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Summary Novel forms of drought are emerging globally, due to climate change, shifting teleconnection patterns, expanding human water use, and a history of human influence on the environment that increases the probability of transformational ecological impacts. These costly ecological impacts cascade to human communities, and understanding this changing drought landscape is one of today’s grand challenges. By using a modified horizon-scanning approach that integrated scientists, managers, and decision-makers, we identified the emerging issues in ecological drought that represent key challenges to timely and effective responses. Here we review the themes that most urgently need attention, including novel drought conditions, the potential for transformational drought impacts, and the need for anticipatory drought management. This horizon scan and review provides a roadmap to facilitate the research and management innovations that will support forward-looking, co-developed approaches to reduce the risk of drought to our socio-ecological systems during the 21st century.

The process of developing a socioenvironmental report card through transdisciplinary collaboration can be used in any system and can provide the foundation for collaborative solutions for sustainable resource management by creating a holistic assessment that balances environmental, economic, and social concerns that incorporates multiple perspectives from multisectoral actors. We demonstrated this in the Mississippi River watershed, USA with the ultimate goal of promoting holistic management of the region's natural resources. But working at the scale of the Mississippi River watershed presents the challenge of working across geographical, organizational, and disciplinary boundaries. The development of a socioenvironmental report card served as the focus for efforts to foster a shared vision among diverse stakeholders in the watershed and to promote transdisciplinary collaboration. The process engaged more than 700 participants from environment, flood control, transportation, water supply, economy, and recreation sectors, from more than 400 organizations representing local, state, and federal government agencies, businesses and trade associations, and private, nonprofit, and academic institutions. This broad engagement in the selection of important themes, indicators, measures, and assessment methods as part of the cocreation of boundary objects aimed to foster social and mutual learning and to develop common understanding and shared visioning among stakeholders with differing perspectives. The process was facilitated by boundary‐spanning organizations, creating an atmosphere of trust by utilizing “third places” for knowledge exchange and integration. This transdisciplinary process also led to collective action through collaboration and selection of restoration and management activities that could improve conditions for multiple sectors simultaneously and/or recognize potential tradeoffs for informed decision making. Integr Environ Assess Manag 2020;16:494–507. © 2020 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC), KEY POINTS We demonstrate that the process of creating a socioenvironmental report card is a practical tool for fostering stakeholder engagement and transdisciplinary collaboration in a complex socioenvironmental system, using the Mississippi River Watershed Report Card as a case study.The process allowed for the engagement of a diverse multisector group of stakeholders through multiple workshops that served as “third places” and the codevelopment of boundary objects such as conceptual diagrams and maps, newsletters, and the report card product itself.The report card results led to a common understanding of key issues that are important to sustainable management, identified information gaps and data needs, and promoted more discussion on the challenges, opportunities, and actions needed to improve the Mississippi River watershed.This process can be used in any system and can provide the foundation for collective action for sustainable management by creating a holistic assessment that balances environmental, economic, and social concerns and that incorporates multiple perspectives from multisectoral actors.

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 examples demonstrate how periodically quantifying coverage of this important foundational habitat answers basic research questions locally, as well as globally, and provides essential information to resource managers. New technologies are enabling more frequent and accurate aerial surveys at greater spatial resolution and lower cost. These advances will support efforts to extend the applications described here to similar issues in other areas.

Early ecosystem health report cards focused on assessing the health of natural ecosystems, producing a “snapshot” of ecosystem health at one point in time. Ecosystem health report cards are used to...

Susan Lynn Williams (1951–2018) was an exceptional marine ecologist whose research focused broadly on the ecology of benthic nearshore environments dominated by seagrasses, seaweeds, and coral reefs. She took an empirical approach founded in techniques of physiological ecology. Susan was committed to applying her research results to ocean management through outreach to decision-makers and resource managers. Susan’s career included research throughout the USA in tropical, temperate, and polar regions, but she specialized in tropical marine ecology. Susan’s scholarship, leadership, and friendship touched many people, leading to this multi-authored paper. Susan’s scholarship was multi-faceted, and she excelled in scientific discovery, integration of scientific results, application of science for conservation, and teaching, especially as a mentor to undergraduate and graduate students and postdoctoral scholars. Susan served in a variety of leadership positions throughout her career. She embodied all facets of leadership; leading by example, listening to others, committing to the “long haul,” maintaining trust, and creating a platform for all to shine. Susan was an important role model for women in science. Susan was also a loyal friend, maintaining friendships for many decades. Susan loved cooking and entertaining with friends. This paper provides an overview of the accomplishments of Susan in the broad categories of scholarship, leadership, and friendship.

Agriculture is fundamental to all three pillars of sustainability, environment, society, and economy. However, the definition of sustainable agriculture and the capacities to measure it remain elusive. Independent and transparent measurements of national sustainability are needed to gauge progress, encourage accountability, and inform policy. Here, we developed a Sustainable Agriculture Matrix (SAM) to quantify national performance indicators in agriculture and to investigate the trade-offs and synergies based on historical data for most countries of the world. The results reveal priority areas for improvement by each country and show that the trade-offs and synergies among indicators often differ. Exceptions to common economic-versus-environmental trade-offs, for example, offer opportunities to learn from countries with synergistic pathways for multiple sustainability indicators. These SAM indicators will improve as data become more available, but this version offers a useful starting point for evaluating progress, identifying priorities for improvement, and informing national policies and actions toward sustainable agriculture., One Earth, 4 (9), ISSN:2590-3322

Seagrass ecosystems are inherently dynamic, responding to environmental change across a range of scales. Habitat requirements of seagrass are well defined, but less is known about their ability to resist disturbance. Specific means of recovery after loss are particularly difficult to quantify. Here we assess the resistance and recovery capacity of 12 seagrass genera. We document four classic trajectories of degradation and recovery for seagrass ecosystems, illustrated with examples from around the world. Recovery can be rapid once conditions improve, but seagrass absence at landscape scales may persist for many decades, perpetuated by feedbacks and/or lack of seed or plant propagules to initiate recovery. It can be difficult to distinguish between slow recovery, recalcitrant degradation, and the need for a window of opportunity to trigger recovery. We propose a framework synthesizing how the spatial and temporal scales of both disturbance and seagrass response affect ecosystem trajectory and hence resilience.

Humans strongly impact the dynamics of coastal systems, yet surprisingly few studies mechanistically link management of anthropogenic stressors and successful restoration of nearshore habitats over large spatial and temporal scales. Such examples are sorely needed to ensure the success of ecosystem restoration efforts worldwide. Here, we unite 30 consecutive years of watershed modeling, biogeochemical data, and comprehensive aerial surveys of Chesapeake Bay, United States to quantify the cascading effects of anthropogenic impacts on submersed aquatic vegetation (SAV), an ecologically and economically valuable habitat. We employ structural equation models to link land use change to higher nutrient loads, which in turn reduce SAV cover through multiple, independent pathways. We also show through our models that high biodiversity of SAV consistently promotes cover, an unexpected finding that corroborates emerging evidence from other terrestrial and marine systems. Due to sustained management actions that have reduced nitrogen concentrations in Chesapeake Bay by 23% since 1984, SAV has regained 17,000 ha to achieve its highest cover in almost half a century. Our study empirically demonstrates that nutrient reductions and biodiversity conservation are effective strategies to aid the successful recovery of degraded systems at regional scales, a finding which is highly relevant to the utility of environmental management programs worldwide.

