Bay Case Study Research Articles

Influence of mineralized organic carbon in marine sediments on ecological heavy metal risk: Bohai Bay case study

The organic matter in sediments can mineralize over time, which impacts the morphology of the heavy metals therein, which in turn affects the assessment of the risks posed by heavy metals. We used the sediments of Bohai Bay as the study object and analyzed the effects of different organic carbon mineralization levels on the concentrations of heavy metals (Cr, Pb, Cu, Zn, and Cd) using water extraction and potassium permanganate oxidation. The mean concentrations of Cd, Pb, Cu, and Zn in Bohai Bay were within the limits recommended by the World Health Organization. The proportions of the active and inert organic carbon fractions were 61.72% and 32.94%, respectively. Organic carbon mineralization most strongly impacted Cd and Pb levels, with releases accounting for 47.92% and 25.75%, respectively, of the oxidizable fractions. The release of all heavy metals, except for Cr, increased with increases in organic carbon mineralization, and heavy metals were released at a maximum rate of 12.94% when the organic carbon was highly mineralized, whereas Cr was released at a maximum of 0.023% during the first stage of organic carbon mineralization. In terms of spatial distribution, the concentration of mineralizable organic carbon in the sediments of the estuaries was substantially higher than that in other marine areas. Estuary sediments were more easily affected by organic carbon mineralization; therefore, the heavy metals in the oxidizable fraction of the estuarine region were more easily transformed into unstable heavy metal forms, posing high risk levels. Therefore, this study highlights the effects of organic carbon mineralization on heavy metal morphology and stability, when evaluating the ecological risk of heavy metals in marine sediments.

Coastal wetland plant community responses to record-high Lake Superior water levels: An Allouez Bay case study

Here we present findings from a natural experiment to better understand coastal wetland plant community responses to rising water levels. Plant communities were monitored in three vegetation zones (submergent, emergent, and wet meadow) at Allouez Bay, a lacustrine coastal marsh, six times over years 2011–2020. Lake Superior water levels reached record-highs in 2017, and again in 2019. During our six sampling campaigns, we encountered eighty-four vascular plant species, seven of which were non-native. Except for reductions in total plant cover in the wet meadow zone, emergent and wet meadow plant communities were only marginally affected by rising water. Percent cover of non-native species did not increase in a clear pattern. Temporal changes in floristic quality were non-significant at the whole site level, and mean coefficient of conservatism values ranged from 5.3 to 6.0. Aquatic vegetation in the submergent zone was most affected by rising water. Submergent zone richness declined from sixteen plant species in 2011 to zero in 2020. Multivariate PERMANOVA analysis showed significant effects of year on site-wide plant composition. Temporal composition changes were predominately driven by species turnover in the submergent vegetation zone, whereby floating aquatic species were replaced by non-floating species from 2011 to 2017, and an absence of aquatic vegetation along research transects in 2020. Tracking regeneration of aquatic vegetation is a focus of future research as unknown effects from prolonged exposure to record-high water levels may affect natural regenerative processes at Allouez Bay, and potentially at other lacustrine Great Lakes wetlands throughout the basin.

The Role of the Archeological Heritage Sites in the Process of Urban Regeneration of UNESCO’s Cities—Boka Bay Case Study

The role of the archeological and cultural heritage sites in the process of urban regeneration in UNESCO’s protected areas becomes more and more important for the natural and cultural heritage protection in the touristic cities with urban expansion. However, there is no clear methodological approach for the inclusion of these important natural and cultural heritage sites in the process of urban regeneration of the cities. The purpose of this study is to analyze how two contemporary urban planning tools, sustainable urban mobility plans and heritage impact assessments, contribute to the protection and sustainable use of archeological sites. The methodology that is used in this study is dual, theoretical, through literature review, and empirical, through the appliance of the case study method and expert observation and mapping of the most valuable archeological sites in Boka Bay. The results of this study show that practical usage of the two proposed tools in the process of urban regeneration could help in cultural and natural heritage protection and their inclusion as drivers of sustainable urban planning and cultural heritage management. The results of the study confirm the authors’ hypothesis that the role of the archeological sites in the process of urban regeneration is evident in the touristic cities in the coastal area of Montenegro, concluding that urban mobility principles and heritage impact assessment studies must be considered in the process of urban regeneration while at the same time cultural (archeological) heritage management is an integral part of this process.

