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 …

Multiple Dimensions Of Functional Diversity Affect Stream Fish Taxonomic Β-Diversity, Luke M. Bower, Lauren Stoczynski, Brandon K. Peoples, Christopher J. Patrick, Bryan L. Brown

VIMS Articles

1. When investigating metacommunity dynamics, functional differences among
species are often assumed to be as important as environmental differences be-
tween sites in determining β-diversity. However, few studies have examined the
influence of functional diversity on β-diversity. We examine the relative importance of regional functional diversity partitioned by niche dimensions and environmental variation in structuring taxonomic β-diversity of stream fishes using a large dataset of stream fish assemblages (hereafter, simply β-diversity). We predicted that both functional diversity and environmental variation play a rolein determining β-diversity.
2. We tested this prediction by modelling the patterns of stream fish β-diversity as
a …

A Global Synthesis Of Human Impacts On The Multifunctionality Of Streams And Rivers, Mario Brauns, Daniel C. Allen, Iola G. Boëchat, Wyatt F. Cross, Verónica Ferreira, Daniel Graeber, Christopher J. Patrick, Et Al

VIMS Articles

Human impacts, particularly nutrient pollution and land-use change, have caused significant declines in the quality and quantity of freshwater resources. Most global assessments have concentrated on species diversity and composition, but effects on the multifunctionality of streams and rivers remain unclear. Here, we analyse the most comprehensive compilation of stream ecosystem functions to date to provide an overview of the responses of nutrient uptake, leaf litter decomposition, ecosystem productivity, and food web complexity to six globally pervasive human stressors. We show that human stressors inhibited ecosystem functioning for most stressor-function pairs. Nitrate uptake efficiency was most affected and was inhibited …

Long-Term Annual Aerial Surveys Of Submersed Aquatic Vegetation (Sav) Support Science, Management, And Restoration, Robert J. Orth, William C. Dennison, Cassie Gurbisz, (...), Kenneth A. Moore, Christopher J. Patrick, (..), David J. Wilcox, Richard A. Batiuk

VIMS Articles

Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984–present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These …

Extreme Event Ecology Needs Proactive Funding, Christopher J. Patrick, Enie Hensel, John S. Kominoski, Beth A. Stauffer, William H. Mcdowell

VIMS Articles

Commentary:

Extreme events such as wildfires, hurricanes, and floods have increased in frequency and intensity. It is no longer a question of if, but rather when and where these events will occur (Stott 2016), with adverse impacts on essential ecosystem
services including clean water, harvestable materials, and carbon sequestration. In some cases, extreme events such as wildfires may have positive impacts on populations and ecosystems. Managing these impacts requires understanding how environmental context as well as ecosystem and disturbance characteristics drive system responses (Hogan et al. 2020). However, funding for ecological extreme events research, such as through the US National …

Connectivity: Insights From The U.S. Long Term Ecological Research Network, David M. Iwaniec, Michael Gooseff, Katherine N. Suding, David S. Johnson, Et Al

VIMS Articles

Ecosystems across the United States are changing in complex and surprising ways. Ongoing demand for critical ecosystem services requires an understanding of the populations and communities in these ecosystems in the future. This paper represents a synthesis effort of the U.S. National Science Foundation-funded Long-Term Ecological Research (LTER) network addressing the core research area of “populations and communities.” The objective of this effort was to show the importance of long-term data collection and experiments for addressing the hardest questions in scientific ecology that have significant implications for environmental policy and management. Each LTER site developed at least one compelling case …

Real-Time Environmental Forecasts Of The Chesapeake Bay: Model Setup, Improvements, And Online Visualization, Aaron Bever, Marjorie A.M. Friedrichs, Pierre St-Laurent

VIMS Articles

Daily real-time nowcasts (current conditions) and 2-day forecasts of environmental conditions in the Chesapeake Bay have been continuously available for 4 years. The forecasts use a 3-D hydrodynamic-biogeochemical model with 1–2 km resolution and 3-D output every 6 h that includes salinity, water temperature, pH, aragonite saturation state, alkalinity, dissolved oxygen, and hypoxic volume. Visualizations of the forecasts are available through a local institutional website (www.vims.edu/hypoxia) and the MARACOOS Oceans Map portal (https://oceansmap.maracoos.org/chesapeake-bay/). Modifications to real-time graphics on the local website are routinely made based on stakeholder input and are formatted for use on a mobile …

