Scientific understanding of the patterns, processes, and potential impacts of ocean acidification has grown substantially over the past decade with the realization that elevated greenhouse gases not only force changes in climatic conditions but also cause changes in ocean carbonate chemistry as the seas absorb increasing amounts of carbon dioxide (CO2) (Howes et al., 2015). Evidence of a collateral effect of climate change – deoxygenation – has similarly emerged (Levin and Breitburg, 2015). Because deoxygenation can result in hypoxia (oxygen depletion detrimental to many organisms), the combined processes are often referred to as ocean acidification and hypoxia, or simply OAH. Together they threaten contemporary coastal ecosystems. In eastern boundary current regions (regions along the eastern margins of the world’s oceans), upwelling brings to the surface deep waters that are naturally enriched in carbon dioxide, and lower in dissolved oxygen. These regions show early impacts of climate change that provide a window into the broader effects of intensifying OAH and their consequences for ocean management. Here we describe ocean change and opportunities for near-term management interventions in the California Current large marine ecosystem. In doing so, we argue that diverse approaches already exist that, in combination, can help sustain ecosystem functions vital to society.
Along the West Coast of North America repeated occurrences of low-oxygen (hypoxic) and high CO2 conditions have caused acute effects and mortality among demersal fish and invertebrates (Chan et al., 2008) and have resulted in large-scale larval mortalities in shellfish hatcheries (Barton et al., 2015). These events have alerted West Coast policy makers and managers to the potential for OAH to affect the condition, productivity, and economic vitality of ocean ecosystems significantly. In 2011, Washington State Governor Christine Gregoire convened a blue ribbon panel to identify actions to reduce the harmful effects of acidification on the State’s multi-million dollar shellfish industry and other coastal resources (Adelsman and Whitely Binder, 2012). Subsequent to that process, a coast-wide scientific panel was convened in 2013 by the governments of the states of California, Oregon, and Washington, and the Canadian province of British Columbia to synthesize relevant information about OAH processes and impacts and to identify solutions (Chan et al., 2016). Both panels were challenged to translate an incomplete, but rapidly evolving, knowledge base about OAH into practical near-term guidance for action. Through these and other efforts, policy makers and resource managers seek to better understand the regional implications of OAH, build a scientific infrastructure for delivering policy- and management-relevant information, and identify and initiate practical interventions that could improve management outcomes as OAH progresses.
Legislatures in two west-coast states have since taken action on ocean acidification and hypoxia. The Washington State Legislature established the Marine Resources Advisory Council in 2013 to work with governmental and non-governmental entities and with scientists to deliver recommendations to the governor and state legislature regarding OA. At the same time, the Washington State Legislature established and funded the Washington Ocean Acidification Center to develop and coordinate scientific research on ocean acidification, including environmental monitoring, numerical modeling, and biological experimentation. More recently, the California State Legislature passed legislation establishing an ocean acidification and hypoxia task force and authorizing funds to support activities of the Ocean Acidification and Hypoxia Program, including those that focus on sustaining and restoring functional nearshore habitats and eelgrass beds that provide habitat for commercial species and improve water quality. Following these actions by individual states, the governors of California, Oregon, and Washington and the premier of British Columbia collectively endorsed the formation of the International Alliance to Combat Ocean Acidification to advance local and regional strategies to address ocean acidification and hypoxia. This initiative is the first such collective action of its kind. In combination, the actions described above strongly signal the concerns of state governments about the impending effects of OAH and their willingness to take pragmatic actions to address the problem.
Ocean and coastal environments from southern British Columbia, Canada, to Baja California, Mexico, are part of the California Current large marine ecosystem (CCLME). Surface waters of the CCLME already show CO2 values that can be three times higher than the current global mean (~1200 µatm versus ~400 µatm; Harris et al., 2013) due to the upwelling of CO2-rich waters. Over recent decades, conditions corrosive to calcified marine organisms have increased in frequency, severity, duration, and spatial extent (Feely et al., 2008; Harris et al., 2013) Moreover, changes observed in the ocean today do not reflect the full amount of anthropogenic CO2 already in the atmosphere, because ocean circulation imposes decadal-scale time lags between CO2 uptake at the ocean surface and subsequent upwelling of deeper CO2-enriched waters (Feely et al., 2008) Even if today’s atmospheric CO2 levels were stabilized, acidification would further intensify over the coming decades, reflecting increases in atmospheric CO2 concentrations that have occurred over the past decades.
At the same time, climate change is exposing the CCLME to increased risk of larger, more frequent and more severe hypoxia events as changes in oxygen solubility, stratification and circulation diminish the resupply of oxygen to the ocean interior (Keeling et al., 2010). Due to deoxygenation of source waters and intensification of upwelling (Garcia-Reyes and Largier, 2010; Sydeman et al., 2014), low-oxygen waters are spreading onto the continental shelf in some regions of the CCLME, bringing them in contact with valuable commercial fisheries (Keller et al., 2015). Moreover, deoxygenation and acidification are linked through biological processes: as organic matter is decomposed, microbial respiration consumes oxygen and produces CO2, adding to the burden of CO2 in seawater that lowers pH and saturation states of carbonate minerals. This biological link explains the co-occurrence of hypoxia and low pH in upwelled waters and may result in local intensification in highly productive zones of the CCLME, increasing the risk of exposure to both hypoxia and acidification (Keeling et al., 2010).
