Scientific Assessment of Hypoxia in U.S. Coastal Waters
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Biogeochemistry of Mediterranean Wetlands: a Review About the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions
water Review Biogeochemistry of Mediterranean Wetlands: A Review about the Effects of Water-Level Fluctuations on Phosphorus Cycling and Greenhouse Gas Emissions Inmaculada de Vicente 1,2 1 Departamento de Ecología, Universidad de Granada, 18071 Granada, Spain; [email protected]; Tel.: +34-95-824-9768 2 Instituto del Agua, Universidad de Granada, 18071 Granada, Spain Abstract: Although Mediterranean wetlands are characterized by extreme natural water level fluctu- ations in response to irregular precipitation patterns, global climate change is expected to amplify this pattern by shortening precipitation seasons and increasing the incidence of summer droughts in this area. As a consequence, a part of the lake sediment will be exposed to air-drying in dry years when the water table becomes low. This periodic sediment exposure to dry/wet cycles will likely affect biogeochemical processes. Unexpectedly, to date, few studies are focused on assessing the effects of water level fluctuations on the biogeochemistry of these ecosystems. In this review, we investigate the potential impacts of water level fluctuations on phosphorus dynamics and on greenhouse gases emissions in Mediterranean wetlands. Major drivers of global change, and specially water level fluctuations, will lead to the degradation of water quality in Mediterranean wetlands by increasing the availability of phosphorus concentration in the water column upon rewetting of dry sediment. CO2 fluxes are likely to be enhanced during desiccation, while inundation is likely to decrease cumulative CO emissions, as well as N O emissions, although increasing CH emissions. Citation: de Vicente, I. 2 2 4 Biogeochemistry of Mediterranean However, there exists a complete gap of knowledge about the net effect of water level fluctuations Wetlands: A Review about the Effects induced by global change on greenhouse gases emission. -
8.4 the Significance of Ocean Deoxygenation for Continental Margin Mesopelagic Communities J
8.4 The significance of ocean deoxygenation for continental margin mesopelagic communities J. Anthony Koslow 8.4 The significance of ocean deoxygenation for continental margin mesopelagic communities J. Anthony Koslow Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Tasmania, Australia and Scripps Institution of Oceanography, University of California, SD, La Jolla, CA 92093 USA. Email: [email protected] Summary • Global climate models predict global warming will lead to declines in midwater oxygen concentrations, with greatest impact in regions of oxygen minimum zones (OMZ) along continental margins. Time series from these regions indicate that there have been significant changes in oxygen concentration, with evidence of both decadal variability and a secular declining trend in recent decades. The areal extent and volume of hypoxic and suboxic waters have increased substantially in recent decades with significant shoaling of hypoxic boundary layers along continental margins. • The mesopelagic communities in OMZ regions are unique, with the fauna noted for their adaptations to hypoxic and suboxic environments. However, mesopelagic faunas differ considerably, such that deoxygenation and warming could lead to the increased dominance of subtropical and tropical faunas most highly adapted to OMZ conditions. • Denitrifying bacteria within the suboxic zones of the ocean’s OMZs account for about a third of the ocean’s loss of fixed nitrogen. Denitrification in the eastern tropical Pacific has varied by about a factor of 4 over the past 50 years, about half due to variation in the volume of suboxic waters in the Pacific. Continued long- term deoxygenation could lead to decreased nutrient content and hence decreased ocean productivity and decreased ocean uptake of carbon dioxide (CO2). -
Hypoxia Infographic