Over the past century, the environment of the Gulf of Mexico has been significantly altered and impaired by extensive human activities. A national commitment to restore the Gulf was finally initiated in response to the unprecedented Deepwater Horizon oil spill in 2010. Consequently, there is a critical need for an assessment framework and associated set of indicators that can characterize the health and sustainability of an ecosystem having the scale and complexity of the Gulf. The assessment framework presented here was developed as an integration of previous ecological risk– and environmental management–based frameworks for assessing ecosystem health. It was designed to identify the natural and anthropogenic drivers, pressures, and stressors impinging on ecosystems and ecosystem services, and the ecological conditions that result, manifested as effects on valued ecosystem components. Four types of societal and ecological responses are identified: reduction of pressures and stressors, remediation of existing stressors, active ecosystem restoration, and natural ecological recovery. From this conceptual framework are derived the specific indicators to characterize ecological condition and progress toward achieving defined ecological health and sustainability goals. Additionally, the framework incorporates a hierarchical structure to communicate results to a diversity of audiences, from research scientists to environmental managers and decision makers, with the level of detail or aggregation appropriate for each targeted audience. Two proof‐of‐concept studies were conducted to test this integrated assessment and decision framework, a prototype Texas Coastal Ecosystems Report Card, and a pilot study on enhancing rookery islands in the Mission‐Aransas Reserve, Texas, USA. This Drivers–Pressures–Stressors–Condition–Responses (DPSCR4) conceptual framework is a comprehensive conceptual model of the coupled human–ecological system. Much like its predecessor, the ecological risk assessment framework, the DPSCR4 conceptual framework can be tailored to different scales of complexity, different ecosystem types with different stress regimes, and different environmental settings. Integr Environ Assess Manag 2019;15:544–564. © 2019 The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals, Inc. on behalf of Society of Environmental Toxicology & Chemistry (SETAC), Key Points The DPSCR4 assessment framework was designed to identify the natural and anthropogenic drivers, pressures, and stressors impinging on ecosystems and ecosystem services, and the ecological conditions that result, manifested as effects on valued ecosystem components.The DPSCR4 assessment framework has been developed as an integration of previous ecological risk– and environmental management–based frameworks for assessing ecosystem health.From this conceptual framework are derived the specific indicators to characterize ecological condition and progress toward achieving defined ecological health and sustainability goals.This conceptual framework is in its essence a comprehensive conceptual model of the coupled human–ecological system.

New York Harbor is a large, iconic and complex body of water that has been extensively modified to support the development of a megacity. These modifications have affected the shorelines, water flow, water quality, habitats and living resources of the harbor. Changes in topography and bathymetry have altered the landscapes and seascapes of the region, largely to support an active shipping port and intense human settlement. New York Harbor has been transformed from a region dominated by marshy shorelines, extensive submersed oyster beds and obstructed entrances to the present-day harbor with hardened shorelines, dredged shipping channels and remnant oysters that are unsafe to consume. However, improvements in water quality, largely due to sewage treatment upgrades, combined with the natural flushing ability of the harbor, have served to help restore or improve the ecological resilience of New York Harbor. Social resilience of the region has been tested with both terrorist attacks and the widespread inundation associated with Superstorm Sandy. Both ecological and social resilience will need to be enhanced to sustain the future development of New York Harbor.

New York Harbor is a complex of interconnected waterways that have supported the rapid development of a thriving megacity and metropolitan region. The water quality of New York, a partner city in the World Harbour Project, is a reflection of the combined impacts of this metropolitan region. Water quality health and trends were assessed between 1996–2017in 9 different reporting regions using publicly available data. Analyses of New York Harbor water quality reveal strong persistent geographic gradients and long-term trends in improving water quality. Data was synthesized for five indicators throughout the New York harbor region including: total nitrogen (TN), total phosphorus (TP), dissolved oxygen (DO), chlorophyll a (chla), and water clarity (secchi disk depth). The health of the waterways surrounding New York City was evaluated and graded on a 0%–100% scale and displayed using a ’stoplight color scheme’. The best water quality in the region evaluated was in the area of the most exchange with the Atlantic Ocean in the Lower Bay near the harbor entrance. Conversely, the most degraded water quality was in the areas of lowest water exchange in dead end canals (Newtown Creek and Flushing Bay) and Jamaica Bay. The Hudson River, East River, Upper Bay, Newark Bay, and Raritan Bay had intermediate water quality. High nutrient levels (TN and TP) were observed throughout New York Harbor, but water clarity, DO and chla levels were variable. Overall, there were improving trends in many water quality parameters over the time period of our study, especially TN. Data used in this analysis can be used as a resource for environmental managers, educators and students to explore health of New York Harbor and its associated waterways. This analysis may be seen as a model for other important and threatened harbors and waterways including partner cities in the World Harbour Project by providing a comparable method for assessing and communicating water quality health.

The response of the marine macroalga Gracilaria edulis (Gmelin) Silva to nutrient pulses of varying magnitude was investigated to test its applicability as a marine bioindicator at two oligotrophic locations. After exposure to nutrient pulses, algal amino acid, tissue nitrogen, and chlorophyll a content were assessed relative to algae incubated under control conditions (no nutrient enrichment). The smallest nutrient pulse involved a nutrient enrichment experiment conducted within a coral atoll, whereas two larger pulses resulted from sewage discharge to a tropical coastal bay. After exposure to the smallest nutrient pulse (10 × ambient), only changes in macroalgal amino acid concentration and composition were detected (mainly as increases in citrulline). At 100 × ambient concentrations, increases in tissue % nitrogen of the macroalgae were detected, in addition to responses in amino acids. Macroalgae exposed to the highest nutrient pulse (1000 × ambient) responded with increased chlorophyll a, tissue nitrogen, and amino acids within the three day incubation period. In contrast to these algal responses, analytical water sampling techniques failed to detect elevated nutrients when nutrient pulses were not occurring. The responses of this algal bioindicator to variable nutrient pulses may provide a useful tool for investigating the source and geographical extent of nutrients entering oligotrophic coastal waters.

