Download or read book Influences of Circulation Processes on Dissolved Oxygen in the Chesapeake Bay written by William C. Boicourt and published by . This book was released on 1992 with total page 59 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Oxygen Dynamics in the Chesapeake Bay written by David E. Smith and published by Schiffer Publishing. This book was released on 1992 with total page 264 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book examines the processes that create and sustain anoxia (the absence of oxygen) and hypoxia (the near absence of oxygen) in bottom waters of the Chesapeake Bay. The authors of the book's four chapters discuss major findings and summarize the gradually developing consensus on the implications of these findings for resource management. William C. Boicourt focuses on the physical aspects of Chesapeake Bay in order to distinguish the role and relative importance of circulation processes in the creation of low dissolved oxygen levels. Thomas C. Malone examines the role of water column processes, including the importance and interaction of nutrients, phytoplankton and zooplankton. Robert Jonas discusses the significance of microbial populations, while W. Michael Kemp and Walter R. Boynton discuss the role and importance of benthicpelagic coupling on Chesapeake Bay dissolved oxygen.

Download or read book Dissolved Oxygen in the Chesapeake Bay written by Gail B. Mackiernan and published by . This book was released on 1987 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved Oxygen in the Chesapeake Bay written by Lawrence W. Harding and published by . This book was released on 1992 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Dissolved Oxygen in the Chesapeake Bay written by Gail B. Mackiernan and published by . This book was released on 1987-03-01 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of Climate Variation and Human Adaptation on the Physical Transport Processes and Water Exchange in Chesapeake Bay written by Jiabi Du and published by . This book was released on 2017 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: The efficiencies of water exchanges in both vertical and horizontal directions reflect the overall impact of various physical processes and serve as important indicators of physical control over a variety of ecological and biogeochemical processes. The vertical exchange between surface layers and bottom layers of a waterbody has proved to exert great control over the hypoxic condition, while the horizontal exchange between an estuary and coastal ocean determines the flushing capacity of the estuary and the retention rate of riverine materials. Various processes, such as tidal flushing, tidal mixing, gravitational circulation, and lateral circulation, can affect water exchange. Therefore, water exchange processes are complex and varying in time and space in estuaries. Besides the impact of numerous forcing variables, large-scale climate oscillation, sea-level rise, and human activities can result in a change of estuarine dynamics. Two biologically relevant timescales, residence time (RT) and vertical exchange time (VET), are used in this study to quantify the overall horizontal and vertical exchange, aiming to understand the physical transport control over the ecosystem functioning in a simpler way. A long-term simulation of VET in the Chesapeake Bay over the period of 1980-2012 revealed a high spatial and seasonal similarity between VET and the dissolved oxygen (DO) level in the mainstem of the Chesapeake Bay, suggesting a major control over the DO condition from the physical transport. Over the past three decades, a VET of about 20 days in the summer usually indicates a hypoxic condition in the mainstem. Strong correlation among southerly wind strength, North Atlantic Oscillation index, and VET demonstrates that the physical condition in the Chesapeake Bay is highly controlled by the large-scale climate variation. The relationship is most significant during the summer, during which time the southerly wind dominates throughout the Chesapeake Bay. By combining the observed DO data with modeled VET, decoupling the physical and biological effect on the DO condition becomes possible. Bottom DO consumption rate was estimated through a conceptual model that links DO with VET. Using observed DO data and modeled VET, the overall biological