SFS Annual Meeting

Oghenekaro Nelson Odume (Primary Presenter/Author)
Rhodes University, South Africa, odume.nelson@gmail.com;

Ntombekhaya Mgaba (Co-Presenter/Co-Author)
Rhodes University, k.mgaba@ru.ac.za;

Paul Mensah (Co-Presenter/Co-Author)
University of Cape Coast, kojomens@hotmail.com;

Neil Griffin (Co-Presenter/Co-Author)
Rhodes University, n.griffin@ru.ac.za;

Zintle Mtintsilana (Co-Presenter/Co-Author)
Rhodes University, mtintsilanaz@gmail.com;

Abstract: Are plasticizers toxic at environmentally realistic concentrations? Plastics have been recognised as physical stressors in the environment, but a growing number of studies have also indicated the potential of plastics as chemical stressors. Two primary pathways have been identified for plastics acting as chemical stressors and these are i) as vectors for absorbed chemicals and ii) leaching of chemicals such as plasticizers added to plastics during their production. Three commonly used plasticizers, which have also been found in aquatic environments are calcium stearate, dibutyl phthalate, and bisphenol A. This study investigates the long-term chronic toxicity of three plasticizers at environmentally realistic concentrations. No short-term mortality risk at environmental levels were found. A limited response of fish egg hatching to plasticizers was found, but this occurred at levels of plasticizer that were higher than those reported from the environment. A clear negative response of snail reproduction was found at levels of bisphenol A that can easily be found in the environment. This was found in M. tuberculate, and the risk may extend to other taxa too.

Marla Valeria Santos-Crespo (Primary Presenter/Author)
Universidad de Puerto Rico, Río Piedras Campus, marla.santos@upr.edu;

Abstract: Thiamethoxam is a neonicotinoid insecticide commonly used in major crops such as rice and cotton. This neurotoxin has been found in surface waters that may contaminate rivers and affect non-target organisms such as decapods. We present changes in behavioral and physical dynamics in the freshwater shredder shrimp, Xiphocaris elongata after exposing them to 200, 400, 600, 800, and 1,000 ug/L of thiamethoxam. Their behavior was assessed using video-monitoring after 15 minutes and 24 hours of exposure and changes in external color were recorded with photographs. Our preliminary results show that locomotion and residual time in the center of the arena assessed is decreased, which may translate to difficulty in avoiding predation and other complications. Therefore, we suggest that thiamethoxam could be potentially toxic to these essential invertebrates at these levels and more research is needed to understand the further implications of their industrial and global use.

Laura Naslund (Primary Presenter/Author)
University of Georgia, laura.naslund@uga.edu;

Jacqueline Gerson (Co-Presenter/Co-Author)
Duke University, jgerson1@gmail.com;

Alexander Brooks (Co-Presenter/Co-Author)
Colorado State University, alex.brooks@colostate.edu;

Amy Rosemond (Co-Presenter/Co-Author)
University of Georgia, rosemond@uga.edu;

David Walters (Co-Presenter/Co-Author)
United States Geological Survey, waltersd@usgs.gov;

Emily Bernhardt (Co-Presenter/Co-Author)
Duke University, ebernhar@duke.edu;

Abstract: Contaminants are transported from aquatic to terrestrial food webs through emerging aquatic insects, but in quantifying these fluxes we have largely focused on stream contaminant concentration as the driver of flux and have not considered other factors which impact insect production. We applied a recently published conceptual model to identify drivers of selenium (Se) fluxes from a river network draining mountaintop removal coal mines. We predicted that Se flux from a given site could be explained by its watershed mining extent, the presence of settling ponds, and network position (tributary vs. mainstem). Although mining extent drove insect Se concentration (p = 0.008, R2= 0.406), the presence of ponds and mainstem location were the primary drivers of Se flux because of their strong impact on emergence production. Median Se fluxes from ponded, mined tributaries were 18 times higher than those from unponded, mined tributaries and were comparable to fluxes from much larger mainstem sites. Thus, contaminant flux was greatest downstream of contaminant inputs or where ponds were created, implying that without capturing drivers of insect production, contaminant fluxes from the river network and accompanying risks to terrestrial predators can be underestimated.

Nika Galic (Co-Presenter/Co-Author)
Syngenta Crop Protection LLC, nika.galic@syngenta.com;

Maxime Vaugeois (Co-Presenter/Co-Author)
University of Minnesota, Twin Cities, mvaugeoi@umn.edu;

Dan Hornbach (Co-Presenter/Co-Author)
Macalester College, hornbach@macalester.edu;

Richard Brain (Co-Presenter/Co-Author)
Syngenta Crop Protection LLC, richard.brain@syngenta.com;

Valery Forbes (Co-Presenter/Co-Author)
University of Minnesota, veforbes@umn.edu;

Adrian Moore (Primary Presenter/Author)
University of Minnesota, Twin Cities, apmoore665@gmail.com;