Patterns of ocean acidification and hypoxia in the CCLME are spatially and temporally complex, because they reflect geographically and temporally variable upwelling currents that bring naturally CO2-rich and dissolved oxygen-poor waters to the coast. This dynamic physical setting in turn interacts with localized processes such as primary production and respiration, land-based inputs of nutrients and acidifying chemical constituents, and freshwater inflows to intensify the coastal expression of OAH (Figure 1; Hales et al., 2016). These time-variant expressions of OAH in the CCLME will shift as climate-induced changes progress and intensify, contributing to the dynamism of the system and creating some amount of irreducible uncertainty (Busch et al., 2015).
Based on what we already know about potential biological and ecological effects, OAH in the CCMLE has the potential to alter critical processes, such as nutrient cycling and food-web interactions, that determine the dynamics, diversity, and biological productivity of coastal and marine ecosystems (Gaylord et al., 2015). However, relatively few projections yet exist concerning OAH effects on the ecology of the CCLME or its societal benefits, which include valuable commercial and recreational fisheries, recreational industries, and coastal wetlands and shoreline habitats. Instead, evidence from laboratory and field studies and projections based on numerical modeling serve as key sources of information for anticipating and bounding expectations about the potential range, magnitude, and predictability of the ecosystem changes ahead (Blackford, 2010; Kroeker et al., 2013).
Controlled laboratory experiments have provided a critical warning that changing ocean chemistry could significantly affect populations of many marine species through effects on physiology and behavior that impair growth, reproduction, and survivorship (e.g., Kroeker et al., 2013; Somero et al., 2016). Diverse taxa and functional groups are vulnerable to current and near-future levels of acidification and hypoxia, with stronger impacts likely where the two stresses co-occur with each other and with a third stressor, increased temperature (Vaquer-Synyer and Duarte, 2008; Somero et al., 2016). Negatively affected species are likely to include those that play critical roles in pelagic food webs (e.g., calcified plankton), in biogenic construction of benthic habitats (e.g., corals, oysters), and in direct support of valuable fisheries (e.g., crabs, demersal and pelagic fishes).
Empirical observations of spatial gradients and temporal patterns suggest that intensifying OAH is associated with declining abundance of calcified taxa, altered ecological communities and food webs, and diminished fishery catches. Detailed studies of the pteropod Limacina helicina along the US west coast have shown that current levels of anthropogenic CO2 are already compromising calcification by this important food source for pink salmon, mackerel, and herring (Bednaršek et al., 2014). Diminished fishery catches have been associated with seasonal spatial gradients in dissolved oxygen along the Oregon shelf (Keller et al., 2010, 2015). Moreover, poor survival of oyster larvae in an Oregon hatchery has been associated with corrosive waters (Barton et al., 2015), and reorganized coastal food webs and increased abundances of pelagic fishes have been associated with historical shifts to lower oxygen conditions in the oceanographically analogous Humboldt Current (Gutiérrez et al., 2009; Salvatteci et al., 2014). Evidence from other marine ecosystems shows that calcifying taxa become less abundant as pH declines in proximity to natural CO2 vents (Hall-Spencer et al., 2008; Fabricius et al., 2014), and that hypoxic zones can cause habitat compression, altered predator-prey interactions, and wholesale shifts in benthic community structure (Breitburg et al., 2009; Levin and Sibuet, 2012).
Based on results from numerical models and incubation experiments, indirect ecological effects – mediated, for example, by changes in biogeochemical cycles and species interactions – are likely to play a critical role in regulating the impacts of OAH on biological communities in the CCLME (Busch et al., 2013, 2014). Acidification has been shown to alter predator-prey relationships of coastal molluscs (Kroeker et al., 2014) and may cause modifications in primary production that propagate through food webs (Nagelkerken and Connell, 2015). Food web and multi-species fishery models developed for the CCLME show that the distribution of impacts among species and functional groups will determine whether ecological interactions among species amplify or dampen acidification impacts on fishery yields (Busch et al., 2013). Models also suggest that interactions among acidification, hypoxia, other climate-related changes, and/or fishing will cause additive and synergistic effects (Kaplan et al., 2010; Ainsworth et al., 2011). Some of these indirect effects could be large and persistent (Benedetti-Cecchi, 2003; Ainsworth et al., 2011).
From a policy and management perspective, ongoing OAH in the CCLME can be characterized as a phenomenon of high impact and high uncertainty, posing challenges similar to other dimensions of climate change that are expected to have multiple and wide-ranging effects on ecosystem structure and process, leading to transitions that are difficult to predict with confidence. Coastal and marine ecosystem managers can, nevertheless, take steps now to support the long-term productivity and benefits of the CCLME under uncertain and rapidly changing conditions by sustaining ecological resilience (e.g., Bernhardt and Leslie, 2013; Billé et al., 2013; Cooley et al., 2016; Seidl, 2014; Weins, 2016).