Stable nitrogen and carbon isotopes (δ15N and δ13C) and elemental content (% nitrogen, % carbon) in oysters (Crassostrea virginica) grown by a network of 132 citizen–scientists (11,600 km2, 87.9 km2 site−1) were examined to test effects of land use, salinity, flushing time, and oyster size on bioindication of human and/or animal nitrogen sources. Oyster δ15N sampled from shallow waters sites throughout Chesapeake Bay and its tributaries exhibited nested spatial patterns: (1) decreasing toward the mouth of Chesapeake Bay (1000s km2) and (2) decreasing, increasing, and not changing toward tributary mouths (100s km2). Distinct isotopic ‘signatures’ in tributaries were associated with the composition of land use, water quality in tributaries and freshwater streams, human and/or animal nitrogen sources, and marine vs. terrestrial nitrogen and carbon sources. Yet at 1000s km2, oyster δ15N varied with flushing time, salinity, and bioindicator size, thus constraining the upper extent for inferring nitrogen sources from bioindicator δ15N to the scale of gradients in these confounding physical and biological factors. Nevertheless, at 100s km2 isotopic ‘signatures’ can be used to infer nutrient sources and transport mechanisms and might have implications for fishery management/enforcement. Ultimately, δ15N and δ13C in bioindicators distributed to citizen–scientists may add substantial value to existing and ongoing programs, networks, monitoring and databases, and might have some use for imputing data gaps where intensive water quality monitoring is lacking.

Fertig, B.; Carruthers, T.J.B., and Dennison, W.C., 2014. Oyster d 15 N as a bioindicator of potential wastewater and poultry farming impacts and degraded water quality in a subestuary of Chesapeake Bay. Journal of Coastal Research, 30(5), 881–892. Coconut Creek (Florida), ISSN 0749-0208. Anthropogenic nitrogen contributes to water quality degradation, but it is difficult to distinguish sources once they are mixed in coastal ecosystems. Natural abundances of stable nitrogen isotopes (d 15 N) were measured in oyster (Crassostrea virginica) tissues (muscle, gills, and mantle) during summer 2006 to summer 2008 to identify nitrogen sources in Monie Bay (a subestuary of Chesapeake Bay) receiving freshwater inputs from three tributary creeks. The creeks (estimated flushing times: 3.5, 5.7, and 37.2 d) vary in size and potential nitrogen sources: septic systems and poultry operations (Monie Creek), crop fertilizer (Little Monie Creek), and wetlands, forest, or both (Little Creek). Grand mean oyster tissue d 15 N values (11.8 6 0.4% in muscle, 10.4 6 0.4% in gills, and 10.5 6 0.3% in mantle) indicated a mixture of human and animal sources. Potential nitrogen loss from denitrification (15.1–24.5%) likely did not substantially modify isotopic values, and d 15 N values were greater than would be expected from atmospheric sources, refuting these alternative explanations. Though dilute, spatial patterns supported the inference that human waste, poultry waste, or both entered Monie Bay from its watershed and the adjacent Wicomico River watershed (via mixing). Calculated nitrogen generation from poultry manure in the watershed (containing 2.5 3 10 3 people) was 2.9 3 10 4 to 1.0 3 10 6 kg of total nitrogen (TN) per year (equivalent to 6.8 3 10 3 –2.3 3 10 5 people), whereas throughout Delmarva Peninsula (containing 1.2 3 10 6 people) it was 3.9 3 10 6 to 1.3 3 10 8 kg TN y � 1 (equivalent to 9.0 3 10 5 –3.1 3 10 8 people). Conservatively estimated (based on 0.038 kg chicken � 1 y � 1 ), poultry in the Monie Bay watershed generated an amount of nitrogen equivalent to that generated by 263% of the human population. Throughout Delmarva Peninsula, poultry generated an amount of nitrogen equivalent to that generated by 76% of the human population. Estuaries commonly receive nutrients from both inside and outside their watersheds, and oyster d 15 N values elucidated this process locally.

Guanabara Bay, a natural tropical embayment in Southeast Brazil adjacent to Rio de Janeiro, is important to the Brazilian economy as it provides areas for shipping, industry, recreation, and tourism. But commercial and residential urban development in the watershed results in water quality degradation. In Guanabara Bay, strong water quality gradients as a function of inputs and tidal flushing were evident. In the watershed, the urban and industrial areas degraded stream water quality, and the best water quality was in the upstream, rural areas. Steps have been initiated to collect or contain litter (ecoboats and ecobarriers) and reduce sewage discharge (sewage treatment plants). In spite of this, urban development continues to degrade Guanabara Bay ecosystem health. Large-scale international events hosted by Rio de Janeiro have brought widespread attention to Guanabara Bay pollution issues. Management actions have been identified to improve Guanabara Bay ecosystem health, including establishing a strong governance structure, restoring water quality in the rivers, bay and beaches, restoring habitats in Guanabara Bay and its watershed, and mitigating for climate change impacts. An ecosystem health report card was generated using monitoring data with stakeholder engagement for both Guanabara Bay and its watershed. The scientifically rigorous and transparent report card process can be used to track Guanabara Bay restoration progress.

The term immersive education is currently used in two educational areas – language education, which involves students being totally immersed in a language and its culture; and virtual education, where teachers use computers and simulation games to immerse learners in a virtual, computer-generated environment that mimics a real-world environment and allows learners to interact with it. This paper uses examples from university teaching practices in marine studies and coastal zone management to make a case for a third definition for immersive education in tertiary settings – educating water managers by immersing and guiding them through real-world situations that involve understanding and managing water, biodiversity, catchments, and people, and the interactions between them. Immersive education of this third kind, and traditional tertiary education approaches such as lectures and demonstrations, are compared, and the advantages of immersive education are discussed. The examples from practice and discussion presented show immersive education as being experiential and real, process-driven, trans-disciplinary, collaborative, participatory, and active, encouraging critical thinking and a renegotiation of power in relationships between participants. Such immersive education develops passion and persuasive capacity in students, providing personal experiences that are memorable and potentially life-changing. Challenges to immersive education in tertiary education, including lack of finances, teacher burn-out, safety concerns, and inertia to maintain the status quo of traditional education, are highlighted, as are ways to overcome these.

Between them, the authors of this paper have over sixty years experience in water education working in primary and secondary schools, universities, field study centres, professional development programs; and with community, industry, and government groups, focusing on coastal zones and catchments. Over the last three years, they have undertaken a systematic process of personal and dialogic reflection and deliberation on this experience, particularly in the area of popular education. This paper presents three key water education lessons gained from this iterative process and provides examples to justify the sagacity of this choice. First and foremost, popular water educators really need to know their participants, what is important to them, why, and what they know already. Second, popular water educators should give their participants an opportunity to share with others what they have learned about water. Lastly, metaphorically speaking, popular educators need to focus their practice on the head, the heart, and the hands. Knowledge, emotion, and action are dialectically interrelated. Integrating them in popular water education is a challenging yet satisfying task that can have significant outcomes.

