Dr. AJ Reisinger’s research focuses on how human activities affect levels of nutrients and other pollutants and impair the quality of soil and water. He is also interested in how pharmaceuticals and personal care products, as well as other emerging contaminants of concern, alter ecosystem functioning in urban environments.
Industry Expertise (3)
Fishery and Aquaculture
Areas of Expertise (5)
Nutrient, Pesticide and Waste Management
Soil, Water, and Aquifer Remediation
Wetlands and Aquatic Ecosystems
Media Appearances (6)
Shipyards Development; COVID Variants; Crayfish Study; What's Good Wednesdays
A new University of Florida study has found that traces of antidepressants and other pharmaceuticals, which are commonly found in bodies of water in Florida and around the globe, are altering the behavior of marine creatures like crayfish. The study looked at crayfish, and how the exposure to antidepressants affected their behavior. Some of the observed behavior included crayfish exhibiting more aggressive behavior when exposed to the antidepressant, and a change in attitude such as the crayfish becoming more bold. AJ Reisinger, Assistant Professor, at the University's Institute of Food and Agriculture, and lead author of the study, joined us to discuss it in more detail.
We pee or flush drugs into waterways—does that matter to aquatic life?
Ars Technica online
The data comes from A.J. Reisinger—assistant professor in the Soil and Water Sciences Department at the University of Florida—and his team, which traveled to the Cary Institute of Ecosystem Studies in 2017. The facility has several artificial streams that mimic natural conditions but allow researchers to control different aspects of the environment. Reisinger's team went out into the field and collected rocks, bugs, leaves, and crayfish and put them into the artificial streams. Crayfish were chosen because they can reach high biomasses in aquatic ecosystems and will "eat anything they can get their claws on. They'll eat bugs, they'll eat algae, they'll eat leaves, they'll eat juvenile fish, even," Reisinger told Ars.
Antidepressants in Our Water Make Crayfish Go Buck Wild
There are trace amounts of many pharmaceuticals in bodies of water around the world, thanks to how humans metabolize our medicines and dispose of wastewater. “When you take a medication, nobody’s body is 100% efficient, so when we take a pill, we might only metabolize and actually use 90%, or 80%, or 70%,” said AJ Reisinger, an assistant professor at the University of Florida’s Soil and Water Sciences Department and lead author of the study. “Whatever is left over and not used by our body will be excreted directly into our toilets, flushed, then through a sewer and into a wastewater treatment plant—or, if the sewer line is leaking, directly into our groundwater.”
University of Florida professor thinks Piney Point Reservoir-like leak unlikely in Gainesville
ABC 20 WCJB online
Dr. AJ Reisinger, an assistant professor of Urban Soil and Water Sciences at UF, thinks that this wastewater could cause awful environmental effects in the bay. “And so the waters that they are pumping have really high levels of nitrogen and phosphorus, which have negative water quality implications for the bay due to potential for fueling red tide events as well as other algal growths and algal blooms and potential fish kills and human health implications,” said Reisinger.
An Urbanized Florida Means More Stormwater Ponds, Invasive Plants
Added study co-author AJ Reisinger: “What our work shows is that stormwater ponds have the potential to facilitate invasive plants by providing them a habitat to colonize in the middle of urban landscapes.”
Low dose, constant drip: Pharmaceutical and personal care pollution impacts aquatic life
To assess toxicity, chemical compounds are evaluated with an 'LC50' test. Organisms of a single species are exposed to increasingly high concentrations of a substance until 50% of the experimental 'population' dies. This concentration is used to set environmentally acceptable limits. "Single-organism lethality does not account for the diversity of species in nature, bioaccumulation, or non-lethal but disruptive impacts that compromise ecosystems," explains co-author A.J. Reisinger of the University of Florida, Gainesville.
Evaluating Instream Restoration Effectiveness in Reducing Nitrogen Export from an Urban Catchment with a Data-Model ApproachJAWRA Journal of the American Water Resources Association
Laurence Lin, Alexander J Reisinger, Emma J Rosi, Peter M Groffman, Lawrence E Band
2021 Urbanization increases stormwater runoff into streams, resulting in channel erosion, and increases in sediment and nutrient delivery to receiving water bodies. Stream restoration is widely used as a Best Management Practice to stabilize banks and reduce sediment and nutrient loads. While most instream nutrient retention measurements are often limited to low flow conditions, most of the nutrient load is mobilized at high stream flows in urban settings. We, therefore, use a process-based stream ecosystem model in conjunction with measurements at low flows and focus on estimation of stream nitrogen retention over the full streamflow distribution. The model provides a theoretical framework to evaluate the geomorphic, hydrologic, and ecological factors that are manipulated by stream restoration, and drive nitrogen retention. We set a model for a pool-riffle sequence restored stream (190 m) in Baltimore County, Maryland and calibrated the model to the in situ measured primary production (Nash–Sutcliffe model efficiency coefficient [NSE] NSE = 0.89), respiration (NSE = 0.74), and nitrate uptake lengths (R2 = 0.88). At the daily scale, simulations showed low nitrogen retention during high flows due to high transport rates, mobilization of stored hyporheic nitrogen, and scouring of periphyton biomass. This result underscores the need to reduce contributing watershed runoff flashiness to promote aquatic nutrient cycling and retention. At monthly and yearly time scale, model predicted a higher percent reduction in summer than in winter and estimated 5.7%–9.5% of annual nitrate reductions. While the model was tested in a pool-riffle sequence restoration design, the approach can be adapted to evaluate a range of channel restoration design characteristics, and the effects of upland watershed restoration to mitigate stormwater loading through both restored and unrestored streams.