Here we use the term ‘resilience’ to mean the capacity of a system to maintain key ecological functions, processes, and feedbacks in the face of perturbations and disruptions (e.g., Levin and Lubchenco, 2008; Billé et al., 2013; Seidl, 2014). Biological diversity (including genetic and functional diversity), food web complexity, habitat diversity, modularity, and spatial connectivity all can contribute to the resilience of coastal and marine ecosystems and can be sustained or restored by coordinated management actions (Bernhardt and Leslie, 2013). Current levels of ecological resilience in the CCLME result from a combination of intrinsic and extrinsic factors such as oceanographic processes, biogeographical history, past disturbances, and human inputs and actions.
Resilience approaches to the problem of OAH should yield benefits under a wide range of alternative future scenarios by delaying abrupt ecosystem change and smoothing transitions to new states when those transitions become inevitable (Bernhardt and Leslie, 2013; Seidl, 2014). Delaying action to address OAH, conversely, will constrain future management options as ecosystem change accelerates and ecosystem function is eroded or lost (Scheffer et al., 2015; Gattuso et al., 2015).
In the policy domain, resilience has gained traction as a goal for ecosystem management more generally (Standish et al., 2014). It has recently been proposed as a goal for regulatory and non-regulatory actions for ameliorating OA in the U.S., such as by restoring oyster beds, considering OA in fisheries management decisions, and changing land use and land development practices in ways that alleviate OA (Cooley et al., 2016). Resilience resonates with decision-makers because it presents a way to maintain or restore ecological states that are desirable or beneficial in a socio-economic context. The adoption of resilience as a credible goal for environmental management has grown as indicators, metrics, and tools for its implementation continue to be developed, tested, and refined (Spears et al., 2015). Ecologists, notably, have for decades recognized resilience as a property of natural systems that persist under conditions of environmental variation; persistence requires resilience (Weins, 2016).
We argue that, with respect to OAH, sustaining or restoring ecological resilience offers a near-term or bridging strategy to slow, ease or even avert ecosystem transitions while scientific understanding grows and new management options emerge. At the same time, we recognize that over the longer term, the progressive intensification of OAH in CCLME ecosystems will increase the risks of crossing critical thresholds that can lead to highly altered states that no longer provide goods and services important to society, including, for example, productive fisheries. The possibility of critical transitions to undesirable states underscores the importance of continuing to mitigate CO2 and other greenhouse gas emissions to limit OAH intensification and effects.
Here we identify practices that can be adopted by managers now to enhance near-term ecological resilience and adaptive capacity in the CCLME. We provide specific examples demonstrating how these approaches already are being implemented under existing legislative mandates, institutions, and decision-making processes (Table 1). Our set of examples is not exhaustive; instead we focus on several of the most obvious and appropriate management tools specific to the CCLME.
|1. Marine Protected Areas (MPAs)|
|Incorporate OAH considerations into MPA site selection and/or network design or refinement.|
|Update management goals and evaluation.|
|Support management-relevant science and monitoring.|
|2. Fisheries Management|
|Advance ecosystem-based policies to guide management.|
|Build decision-maker understanding.|
|Invest in expanding scientific knowledge and tools.|
|3. Coastal Management|
|Protect ecosystems that sequester carbon.|
|Integrate OAH into coastal ecosystem management frameworks and actions.|
|Support research to advance management approaches.|
Marine Protected Areas. Marine protected areas (MPAs) are a spatial management tool widely used to sustain living marine resources. MPAs in the CCLME region are established under a number of authorities and differ in their specific objectives, regulations, and levels of protection (Gleason et al. 2013); collectively, they cover more than 114,000 square nm and 40% of the US Exclusive Economic Zone (National Marine Protected Areas Center, 2013). Of these, the most restrictive MPAs are designated as fully no-take areas. Other MPAs allow the take of a restricted set of species while affording substantial protection to most resident species and the benthic habitat. Still other MPAs, for example, the National Marine Sanctuaries, focus on education, outreach, and research, while limiting some human uses. Many of these MPAs, especially those that limit the extraction of living marine resources and protect benthic habitat, are expected to provide ecological benefits both within and beyond their boundaries, such as protecting biodiversity, maintaining food web functions, and sustaining larval production and connectivity (Micheli et al., 2012; Barnett and Baskett, 2015). Existing MPAs and MPA networks and those established in the future thus have the potential to help support regional ecological resilience and adaptive capacity as OAH intensifies.
At the same time, OAH threatens to significantly change or degrade the biological and ecological attributes and processes that many of these MPAs were designed to protect, for example, through negative effects on physiology, behavior, and abundance that propagate through populations and communities. As a consequence, the performance of some MPAs may not meet expectations established at the time of their designation. Some MPAs may be especially vulnerable to ecological disruption if they are exposed to local environmental stressors; for example, some areas along the Oregon coast periodically experience fish and invertebrate mortality during hypoxic events (Chan et al., 2008) and appear particularly susceptible to acidification (Harris et al., 2013).