Improving reliability of logging process: A Bohai Bay case study

AbstractDrilling and logging are important links in oil and gas development, and the accurate acquisition of operation data directly affects the development efficiency of oil and gas reserves. Under the dual pressure of safety and economy, it is essential to find out how to improve the quality of logging, especially the quality of logging while drilling. This article focuses on logging technology applied in the Bohai Bay field. Drilling engineering data from several sites are analyzed to identify factors influencing the reliability performance of formation pressure tests. The analysis is conducted using the commercial drilling engineering software JewelSuite. Two types of main failure phenomena are summarized: lost seal, time out. Next, logging reliability improvement technologies are proposed based on the results of reliability analysis, such as resolution improvement, bottom hole assembly optimization, and on‐site construction operation procedures. These technologies can achieve more efficient and accurate formation pressure acquisition while providing important data for later productivity prediction and development. The practice has proved that the improved technologies can reduce failures by nearly 66.7%, and can also reduce cost by more than 33.84 M USD.

Transitioning to co-management in Caribbean reef fisheries: Tela Bay case study

Caribbean fisheries are characterized by their heterogeneous socio-ecological conditions. Paradoxically, they are generally managed through a top-down, government centered, one-size fits all approach. Here, we assessed the governance and socioeconomic context of a Caribbean reef fishery (Tela Bay, Honduras), to disentangle the main challenges and opportunities faced during the transition to fisheries co-management. Similar to the rest of the region, Tela Bay communities depend on reef fisheries for their livelihoods and food security but they turned to co-management as a means to achieve a sustainable fishery. We identified four main challenges for the successful implementation of co-management, these were: (1) weak institutions, (2) financial constraints, (3) reduced group cohesion due to the high heterogeneity among stakeholders and (4) lack of formal legal agreements to legitimize co-management arrangements. Despite these challenges, the Tela Bay communities were able to successfully implement co-management, due to 2 key aspects: (1) bridging organizations that fostered multilevel collaboration, promoted participation, strengthened organizations, generated financial support and improved accountability and (2) social capital, reflected through community participation, cooperation, trust and conflict resolution mechanisms. The Tela Bay case study has contributed to sustainability science by demonstrating that the conceptualization of co-management differs according to the socioeconomic context of the fishery. In its early implementation in Caribbean fisheries, co-management should be viewed as institution building and governance. Thus, successful case studies must continue to be monitored to scale-up these efforts in the region.

The first application of compositional data analysis (CoDA) in a multivariate perspective for detection of pollution source in sea sediments: The Pozzuoli Bay (Italy) case study

In the last decades, investigating geochemistry of sea sediments has been challenging in the eastern sector of Pozzuoli Bay, source of the metal(loid)s has been a matter of debate and the proposed origin of potentially toxic elements (PTEs) has been occasionally inconsistent. In this study, compositional data analysis (CoDA) was used because the results are independent of the measurement unit, the selected subgroup of elements and the order of chemicals in the dataset. The robust variant of principal component analysis (PCA) indicated that Hg, Cd, Cu, Pb and Zn were positively correlated with mud and organic matter in the sediments deposited in front of the former industrial site. Concentrations of these metals decrease along the cores and in the distal zone. Nevertheless, Al, As, V, Fe, Cr, Ni and sand form an association along the coast which strengthens with increasing distance from fumaroles in the proximal zone. It suggests that arsenic was mainly originated from the pyroclastic deposits of Campi Flegrei and some of the seepages with hydrothermal component, supported by low contribution of the variables in robust PCA of the sediments from distal zone. Therefore, this pioneering article suggests CoDA as a powerful tool for answering the long-lasting questions over sediment geochemistry in polluted areas.

