Tributyltin in marine sediments and Philippine green mussels (Perna viridis) in Manila Bay

Tributyltin (TBT) is a pollutant, mainly introduced to the environment as insecticides, fungicides, bactericides, wood preservatives and marine antifouling agent. Concentrations of TBT and its degradation products were isolated from the bivalve Perna viridis and marine sediments collected from selected coastal areas along Manila Bay. In all samples, the extremely toxic TBT compound was detected, calculated as Sn. In sediments, measured concentration ranged from the limit of detection of 0.5 to 9.0 ng Sn g^?1. Highest levels of TBT were observed at the inner and northern part of the bay, adjacent to coastal areas of varying land and water use (i.e., aquaculture, fishpond, mangrove forests, industrial establishments, and ports). However, the levels decrease near the bay entrance. Accumulation in this area can also be deduced from the movement of the prevailing wind and hydrodynamic behavior of the bay during the time of sampling, which transports suspended sediments from the eastern coast of Manila to the northern coast of Bulacan. In green mussels, the levels of TBT ranged from 2.1 to 8.9 ng Sn g^?1. While these values are relatively low, concentrations as low as 0.659 ng Sn g^?1 have been reported to be toxic to molluscs. The environmental levels of organotin species determined in the samples are comparatively low by global standards. Nevertheless, there is a need to estimate the levels of TBT in coastal waters and its associated uses, to evaluate the effectiveness of imposed regulation prohibiting the application of organotin compounds (OTs) as biocides in antifouling agents on ships and aquaculture facilities.     

片体间距对高速三体船水动力性能影响的比较分析(英文)

This paper numerically investigates the influence of separation variation of the outriggers on the hydrodynamic performance of a high speed trimaran (HST) aiming at improving its applicability in diverse realistic disciplines. The present investigation was performed within the framework of the 2-D slender body method (SBM) by calculating the resistance of three symmetric trimaran series moving in a calm free surface of deep water. Each trimaran series comprises of 4681 configurations generated by considering 151 staggers (50%≤α≤+100%), and 31 separations (100%≤β≤400%) for 81 Froude numbers (0.20≤Fn≤1.0). In developing the three trimaran series, Wigley-st, AMECRC-09, and NPL-4a models were used separately for both the main and side hulls of each individual series models. A computer macro named Tri-PL was created using the Visual Basic for Applications. Tri-PL sequentially interfaced Maxsurf then Hullspeed to generate the models of the three trimaran series together with their detailed hydrostatic particulars, followed by their resistance components. The numerical results were partially validated against the available published numerical calculations and experimental results, to benchmark the Tri-PL macro and hence to rely on the analysis outcomes. A graph template was created within the framework of SigmaPlot to visualize the significant results of the Tri-PL properly.     

Monitoring and modeling of coastal waters in support of environmental preservation

The improved monitoring and modeling capability resulting from recent technological advances in oceanographic sensors, computer processing power, and telecommunications can play a major role in environmental preservation. In particular, this capability can help improve: safe navigation and thus the prevention of maritime accidents that lead to hazardous spills; the effective cleanup of hazardous spills when they do occur; the real-time assessment of water quality problems; the assessment of long-term trends and variability due to both anthropogenic and climate change effects; and the understanding of key physical, chemical, and ecological processes. Presented at the International Conference on Technologies for Marine Environment Preservation (MARIENV’95), Tokyo, Japan, September 24–29, 1995     

The impact of low sulphur fuel requirements in shipping on the competitiveness of roro shipping in Northern Europe

Annex VI of the MARPOL Convention aims for a reduction in sulphur oxide emissions from ships. The limits applicable at sea in Emission Control Areas (ECAs) were reduced from 1.5% to 1% in 2010 and are planned to be further reduced to 0.1%, effective from 1 January 2015. This paper analyses the impact of the International Maritime Organization’s Tier II/III standards introduced by Annex VI amendments adopted in October 2008 on costs and prices of roro (roll on/roll off) traffic in the ECAs in North Europe and on the competitiveness of roro shipping in the ECAs compared to trucking. We demonstrate that the new Annex VI agreement may be quite costly for the participants in the shipping industry and will result in higher freight rates. Based on a detailed price analysis on modal competition between the roro/truck option and the ‘truck only’ option on thirty origin–destination routes linked to the ECAs, we conclude that the use of low sulphur fuel is expected to increase the transport prices particularly on the origin–destination relations with a medium or long short sea section. The paper also presents the results of a survey among leading short sea operators in the ECAs in view of providing more insight on expected modal shifts and price elasticity in the short sea market.     