Going forward, designation of new MPAs and refinements to existing MPA networks will require consideration of current and future OAH conditions. MPAs established in areas less exposed to OAH can potentially serve as temporal or spatial refugia that provide habitat for vulnerable species and as source populations for repopulating areas subject to transient OAH intensification (Strong et al., 2014). Alternatively, MPAs established in areas that are naturally subject to more intense or more variable OAH conditions could serve to protect populations that have developed greater physiological tolerance or that are more genetically diverse in traits that confer such tolerance, and therefore have the potential for rapid evolutionary adaptation (Strong et al., 2014). By explicitly considering the adaptive capacity of species and incorporating evolutionary perspectives into MPA planning and management, managers can increase the likelihood that the behavioral, physiological, or evolutionary responses of key species to changing environmental conditions will shift in ways that promote their persistence and abundance under novel environmental conditions (Beever et al., 2016). While the adaptive capacity of populations or species may be difficult to assess quantitatively, a useful approximation can be obtained from observations of OAH variability in locations where focal species persist, based on the assumption that persistence under conditions of extreme variability indicates genetically-based capacity to tolerate extreme conditions.
Goals and performance metrics for many MPAs may need to be recalibrated in light of OAH. Performance metrics based on the status of current species assemblages will become less meaningful as systems undergo OAH-related transitions. Alternative or additional metrics that assess the functions, services, and attributes of the system vis-à-vis ecological resilience (e.g., food web complexity, biodiversity, connectivity), but that are independent of particular species assemblages, may become more useful and can be developed; in some cases, these metrics already are under development. Clearly acknowledging the potential magnitude and uncertainty of ongoing changes due to OAH will generate more realistic expectations about MPA performance among policy-makers, managers, and stakeholders.
Informing the design of future policy or management interventions with an understanding of how ecosystems could change under OAH will require the development of targeted, context-specific models and scenario analyses. Scenarios can be based on model simulations and used to reflect alternative outcomes under differing conditions. Sustained environmental monitoring of OAH conditions can provide the data to inform, improve, and validate such models and scenarios. More generally, monitoring within and adjacent to MPAs can be used to assess OAH in ways that are management-relevant, such as by illuminating potential associations between changing ocean chemistry and ecosystem effects or by evaluating whether or how MPAs contribute to regional ecological resilience under OAH.
The value of using MPAs as research reserves to control for human-use variables is likely to grow as OAH progresses. Such research reserves can help test management interventions beyond the effects of fishing. For example, MPAs that protect submerged aquatic vegetation and other forms of blue carbon (i.e., carbon naturally stored in coastal ecosystems) may help us quantify the value of such resources for achieving greenhouse gas reduction targets and could serve as important additions to a larger portfolio of strategies designed to foster ecological resilience.
Fisheries management. National, tribal, and state governments all participate in managing commercial and recreational fisheries in the CCLME. While OAH effects on fisheries in the CCLME are not yet well understood, the potential exists for significant impacts on fishery yields due to changes in behavior, growth, and survivorship among target and non-target species (e.g., Branch et al., 2013; Busch et al., 2013).
The recent move towards managing fisheries within an ecosystem context provides what may be the best opportunity for realistically considering OAH in fishery management decisions. Although stock-specific management plans historically guided fishery harvests, US fishery scientists and managers have been moving over the past decade towards better accounting for ecological interactions and dynamics (e.g., Field and Francis, 2006; Pacific Fishery Management Council, 2013). Ecosystem-based fishery management plans seek to sustain the full range of functional groups in fisheries ecosystems (i.e., producers to consumers and habitat-providers), account for key processes and feedbacks, and allow consideration of more environmental variables and uncertainties (including OAH) to be part of the management planning process (Collie et al., 2016). As a consequence, ecosystem-based fishery management plans are more likely to support ecosystem resilience (e.g., Levin and Lubchenco, 2008) and maintain productive fisheries under intensifying OAH.
Within the CCLME, the Pacific Fishery Management Council in 2013 adopted the Fishery Ecosystem Plan to move ecosystem science into planning and policies and to provide a general framework for addressing uncertainties that stem from consideration of natural and anthropogenic changes in fishery management decisions. However, most fishery decision-makers and stakeholders do not yet have a good understanding of how the potential impacts and uncertainties of OAH might be integrated into setting harvest control rules, designing stock rebuilding strategies, or establishing other fishery policies. Building this understanding is essential.
Some of the decision-support tools that inform fisheries decisions can be adjusted to better integrate OAH considerations. Assessments of the vulnerability of benthic habitats to trawling, for example, could be enhanced to address the susceptibility of benthic organisms that create biogenic habitats (e.g., corals and sponges) to changing OAH conditions. The siting of MPAs established for the protection of fish species could be improved by considering the spatial arrangement of areas that are more or less vulnerable to acidification or hypoxia. The growing use of integrated modeling frameworks to run simulations and compare alternative management strategies (e.g., management strategy evaluation) presents an opportunity for incorporating OAH into fisheries decisions by adjusting how the models treat uncertainty and environmental variation (Collie et al., 2014; Punt et al., 2014). At the same time, scenario-based models are being used to explore the effects of OAH on fishery yields, food webs, and biodiversity in the CCLME (e.g., Kaplan et al., 2010; Busch et al., 2013). Continuing development and refinement of such models can help to determine how alternative OAH scenarios or management choices affect fisheries impacts and yields; they can also reveal specific indicators with which to measure progress.
