Sediment profile imaging (SPI) and micro-electrode technologies in impact assessment studies: Example from two fjords in Southern Chile used for fish farming

Two state-of-the-art techniques were used to assess the impact of organic loading from fish farming in two fjords of Southern Chile, Pillan and Reñihue Fjords. A sediment profile imaging (SPI) camera was deployed and sediment microprofiles (oxygen, H₂S, redox and pH) were measured in undisturbed sediment cores collected using a HAPS corer. Four out of seven stations in Pillan Fjord were found to be severely disturbed: SPI images showed azoic conditions (no apparent Redox Potential Discontinuity layer, no evidence of aerobic life form, presence of an uneaten fish food layer, negative OSI scores). These findings were corroborated by very high oxygen consumption rates (700–1200 mmol m^− 2 day^− 1), H₂S concentrations increasing quickly within the sediment column and redox potential decreasing towards negative values within a few mm down core. Results for Reñihue Fjord were not so straightforward. SPI images indicated that most of the stations (R3 to R7) presented well-mixed conditions (high apparent RPD layers, presence of infauna, burrows, etc.), but oxygen profiles yielded consumption rates of 230 to 490 mmol m^− 2 day^− 1 and organic carbon mineralization of 2.16 to 4.53 g C m^− 2 day^− 1. These latter values were close to the limit of aerobic degradation of organic matter although no visible changes were recorded within the sediment column. In view of our findings, the importance of integrating multidisciplinary methodologies in impact assessment studies was discussed.     

Lights, camera and acoustics: Assessing macrobenthic communities at a dredged material disposal site off the North East coast of the UK

This study presents the results of a trial assessment based on a combination of sampling techniques at a dredged material disposal site located off the North East coast of the UK, over 2001 to 2004. The site was surveyed with a high-resolution sidescan sonar system producing a mosaic with 100% coverage of the survey area. Benthic communities and sediments were ground-truthed using a Hamon grab with a video camera. Additionally, the area was also sampled in 2003 with a Sediment Profile Imaging (SPI) camera, which complemented other techniques by providing in situ information on sediment quality, and biogenic activities. An assessment is made of the benefits of combining the results from conventional methods, principally using grab samples, with those from acoustic techniques and optical imaging devices to determine seafloor and macrobenthic conditions. This information has the potential to contribute to the enhancement of routine monitoring programmes within UK waters.     

Carbon flows in Baltic Sea food webs — a re-evaluation using a mass balance approach

The brackish Baltic Sea has been seen as particularly suitable for studies of food webs. Compared to fully marine ecosystems, it has low species diversity, which means fewer trophic linkages to analyse. The Baltic Sea is also one of the best-studied areas of the world, suggesting that most data requirements for food web models should be fulfilled. Nevertheless, the influence of physical and biological factors on trophic interactions and biogeochemical patterns varies spatially in the Baltic Sea, adding considerable complexity to food web studies. Food web structure and processes can be described and compared quantitatively between areas by estimating the flow of matter or energy through the organisms. Most such models have been based on carbon, though studies of complementary flows of other elements limiting production, such as nitrogen and phosphorus would be desirable. However, since ratios between carbon and other elements are used in calculating these flows, it is crucial, as a first step, to quantify the flows of carbon as accurately as possible.In this study, we used the EcopathII software (ver 3.1) to analyse models of carbon flow through the food webs in the three main areas of the Baltic Sea; the Baltic proper, Bothnian Sea and Bothnian Bay. A previously published study on carbon flow in the Baltic Sea [Elmgren, R. 1984. Trophic dynamics in the enclosed, brackish Baltic Sea. Rapp. P.-V. Reun. — Cons. Int. Explor. Mer. (183) 152–169.] was complemented with the data on respiration and flow to detritus [Wulff, F., Ulanowicz, R. 1989. A comparative anatomy of the Baltic Sea and Chesapeeake Bay ecosystems. In: F. Wulff, J.G. Field, K.H. Mann (Eds.), Flow Analysis of Marine Ecosystems: Theory and Practice. New York: Springer-Verlag.] in order to present complete mass balance models of carbon. The purpose of re-evaluating previous models with new analytic tools was to check how well their carbon flows balance, and to provide a basis for improved mass balance models using more recent data, including nutrients other than carbon.The resulting mass balance networks for the Baltic proper, Bothnian Sea and the Bothnian Bay were shown to deviate from steady state. There was an organic carbon surplus of 45, 25 and 18 g C m⁻² year⁻¹ in the pelagic zones of the Baltic proper, Bothnian Sea and Bothnian Bay, respectively. The Ecopath network analysis confirmed that the overall carbon flow was highest in the Baltic proper, somewhat lower in the Bothnian Sea and much lower in the Bothnian Bay. The only clear differences in food web structure between the basins was that the average trophic level was lower for demersal fish in the Bothnian Sea and higher for macrofauna in the Bothnian Bay, compared to the other basins. The analysis showed weakness in our current understanding in Baltic Sea food webs and highlighted areas where improvements could be made with more recent data.     

Dynamics of five-bar COBOT using differential mechanism

COBOT is a new kind of collaborative robot, which can work with people in a shared space. In this paper a new kind of CVT using differential mechanism is introduced, which is major parts of five-bar COBOT and based the feature of nonhlonnmie constraint. The dynamic model of differential mechanism and five-bar architecture COBOT is founded. There are two kinds of coupled mode of two CVT:serial and parallel. In this paper, we present the dynamic model of serial and parallel COBOT take five-bar COBOT as research object. From the dynamic analysis foregoing, both serial and parallel COBOT model are have the feature of nonholonomic constraint. The ending track and moving state are controlled by the force of control motor and operator. The control motor can not control the movement and ending track of COBOT witbout the cooperation of cperator.     

