Amy Rosemond | The University of Georgia (original) (raw)

Papers by Amy Rosemond

The ISME Journal, Jul 21, 2017

Journal of The American Water Resources Association, May 19, 2023

Rapidly growing cities along the Interstate‐85 corridor from Atlanta, GA, to Raleigh, NC, rely on... more Rapidly growing cities along the Interstate‐85 corridor from Atlanta, GA, to Raleigh, NC, rely on small rivers for water supply and waste assimilation. These rivers share commonalities including water supply stress during droughts, seasonally low flows for wastewater dilution, increasing drought and precipitation extremes, downstream eutrophication issues, and high regional aquatic diversity. Further challenges include rapid growth; sprawl that exacerbates water quality and infrastructure issues; water infrastructure that spans numerous counties and municipalities; and large numbers of septic systems. Holistic multi‐jurisdiction cooperative water resource planning along with policy and infrastructure modifications is necessary to adapt to population growth and climate. We propose six actions to improve water infrastructure resilience: increase water‐use efficiency by municipal, industrial, agricultural, and thermoelectric power sectors; adopt indirect potable reuse or closed loop systems; allow for water sharing during droughts but regulate inter‐basin transfers to protect aquatic ecosystems; increase nutrient recovery and reduce discharges of carbon and nutrients in effluents; employ green infrastructure and better stormwater management to reduce nonpoint pollutant loadings and mitigate urban heat island effects; and apply the CRIDA framework to incorporate climate and hydrologic uncertainty into water planning.

Freshwater Biology, Feb 13, 2023

Around the world, researchers are reporting declines in insect fauna. Although uncommonly evaluat... more Around the world, researchers are reporting declines in insect fauna. Although uncommonly evaluated in high‐profile studies of insect declines, the community context of population trends can facilitate interpretation of the causes and consequences of such losses. Here, we aimed to explore the shifts in a well‐studied invertebrate community of a blackwater river and identify potential catalysts of such change. We compared the density, biomass and community structure of freshwater invertebrate assemblages separated by more than 30 years in the Ogeechee River, in the southeastern U.S.A., and found biomass declines. We also evaluated long‐term trends in river discharge, water temperature and precipitation. Overall, the biomass in the 2010s was approximately 60% of the total in the 1980s. Community analyses indicated that this decline was associated with reduced densities of large‐bodied, filter‐feeding insects, particularly Hydropsychidae caddisflies (Trichoptera). Conversely, predators and small‐bodied primary consumers increased in density, although their contributions to overall biomass were minimal and their increased density was not sufficient to compensate for biomass declines. Seasonal shifts in both invertebrate populations and environmental parameters were evident, especially when focusing on discharge and dissolved organic carbon. Through a combination of direct analysis and the use of established research on the metabolic dynamics of the study site, we determined that the overall decline of freshwater invertebrate biomass may have been driven by climate‐related changes in flood dynamics: seasonal flooding that facilitates delivery of floodplain carbon to filter‐feeding consumers had decreased over several decades. Water temperature also had increased and was likely to have had effects on the invertebrate assemblages. Whole‐community evaluations such as this one, in contrast to single‐taxon and abundance‐based studies, provide critical information to elucidate the dynamics of freshwater impairment and insect loss in the Anthropocene.

Few areas of food web theory have attracted as much interest as the elucidation of the relative i... more Few areas of food web theory have attracted as much interest as the elucidation of the relative importance of resource limitation and predation in limiting or controlling the various trophic levels in food chains. Elton, in his Animal Ecology (1927), recognized the importance of food chains, the discrete trophic levels within them, and the pyramid of decreasing numbers of animals as the trophic level increased. Lindeman (1942) provided the interpretation of trophic structure in terms of energetics, describing the dependence of higher trophic levels on energy passed up the chain through consumption.

Biological Reviews, Dec 17, 2020

Journal of Phycology, Jun 1, 2000

Skip to Main Content. Due to scheduled maintenance access to the Wiley Online Library may be disr... more Skip to Main Content. Due to scheduled maintenance access to the Wiley Online Library may be disrupted as follows: Saturday, 30 October - New York 0700 EDT to 0900 EDT; London 1200 BST to 1400 BST; Singapore 1900 SGT to 2100 SGT. ...

Ecological Applications, Apr 1, 2015

AGUSM, May 1, 2005

ABSTRACT Litter decomposition in streams occurs as a function of microbial and invertebrate proce... more ABSTRACT Litter decomposition in streams occurs as a function of microbial and invertebrate processing, as well as abiotic factors. Abiotic factors, such as streamwater nutrient concentrations, may change the relative importance of groups of microorganisms, as well as invertebrates, to leaf breakdown. We plan to quantify the relative contributions of bacteria, fungi, and invertebrate processing on decaying leaves in a reference and treatment stream (experimentally enriched with N & P for 4.5 yrs) at the Coweeta Long Term Ecological Research site in North Carolina, USA. Leaf packs of maple or rhododendron leaves were periodically retrieved to determine decay rates. Microbial activity was measured as respiration, fungal biomass was determined by measuring ergosterol concentration, and bacterial biomass was determined by epifluorescence microscopy. Breakdown rates were dramatically faster in the nutrient enriched stream than the reference stream, associated with greater microbial activity and presumably, invertebrate feeding. Based on whole-system response by microorganisms, we predict that nutrient enrichment will lead to greater contributions of fungi, relative to bacteria, to leaf breakdown. Our results show that enrichment can fundamentally alter the rate of organic matter breakdown in streams, and will test whether enrichment also changes the relative roles of groups of organisms contributing to breakdown processes.