Convincing policy makers to incorporate OAH into the potentially costly and sometimes contentious decisions that guide fishery harvests in the CCLME will require a clearer understanding of OAH impacts and better appraisal of management choices that can optimize fishery yields under OAH. Given the need for clear evidence on which to base decisions, indicators that reflect OAH conditions and their effects on fisheries and ecosystems should be viewed as integral components of monitoring programs.
Coastal management. Coastal regions of the CCLME experience more intense and variable OAH conditions than those farther offshore (Harris et al., 2013). Partially enclosed embayments and estuarine waters where local drivers of eutrophication-enhanced OAH are strong, such as parts of Puget Sound, are especially susceptible (Feely et al., 2010). In such places, effective management of water quality can help reduce local intensification of OAH. For example, nutrients released to coastal waters from upland areas contribute to OAH by fueling phytoplankton growth. Where phytoplankton are abundant (e.g., in eutrophic waters), microbial decay of the organic matter produced by phytoplankton contributes to local acidification by increasing CO2 concentrations while inducing hypoxia. Coastal eutrophication is a problem familiar to water quality managers, who have developed means to control nutrient pollution through laws and regulations. Fully implementing existing laws and regulations, and modifying existing water quality standards and thresholds to better address OAH, can help managers tackle the emerging problem of OAH (Boehm et al., 2015; Weisberg et al., 2016).
Stratification, tides, and river forcing combine to control how long land-based nutrients and organic matter remain in estuarine and coastal waters, and thus determine the net effects of photosynthesis, respiration, and decomposition on the chemistry of these waters. In areas experiencing strong stratification, photosynthesis in the surface layer may become uncoupled from decomposition in lower layers, exacerbating deoxygenation and acidification at depth. Opportunities may exist in some estuaries and bays to restore coastal features in ways that mitigate local OAH, such as by altering built structures or other impediments that limit flushing.
Opportunities are emerging for coastal managers to include carbon management as a growing part of their portfolio. In this regard, avoiding conversion of coastal systems to low-carbon systems — those that store less carbon — can be an important first step, for example, by preventing the release of carbon now stored in coastal sediments and preserving carbon stored as living biomass. First critical steps in this regard are to inventory carbon stocks in nearshore environments and amend management strategies to protect or enhance valuable carbon reservoirs. Such practices can be integrated with broader climate change policies, for example, those that encourage sequestration or establish a market value for carbon via offset credits, for greater effect.
Considerable interest now centers on the potential for submerged aquatic vegetation (e.g., seagrasses, kelp) to improve local OAH conditions in the near term, and to sequester carbon in the longer term (Mcleod et al., 2011). Although this potential is an area of active investigation, a scientific consensus does not yet exist on the general efficacy of such approaches. However, vegetation management is already part of coastal management in many areas of the CCLME, and often is required by law or regulation. The organic matter produced by seagrasses, kelps, and other macroalgae typically is more resistant to microbial decay than that produced by phytoplankton. It therefore is more likely to become buried in sediments or be transported to deeper areas offshore, effectively removing carbon from the local system in areas where rates of deposition or offshore transport are high. Managing submerged aquatic vegetation to slow or reduce OAH by promoting carbon sequestration is, for now, experimental; further research is required to evaluate its effectiveness. Nevertheless, protecting submerged vegetation to the extent now specified by law or regulation has the potential to produce benefits while preserving options for future management actions related to carbon storage.
Diverse organizations and institutions in the CCLME – including the National Estuary Program, National Estuarine Research Reserves, and various local and regional initiatives – now help manage watersheds and ecosystems at the land-sea interface by convening interested parties, developing place-based scientific knowledge and plans, and delivering public education. These organizations provide a means for building local understanding and for spurring local actions to improve OAH conditions by reducing land-based inputs, protecting submerged aquatic vegetation, and/or modifying coastal structures. National, regional, and state organizations that provide technical assistance, develop public education materials, and fund applied science can help speed such local and regional efforts.
Along the west coasts of the USA, Canada, and Mexico, the highly productive California Current large marine ecosystem provides goods and services that contribute to one of the world’s largest regional economies. At the same time, the CCLME is experiencing rapid changes in environmental conditions. Ocean acidification in the CCLME already is more intense than those in many other coastal regions, and hypoxic events are occurring more widely and more often; both of these changes threaten the natural productivity of this system and serve as indications of larger changes that will be associated with climate change in the future.
Despite these rapid changes, practical options are available now to help ameliorate their effects on populations and ecosystems. Managers on the US west coast have the opportunity to use established practices in new and more coordinated ways to help foster ecosystem resilience under conditions of persistent uncertainty. The approaches we have identified comprise a suite of adaptive responses that can be evaluated and modified as ocean conditions progressively move beyond the range experienced over recent centuries and millennia. The early impacts of ocean change in the CCLME offer an important and perhaps unparalleled learning opportunity for human adaptation to rapid ocean change.
No original data were generated.
This contribution is a product of the Ecosystems Working Group of the West Coast Ocean Acidification and Hypoxia Science Panel. We thank the full Panel for providing input and thank E Ramanujam for editorial and programmatic assistance.
