A rising tide of acidity is overwhelming the global ocean. Estuaries and near-shore waters fall under the jurisdiction of states and the federal government, mandating treatment under the Clean Water Act (CWA), but criteria for action are uncertain and unclear. The acidity of the marine environment has increased by roughly a third since 1750, changing chemical processes vital to life, including shell and coral formation and the growth of bony structures in fish. This massive change in ocean chemistry is a growing water quality problem that focuses attention on the surprisingly difficult business of determining whether and how a particular water quality standard has been violated. Such attention brings with it a larger question of whether water quality criteria are legally sufficient under the CWA if they are difficult or impossible to test as a practical matter, and highlights the changing role of the act as it is used to combat a new class of water pollution.
Topic: Land-sea Interactions
Sea level along most of California’s coast is rising and the best science available suggests it will continue to rise at an increasing rate in the future. In addition, climate change will bring higher air and water temperatures, changes in precipitation and runoff, thus changes in water supplies and quality, and more extreme tides and storm surges that will aggravate coastal flooding and erosion. While uncertainty remains as to how these changes will unfold in any one place along the coasts and embayments of California, further change is assured.
Are coastal professionals preparing for these changes? This report presents results of a survey of California coastal managers that shows that neither the state nor coastal communities are standing by until science and policy questions are settled. Communities along both the open ocean coast and along bay and estuarine shorelines are beginning to plan for climate change impacts. Despite scientific uncertainties and the economic challenges of recent years, they are rising to the challenge of coastal climate change. In light of already experienced changes, and the scientifically robust projections of additional and accelerating impacts of climate change in the future, this survey aimed to assess coastal professionals’ concerns with climate change impacts, their activities to date to plan and prepare for them, and the needs and barriers they encounter in planning for climate change.
California’s ocean is becoming more acidic as a result of increased atmospheric carbon dioxide (CO2) and other pollutants. This fundamental change is likely to have substantial ecological and economic consequences for California and worldwide.
This document is intended to be a toolbox for understanding and addressing the drivers of an acidifying ocean. We first provide an overview of the relevant science, highlighting known causes of chemical change in the coastal ocean. We then feature a wide variety of legal and policy tools that California’s government agencies can use to mitigate the problem.
The State has ample legal authority to address the causes of ocean acidification; what remains is to implement that authority to safeguard California’s iconic coastal resources.
Increasing concerns regarding oil spills, air pollution, and climate change associated with fossil fuel use have increased the urgency of the search for renewable, clean sources of energy. This assessment describes the potential of Ocean Thermal Energy Conversion (OTEC) to produce not only clean energy but also potable water, refrigeration, and aquaculture products. Higher oil prices and recent technical advances have improved the economic and technical viability of OTEC, perhaps making this technology more attractive and feasible than in the past. Relatively high capital costs associated with OTEC may require the integration of energy, food, and water production security in small island developing states (SIDSs) to improve cost-effectiveness. Successful implementation of OTEC at scale will require the application of insights and analytical methods from economics, technology, materials engineering, marine ecology, and other disciplines as well as a subsidized demonstration plant to provide operational data at near-commercial scales.
The effect of Ocean Acidification (OA) on marine biota is quasi-predictable at best. While perturbation studies, in the form of incubations under elevated pCO2, reveal sensitivities and responses of individual species, one missing link in the OA story results from a chronic lack of pH data specific to a given species' natural habitat. Here, we present a compilation of continuous, high-resolution time series of upper ocean pH, collected using autonomous sensors, over a variety of ecosystems ranging from polar to tropical, open-ocean to coastal, kelp forest to coral reef. These observations reveal a continuum of month-long pH variability with standard deviations from 0.004 to 0.277 and ranges spanning 0.024 to 1.430 pH units. The nature of the observed variability was also highly site-dependent, with characteristic diel, semi-diurnal, and stochastic patterns of varying amplitudes. These biome-specific pH signatures disclose current levels of exposure to both high and low dissolved CO2, often demonstrating that resident organisms are already experiencing pH regimes that are not predicted until 2100. Our data provide a first step toward crystallizing the biophysical link between environmental history of pH exposure and physiological resilience of marine organisms to fluctuations in seawater CO2. Knowledge of this spatial and temporal variation in seawater chemistry allows us to improve the design of OA experiments: we can test organisms with a priori expectations of their tolerance guardrails, based on their natural range of exposure. Such hypothesis-testing will provide a deeper understanding of the effects of OA. Both intuitively simple to understand and powerfully informative, these and similar comparative time series can help guide management efforts to identify areas of marine habitat that can serve as refugia to acidification as well as areas that are particularly vulnerable to future ocean change.
This study quantifies dissolved inorganic nitrogen (DIN), soluble reactive phosphorous (SRP), and microbial pollutant inputs to a tropical embayment, Hanalei Bay, Kaua'i, Hawai'i from rural watersheds during two field excursions during non-storm conditions. We employ land cover analysis and a suite of nucleic acid fecal source tracking markers (host-specific Bacteroidales and human enterovirus) to identify sources of pollutants to the bay. The highest concentrations of DIN and SRP are in streams draining watersheds with large areas of cultivated land, suggesting fertilizer is a source of these nutrients to the streams and coastal waters. Pollutant areal loading correlates with the fractions of urban and cultivated land cover. Microbial source tracking indicates the presence of human, pig, and ruminant feces in the streams. This work provides preliminary evidence that human development affects loading of DIN, SRP, and microbial pollutants to tropical coastal waters; further study is needed to confirm this. Additionally, results point to a mix of microbial pollutant sources.
