rarely examined these processes simultaneously. We used nutrient diffusing substrates to add nutrients and an electric fence to exclude invertebrates across a velocity gradient of 2-30 cm/second. We measured algal biomass (chlorophyll a), organic matter (ash-free dry mass), and several pigments representing algal community composition. ANOVAs showed that algal biomass responded to nutrient but not consumer treatments, with current velocity positively affecting algal responses to limiting nutrients. In contrast, organic matter decreased significantly with consumers but did not respond to nutrient additions. Finally, algal community composition responded to nutrient additions and current velocity but not consumer treatments. Nitrogen+Phosphorus treatments increased the proportion of cyanobacteria and decreased the proportion of green algae, while current velocity increased the proportion of green algae but decreased the proportion of diatoms. These experiments measured treatment effects on early successional periphyton communities (up to 16 days old), but future experiments will focus on more developed communities across a wider velocity range.

Whitney Beck (Primary Presenter/Author), Environmental Protection Agency, Beck.Whitney@epa.gov;


LeRoy Poff (Co-Presenter/Co-Author), Colorado State University, n.poff@rams.colostate.edu;


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5/23/2018  |   10:00 - 10:15   |  330 B

LIGHT AND WAVE EXPOSURE DRIVE LITTORAL BENTHIC PRIMARY PRODUCTION IN LAKE ERIE AND GEORGIAN BAY, LAKE HURON Attached algae can contribute substantially to whole-lake primary production in basins with extensive littoral zones, but algal production on hard substrates is limited by light availability and physical disturbance. Benthic algal productivity is measured infrequently in the Laurentian Great Lakes, but could be substantial in shallow basins, like Western Lake Erie. We measured algal productivity on rocks in Lake Erie (2016 and 2017) and in Lake Huron (2016). Mean productivity varied between 17 and 191 mg C/m2/hr in Lake Erie and ranged from 7 to 49 mg C/m2/hr in Lake Huron. Light-saturated productivity in Lake Erie increased with depth reaching a maximum at 40% surface irradiance. In Lake Huron, algal productivity varied little with depth. Based on mixed effects models, light and exposure to wave action in Lake Erie and Lake Huron best predicted variability in attached algal productivity. High nutrient availability promotes attached algal biomass in Lake Erie, but wave disturbance limits biomass accrual to deeper areas where light is limiting. High water clarity in Lake Huron increases the extent of suitable habitat for attached algae, but low nutrients limit biomass and productivity.

Leon Katona (Primary Presenter/Author), Wright State University , katona.2@wright.edu;


Hannah Fazekas (Co-Presenter/Co-Author), Wright State University, voss.14@wright.edu;


Soren Brothers (Co-Presenter/Co-Author), Utah State University, soren.brothers@usu.edu;


Paul Sibley (Co-Presenter/Co-Author), University of Guelph, psibley@uoguelph.ca ;


Yvonne Vadeboncoeur (Co-Presenter/Co-Author), Wright State University, yvonne.vadeboncoeur@wright.edu;


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5/23/2018  |   10:15 - 10:30   |  330 B

TEMPERATURE-NUTRIENT INTERACTIONS REGULATE BIOFILM SPECIES COMPOSITION IN NITROGEN-POOR SYSTEMS Key drivers of ecosystem structure and function including eutrophication and climate warming are altering watershed attributes in ways that fundamentally change stream biofilm species composition. For example, in N-poor ecosystems, N₂-fixing taxa can consist of palatable diatoms in the Rhopalodiaceae or less-palatable cyanobacteria such as Nostoc and Anabaena spp. Which taxa thrive under various temperature and nutrient (N and P availability) conditions can influence rates of nutrient cycling as well as larger-scale food web dynamics. We manipulated temperature as well as N and P availability in a streamside channel experiment in the Hengill region of Iceland to assess their interactive effects on biofilm structure. In N-poor channels, N₂-fixing cyanobacteria and/or diatoms generally dominated, although biofilms accrued little biomass and had more variable assemblage structure at the lowest temperatures. Rhopalodiaceae, especially Rhopalodia, increased under warmer, N-poor conditions, particularly with the addition of P. In contrast, with N addition, biofilm structure quickly shifted to non-N₂-fixing diatoms, including Melosira, while high P stimulated growth of green algae. Our results reinforce how among taxa variation in different modes of resource acquisition and demand drives ecosystem responses to eutrophication and warming.

Paula Furey (Primary Presenter/Author), St. Catherine University, pcfurey@stkate.edu;


Jill Welter (Co-Presenter/Co-Author), St. Catherine University, jill.welter@gmail.com;


Delorianne Sander (Co-Presenter/Co-Author), St.Catherine University, drsander12@gmail.com;


Lyndsie Collis (Co-Presenter/Co-Author), The Ohio State University, collis.21@buckeyemail.osu.edu;


Jonathan P. Benstead (Co-Presenter/Co-Author), University of Alabama, jbenstead@ua.ed;


Wyatt Cross (Co-Presenter/Co-Author), Montana State University, wyatt.cross@montana.edu ;


Jim Hood (Co-Presenter/Co-Author), The Ohio State University, Hood.211@osu.edu;


Alexander D. Huryn (Co-Presenter/Co-Author), The University of Alabama, huryn@ua.edu;


Philip Johnson (Co-Presenter/Co-Author), University of Alabama, Pjohnson@eng.ua.edu;


Jón Ólafsson (Co-Presenter/Co-Author), Marine and Freshwater Research Institute, josh@veidimal.is;


Gisli Mar Gislason (Co-Presenter/Co-Author), University of Iceland, gmg@hi.is;


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