Science, Aug 13, 2020

A recent rule is inconsistent with science and will compromise the integrity of U.S. waters. The ... more A recent rule is inconsistent with science and will compromise the integrity of U.S. waters. The Navigable Waters Protection Rule (NWPR) (1), which was published in April by the U.S. Environmental Protection Agency (EPA) and the Department of the Army (“the Agencies”), has redefined “waters of the U.S.” (WOTUS) to restrict federal protection of vulnerable waters (2). With its emphasis on “continuous surface connections” and “permanen[ce],” the NWPR removes or reduces protection for U.S. waters, including millions of miles of streams and acres of wetlands, many of which comprise headwaters that are critical for sustaining water quality and healthy watersheds (3) (see the figure). Although the Agencies claim to have “looked to scientific principles to inform” the NWPR, science has been largely ignored and oversimplified. These new exclusions are based on selective parsing of statutory language and earlier case law, rather than on previously established, science-based interpretations of the U.S. Federal Water Pollution Control Act, commonly known as the Clean Water Act (CWA) (4). The EPA's own Science Advisory Board (SAB) found sufficient evidence to conclude that “…the proposed Rule lacks a scientific justification, while potentially introducing new risks to human and environmental health” (5). Responding to this unprecedented distortion of science and rollback in water protections, which went into effect nationwide on 22 June, will require coordinated efforts among scientists, lawmakers, and resource managers.

Freshwater Science, Mar 1, 2012

Freshwater Biology, Apr 17, 2015

Global Change Biology, Oct 12, 2017

Oecologia, Jul 1, 1993

Using stream-side, flow-through channels, I tested for the effects of nutrients (NU) (nitrogen pl... more Using stream-side, flow-through channels, I tested for the effects of nutrients (NU) (nitrogen plus phosphorus), irradiance (L), and snail grazing (G) on a benthic algal community in a small, forested stream. Grazed communities were-dominated by a chlorophyte (basal cells ofStigeoclonium) and a cyanophyte (Chamaesiphon investiens), whereas ungrazed communities were comprised almost entirely of diatoms, regardless of nutrient and light levels. Snails maintained low algal biomass in all grazed treatments, presumably by consuming increased algal production in treatments to which L and NU were increased. When nutrients were increased, cellular nutrient content increased under ambient conditions (shaded, grazed) and biomass and productivity increased when snails were removed and light was increased. Together, nutrients and light had positive effects and grazing had negative effects on biomass (chlorophylla, AFDM, algal biovolume) and chlorophyll-and areal-specific productivity in ANOVAs. However, in most cases, only means from treatments in which all three factors were manipulated (ungrazed, +NU&L treatments) were significantly different from controls; effects of single factors were generally undetectable. These results indicate that all three factors simultaneously limited algal biomass and productivity in this stream during the summer months. Additionally, the effects of these factors in combination were in some cases different from the effects of single factors. For example, light had slight negative effects on some biomass parameters when added at ambient snail densities and nutrient concentrations, but had strong positive effects in conjunction with nutrient addition and snail removal. This study demonstrates that algal biomass and productivity can be under multiple constraints by irradiance, nutrients, and herbivores and indicates the need to employ multifactor experiments to test for such interactive effects.

Freshwater Science, Mar 1, 2020

Elevated streamwater nitrogen (N) and phosphorus (P) concentrations can stimulate microbial activ... more Elevated streamwater nitrogen (N) and phosphorus (P) concentrations can stimulate microbial activity on detrital C and accelerate its breakdown in stream ecosystems. Our study evaluated whether nutrient–detrital relationships are robust across a moderately altered land-use gradient and can be used to identify functional impairment of stream ecosystems. We tested the relative importance of N vs P as likely drivers of these responses, whether responses differed for labile or recalcitrant standardized substrates, and whether responses were detectable across streams with other stressors, which can potentially mask nutrient effects. Two studies were conducted in 23 sites in southeastern US streams. These streams differed in land use and exhibited low-to-moderate gradients in N and P. In study 1, we used 9 sites to compare the relationships between nutrient (N and P) concentrations and microbial respiration and breakdown of 2 standardized C substrates: recalcitrant oak wood veneer and labile cellulose sponge. Both of these substrates are low in nutrient content but differ structurally. In the best supported models, respiration and breakdown rates were positively related to streamwater P, but not N, after 4 wk of stream incubation. Microbial respiration increased 4.2 and 1.2× and breakdown increased 1.8 and 2.3× on cellulose and wood, respectively, across the P gradient. Temperature (+) and specific conductivity (−) were also in top models for wood respiration. Respiration and breakdown were highly correlated for both substrates, indicating the importance of microbial processing in driving breakdown rates. In study 2, we used 23 sites to test for association between landscape nutrient (N and P) gradients and wood veneer breakdown and whether detrital stoichiometry was a better predictor of breakdown than streamwater nutrient concentrations. Wood breakdown was related to P, but not N, and increased 4.1× in 12 wk across the P gradient. Wood nutrient content (increased %N and %P, reduced C∶N and C∶P) was also related to streamwater P and better predicted breakdown (C∶P r2 = 0.75, C∶N r2 = 0.87) than streamwater nutrient concentrations. Streamwater P concentrations appeared to stimulate breakdown to a degree that indicates impaired stream function. Our study showed that standardized detrital substrates responses to nutrients 1) were greater to streamwater P than N concentration gradients, 2) occurred on both labile and recalcitrant substrates, and 3) were detectable across landscape gradients with other stressors (e.g., temperature, specific conductivity). These responses likely reflect effects of excess nutrients on diverse C resources in these streams. Wood veneers integrated streamwater nutrient effects, were resistant to physical abrasion, and exhibited significant mass loss even when detritivores were excluded, indicating their value in stream functional assessments under a wide range of stream conditions.