The West Coast Ocean Acidification and Hypoxia Panel was convened by the California Ocean Science Trust and supported by the California Ocean Protection Council, the California Ocean Science Trust, and the Institute of Natural Resources, Oregon. TK contributed with support from the Washington Ocean Acidification Center.
The authors have no competing interests to declare.
Adelsman H and Whitely BL 2012. Ocean acidification: From knowledge to action, Washington State’s strategic response In: Washington State Blue Ribbon Panel on Ocean Acidification. Olympia, Washington: Washington Department of Ecology. Publication no 12–01–015. Available at: https://fortress.wa.gov/ecy/publications/SummaryPages/1201015.html.
Ainsworth CH Samhouri JF Busch DS Cheung WWL Dunne J et al. 2011. Potential impacts of climate change on Northeast Pacific marine food webs and fisheries. ICES J Mar Sci 68: 1217–1229, DOI: http://dx.doi.org/10.1093/icesjms/fsr043
Barnett LAK and Baskett ML 2015. Marine reserves can enhance ecological resilience. Ecol Lett 18: 1301–1310, DOI: http://dx.doi.org/10.1111/ele.12524
Barton A Waldbusser GG Feely RA Weisberg SB Newton JA et al. 2015. Impacts of coastal acidification on the Pacific Northwest shellfish industry and adaptation strategies implemented in response. Oceanography 28(2): 146–159, DOI: http://dx.doi.org/10.5670/oceanog.2015.38
Bednaršek N Feely RA Reum JCP Peterson B Menkel J et al. 2014. Limacina helicina shell dissolution as an indicator of declining habitat suitability owing to ocean acidification in the California Current Ecosystem. Proc Biol Sci 281: 20140123.DOI: http://dx.doi.org/10.1098/rspb.2014.0123
Beever EA O’Leary J Mengelt C West JM Julius S et al. 2016. Improving conservation outcomes with a new paradigm for understanding species’ fundamental and realized adaptive capacity. Conservation Letters 9: 131–137, DOI: http://dx.doi.org/10.1111/conl.12190
Benedetti-Cecchi L 2003. The importance of the variance around the mean effect size of ecological processes. Ecology 84: 2335–2346, DOI: http://dx.doi.org/10.1890/02-8011
Bernhardt JR and Leslie HM 2013. Resilience to climate change in coastal marine ecosystems. Ann Rev Mar Sci 5: 371–92, DOI: http://dx.doi.org/10.1146/annurev-marine-121211-172411
Billé R Kelly R Biastoch A Harrould-Kolieb E Herr D et al. 2013. Taking action against ocean acidification: a review of management and policy options. Environ Manage 52: 761–779, DOI: http://dx.doi.org/10.1007/s00267-013-0132-7
Blackford JC 2010. Predicting the impacts of ocean acidification: Challenges from an ecosystem perspective. J Mar Syst 81: 12–18, DOI: http://dx.doi.org/10.1016/j.jmarsys.2009.12.016
Boehm AB Jacobson MZ O’Donnell MJ Sutula M Wakefield WW et al. 2015. Ocean acidification science needs for natural resource managers of the North American west coast. Oceanography 28(2): 170–181, DOI: http://dx.doi.org/10.5670/oceanog.2015.40
Branch TA, DeJoseph BM, Ray LJ and Wagner CA 2013. Impacts of ocean acidification on marine seafood. Trends Ecol Evol 28: 178–86, DOI: http://dx.doi.org/10.1016/j.tree.2012.10.001
Breitburg DL, Hondorp DW, Davias LA and Diaz RJ 2009. Hypoxia, nitrogen, and fisheries: integrating effects across local and global landscapes. Ann Rev Mar Sci 1: 329–49, DOI: http://dx.doi.org/10.1146/annurev.marine.010908.163754
Busch DS, Harvey CJ and McElhany P 2013. Potential impacts of ocean acidification on the Puget Sound food web. ICES J Mar Sci 70: 823–833, DOI: http://dx.doi.org/10.1093/icesjms/fst061
Busch DS, Maher M, Thibodeau P and McElhany P 2014. Shell condition and survival of Puget Sound pteropods are impaired by ocean acidification conditions. PLoS ONE 9: e105884.DOI: http://dx.doi.org/10.1371/journal.pone.0105884
Busch DS, O’Donnell MJ, Hauri C, Mach KJ, Poach M, Doney SC and Signorini SR 2015. Understanding, characterizing, and communicating responses to ocean acidification: Challenges and uncertainties. Oceanography 28: 30–39, DOI: http://dx.doi.org/10.5670/oceanog.2015.29
Chan F Barth JA Lubchenco J Kirincich A Weeks H et al. 2008. Emergence of anoxia in the California current large marine ecosystem. Science 319: 920.DOI: http://dx.doi.org/10.1126/science.1149016
Chan F Boehm AB Barth JA Chornesky EA Dickson AG et al. 2016. The West Coast Ocean Acidification and Hypoxia Science Panel: Major Findings, Recommendations, and Actions. Oakland, California, USA: California Ocean Science Trust. April 2016