Exposure to a common antidepressant alters crayfish behavior and has potential subsequent ecosystem impactsEcosphere
Alexander J Reisinger, Lindsey S Reisinger, Erinn K Richmond, Emma J Rosi
2021 Pharmaceuticals are ubiquitous in aquatic environments, yet little is known regarding their impacts on ecological processes. Selective serotonin reuptake inhibitors (SSRIs) are frequently prescribed human antidepressants and have been shown to alter crayfish behavior. These behavioral alterations are particularly relevant as crayfish play a central role in freshwater ecosystems and often reach high biomass in anthropogenically influenced environments commonly exposed to pharmaceutical contamination. Using a 14-d artificial stream experiment, we exposed spinycheek crayfish (Faxonius limosus) to citalopram, a common SSRI, at an environmentally realistic concentration (0.5 µg/L). We used a Y-shaped flume to quantify the effects of SSRI exposure on crayfish behavior and food/conspecific preference. We also tested the interacting effects of citalopram and crayfish on habitat-specific and whole-stream ecosystem functions and biomass. Crayfish exposed to SSRIs exhibited increased boldness (time to emerge from shelters; P < 0.05) and spent more time orienting to food resources than nonexposed crayfish. Crayfish increased water column chlorophyll a (P < 0.01) and benthic organic matter (P = 0.03). Furthermore, crayfish potentially increased water column respiration (P = 0.09) and potentially decreased nitrate uptake (P = 0.05). SSRI exposure exhibited a potential effect of decreasing benthic chlorophyll a (P = 0.07), but there were no significant CRAY+SSRI interactions. Neither crayfish nor SSRI treatments affected whole-stream metabolism. These results suggest that citalopram has the potential to affect algal biomass but did not affect ecosystem functioning. However, alterations to crayfish behavior driven by SSRI exposure could lead to subsequent ecosystem-level effects as crayfish did affect various response metrics. We were unable to detect the effects of altered crayfish behavior at the ecosystem scale during our study, likely due to the short time frame (2 weeks) of our experiment. Further work is needed to quantify longer-term ecosystem consequences of sublethal effects of pharmaceuticals, but these results show that ecological responses to pharmaceuticals should consider the entire ecosystem.
Water column contributions to the metabolism and nutrient dynamics of mid-sized riversBiogeochemistry
Alexander J Reisinger, Jennifer L Tank, Robert O Hall, Emma J Rosi, Michelle A Baker, Laurel Genzoli
2021 Lotic and lentic ecosystems are traditionally viewed as dominated by either benthic or water column processes. However, mid-sized rivers represent a transition zone where both benthic and water column processes may both contribute substantially to ecosystem dynamics. Ecosystem processes such as gross primary production (GPP), ecosystem respiration (ER), or nutrient uptake, and the relative contribution of the water column to these processes at the reach scale, are poorly understood in non-wadeable, mid-sized rivers. To clarify the role of the water column at the reach-scale, and to quantify controls on water column processes, we measured GPP, ER, and uptake of nitrate (NO3−), ammonium (NH4+), and soluble reactive phosphorus (SRP) in the water columns of 15 mid-sized rivers (discharge: 13.5–83.3 m3 s−1) spanning nutrient and total suspended solids gradients. We compared water column metabolic and nutrient uptake rates to reach-scale rates to estimate the contribution of the water column to the entire river. Water column metabolism was autotrophic on the day when measured, GPP increased with nutrient availability, and the water column contributed more to whole river GPP than to ER. Water column nutrient uptake increased with GPP across solutes, and there was a positive relationship between human land use and water column uptake of NO3−–N and SRP. The water column accounted for a substantial proportion of reach-scale metabolism and nutrient uptake, but this contribution depended on suspended material and nutrient availability. Integrating the water column into theory describing lotic ecosystem function should clarify mechanisms controlling metabolism and nutrient processing and enhance management of non-wadeable rivers.
Vegetation management and benthic macroinvertebrate communities in urban stormwater ponds: implications for regional biodiversityUrban Ecosystems
James S Sinclair, Lindsey S Reisinger, Carrie R Adams, Eban Bean, Alexander J Reisinger, Basil V Iannone
2020 Designed ecosystems (e.g., gardens or engineered ponds) are increasingly common components of urban landscapes and contribute valuable ecosystem services. However, management of designed ecosystems is typically vegetation-centric and often does not consider associated fauna. Urban ponds typify this relationship as their vegetation is managed to improve ecosystem services, such as aesthetics and stormwater runoff mitigation, but it is unclear how pond management affects associated organisms. Here, we used urban stormwater ponds as a study system to determine how vegetation management related to benthic macroinvertebrate communities in these systems. We compared macroinvertebrates across a range of actively managed to unmanaged stormwater ponds and differentiated direct relationships with vegetation structure from indirect relationships of vegetation modulating pond chemistry. Pond vegetation and chemistry had little influence on macroinvertebrate abundance or diversity but did explain substantial variability in community composition (34%). Actively managed stormwater ponds with simpler vegetation structure were dominated by Amphipoda (scuds) and Diptera (primarily midges), unmanaged ponds with more complex structure were dominated by Oligochaeta (worms), and ponds with intermediate structure were dominated by a variety of macroinvertebrates. These community associations with vegetation management primarily occurred indirectly via changes in pond chemistry, such as unmanaged ponds with higher tree and shrub cover harboring macroinvertebrates characteristic of low oxygen environments. Additionally, variation in management maximized community differences because different macroinvertebrate orders dominated at different management intensities. Variability in the management intensity of plant communities in stormwater ponds may therefore be a feasible strategy to enhance regional benthic macroinvertebrate biodiversity in urban landscapes.