Shipwrecks: The past in the present

Abstract

Historic shipwrecks are a recently recognized group of historic resources. These shipwrecks attract sport divers, archeologists, and treasure hunters. States have always claimed the historic shipwrecks embedded in their submerged lands. States manage these resources as part of their historic preservation programs. However, since 1981, state authority has been challenged by the federal court sitting in admiralty. Cases have been decided in Florida, Massachusetts, Maryland, Texas, and Georgia; however, only one Florida case went against the states but the expensive litigation has been a drain on state treasuries.

Bills currently before the U.S. Congress will affirm state title and encourage states to put effort into state programs for historic shipwrecks. This article briefly describes the populations interested in shipwrecks, current case law, state law and state programs, and finally the federal legislative proposal.     

Military contracts to water transportation services in the United States

Long excluded from academic analysis, military expenditures on water transportation are a significant aspect of the industry, especially given the rapid increases in the U.S. military budget in the 1980s. This paper begins with an overview of military relations with the water transporation industry; next, it proceeds to a survey of the spatial dimensions of prime contracts awarded to water transporation and dredging firms in the U.S. Thirdly, it explores their economic impacts on teh U.S. economy using input-output analysis.     

Water quality and shellfish management in tillamook bay,Oregon

The contamination of shellfish by pathogenic bacteria and viruses is a concern of shellfish producers, distributors, and consumers. To address these water quality concerns, the National Shellfish Sanitation Program has classified shellfish growing waters as approved, conditionally approved, or prohibited. The Tillamook estuary is one of Oregon's primary shellfish harvest areas. Degradation of water quality in Tillamook Bay has been linked to oyster bed closures, declines in salmonid populations, and decreases in recreational use of estuarine resources. In this study, water quality concerns related to shellfish management are addressed by examining the patterns of fecal coliform bacteria (FCB) concentration in Tillamook Bay. A oneway analysis of variance was used to compare log‐transformed FCB concentrations in prohibited, restricted, and conditional shellfish management areas. We found (I) a difference in Tillamook Bay water quality between all three areas and (2) a change in FCB concentrations through time in each management area. Since the designation of shellfish management areas affects the economy and public health, monitoring practices need to be reevaluated in order to draw more refined conclusions about water quality trends in Tillamook Bay.     

Inter-annual variability of hypoxic conditions in a shallow estuary

Water quality data from two monitoring programs in the Pamlico River Estuary (PRE) were analyzed for dissolved oxygen (DO), salinity, temperature, and nutrient concentrations. Data were collected bi-weekly at 8 stations from 1997 to 2003 by East Carolina University and continuously at three stations from 1999 to 2003 by the U.S. Geological Survey. Hypoxic conditions were observed mostly in the upper to middle estuary, but the frequency of hypoxic events varied between years. During June to October in 1997–1999 (referred to as the oxic summers) bottom water hypoxia (DO < 2 mg l^− 1) was found in 8.7% of the observations. By contrast, during June to October in 2001–2003 (referred to as the hypoxic summers), 37.9% of the total measurements had DO concentrations less than 2 mg l^− 1. The more frequent and/or prolonged hypoxic conditions during the hypoxic summers were closely associated with stronger salinity stratification and greater loadings of nutrient and particulate matter.Salinity stratification appeared to be governed by patterns of freshwater discharge, and frequency of wind mixing events. The “oxic” summers were characterized by continuous low freshwater inflow (except one extremely high flow event due to hurricanes), stronger northeastward wind, and more frequent wind mixing events. In contrast, the hypoxic summers were characterized by frequent moderate freshwater inflow events, and fewer wind mixing events.The greater loadings of nutrient (nitrate, ammonium, and phosphate) and particulate matter during the hypoxic summers were primarily due to higher river discharges. At the head of the PRE, no significant differences were found in concentrations of nutrient and particulate nitrogen between the oxic and the hypoxic summers. In addition, chlorophyll a concentrations were averaged above 30 μg l^− 1 (maximum 167 μg l^− 1) during the hypoxic summers, significantly higher than those during the oxic summers (averaged around 15 μg l^− 1).     