Planning to adaptation: Informing regional nature-based adaptation to improve coastal resiliency in Santa Monica Bay

Los Angeles County is known for its wide sandy beaches, coastal boardwalks, and beach commerce and tourism. Planning for sea level rise and associated coastal hazards poses unique challenges in highly populated urban communities; in particular, sandy beaches play an important role in buffering the land from sea level rise, coastal storms, and associated flooding. With increasing pressure to prepare for and adapt to sea level rise, boundary organizations such as USC Sea Grant and The Bay Foundation are helping coastal communities build their capacity to respond to changing shorelines by providing and translating best available science, providing planning and technical support, building partnerships, and implementing adaptation strategies. This paper evaluates the process and provides recommendations for translating science to on-the-ground planning and adaptation efforts in coastal communities. Regionally, USC Sea Grant’s AdaptLA initiative works with coastal communities to communicate sea level rise science and provide managers with information and tools to assess vulnerabilities and begin to plan for adaptation. Informed by detailed, scaled-down climate change models and science-based demonstration projects, some AdaptLA participants initiated demonstration adaptation projects such as the Santa Monica Beach Restoration Pilot Project discussed in this paper. The Santa Monica Bay case study highlights a sea level rise adaptation process, from community capacity building to planning nature-based adaptation, using beach restoration. Lessons learned from demonstration projects in the region can inform similar projects and potential scaling up of nature-based adaptation on sandy beaches. Through the collective effort of boundary organizations, coordination with multiple jurisdictions and agencies, and community support, this case study demonstrates a model for implementing naturebased adaptation in urban coastal communities.

Assessment of Satellite-Based Chlorophyll-a Algorithms in Eutrophic Korean Coastal Waters: Jinhae Bay Case Study

Jinhae Bay, one of the most important aquaculture areas in Korean coastal waters, has suffered from serious environmental problems due to intensive anthropogenic activities since the 1970s. Determining the response of coastal ecosystems in Korea to anthropogenic activities requires understanding the characteristics of chlorophyll-a concentration (Chl-a), and the high spatiotemporal resolution of the Geostationary Ocean Color Imager (GOCI) can aid these efforts. However, producing reliable satellite-based Chl-a estimates is challenging in optically complex coastal waters and the Chl-a estimation algorithms must be assessed regionally. Based on in situ Chl-a measurements collected in Jinhae Bay between 2011 and 2016, we evaluated GOCI-derived Chl-a estimates obtained using six ocean color Chl-a algorithms: two standard open ocean algorithms, one GOCI-standard algorithm, and three Tassan’s algorithms regionally modified for Korean waters. All of the algorithms tended to underestimate high Chl-a values >0.9 mg m–3. The Yellow Sea Large Marine Ecosystem Ocean Color Project (YOC) algorithm, one of the modified Tassan’s algorithms, provided the best fit to the in situ Chl-a measurements in Jinhae Bay (r=0.51 , p<0.05 ), including appropriate representations of the spatial and temporal variation. Therefore, this algorithm can be considered a baseline approach for satellite-based long-term coastal monitoring systems in Jinhae Bay.

A Generalized Additive Model approach to evaluating water quality: Chesapeake Bay case study

Nutrient reduction efforts have been undertaken in recent decades to mitigate the impacts of eutrophication in coastal and estuarine systems worldwide. To track progress in response to one of these efforts we use Generalized Additive Models (GAMs) to evaluate a diverse suite of water quality constituents over a 32-year period in the Chesapeake Bay, an estuary on the east coast of the United States. Model development included selecting a GAM structure to describe nonlinear seasonally-varying changes over time, incorporating hydrologic variability via either river flow or salinity, and using interventions to model method or laboratory changes suspected to impact data. This approach, transferable to other systems, allows for evaluation of water quality data in a statistically rigorous way, while being suitable for application to many sites and variables. This enables consistent generation of annual updates, while providing a tool for developing insights to a range of management- and research-focused questions.

A unified approach for protecting listed species and ecosystem services in isolated wetlands using community-level protection goals

