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Citation

Wilson, A. E., J. L. Pollock, I. Billick, C. Domingo, E. G. Fernandez-Figueroa, E. Nagy, T. D. Steury, and A. Summers. 2018. Assessing science training programs: Structured undergraduate research programs make a difference. BioScience 68(7):529-534. (Editor’s Choice) (2018 College of Agriculture High Impact Paper of the Year Award)

Abstract

Training in science, technology, engineering, and mathematics (STEM) is a top priority for driving economic growth and maintaining technological competitiveness. We propose that exposure to a rigorous research program as an undergraduate leads to success in a research STEM career. We compared the scientific outcomes of 88 participants from five National Science Foundation Research Experiences for Undergraduates (REU) Site programs with demographically similar applicants to assess the impact that formal, organized, and funded undergraduate summer research experiences have on participants. Our study demonstrates that REU participants are more likely to pursue a PhD program and generate significantly more valued products, including presentations, publications, and awards, when compared with applicants. We believe that key components of the program include funding for personal and professional needs; access to diverse intellectual, analytical, and field resources; and the presence of other undergraduate researchers who support each other and share their goals and interests.

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Delaney, M., A. ArchMiller, D. P. Delaney, A. E. Wilson, and E. J. Sikora. 2018. Effectiveness of fungicide on soybean rust in the southeastern United States: a meta-analysis. Sustainability 10:1784.

Abstract

Soybean rust (SBR), caused by the fungus Phakopsora pachyrhizi Sydow, has been of concern to soybean (Glycine max Merrill) growers in the southern United States since its introduction in 2004. As this fungus develops, pustules become numerous on the underside of leaves, which then turn yellow and drop prematurely, resulting in fewer pods, and poorly developed seeds. Our objective was to evaluate the efficacy of fungicide use in controlling SBR by conducting a meta-analysis of 61 published and unpublished trials across the southern United States from 2004 to 2014. We analyzed fungicide efficacy based on factors such as specific classes of fungicide, active ingredients, number of fungicide applications, target growth stage upon initial application, level of disease pressure, and year of the study. Fungicides significantly increased yield and 100-seed weight and decreased the severity of SBR. The means of SBR severity, yield, and 100-seed weight in fungicide-treated plants were 9% (95% confidence interval: 2%, 21%), 128% (121%, 135%), and 121% (116%, 128%), respectively, of those calculated in the control plants. By using meta-analysis to analyze fungicide efficacy across multiple field trials, we were able to determine that one application of a strobilurin fungicide when plants were either beginning pod development (R3) or developing seeds (R5) was the most cost-effective approach to controlling SBR and increasing 100-seed weight.

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Baker, B. C., A. E. Wilson, and J. T. Scott. 2018. Phytoplankton N2 fixation efficiency and its effect on harmful algal blooms. Freshwater Science 37(2):264-275.

Abstract

Toxin production during harmful algal blooms (HABs) depends on N availability. However, the role of N2 fixation as a mechanism to fuel ‘new’ N into HABs and increase their toxicity has not been well studied. We quantified the effects of N∶P supply ratios on N2-fixation efficiency in HABs from 3 warm-temperate man-made reservoirs. We enriched mesocosms with the same concentration of P (112 µg P/L) but differing amounts of N (50‒2500 µg N/L) labeled with a 15N tracer to simulate HABs growing along a large molar N∶P gradient (1‒50). N2 fixation increased significantly at low N∶P but generally did not alleviate N limitation and lead to accumulating N and phytoplankton biomass efficiently unless the magnitude of stoichiometric imbalance was low. Furthermore, microcystin concentrations >1.0 µg/L occurred only in mesocosms receiving N∶P = 50 supply and only in the reservoir with detectable concentrations of microcystin at the beginning of the experiment. These results suggest that HABs in P-rich reservoirs may yield significantly more biomass and potentially become more toxic when reactive N is plentiful in the water column relative to P. Thus, reducing N concentrations can be useful as a supplement to the primary P reduction strategies used to minimize the harmful effects of algal blooms.

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Yang, Z., R. P. Buley, E. G. Fernandez-Figueroa, M. U.G. Barros, S. Rajendran, and A. E. Wilson. 2018. Hydrogen peroxide treatment promotes chlorophytes over toxic cyanobacteria in a hyper-eutrophic aquaculture pond. Environmental Pollution 240:590-598. 

