Wednesday, May 25, 2016
10:30 - 12:00

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10:30 - 10:45: / 304-305 DETECTING AND MAPPING CYANOBACTERIA BLOOMS USING REMOTE SENSING AND CLASSIFICATION TREES

5/25/2016  |   10:30 - 10:45   |  304-305

DETECTING AND MAPPING CYANOBACTERIA BLOOMS USING REMOTE SENSING AND CLASSIFICATION TREES Harmful algal blooms of toxigenic cyanobacteria (cyanoHABs) are becoming more prevalent with changing climate and continued eutrophication of surface waters. CyanoHABs can be detrimental to lake ecosystems and can potentially threaten the health of humans exposed to cyanoHAB toxins. Remote sensing has potential for providing cheap, fast, and reliable monitoring of cyanoHABs, as relative reflectance of different wavelengths of light can be used to estimate the concentrations of algal pigments in water. We used an eight-year water quality dataset from a subtropical reservoir paired with corresponding satellite images to build a classification tree model predicting blooms using both chlorophyll and phycocyanin as proxies for total algal and cyanobacterial densities, respectively. Classification trees built using reflectance values of red, blue, and green light and their ratios successfully predicted chlorophyll and phycocyanin concentrations. Our analysis validates remote sensing as an effective and practical monitoring tool for cyanoHABs in subtropical reservoirs and demonstrates that remote sensing can serve as an integral tool in ecosystem and human health risk management.

Katherine V. Hooker (Primary Presenter/Author, Co-Presenter/Co-Author), University of Oklahoma, khooker@ou.edu;


Thayer Hallidayschult ( Co-Presenter/Co-Author), University of Oklahoma, thayer@ou.edu;


Jie Wang ( Co-Presenter/Co-Author), University of Oklahoma, jiewang@ou.edu;


Jessica Beyer ( Co-Presenter/Co-Author), University of Oklahoma, beyer@ou.edu;


Brandon Chien ( Co-Presenter/Co-Author), University of Oklahoma, Brandon.T.Chien-1@ou.edu;


Daniella L. Glidewell ( Co-Presenter/Co-Author), University of Oklahoma, Daniella.L.Glidewell-1@ou.edu;


Xiangming Xiao ( Co-Presenter/Co-Author), University of Oklahoma, xiangming.xiao@ou.edu;


K. David Hambright ( Co-Presenter/Co-Author), University of Oklahoma, dhambright@ou.edu;


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10:45 - 11:00: / 304-305 PATTERNS OF CYANOBACTERIAL DOMINANCE AND SUCCESSION IN TWO CONTRASTING KLAMATH BASIN SYSTEMS DOMINATED BY APHANIZOMENON AND MICROCYSTIS.

5/25/2016  |   10:45 - 11:00   |  304-305

PATTERNS OF CYANOBACTERIAL DOMINANCE AND SUCCESSION IN TWO CONTRASTING KLAMATH BASIN SYSTEMS DOMINATED BY APHANIZOMENON AND MICROCYSTIS. Long-term phytoplankton and environmental data in the Klamath River system were used to describe contrasting cyanobacterial dominance and seasonal succession. The upstream source of the Klamath River is hypereutrophic Upper Klamath Lake (UKL) characterized by high phosphorus (P) and low nitrogen (N) values during the early season that coincide with massive blooms of diazotrophic Aphanizomenon flos-aquae. Subsequent to an annual bloom decline and the release of N previously garnered by the N-fixing Aphanizomenon, non-diazotrophic Microcystis co-dominated during the remainder of the season. In contrast, mainstem reservoirs (Copco and Irongate) located ~105km downstream are dominated primarily by non-diazotrophic Microcystis blooms, the timing of which was tied to export of nitrogen from UKL. Although the seasonal timing of blooms was also related to water temperature, available inorganic N ultimately brought into the system via fixation by Aphanizomenon was the primary driver of Microcystis timing and dominance both in UKL and in downstream reservoirs. Inter-annually the ratio of inorganic N:inorganic P (values <1 were characterized by Aphanizomenon) and availability of ammonia and nitrate dictated the relative dominance of diazotrophic vs. non-diazotrophic species.