Advancing Estuarine Ecological Forecasts: Seasonal Hypoxia In Chesapeake Bay, Donald Scavia, Isabella Bertani, (...), Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Ecological forecasts are quantitative tools that can guide ecosystem management. The coemergence of extensive environmental monitoring and quantitative frameworks allows for widespread development and continued improvement of ecological forecasting systems. We use a relatively simple estuarine hypoxia model to demonstrate advances in addressing some of the most critical challenges and opportunities of contemporary ecological forecasting, including predictive accuracy, uncertainty characterization, and management relevance. We explore the impacts of different combinations of forecast metrics, drivers, and driver time windows on predictive performance. We also incorporate multiple sets of state-variable observations from different sources and separately quantify model prediction error and measurement …

The Application Of Metacommunity Theory To The Management Of Riverine Ecosystems, Christopher J. Patrick, Kurt E. Anderson, Brown L. Brown, Et Al

VIMS Articles

River managers strive to use the best available science to sustain biodi versity and ecosystem function. T o achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from differ- ent communities potentially interact with local-scale environmental drivers to influ- ence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this article, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of …

Preparing Scientists, Policy-Makers, And Managers For A Fast-Forward Future, Richard B. Norgaard, John A. Wiens, (...), Elizabeth A. Canuel, Et Al

VIMS Articles

Ecosystems in the Sacramento–San Joaquin Delta are changing rapidly, as are ecosystems around the world. Extreme events are becoming more frequent and thresholds are likely to be crossed more often, creating greater uncertainty about future conditions. The accelerating speed of change means that ecological systems may not remain stable long enough for scientists to understand them, much less use their research findings to inform policy and management. Faced with these challenges, those involved in science, policy, and management must adapt and change and anticipate what the ecosystems may be like in the future. We highlight several ways of looking ahead—scenario …

Restoration Of Seagrass Habitat Leads To Rapid Recovery Of Coastal Ecosystem Services, Robert J. Orth, Jonathan S. Lefcheck, Karen S. Mcglathery, Lillian Aoki, Mark Luckenbach, Kenneth A. Moore, Matthew P.J. Oreska, Richard A. Snyder, David J. Wilcox, Bo Lusk

VIMS Articles

There have been increasing attempts to reverse habitat degradation through active restoration, but few largescale successes are reported to guide these efforts. Here, we report outcomes from a unique and very successful seagrass restoration project: Since 1999, over 70 million seeds of a marine angiosperm, eelgrass (Zostera marina), have been broadcast into mid-western Atlantic coastal lagoons, leading to recovery of 3612 ha of seagrass. Well-developed meadows now foster productive and diverse animal communities, sequester substantial stocks of carbon and nitrogen, and have prompted a parallel restoration for bay scallops (Argopecten irradians). Restored ecosystem services are approaching historic levels, but we …

Trace Metal Availability Affects Greenhouse Gas Emissions And Microbial Functional Group Abundance In Freshwater Wetland Sediments, George Giannopoulos, Katherine R. Hartop, Bonnie L. Brown, Bongkeun Song, Lars Elsgaard, Rima B. Franklin

VIMS Articles

We investigated the effects of trace metal additions on microbial nitrogen (N) and carbon (C) cycling using freshwater wetland sediment microcosms amended with micromolar concentrations of copper (Cu), molybdenum (Mo), iron (Fe), and all combinations thereof. In addition to monitoring inorganic N transformations (NO₃^–, NO₂^–, N₂O, NH₄⁺) and carbon mineralization (CO₂, CH₄), we tracked changes in functional gene abundance associated with denitrification (nirS, nirK, nosZ), dissimilatory nitrate reduction to ammonium (DNRA; nrfA), and methanogenesis (mcrA). With regards to …

Single-Use Plastics And Covid-19: Scientific Evidence And Environmental Regulations, Robert C. Hale, Bk Song

VIMS Articles

Waste plastics are a serious and growing environmental problem. Less than 10% of plastics are recycled, with most discarded in landfills, incinerated, or simply abandoned.1 Single-use plastics constitute about half of plastic waste. While most plastics are used and initially disposed of on land, much eventually enters aquatic ecosystems.2 Wildlife mortalities result from encounters (e.g., ingestion and entanglement) with large debris, including plastic bags. Such bags are excluded from many recycling programs, as they can entangle machinery. Most plastics do not readily biodegrade in the environment. However, they can be embrittled by UV exposure and fragment into microplastics (mm) and …