Management of corals and coral ecosystems in the United States

Abstract

Corals and coral communities provide substantial societal benefits by virtue of their recreational and esthetic appeal, the habitat provided for commercially harvested fish and shellfish, the structural foundation provided for productive coastal ecosystems, and the market value of harvested coral specimens. Coral resources are subject to adverse effects from pollution, dredging, specimen collecting, anchor damage, commercial fishing, overharvesting, and activities related to offshore petroleum development. Management programs which protect coral resources in the United States comprise a patchwork of separate federal and state programs. They attempt to adapt broad regulatory authorities for parks, fisheries, offshore mineral resources, and other subjects for the purpose of coral conservation. These programs embody species‐specific, area‐specific, and generic approaches to coral management. This paper traces the evolution of U.S. coral management programs and comments on their respective strengths and weaknesses. Alternative approaches for strengthening management systems could include new coordinating committees, legislation, memoranda of agreement between involved agencies, and others.     

Protecting Estuaries and Coastal Wetlands through State Coastal Zone Management Programs

This article, one part of the National Coastal Zone Management Effectiveness Study, evaluates the effectiveness of state coastal management programs in protecting estuaries and coastal wetlands. State programs were evaluated in a four-step, indicatorbased process to estimate (1) the relative importance of the issue; (2) the potential effectiveness of programs based on the policies, processes, and tools used; (3) outcome effectiveness based on on-the-ground indicators; and (4) overall performance, where outcome effectiveness was compared to issue importance and potential effectiveness. State evaluations were synthesized to provide a national perspective on CZM contributions and effectiveness in estuary and wetland protection. Although on-the-ground outcome data were sparse, they were sufficient to determine at least probable levels of effectiveness for about one-third of the states. Of these states, 80% were performing at expected or higher levels, considering how important the issue was in their state, and the scope and strength of the policies, processes, and tools they had deployed. Monitoring and record keeping, freshwater wetland management, and the use of nonregulatory restoration in coastal management were common program weaknesses. The evaluation approach and indicators used here are recommended as a starting point for designing a national monitoring and performance evaluation system addressing this CZM objective.     

State Wetland Protection: A Matter of Context?

Models of integrated management emphasize the role of the surrounding socioeconomic and political environment in influencing management choices for natural resources. In this study, we explore a model that examines the influence of socioeconomic and political variables on the wetland management programs of U.S. states. Logistic regression was used to identify environmental, socioeconomic, and political variables that explained variation in state wetland programs. The likelihood of strong planning, nonregulatory, regulatory, and overall programs increases as the importance of fisheries in the state increases (p &lt; 0.05), but decreases as population density increases (p &lt; 0.15). Furthermore, there is an increasing likelihood of stronger regulatory and overall programs as environmental group activity and industry importance increases (p &lt; 0.05). These findings provide empirical evidence to support the contention that management approaches used in one state often must be adapted to fit the realities of another given state.     

Climate Variability and Estuarine Water Resources: A Case Study from Tampa Bay,Florida

Natural variability in the myriad of physical processes that impact and control estuaries occurs at time scales that typically may exceed or partly exceed many monitoring programs. With respect to documenting and monitoring impacts of human influences- on estuaries, it is therefore important to frame the results of short-term monitoring programs within the context of longer term natural variability in the environment. In the Tampa Bay, Florida area, climate variability strongly influences seasonal precipitation, stream flow, and salinity. In particular, El Niño-Southern Oscillation impacts during the winter have the potential to influence both the availability of surface water for water supply withdrawal and the evaluation of the impacts of surface water withdrawals on the ecosystem.     

