Marine reserves—the need for networks

Meiofauna associated with bryophyte and gravel habitats in two small alpine streams was investigated to determine its potential importance to stream communities. These invertebrates are traditionally neglected in stream surveys and their ecological roles poorly understood. Twenty‐one operational taxonomic units (OTUs) were found during the study, of which at least six were undescribed (two Copepoda and four Acarina). Meiofaunal densities were higher at the unshaded site than the shaded site, and higher within bryophyte than gravel habitats. Stepwise multiple regression analyses illustrated the importance of bryophytes to members of the meiofauna in each stream, and different meiofaunal communities were found associated with aquatic bryophytes and gravels. The high densities of Chironomidae, Nematoda, Copepoda, Tardigrada, and Rotifera associated with bryophytes may reflect the food value of the high periphyton biomass associated with these plants, and the shelter they offer from fast water currents. Although hyporheic meiofaunal taxa are known to move into interstices of mineral substratum for shelter, meiofauna associated with bryophytes dwell among stems and in leaf axils where they also find shelter. Because bryophyte‐dwelling meiofauna occur in very high densities, they probably play an important, if as yet unknown, role in energy transfer in streams.     

A Maximum-Entropy Method for Estimating the Spectrum

Based on the maximum-entropy(ME)principle,a new power spectral estimator for random waves is derived in the form of S～(ω)=a/8H~2(2π)~(d 1)ω~-~((d 2))exp[-b(2π/ω)~n],by solving a variational problem subject to some quite general constraints.This robust method is comprehensive enough to describe the wave spectra even in extreme wave conditions and is superior to periodogram method that is not suitable to process comparatively short or intensively unsteady signals for its tremendous boundary effect and some inherent defects of FFT.Fortunately,the newly derived method for spectral estimation works fairly well,even though the sample data sets are very short and unsteady,and the reliability and efficiency of this spectral estimator have been preliminarily proved.     

A three-layer model for the thermal structure in the Huanghai Sea

A one-dimentional three-layer model for the thermal structure in the Huanghai Sea is presented in this study, me model consists of the upper mixed layer caused by heating and wind mixing, the lower mixed layer driven by tidal mixing, and the thermocline with certain thickness. The entrainment velocities of the upper and lower layers are obtained respectively. The results show that the model is capable of describing the development and decline processes of the seasonal thermocline in the Huanghai Sea, simulating successfully the Huanghai Sea Cold Water Mass, the nearshore front and surface cold water off North Jiangsu and explaining reasonably their formation mechanisms as well as the strong thermocline off Qingdao. It is suggested that the tidal mixing plays key role in the formation of the nearshore front off North Jiangsu and the strong thermocline off Qingdao. The wind mixing and the tidal mixing make the lower layer water with high nutrients go up to the upper layer. This physical process may be sig     

A stability analysis for the sheared oil film contained by the boom

According to the observation in experiment of stability of the oil film, the assumption of velocity distribution for both the water flow and the oil film is introduced. On the basis of the assumption, Orr-Sommerfeld stability equation is applied to develop the method of determining the critical velocity of the oil film, and the criterion for stability of the oil film is obtained. Meanwhile, a formula describing the relation between the thickness of the oil film and the velocity of the water flow is also given and examined by the laboratory experiment.     

A two-layers model for the summer circulation of the East China Sea

Ａｔｗｏ－ｌａｙｅｒｓｍｏｄｅｌｆｏｒｔｈｅｓｕｍｍｅｒｃｉｒｃｕｌａｔｉｏｎｏｆｔｈｅＥａｓｔＣｈｉｎａＳｅａ￥ＬｉａｎｇＸｉａｎｇｓａｎａｎｄＳｕＪｉｌａｎ（ＳｅｃｏｎｄＩｎｓｔｉｔｕｔｅｏｆＯｃｅａｎｏｇｒａｐｈｙ，ＳｔａｔｅＯｃｅａｎｉｃＡｄ...     

Marine geodesy— a direction for the future

The sensitivity of the ocean mixed layer response to different parameters such as model horizontal resolution, vertical temperature gradient and eye size is investigated in response to moving Indian Ocean cyclone. For this, a one and one-half layer wind-driven reduced-gravity ocean model is forced with synthetic cyclonic vortex. The sensitivity studies are carried out for a cyclone moving along idealized tracks, initially and then for three observed cyclones (TC 01A), (TC02B) and (TC04A) during 2004. Increasing model resolution resulted in stronger ocean response. The role of initial vertical temperature gradient in modulating the ocean response is found to be important.     