Collie JS Botsford LW Hastings A Kaplan IC Largier JL et al. 2016. Ecosystem models for fisheries management: finding the sweet spot. Fish Fish 17: 101–125, DOI: http://dx.doi.org/10.1111/faf.12093
Cooley SR, Ono CR, Melcer S and Roberson J 2016. Community-level actions that can address ocean acidification. Front Mar Sci 2: 128.DOI: http://dx.doi.org/10.3389/fmars.2015.00128
Fabricius KE, De’ath G, Noonan S and Uthicke S 2014. Ecological effects of ocean acidification and habitat complexity on reef-associated macroinvertebrate communities. Proc R Soc B 281: 20132479.DOI: http://dx.doi.org/10.1098/rspb.2013.2479
Feely RA Alin SR Newton J Sabine CL Warner M et al. 2010. The combined effects of ocean acidification, mixing, and respiration on pH and carbonate saturation in an urbanized estuary. Estuarine, Coastal and Shelf Science 88: 442–449, DOI: http://dx.doi.org/10.1016/j.ecss.2010.05.004
Feely RA, Sabine CL, Hernandez-Ayon JM, Ianson D and Hales B 2008. Evidence for upwelling of corrosive “acidified” water onto the continental shelf. Science 320: 1490–1492, DOI: http://dx.doi.org/10.1126/science.1155676
Field JC and Francis RC 2006. Considering ecosystem-based fisheries management in the California Current. Mar Policy 30: 552–569, DOI: http://dx.doi.org/10.1016/j.marpol.2005.07.004
Garcia-Reyes M and Largier J 2010. Observations of increased wind-driven coastal upwelling off central California. J Geophys Res 115(C04): 011.DOI: http://dx.doi.org/10.1029/2009JC005576
Gattuso J-P Magnan A Billé R Cheung WWL Howes EL et al. 2015. Contrasting futures for ocean and society from different anthropogenic CO2 emissions scenarios. Science 349: 45.DOI: http://dx.doi.org/10.1126/science.aac4722
Gaylord B Kroeker KJ Sunday JM Anderson KM Barry JP et al. 2015. Ocean acidification through the lens of ecological theory. Ecology 96: 3–15, DOI: http://dx.doi.org/10.1890/14-0802.1
Gleason M, Fox E, Ashcraft S, Vasques J, Whiteman E, Serpa P, Saarman E, Caldwell M, Frimodig A, Miller-Henson M, Kirlin J, Ota B, Pope E, Weber M and Wiseman K 2013. Designing a network of marine protected areas in California: achievements, costs, lessons learned and challenges ahead. Ocean Coast Manag 74: 90–101, DOI: http://dx.doi.org/10.1016/j.ocecoaman.2012.08.013
Gutiérrez D Sifeddine A Field DB Ortlieb L Vargas G et al. 2009. Rapid reorganization in ocean biogeochemistry off Peru towards the end of the Little Ice Age. Biogeosciences 6: 835–848, DOI: http://dx.doi.org/10.5194/bg-6-835-2009
Hales B Chan F Boehm AB Barth JA Chornesky EA et al. 2016. Multiple stressor considerations: Ocean acidification in a deoxygenating ocean and a warming climate In: Oakland, California, USA: California Ocean Science Trust. April 2016
Hall-Spencer JM Rodolfo-Metalpa R Martin S Ransome E Fine M et al. 2008. Volcanic carbon dioxide vents show ecosystem effects of ocean acidification. Nature 454: 96–99, DOI: http://dx.doi.org/10.1038/nature07051
Harris KE, DeGrandpre MD and Hales B 2013. Aragonite saturation state dynamics in a coastal upwelling zone. Geophys Res Lett 40: 2720–2725, DOI: http://dx.doi.org/10.1002/grl.50460
Howes EL, Joos F, Eakin CM and Gattuso J-P 2015. An updated synthesis of the observed and projected impacts of climate change on the chemical, physical and biological processes in the oceans. Front Mar Sci 2: 36.DOI: http://dx.doi.org/10.3389/fmars.2015.00036
Kaplan I, Levin P, Burden M and Fulton EA 2010. Fishing Catch Shares in the Face of Global Change: A Framework For Intergrating Cumulative Impacts and Single Species Management. Can J Fish Aquat Sci 67: 1968–1982, DOI: http://dx.doi.org/10.1139/F10-118
Keller AA Ciannelli L Wakefield WW Simon V Barth JA et al. 2015. Occurrence of demersal fishes in relation to near-bottom oxygen levels within the California Current large marine ecosystem. Fish Oceanogr 24: 162–176, DOI: http://dx.doi.org/10.1111/fog.12100
Keller AA Simon V Chan F Wakefield WW Clarke ME et al. 2010. Demersal fish and invertebrate biomass in relation to an offshore hypoxic zone along the US west coast. Fish Oceanogr 19: 76–87, DOI: http://dx.doi.org/10.1111/j.1365-2419.2009.00529.x
Kroeker KJ Kordas RL Crim R Hendriks IE Ramajo L et al. 2013. Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming. Glob Chang Biol 19: 1884–1896, DOI: http://dx.doi.org/10.1111/gcb.12179
