If you are interested in chairing a contributed session, please contact meetings@aslo.org with your name, institution, email address and experience with the sessions’ topic.
Lead Organizer: María González, Miami University (gonzalmj@miamioh.edu)
Presentations
05:30 PM
Investigating nearshore benthic ecosystem structure in the Kachemak Bay, Alaska NERR (7732)
Primary Presenter: Jonah Jossart, University of Alaska Fairbanks (jrjossart@alaska.edu)
Benthic communities are important components of nearshore ecosystems, where they process organic matter, mediate nutrient and oxygen fluxes in the benthos, and provide food for higher trophic level organisms. Furthermore, they are largely composed of non-motile organisms that feed on organic matter sinking from above, and thus tend to reflect average conditions, integrating over short-term sources of variation such as tidal signals, pulses of primary production, and changes in freshwater runoff, making studying them an important tool in understanding nearshore ecosystems. In partnership with the Kachemak Bay National Estuarine Research Reserve, this project seeks to characterize benthic community composition and organic matter processing across multiple adjacent bays along southern Kachemak Bay, with a focus on communities below active mariculture operations. Sediment cores were manually collected via SCUBA from eight sites spanning four bays. Cores were analyzed for community composition, microbial biomass, sediment grain size, sediment total organic carbon. Sediment grain size varied by location, most with high percentages of gravel and sand. Polychaetes were partitioned into feeding guilds in which subsurface deposit and suspension feeders were most dominant. Infaunal carbon biomass and microbial biomass at each location were comparable and ranged between 0-30 g C/m. Sediment total organic carbon varied between 250-2000 g C/m among locations. Benthic community composition was similar across adjacent bays but exhibited variability in correspondence to their sediment type.
05:30 PM
Submerged aquatic plant diversity and growth form distribution in north temperate lakes (7697)
Primary Presenter: Linden Taylor, University of Wisconsin-Madison (lataylor6@wisc.edu)
Water chemistry is known to be an important driver of submerged aquatic plant community composition in lakes. However, our understanding of the extent that water chemistry and biotic interactions influence the submerged aquatic plant growth forms–elodeids, taller statured plants with stems, and isoetids, shorter statured plants with basal rosettes–is still developing. This research assesses submerged aquatic plant growth form frequency and species richness along an alkalinity gradient–a proxy for bicarbonate availability–in lakes in Vilas County, Wisconsin selected for the North Temperate Lakes LTER Regional Lakes Survey. We additionally assess frequency of the regionally rarer isoetid growth form as a function of local plant coverage and compare growth form frequency in 2015 and 2022. Twenty-eight lakes were surveyed with the Point-intercept (PI) aquatic plant survey method along a spaced grid of points in the littoral zone. We found an increase in elodeid frequency and species richness and decrease in isoetid frequency and species richness along a bicarbonate availability gradient, demonstrating the importance of modes of carbon uptake for submerged aquatic plant growth form distribution. We also found a discernable decline in isoetid frequency and increase in elodeid frequency in oligotrophic, low development lakes from 2015 to 2022, suggesting abrupt ecological change by introduction of competitive vegetation.
05:30 PM
THE IGNORED LAKE: USING ENVIRONMENTAL DNA TO CHARACTERIZE INVERTEBRATE ASSEMBLAGES OF LAKE MAUREPAS, LOUISIANA (7833)
Primary Presenter: Camryn Bigelow, Southeastern Louisiana University (camryn.bigelow@selu.edu)
Lake Maurepas is an oligohaline lake in southeastern Louisiana, USA that lies on the western end of the Lake Pontchartrain basin. While Lake Pontchartrain has been studied extensively, there is a relative lack of information regarding the organismal diversity in Lake Maurepas, especially in regards to its invertebrate assemblages. The primary purpose of this study is to characterize the spatial and temporal variability in the macroinvertebrate assemblage in Lake Maurepas using environmental DNA (eDNA). We are sampling the lake every three months to assess temporal and spatial variability in the assemblages. So far, we have collected water and soil samples from two seasons (winter and spring) from inshore and offshore sites. Our samples have been extracted and PCR amplification of a 313 bp fragment of the cytochrome oxidase I gene (mtDNA) is underway. To date, we have cultivated a reference library of invertebrates collected from Lake Maurepas and have Sanger sequenced them. We are preparing eDNA samples for Illumina sequencing and development of our analytical pipeline is underway. We will present an update of the current status of the project and highlight the field and laboratory methodology. We expect to see low overall invertebrate diversity across all sites but with a greater degree of spatial variation in species richness for the inshore samples, possibly related to the inflowing freshwater rivers that enter the lake in the north and western portions of the lake
05:30 PM
COMMUNITY SCIENCE PARTICIPANTS INVESTIGATE LAKE ERIE WATERSHED MICROBIOMES (7899)
Primary Presenter: Megan Ginther, University of Toledo (megan.ginther@rockets.utoledo.edu)
Community-driven science combines the resources of academic researchers with the efforts of local communities, creating an effective approach to broadening participation while enhancing the scope of scientific studies. In response to declining water quality in the western basin of Lake Erie, we have developed an environmental DNA (eDNA) biomonitoring program that focuses on recreational areas in the watershed. We used high throughput sequencing that targets microbial eukaryotes (18S rRNA) and prokaryotes (16S rRNA) to census the foundation of the aquatic food web of the western basin of Lake Erie. Community participants captured eDNA using a 0.22-micron filtration system. In terms of program success, ERIeDNA hosted eight BioBlitz events with a total of eighteen sampling sites across the watershed using these methods. We found that microbial prokaryotes had the highest alpha diversity at the Maumee River sites, while two of the Ottawa River sites had the lowest alpha diversity. This contrast may be explained by the hydrogeological differences between these two rivers. The Maumee River has a higher nutrient accumulation due to its watershed size and its surrounding land use type being primarily agriculture. This increased availability of nutrients allows for the potential for increased niche space, and thus more diversity. By cultivating a diverse network of community partners, we not only educated the public on water quality issues affecting human health and sustainability, but we also deepened our understanding of microbial communities within the Lake Erie watershed.
