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The dynamics of shallow-water coastal environments are controlled by external drivers—sea level rise, storms, and sediment and nutrient supplies—and by internal feedbacks. Interactions of biotic processes (vegetation growth, trophic dynamics) and abiotic drivers can lead to nonlinear responses to changing conditions and to the emergence of thresholds, hysteresis, and alternative stable states. We develop a conceptual framework for studying interactions between the dynamics of marshes and habitats in shallow coastal bays with unconsolidated sediments (seagrass, oyster reefs). Using examples primarily from the Virginia Coast Reserve Long Term Ecological Research site, we show that in the subtidal part of the landscape, two alternative stable states can exist—one dominated by seagrass up to a certain depth that represents a tipping point to the second, unvegetated stable state. The depth limit of the seagrass stable state is influenced by (1) the positive feedback of vegetation on reducing sediment suspension and improving the light environment for growth, (2) climate (e.g., temperature), and (3) water quality. Two stable states are also present in intertidal areas, with salt marshes lying above mean sea level and tidal flats below mean sea level. State transitions are driven by sediment availability, sea level rise, the relative strength of wind waves with respect to tidal currents, and the biotic feedback of vegetation on sediment stabilization and accretion. State-change dynamics in one system may propagate to adjacent systems, and this coupling may influence the landscape-scale response to environmental change. Seagrass meadows and oyster reefs affect adjacent marshes both positively (wave attenuation) and negatively (reduced sediment supply), and marsh-edge erosion could negatively influence the light environment for seagrass growth. Forecasting the resilience of coastal ecosystems and the landscape-scale response to environmental change in the next century requires an understanding of nonlinear dynamics, including the possibility of multiple stable states, the coupled evolution of adjacent systems, and potential early warning signs of thresholds of change.

The dynamics of shallow-water coastal environments are controlled by external drivers—sea level rise, storms, and sediment and nutrient supplies—and by internal feedbacks. Interactions of biotic processes (vegetation growth, trophic dynamics) and abiotic drivers can lead to nonlinear responses to changing conditions and to the emergence of thresholds, hysteresis, and alternative stable states. We develop a conceptual framework for studying interactions between the dynamics of marshes and habitats in shallow coastal bays with unconsolidated sediments (seagrass, oyster reefs). Using examples primarily from the Virginia Coast Reserve Long Term Ecological Research site, we show that in the subtidal part of the landscape, two alternative stable states can exist—one dominated by seagrass up to a certain depth that represents a tipping point to the second, unvegetated stable state. The depth limit of the seagrass stable state is influenced by (1) the positive feedback of vegetation on reducing sediment suspension and improving the light environment for growth, (2) climate (e.g., temperature), and (3) water quality. Two stable states are also present in intertidal areas, with salt marshes lying above mean sea level and tidal flats below mean sea level. State transitions are driven by sediment availability, sea level rise, the relative strength of wind waves with respect to tidal currents, and the biotic feedback of vegetation on sediment stabilization and accretion. State-change dynamics in one system may propagate to adjacent systems, and this coupling may influence the landscape-scale response to environmental change. Seagrass meadows and oyster reefs affect adjacent marshes both positively (wave attenuation) and negatively (reduced sediment supply), and marsh-edge erosion could negatively influence the light environment for seagrass growth. Forecasting the resilience of coastal ecosystems and the landscape-scale response to environmental change in the next century requires an understanding of nonlinear dynamics, including the possibility of multiple stable states, the coupled evolution of adjacent systems, and potential early warning signs of thresholds of change.

Section 388 of the Energy Policy Act of 2005 (EPAct) gave the US Department of the Interior(DOI) jurisdiction over activities that “produce or support production, transportation, or transmission of energy from sources other than oil or gas” (43 U.S.C. § 1337(p)(C) & (D)). The Secretary of the Interior delegated this authority to the Minerals Management Service (MMS). On April 29, 2009, MMS published a final rule entitled Renewable Energy and Alternative Uses of Existing Facilities on the Outer Continental Shelf (“final rule” or “regulatory framework”; 30 C.F.R. Part 285). In the final rule, MMS established procedures for authorizing and managing renewable energy projects on the Outer Continental Shelf (OCS). This article briefly explains the contours of MMS jurisdiction, the procedures for obtaining authorizations for renewable energy activities on the OCS, and the status of current OCS renewable energy leasing activities. MMS recognizes that it must balance a multitude of existing and evolving OCS interests, so in launching the offshore renewable energy program, the bureau is committed to securing the involvement of all entities that hold these interests.