Jacob Kann (Primary Presenter/Author), Aquatic Ecosystem Sciences, jacob@aquatic-ecosciences.com;


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11:00 - 11:15: / 304-305 EXAMINING SPATIAL AND TEMPORAL DYNAMICS OF MICROCYSTIS AEUGINOSA AND MICROCYSTIN IN A LOW NUTRIENT LAKE IN NORTHWESTERN MICHIGAN

5/25/2016  |   11:00 - 11:15   |  304-305

EXAMINING SPATIAL AND TEMPORAL DYNAMICS OF MICROCYSTIS AEUGINOSA AND MICROCYSTIN IN A LOW NUTRIENT LAKE IN NORTHWESTERN MICHIGAN Since the invasion of Dreissenid mussels to the Laurentian Great Lakes (1988), there has been an increase in Microcystis blooms as a direct result of nutrient manipulations and selective filtration (Vanderploeg et al., 2001). Dreissenid mussels also facilitate the formation of blooms in low nutrient systems formerly unable to support high concentrations of cyanobacteria (Raikow et al., 2004). For our study, we examined spatial and temporal dynamics of Microcystis aeruginosa and microcystin in Little Traverse Lake, a recreational, low-nutrient lake in northwestern Michigan. We looked for spatial and temporal patterns in the factors explaining Microcystis abundances and microcystin concentrations, sampling in early summer before peak bloom occurred, late summer during peak bloom, and autumn after peak bloom. Because this cyanobacteria overwinters on the sediment, we also collected and analyzed benthic Microcystis samples. Multiple linear regression analyses for all three sampling dates were compared to elucidate temporal patterns in Microcystis and microcystin, and Global Moran’s I was used to test for spatial autocorrelation among variables. When significant autocorrelation existed, kriging was used to further analyze spatial patterns.

Jacob Gaskill (Primary Presenter/Author), Grand Valley State University, gaskillj@mail.gvsu.edu;


Megan Woller-Skar ( Co-Presenter/Co-Author), Grand Valley State University, wollerm@gvsu.edu;


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11:15 - 11:30: / 304-305 BENTHIC MACROINVERTEBRATES IN A CALIFORNIA RIVER BIOACCUMULATE CYANOTOXINS PRODUCED BY CYANOBACTERIAL MATS

5/25/2016  |   11:15 - 11:30   |  304-305

BENTHIC MACROINVERTEBRATES IN A CALIFORNIA RIVER BIOACCUMULATE CYANOTOXINS PRODUCED BY CYANOBACTERIAL MATS Benthic algae provide food and refuge for benthic macroinvertebrates in Mediterranean rivers. However, when toxic cyanobacterial mats proliferate each summer in Northern California’s Eel River, the effect on benthic macroinvertebrates is unknown. During summer 2015 at four sites in the Eel River, we collected benthic macroinvertebrates from replicate cobbles covered with cyanobacterial mats (Phormidium spp.) and adjacent cobbles without cyanobacterial mats. Macroinvertebrates were separated into order and counted, lyophilized, and cyanotoxin concentrations (anatoxin-a and microcystins) in their biomass measured. Cyanotoxins were detected (0-6 ug / g DW) in macroinvertebrates from cobbles both with and without cyanobacterial mats. All common insect orders, except Megaloptera and Odonata, had at least one sample test positive for anatoxin-a, while only Lepidopteran samples contained no microcystin. The assemblage compositions on cobbles with and without mats were also different, with an increase in the proportion of Dipterans inhabiting mats compared to cobbles. The presence of cyanotoxins in macroinvertebrates inhabiting cobbles devoid of macroscopic cyanobacterial mats, suggests cyanotoxins could be widespread in benthic river food webs when cyanobacterial mats proliferate.

Keith Bouma-Gregson (Primary Presenter/Author), University of California, Berkeley, kbg@berkeley.edu;


Raphael Kudela ( Co-Presenter/Co-Author), University of California, Santa Cruz, kudela@ucsc.edu;


Mary Power ( Co-Presenter/Co-Author), University of California, Berkeley, mepower@berkeley.edu;
Dr. Mary E. Power is Professor in the Department of Integrative Biology at the University of California, Berkeley. She was awarded an honorary doctorate by Umea University, the Kempe Medal for distinguished ecologists, and the Hutchinson Award from the American Society of Limnologists and Oceanographers. She is a member of the California Academy of Science, the American Academy of Arts and Sciences, and National Academy of Sciences, USA. She has served on the Editorial Board of PNAS (2014 to present) and Science (2006-2009). Mary also served as President of the American Society of Naturalists, and of the Ecological Society of America. Since 1988, she has been the Faculty Director of the Angelo Coast Range Reserve, (one of the UC Natural Reserve System sites, a 3500 ha reserve protected for university teaching and research). She has studied food webs in temperate and tropical rivers, as well as linkages of rivers, watersheds and near-shore environments. Focal organisms include cyanobacteria, algae, invertebrates, fish, estuarine crustaceans and terrestrial grasshoppers, spiders, lizards, birds and bats. By studying how key ecological interactions depend on landscape and temporal contexts, her group hopes to learn how river-structured ecosystems will respond to changes over space and time in climate, land use, and biota. Her group also collaborates closely with Earth and atmospheric scientists in site-based research to investigate linkages among riverine, upland, and near-shore ocean ecosystems.