This work aimed to understand the distribution of five bacterial pathogens in O'ahu coastal streams and relate their presence to microbial indicator concentrations, land cover of the surrounding watersheds, and physical-chemical measures of stream water quality. Twenty-two streams were sampled four times (in December and March, before sunrise and at high noon) to capture seasonal and time of day variation. Salmonella, Campylobacter, Staphylococcus aureus, Vibrio vulnificus, and V. parahaemolyticus were widespread -12 of 22 O'ahu streams had all five pathogens. All stream waters also had detectable concentrations of four fecal indicators and total vibrio with log mean ± standard deviation densities of 2.2 ± 0.8 enterococci, 2.7 ± 0.7 Escherichia coli, 1.1 ± 0.7 Clostridium perfringens, 1.2 ± 0.8 F(+) coliphages, and 3.6 ± 0.7 total vibrio per 100 ml. Bivariate associations between pathogens and indicators showed enterococci positively associated with the greatest number of bacterial pathogens. Higher concentrations of enterococci and higher incidence of Campylobacter were found in stream waters collected before sunrise, suggesting these organisms are sensitive to sunlight. Multivariate regression models of microbes as a function of land cover and physical-chemical water quality showed positive associations between Salmonella and agricultural and forested land covers, and between S. aureus and urban and agricultural land covers; these results suggested that sources specific to those land covers may contribute these pathogens to streams. Further, significant associations between some microbial targets and physical-chemical stream water quality (i.e., temperature, nutrients, turbidity) suggested that organism persistence may be affected by stream characteristics. Results implicate streams as a source of pathogens to coastal waters. Future work is recommended to determine infectious risks of recreational waterborne illness related to O'ahu stream exposures and to mitigate these risks through control of land-based runoff sources.
Persistent organic pollutants (POPs) are recognized manmade threats to sea turtle populations, but substantial uncertainty exists surrounding their exposure to contaminants and their sensitivity to toxic effects. This uncertainty creates difficulty for conservation managers to make informed decisions for the recovery of these threatened species. To provide baseline concentrations and spatial comparisons, we measured a large suite of POPs in loggerhead sea turtle (Caretta caretta) egg yolk samples collected from 44 nests in three distinct U.S. locations: North Carolina (NC), eastern Florida (E FL), and western Florida (W FL). The POPs included polychlorinated biphenyls (PCBs), organochlorine pesticides such as dichlorodiphenyltrichloroethanes (DDTs), chlordanes, mirex, dieldin, hexachlorocyclohexanes (HCHs), hexachlorobenzene, and toxaphene congeners, as well as polybrominated diphenyl ether congeners (PBDEs). Persistent organic pollutant concentrations were lowest in W FL, intermediate in E FL, and highest in NC egg samples, with several statistically significant spatial differences. This increasing gradient along the southeast coast around the Florida peninsula to North Carolina was explained partly by the foraging site selection of the nesting females. Data from previous tracking studies show that NC nesting females feed primarily along the U.S. eastern coast, whereas W FL nesting females forage in the Gulf of Mexico and Caribbean Sea. The E FL nesting females forage in areas that overlap these two. The foraging site selection also results in exposure to different patterns of POPs. An unusual PBDE pattern was seen in the NC samples, with nearly equal contributions of PBDE congeners 47, 100, and 154. These findings are important to managers assessing threats among different stocks or subpopulations of this threatened species.
As the level of atmospheric carbon dioxide (CO2) continues to rise, so too does the amount of CO2 in the ocean (1, 2), which increases the ocean's acidity. This affects marine ecosystems on a global scale in ways we are only beginning to understand: for example, impairing the ability of organisms to form shells or skeletons, altering food webs, and negatively affecting economies dependent on services ranging from coral reef tourism to shellfish harvests to salmon fisheries (3–5). Although increasing anthropogenic inputs drive acidification at global scales, local acidification disproportionately affects coastal ecosystems and the communities that rely on them. We describe policy options by which local and state governments—as opposed to federal and international bodies—can reduce these local and regional “hot spots” of ocean acidification.
The land–sea interface is a complex social–ecological system characterized by natural ecological processes and human-induced changes. Holistic management of the shoreline is a critical element of an ecosystem-based approach to the land–sea interface in coastal zone management (CZM) programs. Anthropogenic alteration of shoreline environments has resulted in significant loss of sandy beach ecosystems and eroded the resilience of these systems to disturbance. We tested the efficacy of CZM programs in managing the land–sea interface under current and future challenges by comparing alternative approaches to shoreline management in two U.S. states (Hawai‘i and North Carolina). Our results show that explicit prohibition of shoreline armoring has been more effective in conserving dynamic coastal environments and communities by passing the risk associated with coastal development from the public trust to private landowners. Over the long-term, robust anti-armoring legislation will de-incentivize risky coastal development projects while preserving coastal environments and the ecological services they provide to society. Policy prescriptions for effective shoreline management and increased coastal resilience under persistent coastal erosion and future sea-level rise are proposed.
