海域承载力研究综述

随着世界人口的急剧增加和陆地资源的快速消耗,向海洋寻求发展成为人类唯一的出路.对海域承载能力及其可持续发展的研究就成为一个关乎人类未来发展的重要课题.对海域承载力的研究进展进行了分类概括,并对其评价指标体系和评价模型进行了归纳总结,为学者们今后的研究提供参考的依据,最后对海域承载力和海洋产业可持续发展的关系进行了回顾和展望.     

Size-dependent, Spatial, and Temporal Variability of Juvenile Walleye Pollock (Theragra chalcogramma) Feeding at a Structural Front in the Southeast Bering Sea

Abstract. The waters surrounding the Pribilof Islands are an important nursery ground for juvenile walleye pollock (Theragra chalcogramma), an important forage fish in the pelagic food web of the productive Bering Sea shelf region. The diet of juvenile pollock was studied in two consecutive years along a transect line crossing from a well‐mixed coastal domain, through a frontal region to stratified water farther offshore. Variability in stomach fullness was high and evidence for increased feeding intensity in the front was weak. Prey diversity and prey size generally increased with increasing fish size, shifting from predominantly small copepods to larger, more evasive prey items such as euphausiids, crab megalopae and fish. The diet of the fish reflected changes in the relative abundance of copepods and euphausiids in the prey fields between years. Juvenile pollock showed increased feeding rates at dusk, and stomach fullness as well as prey condition were generally lowest just before sunrise; however, the proportion of euphausiids increased in the diet of pollock caught at night, suggesting that some food was also ingested during darkness. Juvenile pollock and their euphausiid prey both vertically migrated above the thermocline at night, although each had a different daytime depth.     

浅海贝类养殖容量研究

贝类养殖容量概念和方法的研究开始较晚,发展较快.目前大多采用生态动力学模型的方法来研究养殖容量,它量化了贝类的生长过程,但关于贝类强烈的生理活动对环境的改造考虑不足,还不能应用于实际生产和海域使用的指导.在原有模型的基础上,导入养殖活动对自身容量反馈的模块,综合考虑影响养殖容量各个因子的权重,建立起生态效益和经济效益最优化的养殖容量模型是以后研究的重点.     

The abundance and distribution of euphausiids and zero-age pollock on the inner shelf of the southeast Bering Sea near the Inner Front in 1997–1999

Acoustic data and net samples were collected during late spring and early fall 1997–1999 to assess zooplankton and micronekton abundance and distribution relative to the Inner Front at three sampling grids (Port Moller, Cape Newenham and Nunivak Island) on the inner shelf of the southeast Bering Sea. Epibenthic scattering layers were observed during May–June and August–September in all three years. Acoustic data were scaled to euphausiid biomass using target strength models. Mean euphausiid biomass determined acoustically for each transect line was 0.7–21 g m⁻², with most values below 5 g m⁻². There was no consistent relationship between the distribution and biomass of euphausiids and the location of the Inner Front. Zero age pollock were observed on the inner shelf in August–September during all years, but were confined primarily to the stratified side of the Inner Front and to the frontal regime. The acoustic data for pollock were scaled to biomass using laboratory measurements of gas bladder dimensions and target strength models. Acoustic determinations of mean transect biomass for euphausiids did not differ from literature values for the inner shelf of the southeast Bering Sea, and pollock biomass on the inner shelf did not differ from that around the Pribilof Islands. Despite recent anomalies in climate and oceanographic conditions on the inner shelf, and high mortality of shorttail shearwaters during 1997, we found no evidence of significant interannual differences in the biomass of euphausiids or zero-age pollock on the inner shelf of the southeast Bering Sea.     