effect on the DO condition can be quantified. The estimated bottom DO consumption rate shows strong seasonal variation and its interannual variation is highly correlated with the nutrient loading. The response of an estuary ecosystem to a change of nutrient loading depends on the flushing capacity of the estuary, which is related to the horizontal water exchange. The overall flushing capacity can be quantified by resident time, which determines the retention and export rates of materials discharged in the estuary. The horizontal exchange in Chesapeake Bay was investigated over the period of 1980-2012. Quantified by the residence time (RT), the horizontal exchange in Chesapeake Bay exhibits high interannual and spatial variability. The 33-year simulation results show that the mean RT of the entire Chesapeake Bay system ranges from 110 to 264 days, with an average value of 180 days, which is smaller than 7.6 months (approximately 230 days) reported in previous studies. There is significant lateral asymmetry of RT in the mainstem, with a larger RT along the eastern bank than that along the western bank in the lower Bay, which is mainly attributed to the horizontal shearing of estuarine circulation and large freshwater input along the western bank. Because of the persistent stratification and estuarine circulation, the vertical difference between the surface RT and bottom RT is dramatic, with a difference as large as 100 days. Relations among RT, river discharge, and strength of estuarine circulation reveal that the variation of horizontal exchange is mainly controlled by the river discharge and modulated by the estuarine circulation. A strengthened estuarine circulation will enhance the water exchange and reduce the RT. By affecting the estuarine circulation, wind forcing has a great impact on the horizontal exchange. The horizontal and vertical exchanges, together, contribute to the unique pattern of riverine material redistribution in Chesapeake Bay. By conducting long-term numerical simulations using multiple passive tracers that are independently released in the headwater of five main rivers (i.e., Susquehanna, Potomac, Rappahannock, York, and James Rivers), the relative contribution of discharge from each river to the total material in the mainstem can be calculated. The results show that the discharge from Susquehanna River has the dominant control on the riverine material throughout the entire mainstem. Despite the smaller contribution from the lower-middle Bay tributaries to the total materials in the mainstem, materials released from these rivers have a high potential to be transported to the middle-upper Bay through the bottom inflow by the persistent estuarine circulation. Depending on the magnitude of river discharge and the location of the tributary, material released at the headwaters of the main five rivers contributes differently to the riverine material in the mainstem. Material released in the upper estuary tends to have a longer residence time and a larger contribution, while materials released near the mouth are subject to a rapid flushing process, a small retention time, and a strong shelf-current induced dilution. The results reveal three distinct spatial patterns for materials released from the main river, tributary, and coastal oceans. One of the potential factors to change the exchange processes is the degree of human activities, such as construction of large infrastructures. With projected intensified hurricane and an accelerated sea-level rise in the 21st century, building storm surge barriers to mitigate the flooding risk has been considered as feasible climate change adaptation strategies in many coastal areas, which will surely affect the ecosystem functioning by affecting the water exchange. Two types of partially embanked storm surge barriers across the mouth of Chesapeake Bay were examined. Under modeled scenarios, surge barriers exert a significant influence on the tide, salinity, residual current, and transport processes. The vertical exchange is weakened, mainly due to the reduction of tidal range and tidal mixing. Even though the stratification is enhanced, the estuarine circulation is weakened due to accumulation of freshwater in the downstream and a decreased horizontal salinity gradient. The overall horizontal exchange is weakened due to a barrier, but the impact varies spatially.