The U.S. national marine sanctuary program: An analysis of the program's implementation and current issues

Abstract

The U.S. National Marine Sanctuary Program was established in 1972 by Title III of the Marine Protection, Research, and Sanctuaries Act (16 U.S.C. §1431 et seq.). In this article, we discuss the development of the sanctuary concept, and the original intent of Congress, and analyze how it was applied by the sanctuary program. Differences in interpretation of the program's purpose are examined, including discussion of the multiple‐use management concept, an important but controversial management technique used in the sanctuaries. The continuing efforts by Congress and the National Oceanic and Atmospheric Administration to clarify the program's purpose are investigated. The program's administrative history is explained and the current sanctuaries and active candidates are briefly described. In light of the 1988 reauthorization of the Marine Sanctuary Act, the current issues facing the program are analyzed. Finally, we draw conclusions and make recommendations for the program's future.     

On the numerical accuracy of the prediction of resistance coefficients in ship stern flow calculations

This article presents a study on the accuracy of the numerical determination of the friction and pressure resistance coefficients of ship hulls. The investigation was carried out for the KVLCC2 tanker at model- and full-scale Reynolds numbers. Gravity waves were neglected, i.e., we adopted the so-called double-model flow. Single-block grids with H–O topology were adopted for all the calculations. Three eddy viscosity models were employed: the one-equation eddy viscosity and the two-equation models proposed by Menter and the TNT version of the two-equation k-ω model. Verification exercises were performed in sets of nearly geometrically similar grids with different densities in the streamwise, normal, and girthwise directions. The friction and pressure resistance coefficients were calculated for different levels of the iterative error and for computational domains of different size. The results show that on the level of grid refinement used, it is possible to calculate the viscous resistance coefficients in H–O grids that do not match the ship contour with a numerical uncertainty of less than 1%. The differences between the predictions of different turbulence models were larger than the numerical uncertainty; however, these differences tended to decrease with increases in the Reynolds number. The pressure resistance was remarkably sensitive to domain size and far-field boundary conditions. Either a large domain or the application of a viscous–inviscid interaction procedure is needed for reliable results. This work was presented in part at the International Conference on Computational Methods in Marine Engineering—MARINE 2007, Barcelona, June 3–4, 2007.     

Three-dimensional numerical wave tank simulations on fully nonlinear wave–current–body interactions

A finite-difference scheme and a marker-and-cell (MAC) method are used for numerical wave tank (NWT) simulations to investigate the characteristics of nonlinear wave motions and their interactions with a stationary three-dimensional body in the presence of steady uniform currents. The Navier–Stokes (NS) equation is solved in the computational domain, and the boundary values are updated at each time-step by a finite-difference time-marching scheme in the frame of a rectangular coordinate system. The fully nonlinear kinematic free-surface condition is satisfied by the marker–density function technique developed for two fluid layers. The incident waves are generated from the inflow boundary by prescribing a velocity profile resembling the motions of a flexible flap wavemaker, and the outgoing waves are numerically dissipated inside an artificial damping zone located at the end of the tank. Using the NS–MAC NWT, nonlinear wave and current interactions around a stationary vertical truncated circular cylinder are studied, and the results are compared with the experimental results of Mercier and Niedzwecki, a time-domain NWT based on linear potential theory, a fully nonlinear NWT, and a second-order diffraction computation. Received: July 3, 2001 / Accepted: September 25, 2001     

Norwegian North Sea action programme: Analysis of measures to reduce nutrient inputs

According to the terms of the Ministerial Declaration on the Protection of the North Sea, input of the nutrients phosphorus (P) and nitrogen (N) to the coast from the Norwegian‐Swedish border to Lindesnes should be reduced by about 50% between 1985 and 1995. The State Pollution Control Authority (SFT) has analyzed how Norway can achieve this reduction in the most cost‐effective way and at the same time achieve the greatest possible improvement in water quality along the Norwegian coast and in its watercourses.

