Maryland Coastal Bays
Maryland's Coastal Bays, the shallow lagoons nestled behind Ocean City and Assateague, comprise a complex ecosystem. These estuarine bays, at the interface between fresh and saltwater, provide habitat for a wide range of aquatic life. But like many coastal systems, they face threats from intense development, nutrients, sediments, and other stresses associated with human activities.
Research Findings
The Integration and Application Network has been using stable isotope techniques to identify nitrogen sources in the Maryland Coastal Bays. This is a summary of some of the findings from this work. Further information can be found in the publications section.
Following an expansive survey in May of 2004, a 2006 study targeted four small regions within the Coastal Bays to assess in detail the nutrient inputs and sources within these regions. The 2004 study identified St. Martin River as a region with high nutrient inputs and overall poor water quality. St. Martin River was included in the 2006 study to further assess sources and inputs to this region. The 2004 study also identified Public Landing and Johnson's Bay as areas with poor water quality due to high total phosphorus, high turbidity and low dissolved oxygen – with no obviously apparent point of riverine source of this poor water quality. Similarly, the Chincoteague Island region showed relatively low water column total nitrogen, but high δ15N (natural isotope abundance), suggesting possible human-derived sources of nitrogen to this area.
Other major findings include:
- Both macroalgae (Gracilaria sp.) and the eastern oyster (Crassostrea virginica) provide information about nitrogen sources. Macroalgae provides a good estimate of broad patterns over short periods of time, whereas oysters take longer to incorporate nitrogen. As a result, each provide complimentary information for water quality monitoring programs.
- Johnsons Bay shows evidence of local freshwater and nutrient inputs inshore.
- Public Landing shows evidence of local inputs of nitrogen and phosphorus.
- St. Martin River (a mini estuary) shows high total nutrient inputs and a flushing gradient.
- Complex waterflows from the inlets around Chincoteague Island influence sources of nitrogen identified with macroalgal and oyster bioindicators.
Oyster δ15N values reveal patterns at a fine scale. In oyster tissue, short-term nutrient fluctuations or pulses are either not incorporated or not significant enough to impact the existing δ15N signature of the tissue. Due to longer nutrient integration periods (compared with macroalgae), patterns within regions can be found. This is particularly apparent in southward gradients at Johnson Bay and around Chincoteague Island, indicating significant anthropogenic effects.
Stable isotope ratios from oyster muscle deployed in the coastal bays in 2006.
Total nitrogen varied across regions in 2004. St. Martin River in the north had high levels of total nitrogen. Middle areas of Maryland's Coastal Bays, such as Public Landing and Johnson Bay, had mid-levels of total nitrogen. Lower Chincoteague Bay had low total nitrogen loads. Stable nitrogen isotope (δ15N) ratios in macroalgae indentified broad regional patterns effectively. Despite differing total nutrient loads in St. Martin River and Chincoteague, the macroalgal δ15N was high at both locations, indicating anthropogenic nitrogen sources. Public Landing had low values of δ15N, suggesting minimal loads from sewage or septic sources, leaving terrestrial agriculture as a potential nutrient source. A similar pattern was found in Johnson Bay. A spike of δ15N inside Mills Island has an unknown source, but microbial processing could also be elevating the δ15N signature.
Stable isotope ratios from macroalgae deployed in the coastal bays in 2004.
Temporal, rather than regional grouping of biological parameters (chlorophyll a, as well as %N, δ15N, δ13C, and C: N in macroalgae) in the non-metric multidimensional scaling analysis indicated that the biological response to nutrients was driven by precipitation. Typical of other shallow coastal ecosystems, nutrients increased primary production, which contributed to reduced water clarity via elevated levels of phytoplankton. However, physical parameters (temperature, salinity, Secchi depth, total nitrogen and total phosphorus) varied regionally, rather than temporally. Athough effects due to rainfall were observed throughout the Coastal Bays, differences between regions were observed.
Physical and biological non-metric multidimensional scaling analysis and correlations in 2006.
Heavy precipitation in June 2006 pulsed nutrients into the coastal lagoons. Salinity and nutrient gradients which emanated from shore, combined with limited overland flow, implicated groundwater total nitrogen transport. This precipitation-driven groundwater nutrient pulse across all regions affected the measured biological parameters.