Long-term non-linear ecosystem-scale changes in water quality and biotic communities in coastal lagoons have been associated with intensification of anthropogenic pressures. In light of incipient changes in Johnson Bay (an embayment of Chincoteague Bay, Maryland-Virginia, USA), examination of nitrogen sources was conducted through synoptic water quality monitoring, stable nitrogen isotope signatures (δ15N) of in situ bioindicators, and denitrification estimates. These data were placed in the context of long-term and broader spatial analyses. Despite various watershed protection efforts, multiyear summer time studies (2004–2007) suggested that high levels of terrestrially derived nutrients still enter Johnson Bay. Total nitrogen concentrations in Johnson Bay were 132% the concentrations in the broader Chincoteague Bay during the late 1970s (mean 2004–2007 was 40.0 – 73.2 μM). Comparing total nitrogen concentrations in Johnson Bay to St. Martin River (consistently the most eutrophic region of these coastal bays), Johnson Bay has increased from 62.5% to 82.5% of the concentrations in St. Martin River during the late 1970s. Though specific sources of nitrogen inputs have not yet been definitively identified, the long-term increase in total nitrogen concentrations occurred despite increased and continued conservation and protection measures. We suggest that investigating nutrient sources can reveal potentially ineffective nutrient policies and that this knowledge can be applied towards other coastal lagoons.

To achieve desired environmental outcomes, environmental condition and trends need to be rigorously measured and communicated to resource managers, scientists, and a broader general audience. However, there is often a disconnect between responsive ecosystem monitoring and decision making for strategic long-term management. This project demonstrates how historical monitoring data can be synthesized and used for future planning and decision making, thereby closing the management feedback cycle. This study linked disparate datasets, collected for a variety of purposes and across multiple temporal and spatial scales, in order to assess and quantify current habitat conditions. The results inform integrated resource management decision-making at Assateague Island National Seashore (Maryland and Virginia, USA) by using ecological reference conditions to identify monitoring needs, areas of high vulnerability, and areas with potential for improved management. The approach also provides a framework that can be applied in the future to assess the effectiveness of these management decisions on the condition of island habitats, and is a replicable demonstration of incorporating diverse monitoring datasets into an adaptive management cycle.

Blooms of the toxic cyanobacterium, Lyngbya majuscula, were observed in Moreton Bay, Australia, beginning in the late 1990s. These dense blooms led to significant human and ecosystem health impacts. Research on the causes of the bloom focused on nutrient interactions (e.g., nitrogen, phosphorus, and iron) and light availability, in particular, light quality. Light quality investigations reported here were instigated because of the abundance of humic-stained water runoff from the catchment that periodically washed into the primary bloom locations. Light quality experiments were conducted on L. majuscula in aquaria using spectral filters to simulate different light regimes. The most pronounced effect on L. majuscula pigment content and productivity rates was the colored water treatment that simulated the humic-stained runoff. Colored water stimulated pigment content (phycoerythrin and chlorophyll a) and productivity (14C uptake) compared with clear water, turbid water, and a combination of turbid/colored water treatments. Previous research identified the importance of humic compounds in making iron bioavailable to L. majuscula. These results, combined with previous studies of L. majuscula and nutrient interactions, were used to construct a conceptual model of the primary causes of L. majuscula blooms in Moreton Bay, Australia. This model is presented in a diagrammatic format to synthesize research results as to the causes of these cyanobacteria blooms. The Lyngbya majuscula model focuses on having sufficient nutrients, particularly bioavailable iron, in a light climate of colored water. This model for toxic cyanobacteria blooms of L. majuscula in Australia also has relevance in other parts of the world.

Progress in achieving desired environmental outcomes needs to be rigorously measured and reported for effective environmental management. Two major challenges in achieving this are, firstly, how to synthesize monitoring data in a meaningful way at appropriate temporal and spatial scales and, secondly, how to present results in a framework that allows for effective communication to resource managers and scientists as well as a broader general audience. This paper presents a habitat framework, developed to assess the natural resource condition of the urban Rock Creek Park (Washington, DC, USA), providing insight on how to improve future assessments. Vegetation and stream GIS layers were used to classify three dominant habitat types, Forest, Wetland, and Artificial-terrestrial. Within Rock Creek Park, Forest habitats were assessed as being in good condition (67% threshold attainment of desired condition), Wetland habitats to be in fair condition (49% attainment), and Artificial-terrestrial habitats to be in degraded condition (26% attainment), resulting in an assessed fair/good condition (60% attainment; weighted by habitat area) for all natural resources in Rock Creek Park. This approach has potential to provide assessment of resource condition for diverse ecosystems and provides a basis for addressing management questions across multiple spatial scales.

Seagrasses, a functional group of marine flowering plants rooted in the world’s coastal oceans, support marine food webs and provide essential habitat for many coastal species, playing a critical role in the equilibrium of coastal ecosystems and human livelihoods. For the first time, the probability of extinction is determined for the world’s seagrass species under the Categories and Criteria of the International Union for the Conservation of Nature (IUCN) Red List of Threatened Species. Several studies have indicated that seagrass habitat is declining worldwide. Our focus is to determine the risk of extinction for individual seagrass species, a 4-year process involving seagrass experts internationally, compilation of data on species’ status, populations, and distribution, and review of the biology and ecology of each of the world’s seagrass species. Ten seagrass species are at elevated risk of extinction (14% of all seagrass species), with three species qualifying as Endangered. Seagrass species loss and degradation of seagrass biodiversity will have serious repercussions for marine biodiversity and the human populations that depend upon the resources and ecosystem services that seagrasses provide.

We analyzed trends in a 23-year period of water quality and biotic data for Chesapeake Bay. Indicators were used to detect trends of improving and worsening environmental health in 15 regions and 70 segments of the bay and to assess the estuarine ecosystem’s responses to reduced nutrient loading from point (i.e., sewage treatment facilities) and non-point (e.g., agricultural and urban land use) sources. Despite extensive restoration efforts, ecological health-related water quality (chlorophyll-a, dissolved oxygen, Secchi depth) and biotic (phytoplankton and benthic indices) metrics evaluated herein have generally shown little improvement (submerged aquatic vegetation was an exception), and water clarity and chlorophyll-a have considerably worsened since 1986. Nutrient and sediment inputs from higher-than-average annual flows after 1992 combined with those from highly developed Coastal Plain areas and compromised ecosystem resiliency are important factors responsible for worsening chlorophyll-a and Secchi depth trends in mesohaline and polyhaline zones from 1986 to 2008.