Long-Term Annual Aerial Surveys Of Submersed Aquatic Vegetation (Sav) Support Science, Management, And Restoration, Robert J. Orth, William C. Dennison, Cassie Gurbisz, Michael Hannam, Jeni Keisman, J. Brooke Landry, Jonathan S. Lefcheck, Kenneth A. Moore, Rebecca R. Murphy, Christopher J. Patrick, Jeremy Testa, Donald E. Weller, David J. Wilcox, Richard A. Batiuk

VIMS Articles

Aerial surveys of coastal habitats can uniquely inform the science and management of shallow, coastal zones, and when repeated annually, they reveal changes that are otherwise difficult to assess from ground-based surveys. This paper reviews the utility of a long-term (1984–present) annual aerial monitoring program for submersed aquatic vegetation (SAV) in Chesapeake Bay, its tidal tributaries, and nearby Atlantic coastal bays, USA. We present a series of applications that highlight the program’s importance in assessing anthropogenic impacts, gauging water quality status and trends, establishing and evaluating restoration goals, and understanding the impact of commercial fishing practices on benthic habitats. These …

Global Change Effects On Plant Communities Are Magnified By Time And The Number Of Global Change Factors Imposed, Kj Komatsu, Ml Avolio, Et Al, David S. Johnson, Et Al

VIMS Articles

Global change drivers (GCDs) are expected to alter community structure and consequently, the services that ecosystems provide. Yet, few experimental investigations have examined effects of GCDs on plant community structure across multiple ecosystem types, and those that do exist present conflicting patterns. In an unprecedented global synthesis of over 100 experiments that manipulated factors linked to GCDs, we show that herbaceous plant community responses depend on experimental manipulation length and number of factors manipulated. We found that plant communities are fairly resistant to experimentally manipulated GCDs in the short term (< 10 y). In contrast, long-term (>= 10 y) experiments show increasing community divergence of …

Toward A Coordinated Global Observing System For Seagrasses And Marine Macroalgae, J. Emmett Duffy, L. Benedetti-Cecchi, Et Al, Robert J. Orth, Et Al

VIMS Articles

In coastal waters around the world, the dominant primary producers are benthic macrophytes, including seagrasses and macroalgae, that provide habitat structure and food for diverse and abundant biological communities and drive ecosystem processes. Seagrass meadows and macroalgal forests play key roles for coastal societies, contributing to fishery yields, storm protection, biogeochemical cycling and storage, and important cultural values. These socio-economically valuable services are threatened worldwide by human activities, with substantial areas of seagrass and macroalgal forests lost over the last half-century. Tracking the status and trends in marine macrophyte cover and quality is an emerging priority for ocean and coastal …

Mechanisms Involving Sensory Pathway Steps Inform Impacts Of Global Climate Change On Ecological Processes, Emily B. Rivest, Brittany Jellison, Gabriel Ng, Et Al

VIMS Articles

Human-caused environmental change will have significant non-lethal and indirect impacts on organisms due to altered sensory pathways, with consequences for ecological interactions. While a growing body of work addresses how global ocean change can impair the way organisms obtain and use information to direct their behavior, these efforts have typically focused on one step of the pathway (e.g., reception of a cue/signal), one sensory modality (e.g., visual), or one environmental factor (e.g., temperature). An integrated view of how aspects of environmental change will impact multiple sensory pathways and related ecological processes is needed to better anticipate broader consequences for marine …

A Systematic Review Of How Multiple Stressors From An Extreme Event Drove Ecosystem-Wide Loss Of Resilience In An Iconic Seagrass Community, Ga Kendrick, Rj Nowicki, Et Al, Rj Orth

VIMS Articles

A central question in contemporary ecology is how climate change will alter ecosystem structure and function across scales of space and time. Climate change has been shown to alter ecological patterns from individuals to ecosystems, often with negative implications for ecosystem functions and services. Furthermore, as climate change fuels more frequent and severe extreme climate events (ECEs) like marine heatwaves (MHWs), such acute events become increasingly important drivers of rapid ecosystem change. However, our understanding of ECE impacts is hampered by limited collection of broad scale in situ data where such events occur. In 2011, a MHW known as the …