Salinity and total nitrogen in 2006.
2004 State of the Bays
The Maryland Department of Natural Resources together with the Maryland Coastal Bays Program and the Integration and Application Network at the University of Maryland Center for Environmental Science has completed the State of the Maryland Coastal Bays Report.
 |
Estuarine health indicators comprised of water quality, living resources and habitat features were used to compare the different bay segments within the Maryland Coastal Bays. The selected estuarine health indicators are responsive to human activities and were measured throughout the Maryland Coastal Bays. Three water quality indicators (water quality index, brown tides, macroalgae), three living resource indicators (benthic index, hard clam abundance, sediment toxicity) and three habitat indicators (seagrass area, wetland area, natural shoreline) were used to rank the estuarine health in each embayment by a team of researchers and technical experts.The final rankings indicated the best to worst estuarine health in the following order: Sinepuxent Bay, Chincoteague Bay, Assawoman Bay, Isle of Wight Bay, Newport Bay and St. Martin River.
|
Sinepuxent Bay
|
Chincoteague Bay
|
Assawoman Bay
|
|||
Isle of Wight Bay
|
Newport Bay
|
St. Martin River
|
State of the Maryland Coastal Bays 2004
Wazniak, C., M. Hall, C. Cain, D. Wilson, R. Jesien, J. Thomas, T. Carruthers, and W. Dennison.
This report summarizes monitoring data collected over
the past several years for water quality, aquatic living resources, and habitat categories. This report documents the most up-to-date status of the water quality and living resources in the Coastal Bays and highlights the management steps being taken to preserve them. It utilizes conceptual diagrams for each reporting region to highlight the key ecosystem processes, biota and estuarine health problems.
Major findings of the report include:
- The primary threats to Maryland’s Coastal Bays are excessive nutrients and sediments from human activities on land.
- Areas of the Coastal Bays that first receive pollutants from human activities are in worse health while those flushed with relatively clean ocean water from inlets are in better health. Conditions are poor in the tributaries (St. Martin River, Newport Bay), fair in the bays behind Ocean City (Assawoman, Isle of Wight), and good in the southern bays (Sinepuxent, Chincoteague).
- Clam and blue crab populations have been relatively stable over the past 10 years, although Coastal Bay blue crab populations are threatened by a parasite. Forage fish populations (small fish that serve as food for many recreationally and commercially important species) have been slowly declining over the past 30 years.
- Seagrasses, which serve a critical role in the health of the Coastal Bays, have been gradually increasing, but are still far below potential population sizes, particularly in the northern bays.
- Several forms of harmful algae are found in the Coastal Bays and may be damaging seagrass and clam populations.
Dr. Bill Dennison briefing Governor O'Malley about the status of the Maryland Coastal Bays during a site visit in summer 2007.
Publications
Fine scale patterns of water quality in three regions of Marylands Coastal Bays: assessing nitrogen source in relation to land use.
Beckert, K., Fertig, B., O'Neil, J., Carruthers, T.J., Wazniak, C., Sturgis, B., Hall, M., Jones, A.B., Dennison, W.C.
Intensive sampling of the Maryland Coastal Bays in May and July of 2007 served to further assess spatial patterns in nutrients, responses of biological indicators, seasons, land use, and nutrient cycling. Trends indicated degraded water quality, high tubidity, increasing total nitrogen and phosphorus concentrations, high natural isotope abundance (δ15N), and low dissolved oxygen. The abundance of crop agriculture and development of the St. Martin River watershed indicates terrestrial sources of poor water quality, especially in upstream reaches, but no such land use connection has been reported for the region of Johnsons Bay. The difference between these two coastal bays may be their flushing and nutrient cycling abilities, in conjunction with adjacent land use.
Shifting Sands: Environmental and cultural change in Maryland's Coastal Bays
William C. Dennison, Jane E. Thomas, Carol J. Cain, Tim J.B. Carruthers, Matthew R. Hall, Roman, V. Jesien, Catherine E. Wazniak, and David E. Wilson
With an expected publication date of summer 2008, Shifting Sands is a ~350-page, full-color, graphic-rich, synthetic book about Maryland's Coastal Bays. A reference for scientists, a guide for resource managers, and educational for the general public, Shifting Sands features chapters on the history, water quality, biodiversity, habitats, and physical setting of the Coastal Bays, as well as putting them in a global context. Six separate chapters on the subwatersheds of the Coastal Bays will take a closer look at the features and issues shaping these systems.