基于围填海的江苏用海承载指数评价研究

为进一步加强海域使用管理,促进海域开发利用和资源环境的可持续发展,文章建立围填海用海承载指数评价指标体系和评价模型,分析江苏13个县级行政区的围填海用海承载指数及其监测预警情况,并提出建议。研究结果表明:江苏围填海用海承载指数评价指标体系包括资源禀赋、开发利用强度、发展潜力和区域约束4个一级指标以及10个二级指标;江苏13个县级行政区的围填海用海承载指数为-0.46～9.63,呈显著的空间差异,其中中部辐射沙洲区的大丰区、东台市和如东县围填海用海承载条件良好,北部连云港市辖区以及南部南通市的通州区和启东市围填海用海承载条件较差;未来应建立围填海用海承载能力监测预警长效机制、严格实行围填海管控制度、合理调整和优化产业布局以及加强政府和社会的协同监督。     

日本海、鄂霍次克海和白令海的古海洋学研究进展

边缘海的存在使大陆和大洋之间的物质和能量交换变得相当复杂。在构造运动和海平面升降的控制下,边缘海和大洋之间时而连通时而隔绝,各种古气候变化信号都在一定程度上被放大。基于近期有关西北太平洋边缘海的古海洋学研究成果,简要概述了日本海、鄂霍次克海、白令海以及北太平洋地区自中新世以来的古气候和古海洋环境演化特征,并认为它们与全球其它地区一样也受控于因地球轨道参数变化引起的太阳辐射率的变化,大尺度的气候变化具有与地球轨道偏心率周期相对应的100ka周期,而41ka的小尺度周期则受地球自转轴斜率变化的控制。一些突发性的气候变化则是由气候不稳定性、海峡的关闭与开启和其它一些地球气候系统的非线性活动所驱动。但同时作为中高纬度边缘海,它们的古海平面、古海水温度、古洋流等古海洋环境因子的变化特征还受到冰盖扩张和退缩、构造运动、冰川性地壳均衡补偿、东亚季风等因素的影响,具有一定的区域特点。     

Structure and sediment distribution in the western Bering Sea

Eleven seismic reflection profiles across Shirshov Ridge and the adjacent deep-water sedimentary basins (Komandorsky and Aleutian Basins) are presented to illustrate the sediment distribution in the western Bering Sea. A prominent seismic reflecting horizon, Reflector P (Middle—Late Miocene in age), is observed throughout both the Aleutian and Komandorsky Basins at an approximate subbottom depth of 1 km. This reflector is also present, in places, on the flanks and along the crest of Shirshov Ridge. The thickness of sediments beneath Reflector P is significantly different within the two abyssal basins. In the Aleutian Basin, the total subbottom depth to acoustic basement (basalt?) is about 4 km, while in the Komandorsky Basin the depth is about 2 km.Shirshov Ridge, a Cenozoic volcanic feature that separates the Aleutian and Komandorsky Basins, is an asymmetric bathymetric ridge characterized by thick sediments along its eastern flank and steep scarps on its western side. The southern portion of the ridge has more structural relief that includes several deep, sediment-filled basins along its summit.Velocity data from sonobuoy measurements indicate that acoustic basement in the Komandorsky Basin has an average compressional wave velocity of 5.90 km/sec. This value is considerably larger than the velocities measured for acoustic basement in the northwestern Aleutian Basin (about 5.00 km/sec) and in the central Aleutian Basin (5.40–5.57 km/sec). In the northwestern Aleutian Basin, the low-velocity acoustic basement may be volcaniclastic sediments or other indurated sediments that are overlying true basaltic basement. A refracting horizon with similar velocities (4.6–5.0 km/sec) as acoustic basement dips steeply beneath the Siberian continental margin, reaching a maximum subbottom depth of about 8 km. The thick welt of sediment at the base of the Siberian margin may be the result of sediment loading or tectonic depression prior to Late Cenozoic time.     

2005黄海声学实验-声传播起伏

2005年夏末、秋初在黄海南部进行一次多家联合海洋声学实验研究,主要目的是研究浅海内波(线形、非线性)及其海洋温度峰面对远距离声传播的起伏效应及其声学方法监测海洋新方法研究。文章综述这几年实验数据处理的一些结果。     