Download or read book Aquatic Pollution written by Edward A. Laws and published by John Wiley & Sons. This book was released on 2017-04-24 with total page 773 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since the publication of the third edition of Aquatic Pollution in 2000, there have been many major developments within the field in terms of research, regulations, and also large-scale catastrophes that have had a significant impact on the aquatic environment; the Deepwater Horizon oil spill and the Fukushima nuclear disaster have taken their toll, and research on ocean acidification has developed enormously over the last decade. Recognizing, controlling, and mitigating aquatic pollution on a global scale is one of the most important and most difficult challenges facing society today. Fully updated to reflect current understanding and discussing these major recent developments, this fourth edition of Aquatic Pollution covers every aspect of pollution associated with urban runoff, acid rain, sewage disposal, pesticides, oil spills, nutrient loading, and more. Case studies of major pollution sites, all original to this new edition, help to illustrate points made in general discussion. Offering unprecedented depth of coverage, and discussing both fresh and sea water environments, this unique text provides a key teaching and learning tool for courses in environmental science, zoology, oceanography, biology, and civil or sanitary engineering, as well as a vital book for government policy makers. It is also an excellent primer for policymakers and activists focused on environmental issues.

Download or read book The Comparative Roles of Suspension Feeders in Ecosystems written by Richard F. Dame and published by Springer Science & Business Media. This book was released on 2006-03-30 with total page 360 pages. Available in PDF, EPUB and Kindle. Book excerpt: Animals are a major link between the water column (pelagic) and the bottom (benthic) habitats in most shallow systems. This coupling is dominated by active processes such as suspension-feeding in which the organism actively uses energy to pump water that is then filtered to remove suspended particles that are consumed while undigested remains are deposited on the bottom. As a result of this feeding on and metabolism of particles, the animals excrete dissolved inorganic and organic waste back into the water column, and thus, become major components in the cycling and feedback of essential elements. With relatively high weight specific filtration rates of 1— 10 liters/hour/gram dry tissue and a propensity to form large aggregated populations (beds, reefs, schools and swarms), these organisms can play an important role in regulating water column processes Although estuarine bivalve molluscs such as oysters and mussels dominate the suspension-feeder literature, other groups including plankton and nekton that are found in estuarine as well as other aquatic systems are also potentially important removers of suspended particles. Thus, a significant part of the NATO Advanced Research Workshop focused on suspension-feeders as controllers of plankton abundance, biomass and diversity, system metabolism, nutrient cycling and scale dependency. Systems dominated by suspension-feeders are typically impacted by human activities including recreation, aquaculture, human and industrial pollution, and bilge water from shipping. Suspension-feeders are often impacted by fisheries and over-exploitation. These impacts commonly result in changes in ecosystem structure either through the food chain concentration of harmful substances or diseases, the introduction of alien species of suspension-feeders, or the instability of suspension-feeders systems through species displacement or phase shifts in the dominance between different suspension-feeding components such as nekton or zooplankton. These issues were addressed near the close of the workshop along with conclusions and syntheses developed by the working groups.

Download or read book Environmental Effects Research on Chesapeake Bay written by Virginia Sea Grant College Program and published by . This book was released on 1989 with total page 225 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Biogeochemistry of Estuaries written by Thomas S. Bianchi and published by Oxford University Press. This book was released on 2007 with total page 721 pages. Available in PDF, EPUB and Kindle. Book excerpt: Offering a comprehensive and interdisciplinary approach to the study of biochemical cycling in estuaries, this text utilises numerous illustrations and an extensive literature base in order to impart the current state-of-the-art knowledge in the field.

Download or read book Nutrient dissolved Oxygen Dynamics in Chesapeake Bay the Roles of Phytoplankton and Micro heterotrophs Under Summer Conditions 1985 written by and published by . This book was released on 1987 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Nutrient dissolved Oxygen Dynamics in Chesapeake Bay the Roles of Phytoplankton and Micro heterotrophs Under Summer Conditions 1985 written by and published by . This book was released on 1987 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Treatise on Estuarine and Coastal Science written by and published by Academic Press. This book was released on 2012-03-06 with total page 4604 pages. Available in PDF, EPUB and Kindle. Book excerpt: The study of estuaries and coasts has seen enormous growth in recent years, since changes in these areas have a large effect on the food chain, as well as on the physics and chemistry of the ocean. As the coasts and river banks around the world become more densely populated, the pressure on these ecosystems intensifies, putting a new focus on environmental, socio-economic and policy issues. Written by a team of international expert scientists, under the guidance of Chief Editors Eric Wolanski and Donald McClusky, the Treatise on Estuarine and Coastal Science, Ten Volume Set examines topics in depth, and aims to provide a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Most up-to-date reference for system-based coastal and estuarine science and management, from the inland watershed to the ocean shelf Chief editors have assembled a world-class team of volume editors and contributing authors Approach focuses on the physical, biological, chemistry, ecosystem, human, ecological and economics processes, to show how to best use multidisciplinary science to ensure earth's sustainability Provides a comprehensive scientific resource for all professionals and students in the area of estuarine and coastal science Features up-to-date chapters covering a full range of topics