Sharing the catch or catching the shares: Catch shares for the western Pacific region?

The applicability of catch shares programs is evaluated for the various fisheries of the Western Pacific Fishery Management Council region in each of the archipelagoes. Implementation of Catch Shares programs in the region is problematic, but would require better data to be done fairly and equitably. Catch shares are currently under initial consideration for the Hawaii and American Samoa longline fisheries and the Hawaii Deep 7 bottomfish fishery. It is argued that current conditions in all the other small boat fisheries in the region make them inappropriate for catch shares management. Overfishing and the “race for fish” are not yet an issue for these fisheries and some are underdeveloped. Catch share programs can cause significant negative social consequences for Western Pacific communities because data on fishermen's participation, catch histories, and motivations to fish for cultural needs is not adequate for any initial allocation scheme to be developed equitably. The prevailing Western Pacific cultural value of sharing the fish by gifting portions, sharing the catch widely and sharing fishing opportunities widely is in clear conflict with the individualized commercial profit motive philosophy of fisheries that are appropriate for catch shares. The small boat fisheries lack adequate monitoring and enforcement, and do not have a total allowable catch or quota. Nor do they usually have a demonstrated need for one. Preliminary community outreach by Council staff and community discussion of catch shares shows a general lack of information yet a potential for strong resistance to the imposition of catch shares.     

Conserving the common heritage of humankind – Options for the deep-seabed mining regime

The seabed in areas beyond national jurisdiction is the common heritage of mankind (CHM), as declared in the 1982 United Nations Convention on the Law of the Sea. The CHM principle requires not only the sharing of benefits (the subject of a parallel article by the authors) but also the conservation and preservation of natural and biological resources for both present and future generations. The International Seabed Authority, tasked with operationalising the CHM principle in the context of deep-seabed mining, has not yet defined which measures it will take to give effect to environmental aspects of the CHM principle. This article seeks to contribute to the discussion about the operationalization of the CHM principle by specifically examining the environmental dimension of the CHM principle. To this end, the article interprets the CHM principle in the context of sustainable development and discusses a number of potential options the Authority could consider to support the application of the CHM principle. These include: funding scientific research to increase knowledge about the deep ocean for humankind; ensuring public participation in the decision-making process; debating the need for and alternatives to deep-seabed mining; determining conservation targets and levels of harm deemed acceptable; limiting environmental impacts; preserving mineable sites for future generations; compensating humankind for environmental harm; and ensuring enforcement.     

Statistic Analysis of the Annual Extreme Wave Parameters for the Coast of China

- According to the need of project design for offshore engineering and coastal engineering, this paper statistically analyses the annual extreme data of waves acquired at 19 observation stations along the coast of China. Five kinds of distribution curves are adopted: Pearson Ⅲ(P-Ⅲ), Log-Extreme I (LE), Log-Normal(LN), Weibull(W) and Exponential r(Eг) to check the adaptability to the long-term distribution of annual extreme of wave in the China Sea areas. The New Curve Fittling Method (NFIT) method and Probability Weighted Moments (PWM) method are used to estimate the distribution parameters and thereby to derive the design wave parameters with different return periods at 19 observation stations. The test results show that by combining Eг distribution and NFIT parameter estimation and optimum seeking by computer, the design wave parameters can be estimated with high accuracy, high speed and high efficiency, and the randomness of the estimated results can be avoided.     

Evidence for water exchange between the South China Sea and the Pacific Ocean through the Luzon Strait

An analysis of historical oxygen data provides evidence on the water exchange between theSouth China Sea (SCS) and the Pacific Ocean (PO). In the vicinity of the Luzon Strait (LS) , the dissolved oxygen concentration of sea water is found to be lower on the Pacific side than on the SCS side at depths between 700 and 1500 m (intermediate layer) , while the situation is reversed above 700 m (upper layer) and below 1 500 m (deep layer). The evidence suggests that water exits the SCS in the intermediate layer but enters it from the Pacific in both the upper and the deep layers, supporting the earlier speculation that the Luzon Strait transport has a sandwiched structure in the vertical. Within the SCS basin, the oxygen distribution indicates widespread vertical movement, including the upwelling in the intermediate layer and the downwelling in the deep layer.     