Kroeker KJ, Sanford E, Jellison BM and Gaylord B 2014. Predicting the effects of ocean acidification on predator-prey interactions: a conceptual framework based on coastal molluscs. Biol Bull 226: 211–222, DOI: http://dx.doi.org/10.1086/BBLv226n3p211
Levin LA and Breitburg DL 2015. Linking coasts and seas to address ocean deoxygenation. Nature Climate Change 5: 401–403, DOI: http://dx.doi.org/10.1038/nclimate2595
Levin SA and Lubchenco J 2008. Resilience, robustness and marine ecosystem-based management. BioScience 58: 27–32, DOI: http://dx.doi.org/10.1641/B580107
Levin LA and Sibuet M 2012. Understanding continental margin biodiversity: a new imperative. Ann Rev Mar Sci 4: 79–112, DOI: http://dx.doi.org/10.1146/annurev-marine-120709-142714
Mcleod E Chmura GL Bouillon S Salm R Björk M et al. 2011. A blueprint for blue carbon: toward an improved understanding of the role of vegetated coastal habitats in sequestering CO2. Front Ecol Environ 9: 552–560, DOI: http://dx.doi.org/10.1890/110004
Micheli F Saenz-Arroyo A Greenley A Vazquez L Espinoza MJA et al. 2012. Evidence that marine reserves enhance resilience to climatic impacts. PLoS One 7: e40832.DOI: http://dx.doi.org/10.1371/journal.pone.0040832
Nagelkerken I and Connell SD 2015. Global alteration of ocean ecosystem functioning due to increasing human CO2 emissions. Proc Natl Acad Sci 112(43): 13272–13277, DOI: http://dx.doi.org/10.1073/pnas.1510856112
National Marine Protected Area Center 2013. The Marine Protected Areas Inventory [WWW Document]. Available at http://marineprotectedareas.noaa.gov/dataanalysis/mpainventory/.
Pacific Fishery Management Council 2013. Pacific Coast Fishery Ecosystem Plan for the US Portion of the California Current Large Marine Ecosystem In: Portland, Oregon: Available at http://www.pcouncil.org/wp-content/uploads/FEP_FINAL.pdf.
Punt AE A’mar T Bond NA Butterworth DS deMoor CL et al. 2014. Fisheries management under climate and environmental uncertainty: control rules and performance simulation. ICES J Mar Sci 71: 2208–2220, DOI: http://dx.doi.org/10.1093/icesjms/fst057
Salvatteci R Gutiérrez D Field D Sifeddine A Ortlieb L et al. 2014. The response of the Peruvian Upwelling Ecosystem to centennial-scale global change during the last two millennia. Clim Past 10: 715–731, DOI: http://dx.doi.org/10.5194/cp-10-715-2014
Scheffer M, Carpenter SR, Dakos V and van Nes EH 2015. Generic indicators of ecological resilience: Inferring the chance of a critical transition. Annu Rev Ecol Evol Syst 46: 145–67, DOI: http://dx.doi.org/10.1146/annurev-ecolsys-112414-054242
Somero GN Beers JM Chan F Hill TM Klinger T et al. 2016. What changes in the carbonate system, oxygen, and temperature portend for the Northeastern Pacific Ocean: A physiological perspective. BioScience 66(1): 14–26, DOI: http://dx.doi.org/10.1093/biosci/biv162
Spears BM Ives SC Angeler DG Allen CR Birk S et al. 2015. Effective management of ecological resilience – are we there yet?. J Appl Ecol 52: 1311–1315, DOI: http://dx.doi.org/10.1111/1365-2664.12497
Standish RJ Hobbs RJ Mayfield MM Bestelmeyer BT Suding KN et al. 2014. Resilience in ecology: Abstraction, distraction, or where the action is?. Biol Cons 177: 43–51, DOI: http://dx.doi.org/10.1016/j.biocon.2014.06.008
Strong AL, Kroeker KJ, Teneva LT, Mease LA and Kelly RP 2014. Ocean acidification 2.0: Managing our changing coastal ocean chemistry. BioScience 64: 581–592, DOI: http://dx.doi.org/10.1093/biosci/biu072
Sydeman WJ Garcia-Reyes M Schoeman DS Rykaczewski TSA et al. 2014. Climate change and wind intensification in coastal upwelling ecosystems. Science 345: 77–80, DOI: http://dx.doi.org/10.1126/science.1251635
Vaquer-Sunyer R and Duarte CM 2008. Thresholds of hypoxia for marine biodiversity. Proc Natl Acad Sci USA 105: 15452–15457, DOI: http://dx.doi.org/10.1073/pnas.0803833105
Weisberg SB Bednarsek N Feely RA Chan F Boehm AB et al. 2016. Water quality criteria for an acidifying ocean: Challenges and opportunities for improvement. Ocean Coastal Management 126: 31–41, DOI: http://dx.doi.org/10.1016/j.ocecoaman.2016.03.010
Wiens JA 2016. Ecological resilience In: Ecological Challenges and Conservation Conundrums: Essays and Reflections for a Changing World. Chichester, UK: John Wiley and Sons, Ltd, DOI: http://dx.doi.org/10.1002/9781118895078.ch31