The protection of listed species through the Ecological Risk Assessment (ERA) process is encumbered by the number and diversity of species that need protection and the limited data available to inform assessments. Ecological communities within isolated ecosystems often contain a number of biologically diverse endemic, endangered, and threatened species, as well as providing numerous ecosystem services (ES). We propose an approach that develops community-level protection goals using isolated wetlands that includes both listed species and Service Providing Units (SPUs) that drive ES for ecological risk assessments (ERAs). Community-level protection goals are achieved by developing a protection community and weighing lines of evidence to determine a set of focal species within that community upon which to base the assessment. Lines of evidence include chemical mechanism of action, likely routes of exposure, and taxa susceptibility, as well as relationships among species, and other ecological factors. We demonstrate the process using case studies of chlorpyrifos in California vernal pools and coal ash effluent in Carolina bays. In the California vernal pool case study, listed species were the primary SPUs for the ES provided by the critical habitat. The weight of evidence demonstrated the honey bee as the focal species for the terrestrial environment and the vernal pool fairy shrimp as the focal species for the aquatic environment. The protection community within the Carolina bay case study was more taxonomically diverse than vernal pools for both listed species and SPUs, with amphibians identified as the focal species for which to target mitigation goals and hazard levels. The approach presented here will reduce the time and resource investment required for assessment of risk to listed species and adds an ES perspective to demonstrate value of assessments beyond listed species concerns.

A method for a rapid measurement of geostrophic currents in coastal waters: A bay case study

Mediante el método de CTD ondulante se calculan las corrientes geostróficas en un par de secciones paralelas cerca de la costa. Las componentes de la velocidad se estiman en cada cuadrilátero formado entre las secciones y las estaciones consecutivas. Con ésta metodología una campaña se puede realizar en tan solo 5 horas, si por ejemplo se considera un transecto de 20 km de longitud, con estaciones a cada 1 km y hasta una profundidad de 300 m. Para verificar esta metodología, se usaron datos de una campaña hidrográfica en Bahía de Banderas donde se tomaron hasta 120 perfiles en dos días de trabajo, con los cuales se realizó una malla regular con técnicas de mapeo objetivo de los campos hidrográficos que al final se compararon con las corrientes geostróficas calculadas mediante las rutinas GSW-TEOS10. La diferencia entre los resultados de la malla regular y las secciones paralelas resulto menor del 3.5%. En el presente estudio, la metodología se probó en una bahía, donde las corrientes observadas mostraron una estructura bien definida y persistente durante el muestreo, por lo que aplicar esta metodología en otras partes de la zona costera, por ejemplo en mar abierto, podría presentar más variabilidad en los resultados.

INTEGRATED DESIGN FOR FLOOD RISK AND SPATIAL QUALITY—EXAMPLES FROM THE DUTCH DELTA PROGRAMME

INTRODUCTION The Netherlands faces a significant flood risk task. In order to remain a safe place to live the Netherlands has to upgrade its extensive flood risk protection system. This results in an elevation and reinforcement task for many of the Netherlands water barriers. When those barriers are positioned in an open landscape, the technical reinforcement is often easy to embed specially. However, many barriers have been built over the years making the reinforcement into a challenging spatial assignment. This article shows different case study examples of a research by design study (performed in the broader context of the Dutch Delta programme) that explores integral design solutions for flood risk and spatial (re)development. The Houston Galveston Bay case study demonstrates the international applicability of the research by design method.

Consolidation characteristics of soft sediments; Newark bay case study

Consolidation characteristics of soft sediments; Newark bay case study

Evaluating nonindigenous species management in a Bayesian networks derived relative risk framework for Padilla Bay, WA, USA.

Many coastal regions are encountering issues with the spread of nonindigenous species (NIS). In this study, we conducted a regional risk assessment using a Bayesian network relative risk model (BN-RRM) to analyze multiple vectors of NIS introductions to Padilla Bay, Washington, a National Estuarine Research Reserve. We had 3 objectives in this study. The 1st objective was to determine whether the BN-RRM could be used to calculate risk from NIS introductions for Padilla Bay. Our 2nd objective was to determine which regions and endpoints were at greatest risk from NIS introductions. Our 3rd objective was to incorporate a management option into the model and predict endpoint risk if it were to be implemented. Eradication can occur at different stages of NIS invasions, such as the elimination of these species before being introduced to the habitat or removal of the species after settlement. We incorporated the ballast water treatment management scenario into the model, observed the risk to the endpoints, and compared this risk with the initial risk estimates. The model results indicated that the southern portion of the bay was at greatest risk because of NIS. Changes in community composition, Dungeness crab, and eelgrass were the endpoints most at risk from NIS introductions. The currents node, which controls the exposure of NIS to the bay from the surrounding marine environment, was the parameter that had the greatest influence on risk. The ballast water management scenario displayed an approximate 1% reduction in risk in this Padilla Bay case study. The models we developed provide an adaptable template for decision makers interested in managing NIS in other coastal regions and large bodies of water.