Phytoplankton communities in the Bering Sea and adjacent seas

Vertical distribution of phytoplankton in early warming season in the eastern Bering Sea and adjacent sea areas was investigated. In the surface layer which was under the influence of newly melted sea ice in the shelf water region of the Bering Sea in May, remarkably dense populations ofThalassiosira hyalina andT. nordenskiöldii and relatively large populations ofFragilaria andNavicula occupied large part of phytoplankton community. In June, although theThalassiosira populations sunk into the bottom layer and withered, a certain part of theFragilaria-Navicula populations was still suspended in subsurface layer. Thus,Fragilaria-Navicula were the leading components of the June community in the shelf region.In the Bering Basin region, no dense phytoplankton populations were developed until a shallow thermocline was established. In June when the shallow thermocline developed near shelf edge,Thalassiosira decipiens burst out. As the shallow thermocline extended from near shelf to central part of the Basin region with surface warming, the areas of blooming also shifted from near shelf to the central part.Contribution No. 73 from the Research Institute of North Pacific Fisheries, Hokkaido University.     

Rationalization of the Bering Sea and Aleutian Islands crab fisheries

In recent years, overcapacity in Bering Sea and Aleutian Islands crab fisheries has resulted in a dangerous race for crab. This paper examines a unique management program developed by the North Pacific Fishery Management Council intended to alleviate these problems, while accommodating a variety of stakeholders dependent on the fisheries. The discussion concludes by identifying some of the most substantial hurdles that the program must overcome to succeed and some characteristics of the fisheries that contribute to the potential to overcome these obstacles.     

Mesopelagic nekton and associated physics of the southeastern Bering Sea

The mesopelagic community of fishes and squids are fundamental in the diet of apex predators, but in most cases their life histories and habitat requirements are poorly understood. In May 1999, a pilot study was conducted to identify mesopelagic nekton, describe dominant physical characteristics of their habitat, and compare their relative abundances over several study sites in the southeastern Bering Sea. Biological samples were collected at 250, 500, and 1000 m depths with an open pelagic rope trawl lined with 1.2-cm mesh in the codend. Net type, mesh size, and trawling techniques were designed to parallel those of extensive Russian research surveys in the western Bering Sea, permitting direct comparisons between study results. Forty-three species of fish and 15 species of cephalopods were identified, including a new species of gonatid squid and a range extension for Paraliparis paucidens, a snailfish never before observed in Alaskan waters. Faunal biomass was high with over 25,000 (1400 kg) fish and squid collected in only 13 trawls. Concentrations of fish in this area surpass published records from the western Bering Sea and North Pacific Ocean by an order of magnitude, driven primarily by Leuroglossus schmidti, a deep-sea smelt. Generally, specimens were of high quality, and new size records were established for several species of fish and squid. The physical environment as determined from altimetry, satellite-tracked drifters, and water properties (temperature and salinity) was typical of the last decade for this area. Spatial patterns in species distribution were observed, but further research is needed to determine whether these are a factor of mesoscale variability or of habitat characteristics.     

Diets of short-tailed shearwaters in the southeastern Bering Sea

In the late 1990s, the southeastern Bering Sea exhibited a number of anomalous conditions, including a major die-off of short-tailed shearwaters (Puffinus tenuirostris), a trans-equatorial migrant that constitutes a major portion of the marine bird biomass in the southeastern Bering Sea. As part of a larger study of the ecological role of the inner or structural front over the southeastern Bering Sea shelf, in 1997–1999, we collected short-tailed shearwaters to determine diet composition. In spring 1997, we found that short-tailed shearwaters were consuming predominately the euphausiid Thysanoessa raschii, a diet expected on the basis of past studies. However, in subsequent years, short-tailed shearwater diets in spring contained increasingly larger proportions of fish, in particular, sandlance (Ammodytes hexapterus), as well as other species of euphausiids (T. inermis in 1999). In summer and fall collections, short-tailed shearwater diets were more varied than in spring, and included both fish (age-0 gadids, 21–35% by weight) and a wider variety of euphausiid species (T. inermis and T. spinifera). In summer and fall, crab zoea (August 1998) and copepods (August 1999) were eaten by shearwaters collected while feeding within the inner front. Diets in 1997–1999 were broader than those found in previous studies of short-tailed shearwaters over the inner shelf and Bristol Bay, which had documented diets composed almost solely of T. raschii. Our data are consistent with the hypothesis that euphausiids were less available to short-tailed shearwaters foraging over the middle and coastal domains of the southeastern Bering Sea in 1997–1999 than has previously been true. Our results are also consistent with hypothesis that the inner front can affect the availability of prey to shearwaters.     