Section 388 of the Energy Policy Act of 2005 (EPAct) gave the US Department of the Interior(DOI) jurisdiction over activities that “produce or support production, transportation, or transmission of energy from sources other than oil or gas” (43 U.S.C. § 1337(p)(C) & (D)). The Secretary of the Interior delegated this authority to the Minerals Management Service (MMS). On April 29, 2009, MMS published a final rule entitled Renewable Energy and Alternative Uses of Existing Facilities on the Outer Continental Shelf (“final rule” or “regulatory framework”; 30 C.F.R. Part 285). In the final rule, MMS established procedures for authorizing and managing renewable energy projects on the Outer Continental Shelf (OCS). This article briefly explains the contours of MMS jurisdiction, the procedures for obtaining authorizations for renewable energy activities on the OCS, and the status of current OCS renewable energy leasing activities. MMS recognizes that it must balance a multitude of existing and evolving OCS interests, so in launching the offshore renewable energy program, the bureau is committed to securing the involvement of all entities that hold these interests.

Some of the most rapid melting of ice sheets and ice shelves around Antarctica has occurred where the Antarctic Circumpolar Current (ACC) is in close proximity to the Antarctic continent. Several mechanisms have been hypothesized by which warming trends in the ACC could lead to warmer temperatures on the Antarctic continental shelves and corresponding thinning of ice shelves. One possibility is that a southward shift in the dominant westerly winds has led to a southward shift in the ACC, bringing comparatively warm (1°C–3°C) Circumpolar Deep Water (CDW) in closer contact with Antarctica; however, satellite altimetry does not provide strong evidence for this option. A second possibility is that stronger winds have led to stronger poleward eddy heat transport, bringing more CDW southward. In addition, submarine canyons and winds are hypothesized to be critical for transporting CDW across the continental shelves. The specific mechanisms and the relative roles of westerly winds, easterly winds, and wind-stress curl remain areas of active research.

Some of the most rapid melting of ice sheets and ice shelves around Antarctica has occurred where the Antarctic Circumpolar Current (ACC) is in close proximity to the Antarctic continent. Several mechanisms have been hypothesized by which warming trends in the ACC could lead to warmer temperatures on the Antarctic continental shelves and corresponding thinning of ice shelves. One possibility is that a southward shift in the dominant westerly winds has led to a southward shift in the ACC, bringing comparatively warm (1°C–3°C) Circumpolar Deep Water (CDW) in closer contact with Antarctica; however, satellite altimetry does not provide strong evidence for this option. A second possibility is that stronger winds have led to stronger poleward eddy heat transport, bringing more CDW southward. In addition, submarine canyons and winds are hypothesized to be critical for transporting CDW across the continental shelves. The specific mechanisms and the relative roles of westerly winds, easterly winds, and wind-stress curl remain areas of active research.

The National Oceanographic Partnership Program (NOPP) consecutively sponsored the Ocean-Systems for Chemical, Optical, and Physical Experiments (O-SCOPE) and Multi-disciplinary Ocean Sensors for Environmental Analyses and Networks (MOSEAN) projects from 1998 through 2008. The O-SCOPE and MOSEAN projects focused on developing and testing new sensors and systems for autonomous, concurrent measurements of biological, chemical, optical, and physical variables from a diverse suite of stationary and mobile ocean platforms. Design considerations encompassed extended open-ocean and coastal deployments, instrument durability, biofouling mitigation, data accuracy and precision, near-real-time data telemetry, and economy—the latter being critical for widespread sensor and system utilization. The complementary O-SCOPE and MOSEAN projects increased ocean sensing and data telemetry capabilities for addressing many societally relevant problems such as global climate change, ocean carbon cycling and sequestration, acidification, eutrophication, anoxia, and ecosystem dynamics, including harmful algal blooms. NOPP support enabled O-SCOPE and MOSEAN to accelerate progress in achieving multiscale, multidisciplinary, sustained observations of the ocean environment. Importantly, both programs produced value-added scientific results, which demonstrated the utility of these new technologies. The NOPP framework fostered strong collaborations among academic, commercial, and government entities, and facilitated technology transfers to the general research community and to long-term observational and observatory programs.