Prymnesium parvum invasion success into coastal bays of the Gulf of Mexico: Galveston Bay case study

The toxic haptophyte Prymnesium parvum regularly forms fish-killing blooms in inland brackish water bodies in the south-central USA. Along the Texas coast smaller blooms have occurred in isolated areas. There appears to be an increasing risk that harmful P. parvum blooms will propagate into open coastal waters with implementation of future water plans. These plans will include increased interbasin water transfers from the Brazos River, regularly impacted by P. parvum blooms, to the San Jacinto-Brazos Coastal Basin, which ultimately flows into Galveston Bay (GB). Persisting source populations of P. parvum in inland waters elevates this risk. Thus, there is a need for an increased understanding of how P. parvum might perform in coastal waters, such as those found in GB. Here, two in-field experiments were conducted to investigate the influence of various plankton size-fractions of GB water on inoculated P. parvum during fall and winter, periods when blooms are typically initiating and developing inland. Stationary- and log-growth phase P. parvum were used to represent high and low toxicity initial conditions. Results revealed that P. parvum could grow in GB waters and cause acute mortality to silverside minnows (Menidia beryllina). Depending on season and growth phase, however, P. parvum growth and toxicity varied in different size fractions. During the fall, P. parvum inoculated from stationary-, but not log-growth phase culture, was negatively affected by bacteria-sized particles. During the winter, bacteria and nanoplankton together had a negative effect on P. parvum inoculated from stationary- and, to a lesser degree, log-growth phase cultures. Intermediate- and large-sized grazers when combined with bacteria and nanoplankton had complex relationships with inoculated P. parvum, sometimes stimulating and sometimes suppressing population growth. Toxicity to fish occurred in almost all plankton size fractions. The inclusion of progressively larger sized plankton fractions resulted in trends of decreased toxicity in treatments inoculated with stationary-, but not log-growth phase P. parvum in the fall. In the winter, however, inclusion of larger sized plankton fractions resulted in trends of increased toxicity to fish in treatments inoculated with both stationary- and log-growth phase P. parvum. This study indicates that understanding P. parvum population dynamics in open waters of estuaries and bays will be challenging, as there appears to be complex relationships with naturally occurring components of the plankton. The observations that P. parvum is able to grow to high population density and produce fish-killing levels of toxins underscores the need for advanced risk assessment studies, especially in light of water use plans that will result in P. parvum invasions of greater size.

Uncertainty in model predictions of Vibrio vulnificus response to climate variability and change: a Chesapeake Bay case study.

The effect that climate change and variability will have on waterborne bacteria is a topic of increasing concern for coastal ecosystems, including the Chesapeake Bay. Surface water temperature trends in the Bay indicate a warming pattern of roughly 0.3–0.4°C per decade over the past 30 years. It is unclear what impact future warming will have on pathogens currently found in the Bay, including Vibrio spp. Using historical environmental data, combined with three different statistical models of Vibrio vulnificus probability, we explore the relationship between environmental change and predicted Vibrio vulnificus presence in the upper Chesapeake Bay. We find that the predicted response of V. vulnificus probability to high temperatures in the Bay differs systematically between models of differing structure. As existing publicly available datasets are inadequate to determine which model structure is most appropriate, the impact of climatic change on the probability of V. vulnificus presence in the Chesapeake Bay remains uncertain. This result points to the challenge of characterizing climate sensitivity of ecological systems in which data are sparse and only statistical models of ecological sensitivity exist.

Vulnerability of pastoral farming in Hawke's Bay to future climate change: Development of a pre‐screening (bottom‐up) methodology

AbstractAlthough future climate change will significantly affect New Zealand's climate, how regional climates will be changed remains highly uncertain. As a consequence, pre‐screening sensitivity analysis is recommended for climate‐sensitive activities. A ‘bottom‐up’ approach intended to serve this purpose in the context of non‐irrigated pasture is developed and demonstrated in the Hawke's Bay context. This is achieved using a simple daily water balance model to simulate near‐surface hydrological processes and empirical relationships between transpiration and pasture dry matter production. The Hawke's Bay case study indicates that the methodology has merit and is worthwhile pursuing nationally (with refinements).

