RAPID: Collaborative Research: Understanding linkages between nutrient quality and phytoplankton assemblage responses to COVID-19 stay-at-home orders in an urban, estuarine system

In addition to health and safety concerns, the global coronavirus (COVID-19) pandemic has had significant impacts on human behavior worldwide, from business and school closures to stay-at-home orders. As a consequence there have been unprecedented and precipitous drops in global travel for work, education, recreation, and other daily activities. The associated declines in fossil fuel consumption and pollution emissions have resulted in improved air quality. Reductions in atmospheric contaminants (particularly nitrogen, N) and deposition of pollutants must also be influencing nutrient cycling and impacting terrestrial and aquatic ecosystem processes. The situation has created a completely novel and large-scale "human experiment" in how sudden changes in socio-economic behavior and mobility patterns may influence the environment. To better understand environmental changes associated with the pandemic, this NSF RAPID project will focus on studies of coastal and estuary aquatic habitats, which are known to be particularly biologically productive and diverse. Researchers will measure key biogeochemical (nutrient) and ecological (phytoplankton, bacteria) metrics using water sampling and satellite observations of an urban estuary on the east coast of the US over the COVID-19 shutdown and reopening periods. This project will also train postdoctoral scholars and graduate students, including those from underrepresented groups in science, while enhancing the understanding of connections between societal activity and coastal ecosystems.

Steep declines in the concentration, thus deposition, of atmospheric pollution (particularly N), combined with shifts in wastewater effluent distribution associated with the COVID-19 shut-down are expected to influence the biogeochemistry and ecology of adjacent coastal waters. Since the dominant N-form, and stoichiometric ratios relative to other nutrients, shape phytoplankton and bacterial community structure, sudden changes in nutrient amounts, quality, and source distribution in an urban estuary could translate to regime shifts in microbial assemblages and biogeochemical processes. The overarching hypothesis of this study is that the sudden decline in human activity due to the COVID-19 pandemic will exert considerable and measurable effects on coastal biogeochemical and physical water quality parameters as well as phytoplankton and bacterial assemblages. While this hypothesis is broadly applicable to developed coastlines worldwide, this study will focus on Long Island Sound (LIS) because it (i) borders the greater New York City (NYC) metropolitan area, specifically the commuting corridor between NY and Connecticut (CT), (ii) is heavily urbanized, (iii) was especially hard-hit by COVID-19, and (iv) NY and CT were among the first states to mandate stay-at-home restrictions, leading to surrounding communities drastically downscaling transportation activity. The research addresses three questions: 1. Have recent changes in human activity (improved air quality and concurrent changes in wastewater inputs) been associated with shifts in key biogeochemical metrics (C, N, P, Si) and stoichiometric ratios? 2. What are the corresponding responses of phytoplankton and bacterial assemblages? 3. How do these changes relate to shifts in bio-optical properties? To answer these timely ecosystem-scale questions, the team will measure key water quality and biogeochemical parameters, as well as evaluate the abundances and composition of phytoplankton and bacterial assemblages. Work will leverage regional water and air quality monitoring and past and ongoing water sampling in LIS. Satellite ocean color imagery will be used to scale-up observations from point measurements to the larger ecosystem.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.