Aquaculture and the poor-Is the culture of high-value fish a viable livelihood option for the poor?

This study evaluates the role of high-value fish culture in the livelihoods of coastal households in southern Thailand. The study shows that grouper culture, promoted as an alternative to destructive fishing practices, can make a substantial contribution to household incomes. However, fishing and aquaculture play contrasting roles in the livelihoods of coastal fishers and should be considered as complementary rather than alternative occupations. The study found that poorer households can benefit significantly from raising grouper in cages if certain conditions are met, including access to credit and the substitution of financial for natural capital.     

Numerical simulation for the two-dimensional nonlinear shallow water waves

This study deals with the general numerical model to simulate the two-dimensional tidal flow, flooding wave (long wave) and shallow water waves (short wave). The foundational model is based on nonlinear Boussinesq equations. Numerical method for modelling the short waves is investigated in detail. The forces, such as Coriolis forces, wind stress, atmosphere and bottom friction, are considered. A two-dimensional implicit difference scheme of Boussinesq equations is proposed. The low-reflection outflow open boundary is suggested. By means of this model,both velocity fields of circulation current in a channel with step expansion and the wave diffraction behind a semi-infinite breakwater are computed, and the results are satisfactory.     

What is the ecosystem approach for fisheries management?

The ecosystem approach for fisheries management is a widely accepted concept and various international instruments require its application. However, there are various interpretations of the ecosystem approach and its application almost always brings about confrontations and resistance among managers, proponents, and stakeholders. This paper categorizes the ecosystem approach into four distinguishable types: bycatch mitigation, multi-species management, protection of vulnerable ecosystems, and integrated approach. Furthermore, the lack of identification and understanding of specific management goals is hampering the application of the ecosystem approach. Unless the stakeholders understand and accept the goals, the ecosystem approach will not succeed.     

A numerical study for the coastal upwelling and the coastal front off Zhejiang coast

A two-dimensional numerical model is constructed to study the interaction between the coastal upwelling and the coastal front off Zhejiang coast in summer. In the f-plane model, the shelf topography, continuous stratification, and Richardson number-dependent eddy coefficients are considered. The results show that the coastal up-welling off Zhejiang in summer can be divided into two regions, the nearshore one (Region A) and the offshore one (Region B). In Region A, the alongshore wind stress has more important effect on the coastal upwelling while in Region B, the upwelling is mainly induced by the Taiwan Warm Current. The results also suggest that the formation of coastal front off Zhejiang in summer is closely related to the strength of the coastal upwelling in Region A.     

Satellite-observed trends in the Arctic sea ice concentration for the period 1979–2016

Arctic sea ice cover has decreased dramatically over the last three decades. This study quanti?es the sea ice concentration(SIC) trends in the Arctic Ocean over the period of 1979–2016 and analyzes their spatial and temporal variations. During each month the SIC trends are negative over the Arctic Ocean, wherein the largest(smallest) rate of decline found in September(March) is-0.48%/a(-0.10%/a).The summer(-0.42%/a) and autumn(-0.31%/a) seasons show faster decrease rates than those of winter(-0.12%/a) and spring(-0.20%/a) seasons. Regional variability is large in the annual SIC trend. The largest SIC trends are observed for the Kara(-0.60%/a) and Barents Seas(-0.54%/a), followed by the Chukchi Sea(-0.48%/a), East Siberian Sea(-0.43%/a), Laptev Sea(-0.38%/a), and Beaufort Sea(-0.36%/a). The annual SIC trend for the whole Arctic Ocean is-0.26%/a over the same period. Furthermore, the in?uences and feedbacks between the SIC and three climate indexes and three climatic parameters, including the Arctic Oscillation(AO), North Atlantic Oscillation(NAO), Dipole anomaly(DA), sea surface temperature(SST), surface air temperature(SAT), and surface wind(SW), are investigated. Statistically, sea ice provides memory for the Arctic climate system so that changes in SIC driven by the climate indices(AO, NAO and DA) can be felt during the ensuing seasons. Positive SST trends can cause greater SIC reductions, which is observed in the Greenland and Barents Seas during the autumn and winter. In contrast, the removal of sea ice(i.e., loss of the insulating layer) likely contributes to a colder sea surface(i.e., decreased SST), as is observed in northern Barents Sea. Decreasing SIC trends can lead to an in-phase enhancement of SAT, while SAT variations seem to have a lagged in?uence on SIC trends. SW plays an important role in the modulating SIC trends in two ways: by transporting moist and warm air that melts sea ice in peripheral seas(typically evident inthe Barents Sea) and by exporting sea ice out of the Arctic Ocean via passages into the Greenland and Barents Seas, including the Fram Strait, the passage between Svalbard and Franz Josef Land(S-FJL),and the passage between Franz Josef Land and Severnaya Zemlya(FJL-SZ).     

