My research focuses on measurements of ecosystem processes and biogeochemistry. Many of the studies include metrics of ecosystem function and seasonal dynamics for evaluation of human impacts and restoration in urban aquatic ecosystems.
Currently, I am conducting research on several themes
1. Biogeochemistry in eutrophic habitats: restoration and invasive species.
Eutrophication, or excess availability of nutrients such as nitrogen (N), phosphorus (P), and carbon (C) has pervasive effects in aquatic ecosystems worldwide. Sources of nutrients to rivers, lakes, and marine ecosystems include fertilizers and wastewater. Eutrophication can lead to low oxygen conditions, reduced biodiversity, and harmful algal blooms. Thus, understanding how excess nutrients are transformed, recycled, or removed by microorganisms is critical for sustaining ecosystem and public health. Our group has researched the capacity for ecosystem restoration to improve nutrient removal and recycling in many projects. We have examined the role of oyster restoration on sediment N cycling in eutrophic, shallow marine ecosystems, and the capacity for native freshwater mussels and invasive clams to sequester and remove N and P in urban rivers. We have used similar analytical approaches to study the effects of salt marsh and sea grass restoration on sediment N dynamics in eutrophic environments in New York City and Long Island.
2. Anthropogenic litter and microplastic in aquatic ecosystems: sources, retention, sinks, and biological interactions
Humans introduce synthetic materials into freshwaters that span a size gradient from dissolved compounds such as nutrients and pharmaceuticals, to suspended particles like nanomaterials, microplastic, (i.e., <5 mm particles), and garbage (i.e., anthropogenic litter; AL). Because it is visually conspicuous and abundant worldwide, the study of AL is a rapidly growing field in marine ecology. Marine AL has several fates, including accumulation on coastal and benthic zones, ingestion, and breakdown into smaller pieces. Rivers are cited as a major source of AL to oceans, but the sources, movement, retention, and interactions of AL with riverine biota are rarely studied. The ecology of AL in rivers is a critical, but unknown piece of the global AL “life cycle.” Our research group has been conducting research on AL and microplastic ecology in rivers. Our overarching objectives are 1) to use the principles and fundamental tools of stream ecology to place data from rivers solidly within the field of global AL research, 2) study the physical, chemical, and biological drivers of AL dynamics in rivers, and 3) reveal basic ecological principles which drive ecosystem function in urban rivers. These data and conceptual approaches will contribute to tools that reduce AL abundance and ecosystem impacts.
3. Citizen-science data and novel management strategies for anthropogenic litter research on Great Lakes beaches
The abundance and distribution of anthropogenic litter (i.e., garbage; AL) is well studied in oceans, but freshwater research lags behind. In particular, marine studies have used data from volunteer beach clean-ups to quantify AL density and infer sources, such as inputs from rivers and fishing. Our research group has cooperated with the Alliance for the Great Lakes to learn from their large, citizen-science datasets, as well as to design and study novel AL management strategies. The long-running Adopt-a-Beach™ (AAB) program has directed volunteer litter collection on Great Lakes beaches since 2003. We have been analyzing subsets of AAB records to quantify total AL density, infer primary sources of AL, characterize seasonal patterns, and compare data to marine beaches. Given that cigarette butt AL is a major source of AL on Great Lakes beaches, our latest projects have been more proactive. We have developed novel management approaches to encourage proper AL disposal, based on successful programs from abroad. These management strategies will be deployed and studied with the assistance of students, volunteers, and AGL scientists in summer 2016 and beyond.