Chesapeake Bay supports a diverse assemblage of marine and freshwater species of submersed aquatic vegetation (SAV) whose broad distributions are generally constrained by salinity. An annual aerial SAV monitoring program and a bi-monthly to monthly water quality monitoring program have been conducted throughout Chesapeake Bay since 1984. We performed an analysis of SAV abundance and up to 22 environmental variables potentially influencing SAV growth and abundance (1984–2006). Historically, SAV abundance has changed dramatically in Chesapeake Bay, and since 1984, when SAV abundance was at historic low levels, SAV has exhibited complex changes including long-term (decadal) increases and decreases, as well as some large, single-year changes. Chesapeake Bay SAV was grouped into three broad-scale community-types based on salinity regime, each with their own distinct group of species, and detailed analyses were conducted on these three community-types as well as on seven distinct case-study areas spanning the three salinity regimes. Different trends in SAV abundance were evident in the different salinity regimes. SAV abundance has (a) continually increased in the low-salinity region; (b) increased initially in the medium-salinity region, followed by fluctuating abundances; and (c) increased initially in the high-salinity region, followed by a subsequent decline. In all areas, consistent negative correlations between measures of SAV abundance and nitrogen loads or concentrations suggest that meadows are responsive to changes in inputs of nitrogen. For smaller case-study areas, different trends in SAV abundance were also noted including correlations to water clarity in high-salinity case-study areas, but nitrogen was highly correlated in all areas. Current maximum SAV coverage for almost all areas remain below restoration targets, indicating that SAV abundance and associated ecosystem services are currently limited by continued poor water quality, and specifically high nutrient concentrations, within Chesapeake Bay. The nutrient reductions noted in some tributaries, which were highly correlated to increases in SAV abundance, suggest management activities have already contributed to SAV increases in some areas, but the strong negative correlation throughout the Chesapeake Bay between nitrogen and SAV abundance also suggests that further nutrient reductions will be necessary for SAV to attain or exceed restoration targets throughout the bay.

In an effort to better portray changing health conditions in Chesapeake Bay and support restoration efforts, a Bay Health Index (BHI) was developed to assess the ecological effects of nutrient and sediment loading on 15 regions of the estuary. Three water quality and three biological measures were combined to formulate the BHI. Water quality measures of chlorophyll-a, dissolved oxygen, and Secchi depth were averaged to create the Water Quality Index (WQI), and biological measures of the phytoplankton and benthic indices of biotic integrity (P-IBI and B-IBI, respectively) and the area of submerged aquatic vegetation (SAV) were averaged to create the Biotic Index (BI). The WQI and BI were subsequently averaged to give a BHI value representing ecological conditions over the growing season (i.e., March-October). Lower chlorophyll-a concentrations, higher dissolved oxygen concentrations, deeper Secchi depths, higher phytoplankton and benthic indices relative to ecological health-based thresholds, and more extensive SAV area relative to restoration goal areas, characterized the least-impaired regions. The WQI, P-IBI and BHI were significantly correlated with (1) regional river flow (r=-0.64, -0.57 and -0.49, respectively; p0.01), (2) nitrogen (N), phosphorus (P) and sediment loads (all positively correlated with flow), and (3) the sum of developed and agricultural land use (highest annual r(2)=0.86, 0.71 and 0.68, respectively) in most reporting regions, indicating that the BHI is strongly regulated by nutrient and sediment loads from these land uses. The BHI uses ecological health-based thresholds that give an accurate representation of the health conditions in Chesapeake Bay and was the basis for an annual, publicly released environmental report card that debuted in 2007.

In January 2003, the US Environmental Protection Agency sponsored a “roundtable discussion” to develop a consensus on the relationship between eutrophication and harmful algal blooms (HABs), specifically targeting those relationships for which management actions may be appropriate. Academic, federal, and state agency representatives were in attendance. The following seven statements were unanimously adopted by attendees based on review and analysis of current as well as pertinent previous data: 1) Degraded water quality from increased nutrient pollution promotes the development and persistence of many HABs and is one of the reasons for their expansion in the U.S. and the world; 2) The composition – not just the total quantity – of the nutrient pool impacts HABs; 3) High biomass blooms must have exogenous nutrients to be sustained; 4) Both chronic and episodic nutrient delivery promote HAB development; 5) Recently developed tools and techniques are already improving the detection of some HABs, and emerging technologies are rapidly advancing toward operational status for the prediction of HABs and their toxins; 6) Experimental studies are critical to further the understanding of the role of nutrients in HAB expression, and will strengthen prediction and mitigation of HABs; and 7) Management of nutrient inputs to the watershed can lead to significant reduction in HABs. Supporting evidence and pertinent examples for each consensus statement is provided herein.

An updated assessment of nutrient related impacts in US estuaries was completed in 2007. This assessment evaluates three components for each estuary: the influencing factors (e.g. land use, nutrient loads), the overall eutrophic condition (e.g. chlorophyll a, presence of nuisance/toxic algae and macroalgae, extent of dissolved oxygen problems, loss of submerged aquatic vegetation), and future outlook. Eutrophication is a widespread problem with 65% of assessed systems showing moderate to high level problems. The most impacted region was the mid-Atlantic. The majority of estuaries assessed, with the exception of North Atlantic systems (Cape Cod north to Maine), are highly influenced by human related activities that contribute to land-based nutrient loads. Conditions were predicted to worsen in 65% and to improve in 19% of the assessed estuaries in the future. Analysis of the extent of change from the early 1990s to the early 2000s, for those systems for which sufficient data were available, shows that conditions mostly remained the same (32 of 58 systems) though changes were observed in several smaller systems; 13 systems improved and 13 systems worsened. Chlorophyll a and HAB impacts have increased in the mid-Atlantic region, the only region with data adequate for comparison. These symptoms are more prevalent in systems with longer residence times, such as coastal lagoons. The successful restoration of seagrass in Tampa Bay is encouraging though future management to sustain the recovery will be difficult given expected population increases. This national assessment illustrates the need for coordinated and integrated action that balances management action, efficient monitoring to assess the effectiveness of the management, focused research, and a communication campaign aimed at engaging the broader community.

The human ecological footprint now extends to the entire globe, and human impacts are the dominant feature of many ecosystems, resulting in our current era being coined the ‘anthropocene’. This is particularly apparent in coastal ecosystems as human populations are increasing rapidly in coastal cities and the ecosystem services in these areas are rapidly being compromised. Science has historically progressed as a series of paradigm shifts and this paper reviews this history of paradigm shifts and makes the case that the next major paradigm shift will be directed at sustainability, resulting in a shift in scientific focus on solving rather than just studying our current environmental problems. Traditionally, science has been extremely effective at data acquisition and then successively less effective at translating this into information, knowledge and finally environmental problem solving. The currently required paradigm shift is to focus on environmental problem solving, filling gaps in knowledge, information and data only as required to solve a particular problem. A key element in turning this process around is better science communication between scientists, key stakeholders and the community. This will require more ‘science communicators’ who can use credibility, tenacity, creativity and virtue to effect solutions.

Coastal ecosystems including coral reefs, mangrove forests, seagrass meadows, and salt marshes are being lost at alarming rates, and increased scientific understanding of causes has failed to stem these losses. Coastal habitats receive contrasting research effort, with 60% of all of the published research carried out on coral reefs, compared to 11-14% of the records for each of salt marshes, mangrove forests, and seagrass meadows. In addition, these highly connected and interdependent coastal ecosystems receive widely contrasting media attention that is disproportional to their scientific attention. Seagrass ecosystems receive the least attention in the media (1.3% of the media reports) with greater attention on salt marshes (6.5%), considerably more attention on mangroves (20%), and a dominant focus on coral reefs, which are the subject of three in every four media reports on coastal ecosystems (72.5%). There are approximately tenfold lower reports on seagrass meadows in the media for every scientific paper published (ten), than the 130-150 media reports per scientific paper for mangroves and coral reefs. The lack of public awareness of losses of less charismatic ecosystems results in the continuation of detrimental practices and therefore contributes to continued declines of coastal ecosystems. More effective communication of scientific knowledge about these uncharismatic but ecologically important coastal habitats is required. Effective use of formal (e.g., school curricula, media) and informal (e.g., web) education avenues and an effective partnership between scientists and media communicators are essential to raise public awareness of issues, concerns, and solutions within coastal ecosystems. Only increased public understanding can ultimately inform and motivate effective management of these ecologically important coastal ecosystems. © 2008 Coastal and Estuarine Research Federation.