Sedimentary environments of the east-central Bering Sea continental shelf

A factor analysis of 180 bottom sediment samples from the east-central Bering Sea continental shelf identifies five factors that account for 95% of the variation in the 17 whole ø size classes that were used as variables. Factor I represents coarse sediments that have been bypassed in areas of active water circulation. Factors II and III represent fine and very fine sands that have been hydraulically sorted, reworked, and mixed. Factor IV represents coarse to medium silt that has been segregated from areas of relatively high energy. Factor V represents both the production of sediments finer than medium silt and deposition within the lowest-energy environment in this area.Modern and palimpsest sediments are areally prevalent over this section of the shelf. Relict sediments occur in only a few small areas. The dispersal of sediments is affected by surface and tidal currents as well as wave action. Ice rafting is not an important geological agent. Data from the eastcentral Bering Sea shelf indicate that sediments on subarctic continental shelves are not necessarily characterized by an abundance of rocky sediments or gravel.     

Sound velocity and related properties of seafloor sediments in the Bering Sea and Chukchi Sea

The Bering Sea shelf and Chukchi Sea shelf are believed to hold enormous oil and gas reserves which have attracted a lot of geophysical surveys. For the interpretation of acoustic geophysical survey results, sediment sound velocity is one of the main parameters. On seven sediment cores collected from the Bering Sea and Chukchi Sea during the 5th Chinese National Arctic Research Expedition, sound velocity measurements were made at 35, 50, 100, 135, 150, 174, 200, and 250 k Hz using eight separate pairs of ultrasonic transducers. The measured sound velocities range from 1 425.1 m/s to 1 606.4 m/s and are dispersive with the degrees of dispersion from 2.2% to 4.0% over a frequency range of 35–250 k Hz. After the sound velocity measurements, the measurements of selected geotechnical properties and the Scanning Electron Microscopic observation of microstructure were also made on the sediment cores. The results show that the seafloor sediments are composed of silty sand, sandy silt, coarse silt, clayey silt, sand-silt-clay and silty clay. Aggregate and diatom debris is found in the seafloor sediments. Through comparative analysis of microphotographs and geotechnical properties, it is assumed that the large pore spaces between aggregates and the intraparticulate porosity of diatom debris increase the porosity of the seafloor sediments, and affect other geotechnical properties. The correlation analysis of sound velocity and geotechnical properties shows that the correlation of sound velocity with porosity and wet bulk density is extreme significant, while the correlation of sound velocity with clay content, mean grain size and organic content is not significant. The regression equations between porosity, wet bulk density and sound velocity based on best-fit polynomial are given.     

The petroleum resource potential of the Bering Sea region

The Bering Sea sedimentary basin comprises the Bering Sea and the adjacent intermontane depressions on the continents. It includes the following subordinate sedimentary basins: the Norton; Bethel; Saint Lawrence; Anadyr; Navarin; Khatyrka; Saint George; Bristol; Cook Inlet; and Aleutian consisting of the autonomous Aleutian, Bowers, and Komandor basins. All of them exhibit significant geological similarity. The Middle and Upper Miocene terrigenous sequences, which are petroliferous through the entire periphery of the Pacific Ocean, are characterized by their high petroleum resource potential in the Bering Sea continental margin as well, which is confirmed by the oil and gas pools discovered in neighboring onshore lowlands. The younger (Pliocene) and older (up to Upper Cretaceous) sedimentary formations are also promising with respect to hydrocarbons. The integral potential oil and gas resources of the Bering Sea sedimentary basin, including the continental slopes, are estimated by the US Geological Survey to be 1120 × 10⁶ t and 965 × 10⁹ m³, respectively.     