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11:30 - 11:45: / 304-305 SPATIOTEMPORAL DYNAMICS OF PHORMIDIUM ACCRUAL AND TOXIN PRODUCTION IN EIGHT NEW ZEALAND RIVERS WITH CONTRASTING NUTRIENT AND FLOW REGIMES

5/25/2016  |   11:30 - 11:45   |  304-305

SPATIOTEMPORAL DYNAMICS OF PHORMIDIUM ACCRUAL AND TOXIN PRODUCTION IN EIGHT NEW ZEALAND RIVERS WITH CONTRASTING NUTRIENT AND FLOW REGIMES Toxic benthic cyanobacterial proliferations, particularly of the genus Phormidium, are an escalating problem in freshwater environments worldwide. Associated terrestrial animal toxicosis events are being reported with increasing prevalence and there are indications of significant impacts to aquatic organisms. This study aimed to elucidate the importance of physiochemical variables in regulating Phormidium accrual. Eight sites were sampled weekly for 30 weeks. Physicochemical samples were collected (e.g., temperature, nutrients and metals) and Phormidium samples for biomass and toxin analysis. Phormidium biomass accrual and toxin concentrations were highly variable spatially and temporally. Generalized additive modelling (GAMs) identified river flow, river, dissolved inorganic nitrogen (DIN) and dissolved reactive phosphorus (DRP) concentrations as important factors regulating Phormidium biomass. Although, the effect of river flow on Phormidium biomass was river specific. Average DIN (0.43 mg/L) and DRP (0.002 mg/L) concentrations coincided with a peak in biomass. GAMs showed a significant relationship between toxin concentrations and low DIN and DRP concentrations. This study highlights the complex interplay between river flow, nutrient dynamics and Phormidium accrual and manipulative experiments are currently being conducted to disentangle these relationships further.

Tara McAllister (Primary Presenter/Author), University of Canterbury, tara.mcallister0@gmail.com;


Susie Wood ( Co-Presenter/Co-Author), Cawthron Institute, Susie.Wood@cawthron.org.nz ;


Ian Hawes ( Co-Presenter/Co-Author), University of Canterbury, ian.hawes@canterbury.ac.nz ;


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11:45 - 12:00: / 304-305 SPECIES MATTER: THE RESPONSE OF DIATOMS AND N2-FIXING ALGAL TAXA TO INCREASING TEMPERATURE AND NITROGEN ADDITION

5/25/2016  |   11:45 - 12:00   |  304-305

SPECIES MATTER: THE RESPONSE OF DIATOMS AND N2-FIXING ALGAL TAXA TO INCREASING TEMPERATURE AND NITROGEN ADDITION In nitrogen-poor streams, the abundance and species composition of N2-fixing algae can determine how, where, and under what conditions nitrogen enters the ecosystem. In a channel experiment set in Hengill, Iceland, we assessed how increasing temperature and nitrogen addition influenced N2-fixation rates and algal species composition. We predicted N2-fixation rates would decrease as more nitrogen became available. We predicted interactions between species-specific nutrient or thermal optima where cyanobacteria and/or diatoms would be most abundant. While N2-fixation rates increased with temperature, rates declined with increasing nitrogen availability. In nitrogen-poor channels, N2-fixing cyanobacteria (e.g. Anabaena and Nostoc spongiaeforme) dominated overall, but diatoms with cyanobacteria endosymbionts like Rhopalodia were only abundant in warmer temperatures. As nitrogen availability increased, green algae and diatoms (e.g. Hannaea and Diatoma) increased, but N2-fixing taxa were generally only abundant in warmer temperatures. In nitrogen-rich channels, diatoms (e.g. Melosira, Synedra, Nitzschia) dominated at all temperatures. Whether temperature and nitrogen interactions favor a particular alga over another is critical information when assessing the effects of N2-fixation on freshwaters, as well as the transfer of nitrogen to higher trophic levels.

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


Jill Welter ( Co-Presenter/Co-Author), St. Catherine University, jrwelter@stkate.edu;


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


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


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


Jonathan Benstead ( Co-Presenter/Co-Author), The University of Alabama, jbenstead@ua.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 S. Ólafsson ( Co-Presenter/Co-Author), Marine and Freshwater Research Institute, Iceland, jon.s.olafsson@hafogvatn.is;


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


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