A requiem for the IFQ in US fisheries?

Despite their apparent economic benefits to harvesters, individual fishing quotas (IFQs) have only been adopted in three US fisheries: Mid-Atlantic surf clam and ocean quahog; South Atlantic wreckfish; and, North Pacific halibut and sablefish. During the 1996 reauthorization of the Magnuson-Stevens Fishery Conservation and Management Act, Congress temporarily blocked implementation of additional IFQ programs in US fisheries. In this paper, we argue that because of the emergence of an alternative, the cooperative, it is unlikely that new IFQs will be adopted in federally managed US fisheries. From an economic perspective, cooperatives offer the advantage of eliminating production externalities that may remain under an IFQ program with relatively large owner classes. More significantly, development of IFQ programs appears to be increasingly overwhelmed by the proliferation of both equity concerns and seemingly interminable rent-seeking behavior — both issues that can effectively block adoption of IFQs. Ironically (and paradoxically?), by reducing the scope of the equity issues acknowledged, the cooperative alternative narrows the pool of claimants and modifies the behavior of the remainder, making implementation more likely. A further irony exists in that IFQs are widely thought to be best designed at the local/regional level while part of the appeal of the cooperative model is that it appears to shortcut the often protracted nature of the local/regional political process by relying on direct intervention from Washington, DC, in the form of actions by Congress or the Justice Department.     

Evaluation of the simulation capability of the Wavewatch Ⅲ model for Pacific Ocean wave

Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model(v3.14 and v4.18) are compared and assessed in this study through comprehensive observations, including altimeter significant wave height, advanced synthetic aperture radar swell, and buoy wave parameters and spectrum. In addition to the evaluation of typically used integral parameters, the spectra partitioning method contributes to the detailed wave system and wave maturity validation. The modified performance evaluation method(PS) effectively reduces attribute numbers and facilitates the overall assessment. To avoid possible misleading results in the root mean square error-based validations, another indicator called HH(indicating the two authors) is also calculated to guarantee the consistency of the results. The widely used Tolman and Chalikov(TC) package is still generally efficient in determining the integral properties of wave spectra but is physically deficient in explaining the dissipation processes. The ST4 package performs well in overall wave parameters and significantly improves the accuracy of wave systems in the open ocean. Meanwhile, the newly published ST6 package is slightly better in determining swell energy variations. The two packages(ACC350 and BJA) obtained from Wavewatch III v3.14 exhibit large scatters at different sea states. The three most ideal packages are further examined in terms of reproducing waveinduced momentum flux from the perspective of transport. Stokes transport analysis indicates that ST4 is the closest to the NDBC-buoy-spectrum-based transport values, and TC and ST6 tend to overestimate and underestimate the transport magnitude, respectively, in swell mixed areas. This difference must be considered,particularly in air–wave–current coupling research and upper ocean analysis. The assessment results provide guidance for the selection of ST4 for use in a background Pacific Ocean hindcast for high wave climate research and China Sea swell type analysis.     

The MIRS Microwave Radiometer–Spectrometer as the Basis for the Convergence Space Experiment

Izvestiya, Atmospheric and Oceanic Physics - The MIRS microwave radiometer–spectrometer is described. The instrument is being developed using a conceptual design that was the first stage of...     

Artificial Neural Networks for the analysis of spread⿿mooring configurations for floating production systems

This work presents the development of Artificial Neural Networks for the analysis of any arbitrarily defined spread-mooring configuration for floating production systems (FPS), considering a given scenario characterized by the water depth, metocean data, characteristics of the platform hull, and the riser layout. The methodology is applied to recent designs of deepwater semi-submersible platforms connected to a large number of risers with asymmetrical layout. In such cases, the design variables may include values for the azimuthal spacing and mooring radius varying along the corners of the platform, besides the pretension and material of the lines. The results of the case study indicated that, given any mooring configuration characterized by the combination of all these design variables, the ANNs provide fairly accurate values for the parameters of the response that are required for the design of mooring systems (typically platform offsets and line tensions).