05:30 PM
Microbial Community Alterations along East Coast Wetlands (8369)
Primary Presenter: Alexandra Figueroa, University of Massachusetts Boston (alexandrafigueroa8@gmail.com)
Fiddler crabs, Minuca pugnax, are bioturbators commonly found in coastal habitats, who can circulate nutrients in sediments on depths up to 15 cm. Throughout the past 2 decades M. pugnax have migrated north as a result of ocean warming. It is unknown how the microbial communities changed as a result of this range expansion along the East Coast of the United States. Soil samples were collected in 4 coastal Long-Term Ecological Research (LTER) sites along the east coast: a mangrove in the Florida Coastal Everglades (FCE) and 3 salt marshes (Plum Island Ecosystem (PIE), Rowley, MA; Virginia Coast Reserve (VCR), VA, and Georgia Coastal Ecosystems Long Term Ecological Research site (GCE), Sapelo Island, GA. At each site, we identified 8-10 plots containing fiddler crab burrows at different densities. We collected 5 mm deep sediment cores in triplicate per area from regions with burrows (up to 2.5 cm in depth of the burrow), adjacent to the burrow, and 10 cm away from the burrow.We extracted microbial DNA from soil samples and sequenced the 16S rRNA to assess microbial community shifts. With range expansion, we hypothesize that microbial communities within burrows will be more similar across latitude than microbial communities in nearby reference sediments due to the homogenizing effect of the crabs.
05:30 PM
Land Use Change and Infection Dynamics in a Multi-Host Helminth (8438)
Primary Presenter: Ipsita Srinivas, University of Wisconsin-Madison (isrinivas@wisc.edu)
Why severe outbreaks occur in some populations and not others, remains an enduring ecological and evolutionary puzzle. When outbreaks of pests or parasites (re)emerge suddenly, climate and land use change are often suspected as underlying causes, especially in aquatic systems. Yet, causally linking specific environmental changes to the dynamics of pests and parasites remains challenging because these organisms are embedded in complex ecosystems with multiple, interconnected drivers that often have nonlinear effects. How do we pinpoint the causes of dynamical shifts in the abundance and incidence of pests and pestilence? How do we accurately predict the effects of global change on future outbreaks? Here, we combine field surveys and structural equation models to understand the relative contributions of endogenous (species diversity, abundance) and exogenous (land use) factors on parasite outbreaks. Our goal is to develop a framework that links across multiple scales of biological organization to provide a mechanistic understanding of the consequences of land use decisions on parasite outbreaks affecting aquatic systems.
05:30 PM
THE POTENTIAL IMPACT OF LYTIC VIRUSES ON THE TAXONOMIC RESOLUTION OF BACTERIOPLANKTON IN PRODUCTIVE FRESHWATER RESERVOIRS (8520)
Primary Presenter: Telesphore Sime-Ngando, CNRS, Centre National de la Recherche Scientifique (telesphore.sime-ngando@ird.fr)
Man-made reservoirs that receive significant inputs of terrestrial organic matter exhibit distinct and diverse bacterial communities. In this study, we used Illumina MiSeq sequencing to assess the bacterial community structure in two productive freshwater reservoirs, Villerest and Grangent, located in Central France. Our analysis revealed that the bacterial communities in both reservoirs varied spatially and temporally. Villerest reservoir was found to harbor more diverse bacterial communities compared to Grangent reservoir. The dominant bacterial groups in both reservoirs were the hgcI clade (Actinobacteria) and Limnohabitans (Betaproteobacteria), which are known to have adaptive strategies related to resource utilization and top-down control. In Villerest reservoir, the occurrence of temporary anoxia due to thermal stratification, especially during summer, promoted the presence of anoxygenic phototrophic and methanotrophic bacteria. Interestingly, we observed a low bacterial richness, which we attributed to viral lysis. This suggests that a small number of highly active bacterial populations sustain high bacterial activity and viral abundances in these reservoirs. Weighted UniFrac analysis indicated that a minimum threshold of 10% viral infection and a virus-to-bacteria ratio of 10 were needed to significantly impact the phylogenetic structure of the bacterial community. Thus, depending on the levels of viral infection, viruses may play a dominant role in shaping and structuring bacterial communities in these man-made freshwater systems, surpassing other top-down factors.
CS09P - Community Ecology
Description
Time: 5:30 PM
Date: 4/6/2024
Room: Madison Ballroom D