Seagrasses, marine flowering plants, are widely distributed along temperate and tropical coastlines of the world. Seagrasses have key ecological roles in coastal ecosystems and can form extensive meadows supporting high biodiversity. The global species diversity of seagrasses is low (< 60 species), but species can have ranges that extend for thousands of kilometers of coastline. Seagrass bioregions are defined here, based on species assemblages, species distributional ranges, and tropical and temperate influences. Six global bioregions are presented: four temperate and two tropical. The temperate bioregions include the Temperate North Atlantic, the Temperate North Pacific, the Mediterranean, and the Temperate Southern Oceans. The Temperate North Atlantic has low seagrass diversity, the major species being Zostera marina, typically occurring in estuaries and lagoons. The Temperate North Pacific has high seagrass diversity with Zostera spp. in estuaries and lagoons as well as Phyllospadix spp. in the surf zone. The Mediterranean region has clear water with vast meadows of moderate diversity of both temperate and tropical seagrasses, dominated by deep-growing Posidonia oceanica. The Temperate Southern Oceans bioregion includes the temperate southern coastlines of Australia, Africa and South America. Extensive meadows of low-to-high diversity temperate seagrasses are found in this bioregion, dominated by various species of Posidonia and Zostera. The tropical bioregions are the Tropical Atlantic and the Tropical Indo-Pacific, both supporting mega-herbivore grazers, including sea turtles and sirenia. The Tropical Atlantic bioregion has clear water with a high diversity of seagrasses on reefs and shallow banks, dominated by Thalassia testudinum. The vast Tropical Indo-Pacific has the highest seagrass diversity in the world, with as many as 14 species growing together on reef flats although seagrasses also occur in very deep waters. The global distribution of seagrass genera is remarkably consistent north and south of the equator; the northern and southern hemispheres share ten seagrass genera and only have one unique genus each. Some genera are much more speciose than others, with the genus Halophila having the most seagrass species. There are roughly the same number of temperate and tropical seagrass genera as well as species. The most widely distributed seagrass is Ruppia maritima, which occurs in tropical and temperate zones in a wide variety of habitats. Seagrass bioregions at the scale of ocean basins are identified based on species distributions which are supported by genetic patterns of diversity. Seagrass bioregions provide a useful framework for interpreting ecological, physiological and genetic results collected in specific locations or from particular species.

South–west Australia contains extensive seagrass meadows along 2,500 km of coastline from the shallow subtidal to 50+ m water depths, and in many of the 51 bar-built estuaries along the coast. There are geomorphological differences between the south and west coasts that result in different patterns of swell exposure influencing the processes that structure seagrass habitats. In this paper, ‘sheltered’, ‘exposed’ and ‘estuarine’ seagrass habitat types are defined for south–west Australia to synthesize processes influencing seagrass communities. Sheltered habitats in south–west Australia are characterized by high light, low to moderate water motion and sporadic disturbance from storms, making them ideal habitats for a diversity of seagrass assemblages. Exposed seagrass habitats are characterized by the presence of strong and consistent ocean swells (3–8 m), predominantly from the south or south–west and seagrasses exhibit a suite of adaptive traits to survive the effects of exposure to ocean swell and associated sand movement. These include morphological features such as heavy fiber reinforcement to strengthen the aboveground stems or leaves, deep vertical rhizomes and life history traits such as rapid growth and high seed set. Within estuarine habitats highly dynamic seagrass communities are the result of fluctuating annual cycles in temperature, light and salinity. Compared to global seagrass meadows, coastal south–west Australian seagrass habitats experience high light, low nutrients and high water movement. Despite these differences, similarities with other regions do exist and here we place the habitats of south–west Australia into a global context using comparative data. The wide array of morphology and life history traits displayed among seagrass species of south–west Australia are presented in a conceptual model including habitat type, physical stressors and seagrass responses. The combination of adaptations to the habitats and processes that define them make south–west Australia a region where there is an unusually high number of co-occurring seagrass species, the highest in the world for a temperate environment (19 species), and approaching the species diversity of many tropical environments. Linking aspects of seagrass habitat, physical aspects of the environment and seagrass life history provides a context for applying knowledge gained from seagrasses in south–west Australia to other coastal ecosystems throughout the world.

Communication among managers, the public, and scientists is the key to successful ecosystem management; however, the varied perspectives and interests of these groups can make such communication difficult. One way to achieve effective communication is to develop a common knowledge base by combining syntheses of key scientific results with information-rich visual elements. Within a management landscape, integrated environmental assessments provide a useful framework for evaluating resources and directing management efforts. The integrated assessment process involves (1) initial investigation, (2) development of a conceptual framework, (3) data navigation, (4) environmental report cards, and (5) science communication. Each step requires the synthesis and visualization of information on the status and trends connected with multiple natural resources. We provide a case study, using examples from selected National Park Service sites in the mid-Atlantic region of the United States. Visual elements (conceptual d...

Human sewage and septic waste are significant sources of nutrient loading to many aquatic ecosystems. Ecologically relevant nitrogen sources can be traced by analyzing nitrogen stable isotope ratios (δ15N signatures) in aquatic plants. Elevated δ15N signatures can suggest increased uptake of nitrogen derived from human and/or animal waste. In the current study, Vallisneria americana, a freshwater angiosperm, was collected from several locations in Upper Saranac Lake, NY, USA. Samples were also collected from Lake George, NY and the Sassafras River, MD, USA. Plant material was analyzed for δ15N and % N; some samples were also analyzed for δ13C, % C, and % P. Results suggest that there is variation in septic inputs to Upper Saranac Lake, with some areas of the lake receiving more input than others. Results also show that increased watershed population density is correlated with elevated δ15N signatures of Vallisneria americana. Taken together, these results suggest that nitrogen stable isotope analysis of aquatic plant tissue is an effective method for assessing and monitoring septic inputs to freshwater ecosystems.