Abstract: In the United States there are approximately 90 freshwater mussel species listed under the federal Endangered Species Act, exhibiting a wide range of life-history traits. Population modeling is integral to facilitating risk assessments, but is time consuming and requires large amounts of, often unavailable, data. One solution is to select and use species that may be representative of a wider group. The objective of this study was to compare the effects of hypothetical stressors on individual-level endpoints of freshwater mussels with different life-history strategies. Using previously described life-history guilds, we selected a federally-listed and non-listed species from each. We then parameterized these species in a Dynamic Energy Budget model and applied hypothetical stressors with different physiological modes of action. We measured effects on individual-level endpoints, such as shell length and fecundity. We compared results between species to determine if responses varied between species with different life-history strategies or listing statuses. These results are intended to help us determine if non-listed species of a particular life-history category can serve as appropriate representatives for listed species in those same categories in risk assessment exercises, such as population modeling.

Stefani Cruz Rosa (Primary Presenter/Author)
University of Puerto Rico Río Piedras, stefani.cruz@upr.edu;

Abstract: With the rapid development of the nanotechnology industry, the world is being attentive to the environmental impacts of manufactured nanoparticles. The production of TiO2 nanoparticles by 2025 is expected that it will reach 2.5 million metric tons. The rapid production and use of TiO 2 nanoparticles result in the direct and indirect release into aquatic environments through bathing, industrial effluent, and engineering applications, causing an influence in the river health and lotic ecosystem function and services. These changes can also affect shrimp larval survival and recruitment. These organisms have high chance of encountering suspended particles of pollutants in their migrations. One species of freshwater shrimp is Atya lanipes, which is known to affect detrital processing and nutrient availability to the rest ecosystem food web. Is important to know how this emerging aquatic pollutant can affect Atya lanipes normal migrations. The objective of this study is to understand the toxic effects of TiO 2 nanoparticles in post hatching Atya lanipes larvae under different nanoparticles concentrations (0.1, 1, 10, 50, 100 mg/L). The bioassay will analyze survival, morphological development and locomotion behavior after 24h, 48h and 72h post exposition times.

Verena C. Schreiner (Co-Presenter/Co-Author)
University of Koblenz-Landau, Institute for Environmental Sciences, schreiner-verena@uni-landau.de;

Moritz Link (Co-Presenter/Co-Author)
University of Koblenz-Landau, Institute for Environmental Sciences, link@uni-landau.de;

Matthias Liess (Co-Presenter/Co-Author)
UFZ - Helmholtz Centre for Environmental Research, matthias.liess@ufz.de;

Ralf Schäfer (Primary Presenter/Author)
University of Koblenz-Landau, Institute for Environmental Sciences, schaefer-ralf@uni-landau.de;

Abstract: Freshwater ecosystems are subject to a multitude of stressors. In agricultural areas, pesticides play a major role. They can enter water bodies via spraydrift, subsurface drainage and runoff. We present the results from a review of field studies on the effects of pesticides on invertebrate communities in freshwater ecosystems. Despite complex pesticide regulation, effects of agricultural pesticide use (mainly insecticides and fungicides) on invertebrate communities have been reported in different regions of the world in the literature. However, most of these studies were conducted in regions of high intensity agriculture such as in Western Europe or North America. Furthermore, most studies were limited to the local or regional scale. Hence, we also present recent results from studies on pesticide pollution and the response of invertebrate communities and adjacent riparian ecosystems from a region with low intensity agriculture in Central Europe. In addition, we report results from a comprehensive large scale monitoring study in Germany. We discuss the problem of establishing causality based on field studies in a community ecological context and outline promising future research directions.

Anna Boatman (Primary Presenter/Author)
North Carolina State University, akboatma@ncsu.edu;

Abstract: Per- and polyfluoroalkyl substances (PFAS) are a ubiquitous and diverse class of “forever chemicals” that are gaining international attention as contaminants of concern. Many of these compounds have been detected in aquatic organisms in nature. It remains unclear how the widely varying structural characteristics of these chemicals affect their bioaccumulation potential. Additionally, it is not possible to elucidate the relative contributions of direct aqueous uptake versus dietary trophic transfer in field-caught organisms. To address these questions, we devised a lab-based strategy to investigate how PFAS accumulate in primary producers (periphyton), primary consumers (the lab-reared mayfly, N. triangulifer), and secondary consumers (D. rario). In our preliminary studies we exposed periphyton and mayfly larvae to mixtures of two PFAS, GenX and PFOA, at environmentally relevant aqueous concentrations. Data tentatively suggest that surface sorption may play a larger role than uptake in periphyton, and that dietary uptake may play a larger role than aqueous uptake in larvae. Further refinement of our approach will allow us to quantify the accumulation of various PFAS moving within the lowest trophic levels of an aquatic food web.