Understanding HYP XIA Hypoxia is an environmental phenomenon where the concentration of dissolved oxygen in the water column decreases to a level that can no longer 1 support living aquatic organisms. The level is often considered to be 2 mg O2 per liter of water or lower. Hypoxic and anoxic (no oxygen) waters have existed throughout geologic time, but their occurrence in shallow coastal and estuarine areas appears to be increasing as a result of human activities. 2 What causes hypoxia? In 2015, scientists determined the Gulf of Mexico dead zone to be 6,474 square miles, which is an area about the size of Connecticut and Rhode Island combined. 3 Major events leading to the formation of hypoxia in the Gulf of Mexico include: Coastal Hypoxia and Eutrophication Sunlight Watershed Areas of anthropogenically-influenced n> In the past century, Hypoxia has become a global concern with estuarine and coastal hypoxia. 550 over 550 coastal areas identified as experiencing this issue. 4 Runoff and nutrient 1 loading of the Mississippi River. Nutrient-rich water from the Mississippi River forms 1960 a surface lens. 1970 Combined, Dead Zones 1980 cover 4x the area of the 1990 Great Lakes. % 2000 Nutrient-enhanced 4 2 primary production, Only a small fraction of the 550-plus Number of dead zones has approximately Today, there is currently about 1,148,000 km2 or eutrophication. hypoxia zones exhibited any signs doubled each decade since the 1960’s. 5 of seabed covered by Oxygen Minimum Phytoplankton growth of improvement. 5 Zones (OMZs) (<0.5 ml of O /liter) 5 is fueled by nutrients. -
Gulf of Mexico Hypoxia Monitoring Strategy
Gulf of Mexico Hypoxia Monitoring Strategy Hypoxia Zone Areal Extent (km2) Interpolation Observations Data Analysis Workshop Steering Committee Trevor Meckley, Alan Lewitus, A White Paper by the Steering Committee of the: Dave Scheurer, Dave Hilmer NOAA National Ocean Service, National 6th Annual NOAA/NGI Hypoxia Research Centers of Coastal Ocean Science Coordination Workshop: Establishing a Steve Ashby Cooperative Hypoxic Zone Monitoring Program Northern Gulf Institute convened by the NOAA National Centers for Steve DiMarco Texas A&M University Coastal Ocean Science and Northern Gulf Institute Steve Giordano on 12-13 September 2016 at the Mississippi State NOAA National Marine Fisheries Service University Science and Technology Center at Rick Greene NASA's Stennis Space Center in Mississippi. EPA Office of Research and Development Stephan Howden University of Southern Mississippi Barb Kirkpatrick Gulf of Mexico Coastal Ocean Observing System Troy Pierce EPA Gulf of Mexico Program Nancy Rabalais Louisiana Universities Marine Consortium Rick Raynie Louisiana Coastal Protection and Restoration Authority Mike Woodside USGS National Water Quality Program Abstract The Gulf of Mexico Hypoxia Monitoring Strategy is a resource to inform the proceedings of the 6th Annual NOAA/NGI Hypoxia Research Coordination Workshop: Establishing a Cooperative Hypoxic Zone Monitoring Program. It provides a framework for a cooperative hypoxia monitoring program based on programmatic and financial requirements that are designed to meet management needs. The Monitoring Strategy includes sections on management drivers, current monitoring capabilities and gaps, and projected programmatic, data, and financial requirements based on the input of multiple partners and the responses from a survey of modelers currently applying deterministic 3D time variable models to Gulf hypoxia assessment and prediction. -
The Potential of Mangroves in the Treatment of Shrimp Aquaculture Effluent on the Eastern Coast of Thailand
The Potential of Mangroves in the Treatment of Shrimp Aquaculture Effluent on the Eastern Coast of Thailand 7 Nina Fancy B. Sc.(Horn), Queen's University, 1999 A Thesis Submitted in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE in the Department of Geography O Nina Fancy, 2004 University of Victoria AII rights reserved. This thesis may not be reproduced in whole or in part, by photocopy or other means, without the permission of the author. Supervisor: Dr. Mark Flaherty ABSTRACT This thesis examines the potential of low-cost, low-maintenance mangroves in the treatment of nutrient-rich effluent originating from a shnmp fmon the coast of Thailand's Chanthaburi province. The objective of this thesis is to identify the environmental impact of shnmp aquaculture effluent and to determine if mangrove wetlands can be used as effective biofiltration areas to remove significant quantities of nitrate, ammonia and nitrite from shrimp wastewater. The study mangrove was found to remove an average of 44.5% of nitrate, 46.6% of ammonia and 59.0% of nitrite from shrimp effluent. The ratio of mangrove treatment area to shrimp fmrequired to adequately treat daily effluxes of wastewater from shrimp fmswas calculated to . be 1: 14. This ratio is significantly less spatially demanding than ratios calculated by .-: P 0 previous researchers and reveals the potential of mangroves to be used as large-scale wastewater treatment areas in shrimp-producing nations. TABLE OF CONTENTS .. ABSTRACT ..............................................................................................................11 -