Fine scale patterns of water quality in three regions of Maryland's Coastal Bays: assessing nitrogen source in relation to land use
Beckert, K., Fertig, B., O'Neil, J., Carruthers, T.J., Dennison, W.C., Fisher, T.
This presentation by graduate students Ben Fertig and Kris Beckert introduces preliminary results from a detailed assessment of nitrogen sources. Focusing on St.Martin River, Johnson Bay, and Sinepuxent Bay, oyster bioindicators and a suite of water quality measurements suggest that these coastal bays are vulnerable to nitrogen loads from various land uses. Trends indicated degraded water quality, high turbidity, increasing total nitrogen and phosphorus concentrations, high natural isotope abundance (δ15N), and low dissolved oxygen. While terrestrial anthropogenic pressures vary within subwatersheds, water quality in these coastal bays is also influenced by differences in flushing and nutrient cycling abilities.
Synthesising research, management, and monitoring
Using a science communication product to drive the synthesis process
This paper presents the process and results of a three-year collaboration between the University of Maryland Center for Environmental Science, the Maryland Department of Natural Resources, and the Maryland Coastal Bays Program. The focus of this collaboration was the conception, design, and production of a full-color, design-layout book synthesizing the current knowledge of the science and monitoring in the Coastal Bays, and highlighting management issues and recommendations. The book is aimed at a broad audience, from the interested layperson to technical scientists and resource managers. Through this project, a partnership was developed and a process established that forms the basis for future projects. A key team of editors was established, representing different research and management agencies, to conceive of the general structure of the book. Relevant experts from a wide range of agency and stakeholder groups were invited to author workshops to determine and layout the content for each of 14 chapters. Each layout workshop brought together experts who shared their perspectives of the Maryland Coastal Bays. Their explanations to each other and to the science communicators sparked a dynamic dialog on the basic underlying processes and the best way to illustrate the message (photographs, maps, conceptual diagrams, tables, graphs). Short, active titles were developed-statements summarizing the essence of the contributed point. Six of the chapters focus on the subwatersheds that make up the Coastal Bays. These chapter workshops were held in the watershed and were made up of participants from homeowner and citizen groups and local, state, and federal government agencies. The dynamic nature of the chapter workshop series resulted in the addition of a new chapter (Management of the Coastal Bays), and the combining of two previously separate chapters (Nutrient Budgets and Water Quality). The Science Communicator role included pursuing, compiling and communicating appropriate text and visual elements, including editing the contributed text to space requirements and for consistency, and creating new visual elements (e.g., conceptual diagrams, photographs, maps). Different techniques were used to determine the most effective communication. Development of a common base map for presenting GIS-based data and maintaining consistency of presentation and spelling of place names, color swatches, and fonts facilitated communication and interpretation of the data.
Biological indicators enhance water quality monitoring in Maryland's Coastal Bays
March 2007
Nutrient point sources such as wastewater treatment plants and non-point sources including agricultural runoff degrade the water quality of Maryland's Coastal Bays through excessive nutrient loading. Identifying specific sources is difficult due to their variety and mixture. Biological indicators can identify nitrogen sources, integrate nitrogen from these sources over time, and detect biologically important nutrients. Mapping identified sources can provide targets for nutrient reduction management actions, monitor management effectiveness, and evaluate the need for increased efforts. This newsletter summarizes data from the 2004 and 2006 water quality surveys of Maryland's Coastal Bays, incorporating the macroalgae Gracilaria sp. and the eastern oyster Crassostrea virginica as bioindicators.
The role of benthic communities in the health of Maryland's Coastal Bays
Prepared by Caroline Wicks, Tim Carruthers, Bill Dennison, Don Webster and Don Meritt
In collaboration with the University of Maryland's Cooperative Extension Service at the Wye Mills Research and Education Center, EcoCheck (NOAA - UMCES partnership) has produced a newsletter on the history and current trends of benthic communities in Maryland's Coastal Bays. Aquatic grasses and shellfish are important components of a healthy ecosystem because they provide a variety of ecosystem services, improve water quality, and are commercially valuable.