Advocating For Science: Amici Curiae Brief Of Wetland And Water Scientists In Support Of The Clean Water Rule, Rc Gardner, E Okuno, Et Al, Je Perry, Et Al

VIMS Articles

The Trump administration has proposed replacing the Clean Water Rule, a 2015 regulation that defined the statutory term Bwaters of the United States^ to clarify the geographic jurisdiction of the Clean Water Act. Since its promulgation, the Clean Water Rule has been subjected to numerous judicial challenges. We submitted an amici curiae brief to the United States Court of Appeals for the Sixth Circuit, explaining why the Clean Water Rule, and its definition of Bwaters of the United States,^ is scientifically sound. The definition of Bwaters of the United States^ is a legal determination informed by science. The best available …

Pattern And Scale: Evaluating Generalities In Crab Distributions And Marsh Dynamics From Small Plots To A National Scale, K Wasson, K Raposa, Et Al, David S. Johnson, Scott Lerberg, Et Al

VIMS Articles

The generality of ecological patterns depends inextricably on the scale at which they are examined. We investigated patterns of crab distribution and the relationship between crabs and vegetation in salt marshes at multiple scales. By using consistent monitoring protocols across 15 U.S. National Estuarine Research Reserves, we were able to synthesize patterns from the scale of quadrats to the entire marsh landscape to regional and national scales. Some generalities emerged across marshes from our overall models, and these are useful for informing broad coastal management policy. We found that crab burrow distribution within a marsh could be predicted by marsh …

Projections Of Atmospheric Nitrogen Deposition To The Chesapeake Bay Watershed, Patrick C. Campbell, Jesse O. Bash, Christopher G. Nolte, Tanya L. Spero, Ellen J. Cooter, Kyle Hinson, Lewis C. Linker

VIMS Articles

Atmospheric deposition is among the largest pathways of nitrogen loading to the Chesapeake Bay Watershed (CBW). The interplay between future climate and emission changes in and around the CBW will likely shift the future nutrient deposition abundance and chemical regime (e.g., oxidized vs. reduced nitrogen). In this work, a Representative Concentration Pathway from the Community Earth System Model is dynamically downscaled using a recently updated Weather Research and Forecasting model that subsequently drives the Community Multiscale Air Quality model coupled to the agroeconomic Environmental Policy Integrated Climate model. The relative impacts of emission and climate changes on atmospheric nutrient deposition …

Restoring The Eastern Oyster: How Much Progress Has Been Made In 53 Years?, Ab Hernandez, Rochelle Brumbaugh, P Fredrick, R Grizzle, Mark Luckenbach, Ch Peterson, C Angelini

VIMS Articles

Coastal ecosystem restoration is accelerating globally as a means of enhancing shoreline protection, carbon storage, water quality, fisheries, and biodiversity. Among the most substantial of these efforts have been those focused on re-establishing oyster reefs across the US Atlantic and Gulf coasts. Despite considerable investment, it is unclear how the scale of and approaches toward oyster restoration have evolved. A synthesis of 1768 projects undertaken since 1964 reveals that oyster substrate restoration efforts have primarily been concentrated in the Chesapeake Bay and the Gulf Coast, have been heavily reliant on oyster shell, and have re-established 4.5% of the reef area …

Living Shorelines Support Nearshore Benthic Communities In Upper And Lower Chesapeake Bay, Tm Davenport, Rochelle D. Seitz, Ke Knick, N Jackson

VIMS Articles

Human population growth and sea-level rise are increasing the demand for protection of coastal property against shoreline erosion. Living shorelines are designed to provide shoreline protection and are constructed or reinforced using natural elements. While living shorelines are gaining popularity with homeowners, their ability to provide ecological services (e.g., habitat provision and trophic transfer) is not well understood, and information is needed to improve coastal and resource management decision-making. We examined benthic community responses to living shorelines in two case-study subestuaries of Chesapeake Bay using a before-after control-impact study design. At Windy Hill, a bulkhead was removed and replaced by …

Host And Symbionts In Pocillopora Damicornis Larvae Display Different Transcriptomic Responses To Ocean Acidification And Warming, Emily B. Rivest, Morgan B. Kelly, Melissa B. Debiasse, Gretchen E. Hofmann