Linking Biodiversity Above and Below the Marine Sediment–Water Interface
Articles Linking Biodiversity Above and Below the Marine Sediment–Water Interface PAUL V. R. SNELGROVE, MELANIE C. AUSTEN, GUY BOUCHER, CARLO HEIP, PATRICIA A. HUTCHINGS, GARY M. KING, ISAO KOIKE, P. JOHN D. LAMBSHEAD, AND CRAIG R. SMITH hanges in the marine environment are evident on Ca global scale (McGowan et al. 1998), and although bio- THE ORGANISMS LIVING ON THE OCEAN diversity in the oceans is poorly described, abundances and FLOOR ARE LINKED TO THOSE LIVING IN distributions of both commercially exploited (Safina 1998) and nonexploited (Pearson and Rosenberg 1978) species have THE OCEAN ABOVE, BUT WHETHER OR changed. Not only have major changes occurred but the rate of alteration of marine ecosystems appears to be accelerating HOW THE BIODIVERSITY IN THESE TWO (e.g., Cohen and Carlton 1998). Unfortunately, the impact of these changes in biodiversity on the basic functioning of ma- REALMS IS LINKED REMAINS LARGELY rine ecosystems remains uncertain, as does the oceans’ capacity UNKNOWN to withstand multiple human disturbances (Snelgrove et al. 1997). The dynamics of many marine ecosystems, as well as of important fisheries, depend on close coupling between benthic (bottom living) and pelagic (water column) organ- The sediment–water interface (SWI) in marine ecosystems isms (Steele 1974). Our knowledge of the natural history of is one of the most clearly defined ecological boundaries on these systems remains limited, and scientific interest in map- Earth. Many organisms in the water column, such as salps ping the diversity of organisms and how they live has been and jellyfish, have flimsy and attenuated morphologies that marginalized in recent years. -
Mixing Between Oxic and Anoxic Waters of the Black Sea As Traced by Chernobyl Cesium Isotopes
Deep-Sea Research, Vol 38. Suppl 2. pp S72>-S745. 1991. 019~149191 53.00 + 0.00 Pnnted 10 Great Bntam © 1991Pergamon Press pic Mixing between oxic and anoxic waters of the Black Sea as traced by Chernobyl cesium isotopes KEN O. BUESSELER, * HUGH D. LIVINGSTON* and SUSAN A. CASSO* (Received 14 August 1989; in revised form 16 November 1990; accepted 28 November 1990) Abstract-The Chernobyl nuclear power station accident in 1986 released readily measureable quantities of fallout 134CS and 137Cs to Black Sea surface waters. This pulse-like input of tracers can be used to follow the physical mixing of the surface oxic waters, now labeled with the Chemobyl tracers, and the deeper anoxic waters, which were initially Chemobyl free. By 1988, there is clear evidence of Chernobyl Cs penetration below the oxic/anoxic interface at deep water stations in the western and eastern basins of the Black Sea. This rapid penetration of surface waters across the pycnocline cannot be explained by vertical mixing processes alone. Data from profiles at the mouth of the Bosporus suggest that significant ventilation of intermediate depths can occur as the outflowmg Black Sea waters are entrained with the inflowing Mediterranean waters, forming a sub-surface water mass which is recognized by its surface water characteristics, i.e. initially a relatively high oxygen content and Chernobyl Cs signal. The lateral propagation ofthis signal along isopycnals into the basin interior would provide a rapid and effective mechanism for ventilating intermediate depths of the Black Sea. This process could also account for the lateral injection of resuspended margin sediments into the basin interior. -
Zooplankton Community Response to Seasonal Hypoxia: a Test of Three Hypotheses