Abstract

Controlling blooms of toxigenic phytoplankton, including cyanobacteria, is a high priority for managers of aquatic systems that are used for drinking water, recreation, and aquaculture production. Although a variety of treatment approaches exist, hydrogen peroxide (H2O2) has the potential to be an effective and ecofriendly algaecide given that this compound may select against cyanobacteria while not producing harmful residues. To broadly evaluate the effectiveness of H2O2 on toxigenic phytoplankton, we tested multiple concentrations of H2O2 on (1) four cyanobacterial cultures, including filamentous Anabaena, Cylindrospermopsis, and Planktothrix, and unicellular Microcystis, in a 5-day laboratory experiment and (2) a dense cyanobacterial bloom in a 7-day field experiment conducted in a nutrient-rich aquaculture pond. In the laboratory experiment, half-maximal effective concentrations (EC50) were similar for Anabaena, Cylindrospermopsis, and Planktothrix (average EC50 = 0.41 mg L-1) but were ∼10x lower than observed for Microcystis (EC50 = 5.06 mg L-1). Results from a field experiment in an aquaculture pond showed that ≥1.3 and ≥ 6.7 mg L-1 of H2O2 effectively eliminated Planktothrix and Microcystis, respectively. Moreover, 6.7 mg L-1 of H2O2 reduced microcystin and enhanced phytoplankton diversity, while causing relatively small negative effects on zooplankton abundance. In contrast, 20 mg L-1 of H2O2 showed the greatest negative effect on zooplankton. Our results demonstrate that H2O2 can be an effective, rapid algaecide for controlling toxigenic cyanobacteria when properly dosed.

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Minasyan, A., C. Christophoridis, A. E. Wilson, S.-K. Zervou, T. Kaloudis, and A. Hiskia. 2018. Diversity of cyanobacteria and the presence of cyanotoxins in the epilimnion of Lake Yerevan (Armenia). Toxicon 150:28-38.

Abstract

This paper presents the first report of cyanobacteria and cyanotoxins from the South Caucasus region, in particular from Lake Yerevan (Armenia). Microcystis, Dolichospermum and Planktothrix were the key genera identified during the growing season. A trend of a remarkable increase in cyanobacterial densities was observed from 2012 to 2013 exhibiting bloom formation in June (by Nostoc linckia) with the highest values in June and August 2013, reaching up to 695.9*103 cells mL−1. Seasonal dependence of cyanobacterial density on temperature, and temperature as a driver for cyanobacterial cells growth and development were suggested. Biogenic nutrients were identified as co-drivers determining species richness and dominance, as well as the distribution of phytoplankton in different parts of the reservoir. Cyanotoxin concentrations in the filtered biomass were reported during July 2012 for both stations of the reservoir (left and right bank). Microcystin-RR (MC-RR) was the most abundant and the most frequently observed cyanotoxin. Lower MC-LR concentrations were identified in all samples from both stations, with the highest values observed at the right bank in July 2012. [D-Asp3]MC-RR, MC-YR, MC-HtyR, [D-Asp3]MC-LR, MC-HilR, MC-WR, MC-LY and MC-LW were also identified in trace levels. Anatoxin-a (ANA) was reported in the samples from both stations during August 2012. Cylindrospermopsin (CYN) was present in trace concentrations in samples from both stations during July and in the sample from the left bank during September.

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Wilson, A. E. and E. G. Fernandez-Figueroa. 2018. Preparing water resource managers to identify and measure toxic cyanobacteria. Streamlines Spring 2018:18.

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Wilson, A. E., E. G. Fernandez, R. Buley, and L. A. Roy. 2018. Is sustainable control of toxic algae a reality for catfish aquaculture? Fish Farming News 2018(1):7-8. 

Abstract

Toxic algae, especially some blue-green algae, pose serious and sometimes fatal consequences for the health of cultured catfish. Some algae are also associated with the production of compounds, such as geosmin and methylisoborneol (MIB), that can make fish fillets taste earthy (off-flavor). Such problems add additional costs and headaches to an already overburdened industry.

Given that algal blooms often occur during warm temperatures and excess nutrient loads, i.e., typical conditions for catfish aquaculture ponds in Alabama and Mississippi, algal bloom management is a necessary component for all aquaculture farms. A variety of bloom control approaches exist, including physical (e.g., mixing, sonication), biological (e.g., herbivores), and chemical (e.g., algaecides). Chemical treatments, such as copper sulfate and potassium permanganate, are the most commonly used because they are usually effective at quickly killing algae. However, their effects on the algal community are short-lived and tend not to promote other, harmless algae, such as green algae.