Corrosion analysis of bulk carriers, Part I: operational parameters influencing corrosion rates

This paper considers the physical processes of corrosion that occur in bulk carriers. Three main types of corrosive environments are identified within a bulk carrier, namely, immersion in seawater, exposure to an enclosed atmosphere, and exposure to porous media. Fundamental variables influencing corrosion in each environment of the cargo hold region, ballast tanks and void spaces are identified. These serve to identify operational parameters that affect bulk carrier corrosion. It is proposed that such parameters can be used to obtain corrosion rate databases representative of vessel operation.     

Improving Tidal Turbine Performance Through Multi-Rotor Fence Configurations

Constructive interference between tidal stream turbines in multi-rotor fence configurations arrayed normally to the flow has been shown analytically, computationally, and experimentally to enhance turbine performance. The increased resistance to bypass flow due to the presence of neighbouring turbines allows a static pressure difference to develop in the channel and entrains a greater flow rate through the rotor swept area. Exploiting the potential improvement in turbine performance requires that turbines either be operated at higher tip speed ratios or that turbines are redesigned in order to increase thrust. Recent studies have demonstrated that multi-scale flow dynamics, in which a distinction is made between device-scale and fence-scale flow events, have an important role in the physics of flow past tidal turbine fences partially spanning larger channels. Although the reduction in flow rate through the fence as the turbine thrust level increases has been previously demonstrated, the within-fence variation in turbine performance, and the consequences for overall farm performance, is less well understood. The impact of turbine design and operating conditions, on the performance of a multi-rotor tidal fence is investigated using Reynolds-Averaged Navier-Stokes embedded blade element actuator disk simulations. Fences consisting of four, six, and eight turbines are simulated, and it is demonstrated that the combination of device- and fence-scale flow effects gives rise to cross-fence thrust and power variation. These cross-fence variations are also a function of turbine thrust, and hence design conditions, although it is shown simple turbine control strategies can be adopted in order to reduce the cross-fence variations and improve overall fence performance. As the number of turbines in the fence, and hence fence length, increases, it is shown that the turbines may be designed or operated to achieve higher thrust levels than if the turbines were not deployed in a fence configuration.

     

船舶SOFC燃料电池与汽轮机联合动力装置能效分析(英文)

Strong restrictions on emissions from marine power plants(particularly SOx,NOx)will probably be adopted in the near future.In this paper,a combined solid oxide fuel cell(SOFC)and steam turbine fuelled by natural gas is proposed as an attractive option to limit the environmental impact of the marine sector.The analyzed variant of the combined cycle includes a SOFC operated with natural gas fuel and a steam turbine with a single-pressure waste heat boiler.The calculations were performed for two types of tubular and planar SOFCs,each with an output power of 18 MW.This paper includes a detailed energy analysis of the combined system.Mass and energy balances are performed not only for the whole plant but also for each component in order to evaluate the thermal efficiency of the combined cycle.In addition,the effects of using natural gas as a fuel on the fuel cell voltage and performance are investigated.It has been found that a high overall efficiency approaching 60%may be achieved with an optimum configuration using the SOFC system.The hybrid system would also reduce emissions,fuel consumption,and improve the total system efficiency.     

A Review of Dunes in Today's Society

Prior to Superstorm Sandy, the importance of dunes had been widely overlooked in many coastal societies. However, the stark contrast between New Jersey coastal areas that were and were not protected by dunes has created a positive paradigm shift in coastal law and public dune opinion. Government officials are mandating the construction of artificial dunes along New Jersey's coast, but it is necessary for communities to first understand the complex nature of these unique systems. With the proper knowledge, a dune can be both a protective structure as well as a working habitat that will ultimately better protect upland infrastructure and improve beach health. However, a general lack of terminological consistency among formal media and governing entities makes properly quantifying and assessing dune health difficult and unwarranted ecological conclusions inevitable. Here, dune terminology, “blowout,” “washout,” and “bowling” is clarified and defined and the dynamic nature of dunes is explained.     

Fisheries–Marine Protected Area–Tourism Interactions in Moalboal,Cebu, Philippines

The development of Integrated Coastal Management (ICM) in the Philippines has been underway for more than 30 years. As coastal communities continue to face dwindling resources from both the land and sea, marine protected areas (MPAs) have been regularly utilized as a community-based marine conservation tool. Recently, marine tourism has begun to exert influence as a driver utilized by local communities to promote the establishment of MPAs. Revenue generated through user-fee systems has begun to influence and shape broker–local–tourist (BLT) interactions in Moalboal, Cebu, Philippines. In this article, an account of the social dynamics surrounding MPAs is presented, sources of tension are identified, and recommendations proposed.     

Marine log transportation and handling systems in british columbia: Impacts on coastal management

Abstract

Over 90 percent of British Columbia's annual log harvest enters into complex water‐based systems of transportation, storage, and handling. These systems have considerable impacts on a wide range of coastal resources and uses. A number of site‐specific conflicts have arisen between forestry and preexisting or emerging values including fisheries, mariculture, recreational boating, and harbor redevelopment. Specific data on the impacts leading to conflict are often fragmentary. However, concerns about highly valued and fragile areas‐particularly estuariesalong with industrial concerns regarding log losses and handling efficiency, have prompted changes in log handling. These include moves to dryland sorting, log bundling, and a redistribution of forestry activities in estuaries to accommodate other values. Conflict adjustments and responses have in the past been largely ad hoc and attempted in a jurisdictional vacuum concerning control of coastal management. A more inclusive strategy is now slowly emerging, which involves the coordinated participation of federal, provincial, and industrial interests.