diversity Article Zooplankton Community Response to Seasonal Hypoxia: A Test of Three Hypotheses Julie E. Keister *, Amanda K. Winans and BethElLee Herrmann School of Oceanography, University of Washington, Box 357940, Seattle, WA 98195, USA; [email protected] (A.K.W.); [email protected] (B.H.) * Correspondence: [email protected] Received: 7 November 2019; Accepted: 28 December 2019; Published: 1 January 2020 Abstract: Several hypotheses of how zooplankton communities respond to coastal hypoxia have been put forward in the literature over the past few decades. We explored three of those that are focused on how zooplankton composition or biomass is affected by seasonal hypoxia using data collected over two summers in Hood Canal, a seasonally-hypoxic sub-basin of Puget Sound, Washington. We conducted hydrographic profiles and zooplankton net tows at four stations, from a region in the south that annually experiences moderate hypoxia to a region in the north where oxygen remains above hypoxic levels. The specific hypotheses tested were that low oxygen leads to: (1) increased dominance of gelatinous relative to crustacean zooplankton, (2) increased dominance of cyclopoid copepods relative to calanoid copepods, and (3) overall decreased zooplankton abundance and biomass at hypoxic sites compared to where oxygen levels are high. Additionally, we examined whether the temporal stability of community structure was decreased by hypoxia. We found evidence of a shift toward more gelatinous zooplankton and lower total zooplankton abundance and biomass at hypoxic sites, but no clear increase in the dominance of cyclopoid relative to calanoid copepods. We also found the lowest variance in community structure at the most hypoxic site, in contrast to our prediction. -
Hypoxia the Gulf of Mexico’S Summertime Foe
Louisiana Coastal Wetlands Planning, Protection and Restoration News September 2004 Number 26 HYPOXIA THE GULF OF MEXICO’S SUMMERTIME FOE More Nitrogen Upstream, Fewer Filters Downstream Caernarvon: A Case Study WaterMarks Interview: John Day, LSU www.lacoast.gov September 2004 Number 26 WaterMarks is published three times a Louisiana Coastal Wetlands Planning, Protection and Restoration News year by the Louisiana Coastal Wetlands Conservation and Restoration Task Force to communicate news and issues Contents of interest related to the Coastal Wetlands Planning, Protection and Restoration Act of 1990. This legislation 3 Hypoxia: funds wetlands enhancement projects The Gulf of Mexico’s Summertime Foe nationwide, designating approximately $50 million annually for work in More Nitrogen Upstream, Louisiana. The state contributes 6 Fewer Filters Downstream 15 percent of the total cost of the project. Can Wetlands Restoration 8 Revitalize Offshore Waters? Caernarvon: 10 A Case Study What Lies Ahead 12 for the Dead Zone? Please address all questions, comments and changes of address to: WaterMarks Interview: James D. Addison 14 John Day, LSU WaterMarks Editor New Orleans District US Army Corps of Engineers P.O. Box 60267 Special thanks to Doug Daigle, Mississippi River Basin Alliance; Dugan Sabins, New Orleans, LA 70160-0267 (504) 862-2201 Louisiana State Hypoxia Committee; Ken Teague, U.S. Environmental Protection Agency; and Robert Twilley, Louisiana State University, for their assistance with e-mail: this issue of WaterMarks. [email protected] For more information about Louisiana’s coastal wetlands and the efforts planned and under way to ensure their survival, check out these sites on the web: www.lacoast.gov www.btnep.org www.saveLAwetlands.org About the Cover Blue Runners, a common Gulf Subscribe species, have the ability to escape To receive WaterMarks, e-mail [email protected] from waters with low oxygen con- For current meetings, events, and other news concerning Louisiana’s coastal tent. -
The Economics of Dead Zones: Causes, Impacts, Policy Challenges, and a Model of the Gulf of Mexico Hypoxic Zone S
58 The Economics of Dead Zones: Causes, Impacts, Policy Challenges, and a Model of the Gulf of Mexico Hypoxic Zone S. S. Rabotyagov*, C. L. Klingy, P. W. Gassmanz, N. N. Rabalais§ ô and R. E. Turner Downloaded from Introduction The BP Deepwater Horizon oil spill in the Gulf of Mexico in 2010 increased public awareness and http://reep.oxfordjournals.org/ concern about long-term damage to ecosystems, and casual readers of the news headlines may have concluded that the spill and its aftermath represented the most significant and enduring environmental threat to the region. However, the region faces other equally challenging threats including the large seasonal hypoxic, or “dead,” zone that occurs annually off the coast of Louisiana and Texas. Even more concerning is the fact that such dead zones have been appearing worldwide at proliferating rates (Conley et al. 2011; Diaz and Rosenberg 2008). Nutrient over- enrichment is the main cause of these dead zones, and nutrient-fed hypoxia is now widely at Iowa State University on January 27, 2014 considered an important threat to the health of aquatic ecosystems (Doney 2010). The rather alarming term dead zone is surprisingly appropriate: hypoxic regions exhibit oxygen levels that are too low to support many aquatic organisms including commercially desirable species. While some dead zones are naturally occurring, their number, size, and *School of Environmental and Forest Sciences, University of Washington, Seattle, Washington, USA; e-mail: [email protected] yCenter for Agricultural and Rural Development, -