Two alternative sets of measures were analyzed, both of which would meet the requirements of the Declaration. The lowest‐cost alternative would have average annual costs of about NKr 930 million (U.S.S150 million), and investments of about NKr 4000 million (U.S. $643 million). However, this set of measures would not take account of local water quality, and measures would therefore not always be introduced where the need is most pressing. SFT proposed that an alternative set of measures be implemented, almost all of which would also help to achieve local goals for water quality. This alternative will have annual costs of about NKr 980 million (U.S.$158 million), and investments of about NKr 4100 million (U.S.$659 million).     

Study of damaged ship motions taking into account floodwater dynamics

This paper presents an application of shallow water theory to describe the motion of floodwater inside a rolling ship in damage condition. The time domain theoretical approach to the coupled problems of ship and water inside compartment motions is briefly described, including the method used to solve for the water motion characteristics and forces exerted on the ship. This approach is applied to the study of the behaviour of a passenger Ro–Ro ship in regular beam seas and numerical results are given for the intact and damaged conditions. Comparison is made with experimental results. For the damaged condition, the characteristics of the floodwater motion are studied in the time domain for a number of different wave frequencies. The shape of the free-surface and phase of water motion in relation to the ship roll motion are shown for several wave frequencies. The dynamic floodwater roll moment is also shown and compared with the static roll moment (flat horizontal free surface), allowing the conclusion that the dynamic roll moment is much larger than the static roll moment, for high wave frequencies, and is in phase opposition in relation to the roll motion.     

Determinants of the damage cost and injury severity of ferry vessel accidents

This study investigates determinants of the property damage cost and injury severity of ferry vessel accidents. Detailed data of individual ferry vessel accidents for the 11-year timeperiod 1991–2001 that were investigated by the U.S. Coast Guard are used to estimate ferry-vessel accident property damage cost and injury severity equations. Tobit regression is used to estimate the former equation and the ordered probit model is used to estimate the latter. Property damage costs include damage costs to the vessel itself, its cargo and contents, and other-property damage (e.g., damage to pier structures and waterfront facilities). Injury severity for a ferry vessel accident is measured as an ordinal variable — no injuries, non-fatal injuries and fatal injuries. Damage cost and injury severity of individual ferry vessel accidents are expressed as functions of the type of vessel accident, vessel characteristics, vessel operation phase, weather/visibility conditions, type of waterway, type of vessel propulsion, type of vessel hull construction and cause of vessel accident. The property damage estimation results suggest that allision, collision and fire ferry vessel accidents incur more vessel property damage cost per vessel gross ton than other types of accidents. The injury severity estimation results suggest that injury severity is greater when the ferry vessel accident is caused by human error as opposed to vessel and environmental factors.     

Mixed analysis of shell and solid elements using the overlaying mesh method

 This article presents a mixed method of analyzing shell elements and solid elements using the overlaying mesh method. In the structural design of a ship's hull, the shell elements are used for the global model. However, the solid elements are necessary to analyze the stress concentration zones or the vicinity of a crack. In such cases, the models are analyzed using zooming analysis, in which the results of a global model analysis are transferred to a local model analysis by imposing boundary conditions. This method is more advantageous than zooming analysis in terms of the accuracy of the solution and the modeling flexibility. Some examples of a plate model with a cracked surface or with a projection are shown in order to demonstrate the effectiveness of the method. Received: August 6, 2002 / Accepted: November 25, 2002 Address correspondence to: S. Nakasumi (sumi@nasl.t.u-tokyo.ac.jp) Updated from the Japanese original, which won the 2002 SNAJ prize (J Soc Nav Archit Jpn 2001;189:219–224; and 190:655–662)     

American Samoa: Establishing a coastal area management model for developing countries

Abstract

Debate over the appropriateness of U.S. approaches to coastal management procedures for developing countries has increased over the past few years. The coastal management program which was developed for American Samoa offers the opportunity to test the utility of the U.S. approach to CZM for developing nations.

American Samoa represents a blend of traditional and new cultures and thus may be a microcosm of developing countries. American Samoa's development of a CZM plan is examined with emphasis on similarities and differences with U.S. experience. A culture‐oriented framework is presented which can shape programs appropriate to developing countries. Finally, a process and a set of guidelines provide an outline for those attempting the difficult task of applying U.S. environmental planning and management to other countries.