Water quality in four regions of the Maryland Coastal Bays: assessing nitrogen source in relation to rainfall and brown tide
Fertig, B., Carruthers, T.J., Wazniak, C., Sturgess, B., Hall, M., Jones, A.B., and Dennison, W.C., November 2006
** NB: 30+ MB file - Right Click and Save rather than opening **
Monitoring water quality and determining nutrient inputs is essential to assess ecosystem health. Partnering with the Maryland Coastal Bays Program and the Department of Natural Resources, this study focused on four regions in Marylands’s Coastal Bays. These regions, St Martins River, Public Landing, Johnson’s Bay, and Chincoteague Island, were found to be nitrogen ‘hotspots’ by the 2004 water quality assessment study. This data report provides a spatially explicit Water Quality Index and extent of sewage / septic nitrogen incorporated by two biological indicators, the macroalgae Gracilaria, and the native oyster, Crassostrea virginica.
Ecosystem health report cards: an approach to integrated assessment
The coastal zone supports a large and increasing human population, as well as a significant fraction of the global biological productivity, including most global fisheries. The diversity of habitats in the global coastal zone is heavily impacted by anthropogenic trapping and modifying of water on its way to the ocean. Integrated ecological assessment of the world’s coastal ecosystems is essential for effective management and remediation. The integration of management, monitoring, and science is required to solve the major environmental problems that are occurring in coastal zones around the world. Effective monitoring requires a significant investment of resources. Field work is expensive, data analysis is time-intensive, data integration requires high level scientific input, and recurring costs are subject to inflationary pressures. Integrated ecological assessment provides feedback on these monitoring investments by measuring the effectiveness of management actions. Societal momentum can then be created by successes in assessment and communication. Effective integrated assessment of ecosystem health must: be hypothesis-driven; be spatially and temporally explicit; be adaptable to changing management needs and research findings; be linked to a communication program; have timely outputs; and be highly visible to stakeholders. This poster presents processes and approaches to performing integrated ecological assessments, using an example from the Coastal Bays of Maryland, U.S.A.
Utilizing spatially intensive data in monitoring Maryland's Coastal Bays
ERF 2005, Oct 16-20, 2005, Norfolk, Virginia
Traditional monitoring programs collect periodic data at a small number of fixed sampling locations. These measurements provide a good baseline for watershed assessment and long-term trends, but may miss smallscale gradients in water quality. Spatially intensive data are useful for identifying localized areas of water quality concern, mapping the extent of harmful algal blooms, and linking degraded areas with adjacent land uses. High density of sampling locations allows the production of statistically valid interpolated maps, and maps which can be integrated over time, which are useful reporting tools. This poster presents the findings from collecting and integrating spatially intensive data in the Maryland's Coastal Bays. Traditional water quality parameters were used together with a biological monitoring technique using the isotopic signature of nitrogen (δ15N) in bioindicator organisms to detect and integrate the effects of anthropogenic nitrogen, such as sewage,septic, and animal waste.
A water quality assessment of the Maryland Coastal Bays including nitrogen source identification using stable isotopes
Jones, A.B., Carruthers, T.J., Pantus, F., Thomas, J., Saxby, T.A., and W. Dennison, October 2004
This data report details the results of an intensive sampling effort by the Integration and Application Network in the Maryland Coastal Bays. A spatially explicit Water Quality Index was developed from standard water quality analyses and a relatively new stable isotope technique. This study was conducted after the production of the State of the Maryland Coastal Bays 2004 Report and provides a more spatially intensive assessment of the region, and includes new data showing the extent of sewage / septic nitrogen within the system.
State of the Maryland Coastal Bays 2004
Wazniak, C., M. Hall, C. Cain, D. Wilson, R. Jesien, J. Thomas, T. Carruthers, and W. Dennison
This report summarizes monitoring data collected over the past several years for water quality, aquatic living resources, and habitat categories. It utilizes conceptual diagrams for each reporting region to highlight the key ecosystem processes, biota and estuarine health problems.