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Wilson, A. E., M. F. Chislock, Z. Yang, M. U.G. Barros, and J. F. Roberts. 2018. Pond bank access as an approach for managing toxic cyanobacteria in beef cattle pasture drinking water ponds. Environmental Monitoring and Assessment 190:247.

Abstract

Forty-one livestock drinking water ponds in Alabama beef cattle pastures during were surveyed during the late summer to generally understand water quality patterns in these important water resources. Since livestock drinking water ponds are prone to excess nutrients that typically lead to eutrophication, which can promote blooms of toxigenic phytoplankton such as cyanobacteria, we also assessed the threat of exposure to the hepatotoxin, microcystin. Eighty percent of the ponds studied contained measurable microcystin, while three of these ponds had concentrations above human drinking water thresholds set by the US Environmental Protection Agency (i.e., 0.3 μg/L). Water quality patterns in the livestock drinking water ponds contrasted sharply with patterns typically observed for temperate freshwater lakes and reservoirs. Namely, we found several non-linear relationships between phytoplankton abundance (measured as chlorophyll) and nutrients or total suspended solids. Livestock had direct access to all the study ponds. Consequently, the proportion of inorganic suspended solids (e.g., sediment) increased with higher concentrations of total suspended solids, which underlies these patterns. Unimodal relationships were also observed between microcystin and phytoplankton abundance or nutrients. Euglenoids were abundant in the four ponds with chlorophyll concentrations > 250 μg/L (and dominated three of these ponds), which could explain why ponds with high chlorophyll concentrations would have low microcystin concentrations. Based on observations made during sampling events and available water quality data, livestock-mediated bioturbation is causing elevated total suspended solids that lead to reduced phytoplankton abundance and microcystin despite high concentrations of nutrients, such as phosphorus and nitrogen. Thus, livestock could be used to manage algal blooms, including toxic secondary metabolites, in their drinking water ponds by allowing them to walk in the ponds to increase turbidity.

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Jameel, Y., S. Stein, E. Grimm, C. Roswell, A. E. Wilson, C. Troy, T. Höök, and G. Bowen. 2018. Physicochemical characteristics of a southern Lake Michigan river plume. Journal of Great Lakes Research 44:209-218.

Abstract

Riverine inputs are a major source of nutrients to the Laurentian Great Lakes and have important effects on nearshore biological processes, where mixing between river and lake water leads to formation of heterogeneous river plumes. We examined the physical and chemical characteristics of the St. Joseph River plume in southern Lake Michigan between May and October 2011, and in October 2012, June 2013 and April 2014. Specific electric conductivity and stable isotopes of water were used to quantify the fraction of river water (FRW) at sampling sites in Lake Michigan. Both tracers predicted similar patterns of FRW among sites; however, there was a systematic offset between the two methods, and specific electric conductivity method under-predicted the FRW by ∼5%. We observed a distinct, seasonally varying river plume, with plume size correlated with flow rate of St. Joseph River. Within the plume, sediments and nutrients were non-conservative and exhibited significant and seasonally varying losses that we attribute to settling of particle-bound nutrients and/or nutrients in particulate phase below the plume. The characteristics and the spatiotemporal heterogeneity of the river plume documented here may have important implications for the nearshore biogeochemistry of the Great Lakes and for understanding the roles of these features in ecological processes in nearshore areas.

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Weaver, R. J., E. S. A. Santos, A. M. Tucker, A. E. Wilson, and G. E. Hill. 2018. Carotenoid metabolism strengthens the link between feather coloration and quality. Nature Communications 9:73. (Clarivate Analytics Web of Science Highly Cited Paper)

Abstract

Thirty years of research has made carotenoid coloration a textbook example of an honest signal of individual quality, but tests of this idea are surprisingly inconsistent. Here, to investigate sources of this heterogeneity, we perform meta-analyses of published studies on the relationship between carotenoid-based feather coloration and measures of individual quality. To create color displays, animals use either carotenoids unchanged from dietary components or carotenoids that they biochemically convert before deposition. We hypothesize that converted carotenoids better reflect individual quality because of the physiological links between cellular function and carotenoid metabolism. We show that feather coloration is an honest signal of some, but not all, measures of quality. Where these relationships exist, we show that converted, but not dietary, carotenoid coloration drives the relationship. Our results have broad implications for understanding the evolutionary role of carotenoid coloration and the physiological mechanisms that maintain signal honesty of animal ornamental traits.

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