Rafael Perez (Primary Presenter/Author)
University of Puerto Rico, rafael.perez13@upr.edu;

Abstract: Urban streams are a concern as cities keep growing. The pollution in these systems may be dangerous to the organisms that inhabit them. Amphidromous fish Sicydium spp. (Ceti) is wildly distributed along the Caribbean. In Puerto Rico, Ceti is found in almost every stream around the island. Ceti larvae develop in the estuaries where it is exposed to the chemicals being transported in the river. This study is focused on urban stream contamination effects on migratory fish Sicydium spp. We use behavior analysis techniques on Ceti larvae raised in water from two estuaries, one of an urban and another from a natural/forested stream. We observed behavioral changes between the larvae, which may be due to the difference in concentration of contaminants at each estuary. Changes in behavior may lead to an increase in predation of the larvae with subsequent reduction of the population and a negative effect on the overall food web. This project helps understand the impact of urban stream contamination, where Sicydium spp. may serve as a great model for future ecotoxicological studies.

Paul Stankus (Co-Presenter/Co-Author)
Savannah River Ecology Laboratory-University of Georgia, stankus@srel.uga.edu;

Dean Fletcher (Co-Presenter/Co-Author)
Savannah River Ecology Laboratory-University of Georgia, fletcher@srel.uga.edu;

Christina Fulghum (Primary Presenter/Author)
Savannah River Ecology Laboratory-University of Georgia, cfulghum@uga.edu;

Abstract: The H-02 wetland system regulates pH and removes metals, primarily Cu and Zn, from an effluent line on the Department of Energy’s Savannah River Site, SC, USA. Effluents are maintained below regulatory limits during base flows. However, biomonitors accumulated higher than expected Cu concentrations downstream of the wetland. Stormwater pulses may reduce the wetland’s effectiveness at metal removal, allowing greater quantities of Cu and Zn to flow downstream. Automated water samplers located upstream and downstream of the treatment cells collected hourly water samples and water quality data. Total and dissolved Cu and Zn concentrations were determined. Storm severity influenced discharge, metal concentrations, fluxes, and form of mobilized metals. Wetland responses changed over time. A first-flush during severe storms elevated metal concentrations, metal flux, and total suspended solids with most Cu being associated with particulates. Later, concentrations, metal flux, and TSS were lower with most Cu in the dissolved phase. Multiple days of elevated discharge resulted in greater metal loads leaving the retention basin and wetland treatment cells. Treatment cells appeared overloaded during large storms. However, more metals entered than left the wetland, so impacts to the receiving stream were reduced.

David Janetski (Co-Presenter/Co-Author)
Indiana University of Pennsylvania, janetski@iup.eud;

Tom Clark (Co-Presenter/Co-Author)
Susquehanna River Basic Commission, tclark@srbc.net;

Alexa Hershberger (Primary Presenter/Author)
Indiana University of Pennsylvania, JLWY@iup.edu;

Abstract: Acid-mine drainage (AMD) has caused significant ecological damage in the Appalachian Region. Iron pyrite exposed during coal mining increases acidity and metal concentrations in streams, which could be detrimental to biology. While remediation is generally effective, why ecosystem components recover at different rates remains uncertain. The Bear Run Watershed presents an ideal study where the fish community and water quality have improved following remediation, but macroinvertebrate recolonization has been slow. To examine whether substrate embeddedness and metal precipitates on substrate are impairing recovery, we sampled macroinvertebrates and algae on artificial and natural substrates in AMD and unimpaired stream reaches in fall 2019. We predicted that algae and macroinvertebrates in AMD reaches would colonize artificial substrates because they lack the metal precipitates that embed natural sediments. While there was no difference in algal responses between AMD and unimpaired reaches, macroinvertebrate abundance showed a trend toward a reach-substrate interaction. This may indicate that the macroinvertebrates are available to recolonize recovering stream reaches, but substrate quality is preventing them from increasing in abundance. We recommend further exploration of how substrate embeddedness caused by metal precipitates may impair macroinvertebrate recolonization after coal mine remediation.

Roberto Reyes-Maldonado (Primary Presenter/Author)
University of Puerto Rico, Rio Piedras, robertoomaldo@gmail.com;

Alonso Ramírez (Co-Presenter/Co-Author)
North Carolina State University, alonso.ramirez@ncsu.edu;

Bruno Marie (Co-Presenter/Co-Author)
University of Puerto Rico, Institute of Neurobiology, brunomariemail@gmail.com;

Abstract: Different markers have been used to detect toxicity in freshwater environments using chironomid larvae. Cellular markers could help to detect toxicity during early stages, anticipating effects at morphological or behavioral levels. The objective of this study is to propose the neuromuscular tissue of Chironomus sp. Florida as a cellular marker. Since this tissue is not known in chironomids, we have described its anatomy by using immunohistochemistry and confocal microscopy to produce anatomical diagrams. Analyzing the first abdominal segment, a total of 62 muscles were described. The ganglion corresponding to this segment has two tracts whose nerves branch into axons that innervate each muscle through a terminal composed of numerous synaptic boutons. The response of one of these terminals was evaluated against temperature, sex and age. Larvae reared at 30ºC were observed to have a higher density of synaptic boutons when compared to larvae reared at 25ºC, something not observed at different ages or sex. Although this study is in a development stage to determine if the studied structures could be used as toxicity markers, it is clear that they are responsive, and their changes are easy to quantify.