Physical Sciences and Mathematics Commons^™

Nitrogen Reductions Have Decreased Hypoxia In The Chesapeake Bay: Evidence From Empirical And Numerical Modeling, Luke T. Frankel, Marjorie A.M. Friedrichs, Pierre St-Laurent, Aaron J. Bever, Rom Lipcius, Gopal Bhatt, Gary W. Shenk

VIMS Articles

Seasonal hypoxia is a characteristic feature of the Chesapeake Bay due to anthropogenic nutrient input from agriculture and urbanization throughout the watershed. Although coordinated management efforts since 1985 have reduced nutrient inputs to the Bay, oxygen concentrations at depth in the summer still frequently fail to meet water quality standards that have been set to protect critical estuarine living resources. To quantify the impact of watershed nitrogen reductions on Bay hypoxia during a recent period including both average discharge and extremely wet years (2016–2019), this study employed both statistical and three-dimensional (3-D) numerical modeling analyses. Numerical model results suggest that …

Marine Heatwaves In The Chesapeake Bay, Piero L. F. Mazzini, Cassia Pianca

VIMS Articles

Prolonged events of anomalously warm sea water temperature, or marine heatwaves (MHWs), have major detrimental effects to marine ecosystems and the world's economy. While frequency, duration and intensity of MHWs have been observed to increase in the global oceans, little is known about their potential occurrence and variability in estuarine systems due to limited data in these environments. In the present study we analyzed a novel data set with over three decades of continuous in situ temperature records to investigate MHWs in the largest and most productive estuary in the US: the Chesapeake Bay. MHWs occurred on average twice per …

Asynchronous Nitrogen Supply And Demand Produce Nonlinear Plant Allocation Responses To Warming And Elevated Co2, Genevieve L. Noyce, Matthew L. Kirwan, Roy L. Rich, J. Patrick Megonigal

VIMS Articles

Terrestrial ecosystem responses to climate change are mediated by complex plant–soil feedbacks that are poorly understood, but often driven by the balance of nutrient supply and demand. We actively increased aboveground plant-surface temperature, belowground soil temperature, and atmospheric CO₂ in a brackish marsh and found nonlinear and nonadditive feedbacks in plant responses. Changes in root-to-shoot allocation by sedges were nonlinear, with peak belowground allocation occurring at +1.7 °C in both years. Above 1.7 °C, allocation to root versus shoot production decreased with increasing warming such that there were no differences in root biomass between ambient and +5.1 °C plots …

Sea-Level Driven Land Conversion And The Formation Of Ghost Forests, Matthew L. Kirwan, Keryn B. Gedan

VIMS Articles

Ghost forests created by the submergence of low-lying land are one of the most striking indicators of climate change along the Atlantic coast of North America. Although dead trees at the margin of estuaries were described as early as 1910, recent research has led to new recognition that the submergence of terrestrial land is geographically widespread, ecologically and economically important, and globally relevant to the survival of coastal wetlands in the face of rapid sea level rise. This emerging understanding has in turn generated widespread interest in the physical and ecological mechanisms influencing the extent and pace of upland to …

Variability And Change In The West Antarctic Peninsula Marine System: Research Priorities And Opportunities, Sian F. Henley, Oscar M. Schofield, Katherine R. Hendry, Irene R. Schloss, Deborah K. Steinberg, Et Al

VIMS Articles

The west Antarctic Peninsula (WAP) region has undergone significant changes in temperature and seasonal ice dynamics since the mid-twentieth century, with strong impacts on the regional ecosystem, ocean chemistry and hydrographic properties. Changes to these long-term trends of warming and sea ice decline have been observed in the 21st century, but their consequences for ocean physics, chemistry and the ecology of the high-productivity shelf ecosystem are yet to be fully established. The WAP shelf is important for regional krill stocks and higher trophic levels, whilst the degree of variability and change in the physical environment and documented biological and biogeochemical …

Embracing Dynamic Design For Climate-Resilient Living Shorelines, Molly Mitchell, Donna M. Bilkovic

VIMS Articles

As natural marshes are lost to erosion, sea level rise, and human activity, small created marshes, (sometimes with ancillary stabilization structures, and frequently called living shorelines) have gained interest as a replacement habitat; providing both shoreline stabilization and restoration of important ecological functions. These living shorelines enhance ecological function while reducing erosion through the use of marsh plants (Table 1). In all but the lowest energy settings, oyster reefs, low rock structures, or other stabilizing material are frequently used to enhance marsh establishment. Due to their ability to stabilize the shoreline with minimal impact to the ecology, living shorelines are …

Marsh Persistence Under Sea-Level Rise Is Controlled By Multiple, Geologically Variable Stressors, Molly Mitchell, Julie Herman, Donna M. Bilkovic, Carl Hershner

VIMS Articles

Introduction: Marshes contribute to habitat and water quality in estuaries and coastal bays. Their importance to continued ecosystem functioning has led to concerns about their persistence.

Outcomes: Concurrent with sea-level rise, marshes are eroding and appear to be disappearing through ponding in their interior; in addition, in many places, they are being replaced with shoreline stabilization structures. We examined the changes in marsh extent over the past 40 years within a subestuary of Chesapeake Bay, the largest estuary in the United States, to better understand the effects of sea-level rise and human pressure on marsh coverage.

A Synergistic Approach For Evaluating Climate Model Output For Ecological Applications, Rochelle Cavanaugh, Ej Murphy, Et Al, Walker O. Smith Jr., Et Al

VIMS Articles

Increasing concern about the impacts of climate change on ecosystems is prompting ecologists and ecosystem managers to seek reliable projections of physical drivers of change. The use of global climate models in ecology is growing, although drawing ecologically meaningful conclusions can be problematic. The expertise required to access and interpret output from climate and earth system models is hampering progress in utilizing them most effectively to determine the wider implications of climate change. To address this issue, we present a joint approach between climate scientists and ecologists that explores key challenges and opportunities for progress. As an exemplar, our focus …