VIMS Articles

As global ocean change progresses, reef-building corals and their early life history stages will rely on physiological plasticity to tolerate new environmental conditions. Larvae from brooding coral species contain algal symbionts upon release, which assist with the energy requirements of dispersal and metamorphosis. Global ocean change threatens the success of larval dispersal and settlement by challenging the performance of the larvae and of the symbiosis. In this study, larvae of the reef-building coral Pocillopora damicornis were exposed to elevated pCO2 and temperature to examine the performance of the coral and its symbionts in situ and better understand the mechanisms of …

Carbon Budget Of Tidal Wetlands, Estuaries, And Shelf Waters Of Eastern North America, Rg Najjar, M Herrmann, R Alexander, Ew Boyer, Dj Burdige, D Butman, W-J Cai, Elizabeth A. Canuel, Rf Chen, Marjorie A.M. Friedrichs, Et Al

VIMS Articles

Carbon cycling in the coastal zone affects global carbon budgets and is critical for understanding the urgent issues of hypoxia, acidification, and tidal wetland loss. However, there are no regional carbon budgets spanning the three main ecosystems in coastal waters: tidal wetlands, estuaries, and shelf waters. Here we construct such a budget for eastern North America using historical data, empirical models, remote sensing algorithms, and process‐based models. Considering the net fluxes of total carbon at the domain boundaries, 59 ± 12% (± 2 standard errors) of the carbon entering is from rivers and 41 ± 12% is from the atmosphere, …

Shoreline Hardening Affects Nekton Biomass, Size Structure,And Taxonomic Diversity In Nearshore Waters, With Responses Mediated By Functional Species Groups, Ms Kornis, Donna Marie Bilkovic, La Davias, S Giordano, Dl Brietburg

VIMS Articles

Coastal shoreline hardening is intensifying due to human population growth and sea level rise. Prior studies have emphasized shoreline-hardening effects on faunal abundance and diversity; few have examined effects on faunal biomass and size structure or described effects specific to different functional groups. We evaluated the biomass and size structure of mobile fish and crustacean assemblages within two nearshore zones (waters extending 3 and 16 m from shore) adjacent to natural (native wetland; beach) and hardened (bulkhead; riprap) shorelines. Within 3 m from shore, the total fish/crustacean biomass was greatest at hardened shorelines, driven by greater water depth that facilitated …

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.

Sea Level Rise May Increase Extinction Risk Of A Saltmarsh Ontogenetic Habitat Specialist, David S. Johnson, Bethany L. Williams

VIMS Articles

Specialist species are more vulnerable to environmental change than generalist species. For species with ontogenetic niche shifts, specialization may occur at a particular life stage making those stages more susceptible to environmental change. In the salt marshes in the northeast U.S., accelerated sea level rise is shifting vegetation patterns from flood-intolerant species such as Spartina patens to the flood-tolerant Spartina alterniflora. We tested the potential impact of this change on the coffee bean snail, Melampus bidentatus, a numerically dominant benthic invertebrate with an ontogenetic niche shift. From a survey of eight marshes throughout the northeast U.S., small snails …

Multifaceted Biodiversity Hotspots Of Marine Mammals For Conservation Priorities, Camille Albouy, Valentine L. Delattre, Bastien Merigot, Christine N. Meynard, Fabien Leprieur

VIMS Articles

Aim: Identifying the multifaceted biodiversity hotspots for marine mammals and their spatial overlap with human threats at the global scale.

Assessing The Impact Of Local And Regional Influences On Nitrogen Loads To Buzzards Bay, Ma, Shanna C. Williamson, Jennie E. Rheuban, Et Al

VIMS Articles

Nitrogen and chlorophyll-a concentrations in estuarine systems often correlate positively with increased nitrogen input. To determine the interactions between nitrogen load, physical drivers, and water quality indicators, we estimated nitrogen inputs to 28 estuaries within the Buzzards Bay, Massachusetts (USA) watershed from 1985 to 2013. Estimates were derived by combining parcel specific wastewater disposal, point source wastewater discharge, land use, and atmospheric nitrogen deposition data with a previously verified nitrogen loading model. Linear regression analysis was used to quantify temporal trends in individual data sets and characterize relationships between variables. The land-use data indicated that fractional coverage of impervious surfaces …