The mid-Atlantic coastal bays are shallow coastal lagoons, separated from the Atlantic Ocean by barrier sand islands with oceanic exchanges restricted to narrow inlets. The relatively poor flushing of these lagoon systems makes them susceptible to eutrophication resulting from anthropogenic nutrient loadings. An intensive water quality and seagrass monitoring program was initiated to track ecological changes in the Maryland and Virginia coastal bays. The purpose of this study was to analyze existing monitoring data to determine status and trends in eutrophication and to determine any associations between water quality and living resources. Analysis of monitoring program data revealed several trends: (1) decadal decreases in nutrient and chlorophyll concentrations, followed by recently increasing trends; (2) decadal increases in seagrass coverage, followed by a recent period of no change; (3) blooms of macroalgae and brown tide microalgae; and (4) exceedance of water quality thresholds: chlorophyll a (15 lg/L), total nitrogen (0.65 mg/L or 46 lmol/L), total phosphorus (0.037 mg/L or 1.2 lmol/L), and dissolved oxygen (5 mg/L) in many areas within the Maryland coastal bays. The water quality thresholds were based on habitat requirements for living resources (seagrass and fish) and used to calculate a water quality index, which was used to compare the bay segments. Strong gradients in water quality were correlated to changes in seagrass coverage between segments. These factors indicate that these coastal bays are in a state of transition, with a suite of metrics indicating degrading conditions. Continued monitoring and intensified management will be required to avert exacerbation of the observed eutrophication trends. Coastal lagoons worldwide are experiencing similar degrading trends due to increasing human pressures, and assessing status and trends relative to biologically relevant thresholds can assist in determining monitoring and management priorities and goals.

The Barnegat Bay-Little Egg Harbor Estuary is classified here as a highly eutrophic estuary based on application of the National Oceanic and Atmospheric Administration's National Estuarine Eutrophication Assessment model. Because it is shallow, poorly flushed, and bordered by highly developed watershed areas, the estuary is particularly susceptible to the effects of nutrient loading. Most of this load (;50%) is from surface water inflow, but substantial fractions also originate from atmospheric deposition (;39%), and direct groundwater discharges (;11%). No point source inputs of nutrients exist in the Barnegat Bay watershed. Since 1980, all treated wastewater from the Ocean County Utilities Authority's regional wastewater treatment system has been discharged 1.6 km offshore in the Atlantic Ocean. Eutrophy causes problems in this system, including excessive micro- and macroalgal growth, harmful algal blooms, altered benthic invertebrate communities, impacted harvestable fisheries, and loss of essential habitat (i.e., seagrass and shellfish beds). Similar problems are evident in other shallow lagoonal estuaries of the Mid-Atlantic and South Atlantic regions. To effectively address nutrient enrichment problems in the Barnegat Bay- Little Egg Harbor Estuary, it is important to determine the nutrient loading levels that produce observable impacts in the system. It is also vital to continually monitor and assess priority indicators of water quality change and estuarine health. In addition, the application of a new generation of innovative models using web-based tools (e.g., NLOAD) will enable researchers and decision-makers to more successfully manage nutrient loads from the watershed. Finally, the implementation of storm water retrofit projects should have beneficial effects on the system.

Although many studies measure the abundance of benthic microalgae (BMA), at the meters squared scale, comparing these studies is difficult due to the variety of sampling, extraction, and analysis techniques. This difficulty is exacerbated by the fact that BMA abundance has high spatial and temporal variability, at all spatial scales. A suitable standard sampling regimen would reduce variation in estimates due to different sample collection and processing greatly facilitating comparisons between studies. This study examined the effect of varying the volume of extraction solvent, sampling core diameter, and sample replication on BMA biomass estimates. Key findings, applicable to all spatial scales, to accurately determine biomass were the use of a minimum sediment to extraction solvent ratio of 1:2 and use of a sampling core diameter of 19 mm. Across a wide range of sediment types, at the meters squared scale and using spectrophotometric techniques, a minimum replication number of 8 was found to be appropriate. We report the significant effect coring depth and units of expression have on BMA biomass estimates across a range of sediment types, highlighting the potential pitfalls when comparing studies.

Subtropical estuaries have received comparatively little attention in the study of nutrient loading and subsequent nutrient processing relative to temperate estuaries. Australian estuaries are particularly susceptible to increased nutrient loading and eutrophication, as 75% of the population resides within 200 km of the coastline. We assessed the factors potentially limiting both biomass and production in one Australian estuary, Moreton Bay, through stoichiometric comparisons of nitrogen (N), phosphorus (P), silicon (Si), and carbon (C) concentrations, particulate compositions, and rates of uptake. Samples were collected over 3 seasons in 1997–1998 at stations located throughout the bay system, including one riverine endmember site. Concentrations of all dissolved nutrients, as well as particulate nutrients and chlorophyll, declined 10-fold to 100-fold from the impacted western embayments to the eastern, more oceanic-influenced regions of the bay during all seasons. For all seasons and all regions, both the dissolved nutrients and particulate biomass yielded N:P ratios

As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives. For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred to as "compliant zones." High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water. Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it directly to management objectives, may have widespread applicability for ecosystem assessment.

The east coast of the Yucatan Peninsula, Mexico, consists of highly permeable limestone, such that surface flow and rivers are absent in this region. Extensive underground cave systems connect sink holes (cenotes) to submarine springs (ojos de aqua), which vent into the seagrass meadows of the adjacent oligotrophic coastal lagoons. This study investigated the potential for these submarine springs to influence nutrient processes within seagrass meadows, by assessing nutrient status of Thalassia testudinum meadows in two contrasting coastal lagoons along the north eastern Yucatan peninsula. Tissue nutrient concentrations as well as δ15N values of T. testudinum were surveyed in the Puerto Morelos Reef Lagoon and the Nichupte Lagoon System, Cancun Hotel Zone, during an extended dry period and again following heavy rainfall. After a period of heavy rainfall, T. testudinum near submarine springs in Puerto Morelos Reef Lagoon had exceptionally high leaf tissue phosphorus concentrations of 0.38±0.06%. These submarine springs may have been a direct source of phosphorus and/or a source of iron to this very iron limited carbonate system. Thalassia testudinum nutrient concentrations suggest that nitrogen loading to the Nichupte Lagoon System is regionally high and has increased over the past decade (mean leaf N: 2.04% N in 1991 to 2.71% N in 2002). Nitrogen content in leaf tissue of T. testudinum was significantly higher within the poorly flushed Nichupte Lagoon System (2.93±0.12% N) than in the well-flushed Puerto Morelos Reef Lagoon (1.80±0.07% N). Stable isotope ratios of nitrogen suggest that this high and increasing nitrogen loading within the Nichupte Lagoon System is a result of wastewater nitrogen (δ15N 9.06±0.07 in northern Nichupte Lagoon System vs. 1.69±0.07 in Puerto Morelos Reef Lagoon).