Coupling and Decoupling of High Biomass Phytoplankton Production and Hypoxia in a Highly Dynamic Coastal System: the Changjiang (Yangtze River) Estuary
fmars-07-00259 May 26, 2020 Time: 17:51 # 1 ORIGINAL RESEARCH published: 28 May 2020 doi: 10.3389/fmars.2020.00259 Coupling and Decoupling of High Biomass Phytoplankton Production and Hypoxia in a Highly Dynamic Coastal System: The Changjiang (Yangtze River) Estuary Feng Zhou1,2*, Fei Chai1,3*, Daji Huang1, Mark Wells3,1, Xiao Ma1, Qicheng Meng1, Huijie Xue3,4, Jiliang Xuan1, Pengbin Wang1,5, Xiaobo Ni1, Qiang Zhao6, Chenggang Liu1,5, Jilan Su5 and Hongliang Li1 1 State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China, 2 School of Oceanography, Shanghai Jiao Tong University, Shanghai, China, 3 School Edited by: of Marine Science, University of Maine, Orono, ME, United States, 4 State Key Laboratory of Tropical Oceanography, South Marta Marcos, China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou, China, 5 Key Laboratory of Marine University of the Balearic Islands, Ecosystem Dynamics, Second Institute of Oceanography, Ministry of Natural Resources, Hangzhou, China, 6 Ningbo Marine Spain Environment Monitoring Center Station, Ministry of Natural Resources, Ningbo, China Reviewed by: Sabine Schmidt, The global increase in coastal hypoxia over the past decades has resulted from a Centre National de la Recherche Scientifique (CNRS), France considerable rise in anthropogenically-derived nutrient loading. The spatial relationship Antonio Olita, between surface phytoplankton production and subsurface hypoxic zones often can Italian National Research Council (CNR), Italy be explained by considering the oceanographic conditions associated with basin size, *Correspondence: shape, or bathymetry, but that is not the case where nutrient-enriched estuarine Feng Zhou waters merge into complex coastal circulation systems. -
Chronicles of Hypoxia: Time-Series Buoy Observations Reveal Annually Recurring Seasonal Basin-Wide Hypoxia in Muskegon Lake – Agreat Lakes Estuary
Journal of Great Lakes Research 44 (2018) 219–229 Contents lists available at ScienceDirect Journal of Great Lakes Research journal homepage: www.elsevier.com/locate/jglr Chronicles of hypoxia: Time-series buoy observations reveal annually recurring seasonal basin-wide hypoxia in Muskegon Lake – AGreat Lakes estuary Bopaiah A. Biddanda a,⁎, Anthony D. Weinke a, Scott T. Kendall a, Leon C. Gereaux a, Thomas M. Holcomb a, Michael J. Snider a, Deborah K. Dila a,b, Stephen A. Long a, Chris VandenBerg a, Katie Knapp a, Dirk J. Koopmans a,c, Kurt Thompson a, Janet H. Vail a,MaryE.Ogdahla,d, Qianqian Liu a,d,ThomasH.Johengend, Eric J. Anderson e, Steven A. Ruberg e a Annis Water Resources Institute and Lake Michigan Center, Grand Valley State University, 740 Shoreline Drive, Muskegon, MI 49441, USA b School of Freshwater Sciences, University of Wisconsin-Milwaukee, Milwaukee, WI 53204, USA c Max Plank Institute for Marine Microbiology, Bremen 28359, Germany d Cooperative Institute for Great Lakes Research, University of Michigan, Ann Arbor, MI 48018, USA e Great Lakes Environmental Research Laboratory, National Oceanic and Atmospheric, Administration, Ann Arbor, MI 48018, USA article info abstract Article history: We chronicled the seasonally recurring hypolimnetic hypoxia in Muskegon Lake – a Great Lakes estuary over 3 Received 13 July 2017 years, and examined its causes and consequences. Muskegon Lake is a mesotrophic drowned river mouth that Accepted 23 December 2017 drains Michigan's 2nd largest watershed into Lake Michigan. A buoy observatory tracked ecosystem changes in Available online 1 February 2018 the Muskegon Lake Area of Concern (AOC), gathering vital time-series data on the lake's water quality from early summer through late fall from 2011 to 2013 (www.gvsu.edu/buoy).