Terrigenous sediment impact on coral recruitment and growth affects the use of coral habitat by recruit parrotfishes (F. Scaridae)

Some major anthropogenic stressors have impacts that occur at infrequent, unpredictable intervals; their effects are difficult to evaluate in a timely manner unless space is substituted for time. In this paper we substitute space for time along an environmental gradient that aliases a predicted temporal response to habitat restoration. We herein describe a 3-year study that combined field experiments and descriptive surveys of a fringing reef at Pelekane Bay, west Hawaii, along a sedimentation gradient from an intermittent stream that episodically discharges from the Kohala Watershed. This degraded watershed is now being restored by grazer exclusion, habitat engineering, and replanting of native flora. Sediment traps, arrays of settling plates, marked branches of endemic finger coral Porites compressa, together with surveys of benthic composition, densities of recruits of economically important parrotfishes, and the relative use of corals by fish recruits, were evaluated during the summers of 2010–2012. As expected, sediment accumulation rate decreased while all coral metrics and the densities, use, and preference of corals by recruit fishes generally increased with distance from the point of sediment discharge. Proportionate abundances of recruit through large adult-sized parrotfishes, overlayed on distributions (mapped by separate study) of sediment impact, allowed us to estimate, as an example, the amount and value of parrotfish rersources that are being unrealized because of sediment impacts on recruit parrotfish. Our Pelekane Bay case study thus illustrates how “space-for-time” substitution can be efficiently applied in an evaluation of potential watershed reclamation of reef resources—at a time considerably prior to likely temporal responses of the reef and its resources to watershed restoration.

The vertical structure of time-mean estuarine circulation in a shallow, rotating, semi-enclosed coastal bay: A Liverpool Bay case study with application for monitoring

A reduced physics Ekman boundary layer solution is developed to infer the vertical structure of time-mean circulation in a shallow tidal environment when the horizontal density and surface slope gradients are misaligned. This generalisation of the classic Heaps (1972) model shows that the time-mean depth weighted flow, or the residual circulation, is usefully constrained by knowledge of the surface velocity, instead of freshwater flux, and the horizontal density gradient.The generalised model is applied to Liverpool Bay. In regions where the Ekman depth scale is less than half the mean fluid depth the residual circulation is well modelled by a water column of uniform density, constant eddy viscosity and linear bottom drag. Lateral variability in long-term mooring observations of depth varying residual flow are attributed to the misalignment of sea surface slope and haline controlled density gradients.A method to infer 3D time-average residual currents in regions of misaligned freshwater density and sea surface slope gradients is presented. The method blends CTD survey data with HF radar surface currents and simulation estimates of viscosity and friction. It is validated against ADCP data in Liverpool Bay. It is speculated that this method could be applied more generally, to correct model biases, as part of a coastal monitoring system.

Towards a probabilistic assessment of process-based, morphodynamic models

Recent advances in the development of numerical, process-based models have led to remarkable performance in reproducing measured decadal morphodynamic developments. The advantage of this type of models is that they have a detailed output allowing for a close analysis of relevant processes. Drawback is that the output is associated with a high level of presumed uncertainty, because of the large number of processes involved and the high quality level of input data required.This study aims to explore possibilities to assess uncertainty levels associated with process-based morphodynamic modeling. In a probabilistic approach we consider the outcome of an ensemble of runs including variations of model input parameters and forcing schematizations. We propose to evaluate model performance by both a skill criterion (How well does the model reproduce observed patterns?), a confidence criterion (How sensitive are model results to uncertain input?) as well as a combination of these criteria. This methodology provides an objective assessment of the performance of process-based morphodynamic models. In addition, it can determine which input parameters cause largest uncertainty in the model outcome.The San Pablo Bay case study shows that 60% of the modeled volume meets the skill and confidence criteria for the depositional period (1856–1887) and 46% for the erosional period (1951–1983). Approximately 50% of the volume allocation meets the confidence criterion for a 30year morphodynamic forecast (1983–2013). Model results are sensitive to model input variations only to a limited extend. We attribute this to the high impact of the San Pablo Bay plan form and bathymetry. The forecast shows continuous erosion of the channel and on the northern shoals and a continuous accretion of the channel slopes, albeit more concentrated in the western part of the channel than in preceding decades.