Download or read book Ecosystem Function Human Activities written by R. David Simpson and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 319 pages. Available in PDF, EPUB and Kindle. Book excerpt: R. David Simpson Norman L. Christensen, Jr. Human Activity and Ecosystem Function: Reconciling Economics and Ecology Recognizing the need to improve social decision making on tradeoffs between economic growth and ecological health, the Renewable Natural Resources Foundation convened a workshop in October 1995 on "Human Activity and Ecosystem Function: Reconciling Economics and Ecology. " While the subtitle perhaps reflected unrealistic expectations, the presentations and discus sions at the workshop were a preliminary step toward that rec onciliation: bringing together ecologists, economists, other nat ural and social scientists, and policy makers to layout the issues, articulate their needs and perspectives, and identify common ground for further work. This volume contains the pa pers presented and reports generated from the workshop. We emphasize ecology and economics in this discussion. We could argue that organizing our inquiry around these diSCiplines is only natural. Ecology is the study of behavior of organisms within complex systems composed of a myriad of other organ isms and their physical environments. Increasingly, this disci pline has focused on how interactions among biological and physical components influence the overall functioning of ecosys tems. These components are increasingly being determined by viii Ecosystem Function and Human Activities human activities. Economics is the study of how we decide which of our needs and wants we choose to satisfy given our limited re sources.

Download or read book Living Marine Resources written by Edwin S. Iversen and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 411 pages. Available in PDF, EPUB and Kindle. Book excerpt: Living Marine Resources provides a thorough, up-to-date introduction to all aspects of fisheries science. This clearly written text offers insight into a topic of increasing importance--the wise utilization and management of sea fisheries to maximize production without exceeding their carrying capacity. Adoption of the approaches presented will improve the conservation and management of the many world fisheries that are suffering from years of inefficient practices. The book is divided into five sections, beginning with an introduction to the ocean environment and the various resource species. Part two examines fisheries biology, including age, growth, fecundity, and mortality, enabling readers to appreciate yield models designed to give estimates of maximum sustainable yield and maximum economic yield. The third part covers gear, methods, and landings and includes material on the handling and processing of seafood as well as aquaculture. In part four, yield models are presented to introduce students to theories on population dynamics, stock assessment, and management. The book concludes with coverage of recreational fisheries, including socioeconomic importance, catch and effort research, management techniques, and their interface with commercial fisheries. Living Marine Resources is an invaluable introduction to the subject for advanced undergraduate and graduate students of fisheries science. In addition, the material presented will be valuable to fishery and social scientists, fishery officers and administrators, and students in biology, engineering, economics, and law.

Download or read book Agriculture and Phosphorus Management written by Andrew N. Sharpley and published by CRC Press. This book was released on 1999-12-20 with total page 256 pages. Available in PDF, EPUB and Kindle. Book excerpt: Using the Chesapeake Bay as a case study, Agriculture and Phosphorus Management discusses the impact and management of phosphorus in watersheds. Although urban and other sources contribute phosphorus to the Bay, the papers presented focus on how its role in agriculture impacts water quality. They review the new guidelines and legislation slated for implementation by 2002 directed towards sustainable nutrient management and strategies for implementing them. Phosphorus, an essential element for plant and animal growth, has long been recognized as necessary to eliminate deficiencies and to maintain profitable crop and livestock production. It can increase the biological productivity of surface waters by accelerating eutrophication. Human activities accelerate the rate of eutrophication - principally by increasing the rate at which phosphorus enters the aquatic system. Written by experts from a range of disciplines Agriculture and Phosphorus Management provides a deeper understanding of the diverse, dynamic, and complex factors controlling the impact of agricultural phosphorus management on production and water quality. Each contributor addresses the questions: what do we know, what do we still need to know, where are the major gaps in our knowledge, and how does the information relate to phosphorus management strategies in the Bay Watershed, and other watersheds? As a result this series of papers provides a unique collection of information of regional, national, and international significance and gives prioritized phosphorus management options for not only the Chesapeake Bay Watershed, but for watersheds around the world.

Download or read book Understanding the Estuary written by Maurice P. Lynch and published by . This book was released on 1988 with total page 666 pages. Available in PDF, EPUB and Kindle. Book excerpt: