Relationships between near-bottom dissolved oxygen and sediment profile camera measures

The United States Environmental Protection Agency (U.S. EPA) and other environmental authorities regulate concentrations of dissolved oxygen (DO) as a measure of nutrient-related eutrophication in estuarine and coastal waters. However, in situ DO concentrations are extremely variable, and their characterization requires an extensive sampling program to provide data over meaningful scales of time and space. In contrast, benthic faunal communities integrate the impacts of low DO over time, and can be rapidly assessed using benthic imaging. The goal of this study was to quantify the relationships between near-bottom dissolved oxygen and measures derived from benthic imaging with a sediment profile camera. We monitored three stations in Narragansett Bay (Rhode Island, USA) for DO and other water quality parameters 15–20 cm above the sediment surface on 15-minute intervals between July and November 2002, and regularly sampled these stations with a sediment profile camera throughout this time period. These soft-sediment stations encompassed several DO environments. We tested for relationships between near-bottom DO and several camera measures, including Nilsson and Rosenberg's Benthic Habitat Quality (BHQ) index, the apparent Redox Potential Discontinuity (aRPD) depth, and various faunal features that can be identified in sediment profile images. Camera measures were examined against a variety of methods of characterizing DO (including mean DO, and the percent of time under various DO thresholds), over a span of time scales from 1 day to 49 days. The best relationship (highest r²) between near-bottom DO and BHQ was found when DO was evaluated as the percent of time under a hypoxic threshold of 2.6 mg l^− 1 over a 28-day time scale (by examining DO records over the 28 days preceding each camera deployment). We found that, over several benthic settings, the BHQ index was successful at identifying environments that had experienced relatively high or low DO over the preceding four weeks. Our sediment profile data showed more variability with DO in the intermediate values of BHQ. We conclude that sediment profile camera measures correlate to DO in areas where low DO is the primary stressor, integrate DO over ecologically relevant time scales, and enable sampling over spatial scales that are meaningful for mapping by virtue of rapid deployment and analysis. We submit that sediment profile camera imagery is a useful assessment and mapping tool for environmental managers interested in benthic condition and in first-order quantitative estimates of near-bottom DO regimes in areas where low DO is the primary benthic stressor.     

Habitat characteristics as determinant of the structure and spatial distribution of epibenthic and demersal communities of Le Danois Bank (Cantabrian Sea, N. Spain)

The purpose of this paper is to detect and describe general trends in the spatial distribution of epibenthic and demersal communities of Le Danois Bank (El Cachucho) in relation to the environmental variables that characterize their habitat by means of multivariate ordination. Data were derived from two multidisciplinary surveys carried out in October 2003 and April 2004 included in the ECOMARG project. The surveys were focused on the study of the physical scenario, including both geological (seabed characterization from bathymetry and backscatter data) and hydrographic features, and the different compartments of the benthic fauna (endobenthic, epibenthic, suprabenthic and demersal communities). For the present study, epibenthos and demersal species were sampled using two different gears, a 3.5 m beam trawl and a Porcupine 39/52 type baca otter trawl respectively. The total species richness combining both samplers ascended to 221, including 71 species of fishes, 65 crustaceans, 35 molluscs, 29 echinoderms, 10 cnidarians and 5 sponges.Multivariate methods were used for the study of the characteristics of communities and habitats. Hierarchical cluster analysis was applied to calculate and visualize similarities between samples in terms of species composition. To assess the amount of variation of faunal densities related to a set of eight environmental variables, a redundancy analysis (RDA) was used. The set of environmental variables used were: depth, near-bottom temperature and salinity, sedimentary typology (dry weight percentages of coarse sands, medium and fine sands, silt and organic matter) and seafloor reflectivity. Using the spatial distribution of the ranges of depth and seafloor reflectivity that characterize the habitats of the faunal assemblages we defined the spatial distribution of the different communities.The multivariate analysis of 18 beam-trawl samples and 15 otter trawl samples showed the existence of 4 main assemblages associated with the more characteristic habitats of the area. The Callogorgia–Chimaera community live mainly in the areas at the top of the Bank (425–550 m depth), where the sediment coverage is lower and there exists a high presence of rocky outcrops. The Gryphus–Galeus community were found in the areas at the top of the Bank covered by medium and fine sand sediments with low organic matter content. The Phormosoma–Trachyrincus community live on the sedimentary terraces that characterize the Bank break (550–800 m) and the Pheronema–Deania community occupy all the deeper (800–1050 m) sedimentary grounds of the inner basin.     

Effect of seaweed proliferation on benthic habitat quality assessed by Sediment Profile Imaging

Changes in sediment quality, with special reference to benthic habitat conditions resulting from macroalgae overgrowth, were studied in the Venice Lagoon, Italy. Data were collected biweekly in spring and summer from 1993 to 1998 and from 2001 to 2002, as part of the macroalgae growth control strategies managed by the Venice Water Authority-Consorzio Venezia Nuova. Benthic habitat conditions were studied by means of Sediment Profile Imaging, which allowed the collection of several variables: aRPD (apparent redox potential discontinuity), prism penetration depth, presence of anoxia on the surface of the sediment, presence of reduced gas bubbles, stage of benthic colonization. All these variables led to the calculation of an environmental index (Organism–Sediment Index, OSI), which was then related to physical variables and macroalgae abundance. Until 1996, the overall benthic habitat of the Venice Lagoon showed almost stressed conditions; from 1997, the seaweed biomass rapidly declined and the OSI increased significantly. The OSI seemed to be affected by seaweed biomass, sediment compactness and water depth. Macroalgae biomass greater than 4.5 kg/m² led to the complete disappearance of stage III of benthic colonization; values as low as 0.70 kg m² already had a severe impact on recolonization. SPI attributes indicated the main mechanisms that could have contributed to the benthic quality: seaweed proliferation is often followed by rapid decay of macroalgae biomass, especially when present in large amounts. The decrease in seaweed biomass often results in oxygen depletion in the water column and thus in the sediment, preventing complete benthic colonization. This research confirms the importance of in situ rapid reconnaissance surveys to assess the impact of eutrophication on the benthic habitat.     

Assessing the Impacts of Gender Integration in Ghana’s Fisheries Sector

Abstract

This article presents the results of an impact assessment of a component of a large scale USAID sustainable fisheries management project initiative aimed at integrating gender and strengthening the role of women in fisheries management in Ghana. The assessment is based on a literature review and qualitative field data collection. It assessed gender integration from three entry points: improving the Ghanaian policy environment for gender in fisheries, empowering women post-harvest processors, and engaging women gleaners in fisheries co-management. The assessment found that an important milestone was the adoption and implementation of the Ghanaian Fisheries Sector’s National Gender Mainstreaming Strategy in 2016. Summarizing the impacts on local post-harvest processors and gleaners, the assessment found that female post-harvest processors have increased capacity, confidence, and engagement in fisheries management. Gender mainstreaming efforts have succeeded in challenging cultural norms about women’s role in fisheries. Women have been exposed to sustainable fisheries management and are better equipped with the knowledge and leadership skills to advocate for good fisheries practices, which they actively demonstrate.     

Risk assessment: An introduction and critique

Abstract

Risk assessment is a methodology which has been used to evaluate the safety of major public projects, notably aerospace programs, liquefied natural gas import facilities, and nuclear power plants.

This article begins with a review of public attitudes toward risk and then describes the basic components of a risk assessment. Subsequent critical analysis suggests the pitfalls inherent in the technique, especially in regard to the establishing of a criterion of safety against which the results of a risk assessment will be compared. The author identifies three such criteria and rejects two of them, including the one most commonly used in federal government agency decision‐making, as unreliable or philosophically unacceptable.

The article concludes with comments on the applicability of risk assessment in coastal zone management.     

Biological Status Assessment of Coral Reefs in Southern Puerto Rico: Supporting Coral Reef Protection Under the U.S. Clean Water Act

Abstract

States and other jurisdictions may protect coral reefs using biological water quality standards outlined by the United States Clean Water Act (CWA). Such protection will require long-term, regional monitoring of the resource using biological indicators and a probability-based sampling design. A 60-station survey targeting nearshore linear coral reef was conducted across southern Puerto Rico in December 2011 to document the status of reef inhabitants using a probabilistic, regional sampling design. The quantity, type and condition of stony corals, fish, gorgonians, and sponges were documented from each station, providing a robust representation of linear reef status and composition across the region. Fish represented 106 unique taxa and stony corals 32 unique taxa. Benthic organisms (stony corals, sponges, and gorgonians) averaged nearly 12 colonies per square meter, more than half of which were gorgonians. Assessment results can be used as a baseline to compare with future regional surveys to quantify change in reef condition over time (trend). Both temporal and spatial changes can be expected after large-scale disturbances like hurricanes Maria and Irma in 2017. The indicators and probabilistic sampling design support the long-term regional monitoring envisioned by the Environmental Protection Agency to implement CWA protections in Puerto Rico and elsewhere.     

Food supply mechanisms for cold-water corals along a continental shelf edge

In recent years it has been documented that deep-water coral reefs of the species Lophelia pertusa are a major benthic habitat in Norwegian waters. However, basic information about the biology and ecology of this species is still unknown. Lophelia live and thrive under special environmental conditions of which factors such as temperature, water depth, water movement and food supply are important. The present work explores the hypothesis that Lophelia forms reefs in places where the encounter rate of food particles is sufficiently high and stable over long periods of time for continuous growth. This is done by relating the distribution of reefs with the results of numerical ocean modelling.Numerical simulations have been performed with an idealized bottom topography similar to what is found outside parts of the Norwegian coast. In the simulations the model is first forced with an along slope jet and then with an idealized atmospheric low pressure. The model results show that the encounter rates between the particles and the water layer near the seabed are particularly high close to the shelf break. This may indicate that many Lophelia reefs are located along the shelf edges because the supply of food is particularly good in these areas.A sensitivity study of the particle supply in the area close to the seabed for increasing latitude has also been done. This shows that the Ekman transport in the benthic layer tends to create a steady supply of food for benthic organisms near the shelf edge away from the equator.     

Risk assessment of inland waterborne transportation using data mining

ABSTRACT

China has constructed a relatively complete inland waterborne transportation system. However, the frequent occurrence of inland water accidents with serious consequences, like the catastrophic Orient Star shipwreck, is an urgent unsolved problem. To reduce such accidents in the future and improve inland waterborne transportation safety, this study uses data mining, mainly containing text mining and association rule mining to risk assess China’s inland waterborne transportation, rather than the traditional quantitative risk assessment model. Text mining enables the risk factors to be objectively identified and distilled from accident reports. The potential relationships between risk variables are explored using association rule mining, based on the FP-Growth algorithm. The results reveal the essential problem facing China’s inland waterborne transportation system: frequent and varied ship accidents; key risk factors include overloading or improper loading, poor navigation visibility, inadequate sailor competence, and insufficient government supervision of shipowners and shipping companies. Combining the actual circumstances of inland waterborne transportation operations, this study proposes relevant recommendations for governments and relevant supervisory departments. The integrated application of text mining and association rule mining serves to avoid uncertainty and subjectivity, and achieve good results proving their scientific nature as a feasible method in water transportation risk research.     

An energy‐mobility beach classification system as a basis for the management of beach resources

Abstract

The successful implementation of structural and nonstructural solution to problems of shoreline erosion is greatly facilitated if the accumulation and analysis of data sets are accomplished within a design framework which has both theoretical validity and practical application. An inventory of beach resources based upon breaking‐wave energy and beach mobility is presented as a basis for a beach classification system. This method should be used with existing inventories compiled by the U.S. Army Corps of Engineers. A simplified means of determining changes in beach position and slope is suggested; this will facilitate gathering data in a daily time series at numerous locations by a minimum number of people. Examples of how the inventories may be conducted and a sample classification system are presented for selected portions of the shoreline of New Jersey.     

Response of coastal zone management programs to sea level rise in the United States

Abstract

State coastal zone management programs are responding to the potential impacts of accelerated sea level rise through a wide range of activities and policies. This article provides a brief overview of the Coastal Zone Management Act and other federal laws that provide the basis for coastal state regulatory activities. It surveys the level of response to sea level rise by state coastal management programs in 24 marines coastal states, from formal recognition to implementation of policies addressing the issue. Individual state CZMP responses and policies that have been implemented or proposed are categorized. The adaptation of sea level rise to ongoing institutional objectives is discussed and policy constraints and trends are summarized.     

The slippery slope of lot consolidation in the Santa Monica Mountains: A program assessment

Abstract

The authors present an assessment of the Coastal Conservancy's efforts to consolidate small, substandard lots in the Santa Monica Mountains. Emphasis is placed on the ‘ ‘lessons learned’ ‘ by the Conservancy in its project experience as those lessons may be applicable to related efforts elsewhere. Finally, alternative means of lot consolidation are suggested. This assessment should be of relevance to other programs nationwide to address the problem of antiquated subdivisions.     

Real-time assessment and prediction on maritime risk state on the Arctic Route

ABSTRACT

Recently, the Arctic Route has become busier with the continuous melting of Arctic ice. However, navigation on the Arctic Route would be much more complex than in normal water as harsh environmental conditions, such as ice-covered water and scarce costal ports that may cause more uncertainty. Nowadays, with the rapid development of sensors on board, more related data has become available. Thus, implementing comprehensive Arctic maritime risk assessment is urgent and necessary in practice. This study proposes an Arctic maritime risk state assessment method including real-time risk state assessment and risk prediction. Specifically, real-time observation samples’ numerical risk state would be firstly obtained with projection pursuit method from 10 risk indicators. Due to the fuzzy uncertainty of single observation set, information diffusion would be applied to provide diffusion estimation on risk probability distribution in order to depict risk state precisely. Also, the accumulated distribution can be regarded as the risk prediction for next time slot and risk entropy is introduced to depict risk tendency directly. Case study based on ‘Yongsheng’ is conducted to demonstrate and verify the effectiveness of the proposed method. The findings can be useful for the operators and management on board during the Arctic voyage.     

How Are Our MPAs Doing? Challenges in Assessing Global Patterns in Marine Protected Area Performance

Without effective management, protected areas are unlikely to achieve the high expectations the conservation and development sectors have for them: conserving biodiversity and alleviating poverty. Numerous marine protected area (MPA) assessment initiatives have been developed at various spatial and temporal scales, including the guidebook How is your MPA doing? These management assessments have been useful to sites to clarify and evaluate their objectives, yet efforts to examine broader regional or global patterns in MPA performance are only beginning. The authors conducted exploratory trend analyses on How is your MPA doing? indicator data collected by 24 MPAs worldwide to identify challenges and areas for future work. Wide variability across sites with regard to the indicators examined and the constructs used to measure them prevented a true meta-analysis. Managers assessed biophysical indicators more often than socioeconomic and governance constructs. Investment by the conservation community to support collecting and reporting high-quality data at the site level would enable a better understanding of the variation in MPA performance, clarify the contribution of MPAs to both biodiversity conservation and poverty alleviation, and help drive better MPA performance. The absence of rigorous and consistent monitoring protocols and instruments and a platform to turn raw MPA monitoring data into actionable information is a critical but under-recognized obstacle to cross-project learning, comparative analyses, and adaptive resource management.     

Fatigue assessment of ship structures based on equivalent wave probability (EWP) concept (1st report): Proposal of EWP concept and its verification by 8600TEU container ship's onboard hull monitoring

A long-term fatigue assessment method based on EWP concept is proposed. ‘Equivalent wave probability (EWP)’ is the fictitious (H_S, T_m)'s joint probability distribution function (JPDF), for which the frequency distribution of the stress variance R², f(R²), calculated by spectral fatigue assessment agrees with the observed one. By choosing probability function p(R²) to fit f(R²), the R²'s statistical model (R2SM) which represents the relation between the EWP parameters and R²'s population parameters is developed, and the Bayesian inference, which can estimate the EWP parameters from the measured R² data is developed. The EWP at the reference position (RP) can be determined by Bayesian inference from the measured R² through the R2SM at RP. To accurately estimate the measured f(R²) at the target position (TP) from the EWP at RP, an R2SM correction factor at TP, denoted by α_TP, is introduced in the process of assimilating R2SM. The resulting R2SM, which has been assimilated by Bayesian inference using measured data, is referred to as data-assimilated R2SM (DAR2SM). The fatigue assessment using EWP at RP as the input of DAR2SM at TP is called Bayes-EWP-DAR2SM analysis. The validity of Bayes-EWP-DAR2SM analysis is verified by using the long-term (about four years) multi(12)-position hull monitoring (HM) data of an 8,600TEU container ship. The fatigue damages estimated by Bayes-EWP-DAR2SM based solely on the stress history of a single sensor are in agreement with measurements with sufficient accuracy, independent of the chosen data assimilation period. This demonstrates that the multi-position fatigue assessment solely through HM at one RP based on EWP concept is realized.     

Revisiting urban hierarchy and specialization from a maritime perspective

ABSTRACT

Port–city relationships have attracted paramount attention from a variety of scientific disciplines for several decades, such as geography, history, planning, regional science, sociology, and economics to name but a few. Yet, the extent to which maritime traffic specialization obeys the same spatial distribution than other economic activities remains underexplored today. This article tackles these lacunae head-on by proposing an empirical analysis of the way vessel tonnage per main categories of flows (e.g. containers, bulks, passengers) coincides with the demographic size of the world’s coastal and inland city-regions, using novel data on global inter-port vessel movements and harmonized population data over the period 1977–2008. Our main results confirm that such traffic is far from being randomly distributed, as its volume, value, and diversity concentrate at the top of the urban hierarchy. This research motivates the need to further integrate physical connectivity into the study of cities and their development mechanisms.     

pH variability and CO2 induced acidification in the North Sea

A coupled carbonate system–marine ecosystem–hydrodynamic model is used to simulate the temporal and spatial variability in pH across the southern North Sea as it relates to the environmental and biological processes affecting CO₂, namely, photosynthesis and respiration, riverine boundary conditions and atmospheric CO₂ concentrations. Annual pH ranges are found to vary from < 0.2 in areas of low biological activity to > 1.0 in areas influenced by riverine signals, consistent with observations and previous studies. It is shown that benthic, as well as pelagic, activity is an important factor in this variability. The acidification of the region due to increased fluxes of atmospheric CO₂ into the marine system is calculated and shown to exceed, on average, 0.1 pH units over the next 50 years and result in a total acidification of 0.5 pH units below pre-industrial levels at atmospheric CO₂ concentrations of 1000 ppm. The potential for measurable changes in biogeochemistry are demonstrated by simulating the observed inhibition of pelagic nitrification with decreasing pH. However, we conclude that there is a lack of knowledge of how acidification might affect the complex interaction of processes that govern marine biogeochemical cycles and a consequent need for further research and observations.     

The ultimate strength of doubler plate reinforced Y-joints under compression loading

It is common practice in the offshore industry to solve the punching shear problem due to compression by using doubler plate. The finite-element method is a useful tool for studying this problem. The aim of this paper is to study the static strength of doubler plate reinforced Y-joints subjected to compression loading. The finite-element method is adopted in numerical parametric studies. The individual influences of the geometric parameters βand τd （ doubler plate to chord wall thickness ratio） and ld/d1 （ dubler plate length to brace diameter ratio） on the ultimate strength are made clear. The results show the size of plate may have important effects on the strength of reinforced joints. It is found that the ultimate strength of Y-joints reinforced with appropriately proportioned doubler plates can be greatly improved nearly up tothree times to un-reinforced Y-joints.     

Response of benthic infauna and epifauna to ocean disposal of red clay dredged material in the New York Bight: A study using sediment-profile imaging, surface imaging and traditional methods

In 1997, approximately 1 million cubic yards of consolidated red clay was dredged from Newark Bay in New Jersey and deposited on the seafloor at an open-water dredged material disposal site located on the inner continental shelf of the New York Bight. To address concerns about the ability of benthic organisms to colonize the seafloor deposits of this compact, organic-poor red clay, monitoring surveys were conducted in 1998 (1 year after disposal) and 2002 (5 years after disposal). The surveys used a combination of sediment imaging and traditional grab sampling methods to characterize physical and biological conditions over the surface of the red clay deposits in comparison to nearby reference areas consisting of either naturally-occurring, sandy surface sediments or deposits of unconsolidated, muddy dredged material. Sediment-surface and sediment-profile images (SPI) collected in summer 2002 indicated that the surface of the red clay deposits had become much smoother and more heterogeneous in texture compared to images collected in 1998. The images also indicated that these deposits had become colonized to a much greater degree by relatively abundant and diverse infaunal and epifaunal communities compared to 1998. Taxonomic analysis of benthic grab samples confirmed the imaging results and indicated relatively high infaunal organism abundance and diversity over the red clay deposits in 2002 compared to the reference areas. However, the structure of the benthic community inhabiting the red clay was fundamentally different from the communities in the reference areas, due to the differences in sediment texture and composition. The combination of imaging and traditional taxonomic approaches used in this study provided much greater insight on the red clay colonization process than either approach by itself.     

Ground-truthing social vulnerability indices of Alaska fishing communities

Abstract

Community vulnerability is increasingly evaluated through quantitative social indices, typically developed using secondary data sources rather than primary data collection. It is necessary to understand the validity of these indices if they will be used to inform policy and decision making. This paper presents a ground-truthing effort to validate quantitative indices that characterize the well-being of Alaska fishing communities. We utilized ethnographic data collected from 13 representative communities and a capital assets framework to ground-truth the indices, in which qualitative ranks of vulnerability were compared against quantitative indices. The majority (73.8%) of ranks were in complete or moderate agreement and the results indicate that most of the indices are representative of community vulnerability; yet some variables utilized to create the indices could be modified to better reflect realities in Alaska. Indices of commercial fishery engagement and reliance appeared to be more reliable than socio-economic indicators, particularly for smaller fishing communities. We also confirmed that the indices do not capture political, or ecological factors that affect levels of community vulnerability. We conclude that quantitative indices of community vulnerability are useful rapid assessment tools; however, they should be validated, and complemented with ethnographic data prior to their implementation as policy making and management tools.