Large blooms of the marine cyanobacterium Lyngbya majuscula in Moreton Bay, Australia (27 degrees 05'S, 153 degrees 08'E) have been re-occurring for several years. A bloom was studied in Deception Bay (Northern Moreton Bay) in detail over the period January-March 2000. In situ data loggers and field sampling characterised various environmental parameters before and during the L. majuscula bloom. Various ecophysiological experiments were conducted on L. majuscula collected in the field and transported to the laboratory, including short-term (2h) C-14 incorporation rates and long-term (7 days) pulse amplitude modulated (PAM) fluorometry assessments of photosynthetic capacity. The effects of L. majuscula on various seagrasses in the bloom region were also assessed with repeated biomass sampling. The bloom commenced in January 2000 following usual December rainfall events, water temperatures in excess of 24 degrees C and high light conditions. This bloom expanded rapidly from 0 to a maximum extent of 8 km(2) over 55 days with an average biomass of 210 g(dw)(-1) m(-2) in late February, followed by a rapid decline in early April. Seagrass biomass, especially Syringodium isoetifolium, was found to decline in areas of dense L. majuscula accumulation. Dissolved and total nutrient concentrations did not differ significantly (P > 0.05) preceding or during the bloom. However, water samples from creeks discharging into the study region indicated elevated concentrations of total iron (2.7-80.6 mu M) and dissolved organic carbon (2.5-24.7 mg L-1), associated with low pH values (3.8-6.7). C-14 incorporation rates by L. majuscula were significantly (P 0.05). These results suggest that the L. majuscula bloom may have been stimulated by bioavailable iron, perhaps complexed by dissolved organic carbon. The rapid bloom expansion observed may then have been sustained by additional inputs of nutrients (N and P) and iron through sediment efflux, stimulated by redox changes due to decomposing L. majuscula mats. (c) 2004 Elsevier B.V. All rights reserved.

Tissue samples of liver and blubber were salvaged from fifty-three dugong (Dugong dugon) carcasses stranded along the Queensland coast between 1996 and 2000. Liver tissue was analysed for a range of heavy metals and blubber samples were analysed for organochlorine compounds. Metal concentrations were similar in male and female animals and were generally highest in mature animals. Liver concentrations of arsenic, chromium, iron, lead, manganese, mercury and nickel in a number of individual animals were elevated in comparison to concentrations previously reported in Australian dugong. Dieldrin, DDT (and its breakdown products) and/or heptachlor epoxide were detected in 59% of dugong blubber samples. In general, concentrations of organochlorines were similar to those reported in dugong 20 years earlier, and were low in comparison to concentrations recorded from marine mammal tissue collected elsewhere in the world. With the exception of lead, the extent of carcass decomposition, the presence of disease or evidence of animal starvation prior to death did not significantly affect dugong tissue concentrations of metals or organochlorines. The results of the study suggest that bioaccumulation of metals and organochlorine compounds (other than dioxins) does not represent a significant risk to Great Barrier Reef dugong populations, particularly in the context of other pressures associated with coastal development and other anthropogenic activities.

The abundance and productivity of benthic microalgae in coral reef sediments are poorly known compared with other, more conspicuous (e.g. coral zooxanthellae, macroalgae) primary producers of coral reef habitats. A survey of the distribution, biomass, and productivity of benthic microalgae on a platform reef flat and in a cross-shelf transect in the southern Great Barrier Reef indicated that benthic microalgae are ubiquitous, abundant (up to 995.0 mg chlorophyll (chl) a m−2), and productive (up to 110 mg O2 m−2 h−1) components of the reef ecosystem. Concentrations of benthic microalgae, expressed as chlorophyll a per surface area, were approximately 100-fold greater than the integrated water column concentrations of microalgae throughout the region. Benthic microalgal biomass was greater on the shallow water platform reef than in the deeper waters of the cross-shelf transect. In both areas the benthic microalgal communities had a similar composition, dominated by pennate diatoms, dinoflagellates, and cyanobacteria. Benthic microalgal populations were potentially nutrient-limited, based on responses to nitrogen and phosphorus enrichments in short-term (7-day) microcosm experiments. Benthic microalgal productivity, measured by O2 evolution, indicated productive communities responsive to light and nutrient availability. The benthic microalgal concentrations observed (92–995 mg chl a m−2) were high relative to other reports, particularly compared with temperate regions. This abundance of productive plants in both reef and shelf sediments in the southern Great Barrier Reef suggests that benthic microalgae are key components of coral reef ecosystems.

While the remote-sensing community attempts to find measures of reef "health" able to be detected and mapped using satellite image data, internationally recognized field assessments are already in place to document benthic cover, among other parameters, as an indicator of coral reef status. Reef Check is one such program, designed in 1996 as a globally applicable, rapid, field-survey protocol for coral reef health monitoring by volunteer divers (Hodgson 1999). The protocol is designed to provide a measure of reef health based on indicator species or families for fish, invertebrates, and substrates. Data collected contribute to a global-scale database on coral reef status for use in management plans (Hodgson 1999). Today, over 5,000 trained volunteer divers are led by more than 160 scientists in surveys of 1,500 reefs in 60 countries. During the survey, they record substrate type directly under a measuring tape at 0.5-m intervals on 4· 20 m consecutive transects between 3- and 10-m depth (Hodgson and Liebler 2002). The Reef Check substrate classification scheme provides information on benthic habitats such as hard coral, dead coral, soft coral, fleshy algae, rock, rubble, sand, silt sponge, and other. This is the same type of information that remote-sensing scientists are often asked to extract from image data by coral reef scientists and managers. Reef Check programs are an important source of reef-health information, yet the data collected will always be point based, and extrapolation to non-surveyed areas will be required. Remotely sensed data can provide a spatially extensive survey if methods are developed to successfully link ground-survey observations, like those provided by Reef Check, with satellite or airborne images. Thus, the objectives of our project were (1) to determine whether Reef Check substrate classes could be successfully mapped with Landsat ETM+ (Enhanced Thematic Mapper Plus) image data, and (2) to determine whether Reef Check data that are currently collected globally may be used for training and assessing the accuracy of remotely sensed image classifications. We address our objectives using a case study in the Capricorn Bunker Group, southern Great Barrier Reef, Australia.

A combination of physical and chemical measurements and biological indicators identified nutrient impacts throughout an Australian subtropical river estuary. This was a balance of sewage inputs in the lower river and agricultural inputs in the mid-upper river, the combined influence being greater in the wet season due to greater agricultural surface runoff. Field sampling in the region was conducted at 6 sites within the river, over 5 surveys to encapsulate both wet and dry seasonal effects. Parameters assessed were tissue nitrogen (N) contents and σ15N signatures of mangroves and macroalgae, phytoplankton nutrient addition bioassays, and standard physical and chemical variables. Strong spatial (within river) and temporal (seasonal) variability was observed in all parameters. Poorest water quality was detected in the middle (agricultural) region of the river in the wet season attributable to large diffuse inputs in this region. Water quality towards the river mouth remained constant irrespective of season due to strong oceanic flushing. Mangrove and macroalgal tissue σ15N and %N proved a successful combination for discerning sewage and agricultural inputs. Elevated σ15N and %N represented sewage inputs, whereas low σ15N and elevated %N was indicative of agricultural inputs. Phytoplankton bioassays found the system to be primarily responsive to nutrient additions in the warmer wet season, with negligible responses observed in the cooler dry season. These results indicate that the Tweed River is sensitive to the different anthropogenic activities in its catchment and that each activity has a unique influence on receiving water quality.