On the recent warming of the southeastern Bering Sea shelf

During the last decade, the southeastern Bering Sea shelf has undergone a warming of 3 °C that is closely associated with a marked decrease of sea ice over the area. This shift in the physical environment of the shelf can be attributed to a combination of mechanisms, including the presence over the eastern Bering Sea shelf of a relatively mild air mass during the winter, especially from 2000 to 2005; a shorter ice season caused by a later fall transition and/or an earlier spring transition; increased flow through Unimak Pass during winter, which introduces warm Gulf of Alaska water onto the southeastern shelf; and the feedback mechanism whereby warmer ocean temperatures during the summer delay the southward advection of sea ice during winter. While the relative importance of these four mechanisms is difficult to quantify, it is evident that for sea ice to form, cold arctic winds must cool the water column. Sea ice is then formed in the polynyas during periods of cold north winds, and this ice is advected southward over the eastern shelf. The other three mechanisms can modify ice formation and melt, and hence its extent. In combination, these four mechanisms have served to temporally and spatially limit ice during the 5-year period (2001–2005). Warming of the eastern Bering Sea shelf could have profound influences on the ecosystem of the Bering Sea—from modification of the timing of the spring phytoplankton bloom to the northward advance of subarctic species and the northward retreat of arctic species.     

Characteristics and variability of the inner front of the southeastern Bering Sea

The inner front of the southeastern Bering Sea shows marked spatial variability in frontal characteristics created by regional differences in forcing mechanisms. Differences in forcing mechanisms (sea ice advance/retreat and storm strength and timing) and early spring water properties result in strong interannual variability in biological, chemical, and physical features near the front. We have developed a simple model based on surface heat flux and water-column mixing to explain the existence of cold belts (Cont. Shelf Res. 19(14) (1999) 1833) associated with such fronts. Hydrography, fluorescence and nutrient observations show that pumping of nutrients into the euphotic zone occurs, and this can prolong primary production at the inner front. The effectiveness of this process depends on two factors: the existence of a reservoir of nutrients in the lower layer on the middle shelf and the occurrence of sufficient wind and tidal energy to mix the water column.     

Climate change and control of the southeastern Bering Sea pelagic ecosystem

We propose a new hypothesis, the Oscillating Control Hypothesis (OCH), which predicts that pelagic ecosystem function in the southeastern Bering Sea will alternate between primarily bottom-up control in cold regimes and primarily top-down control in warm regimes. The timing of spring primary production is determined predominately by the timing of ice retreat. Late ice retreat (late March or later) leads to an early, ice-associated bloom in cold water (e.g., 1995, 1997, 1999), whereas no ice, or early ice retreat before mid-March, leads to an open-water bloom in May or June in warm water (e.g., 1996, 1998, 2000). Zooplankton populations are not closely coupled to the spring bloom, but are sensitive to water temperature. In years when the spring bloom occurs in cold water, low temperatures limit the production of zooplankton, the survival of larval/juvenile fish, and their recruitment into the populations of species of large piscivorous fish, such as walleye pollock (Theragra chalcogramma), Pacific cod (Gadus macrocephalus) and arrowtooth flounder (Atheresthes stomias). When continued over decadal scales, this will lead to bottom-up limitation and a decreased biomass of piscivorous fish. Alternatively, in periods when the bloom occurs in warm water, zooplankton populations should grow rapidly, providing plentiful prey for larval and juvenile fish. Abundant zooplankton will support strong recruitment of fish and will lead to abundant predatory fish that control forage fish, including, in the case of pollock, their own juveniles. Piscivorous marine birds and pinnipeds may achieve higher production of young and survival in cold regimes, when there is less competition from large piscivorous fish for cold-water forage fish such as capelin (Mallotus villosus). Piscivorous seabirds and pinnipeds also may be expected to have high productivity in periods of transition from cold regimes to warm regimes, when young of large predatory species of fish are numerous enough to provide forage. The OCH predicts that the ability of large predatory fish populations to sustain fishing pressure will vary between warm and cold regimes.The OCH points to the importance of the timing of ice retreat and water temperatures during the spring bloom for the productivity of zooplankton, and the degree and direction of coupling between zooplankton and forage fish. Forage fish (e.g., juvenile pollock, capelin, Pacific herring [Clupea pallasii]) are key prey for adult pollock and other apex predators. In the southeastern Bering Sea, important changes in the biota since the mid-1970s include a marked increase in the biomass of large piscivorous fish and a concurrent decline in the biomass of forage fish, including age-1 walleye pollock, particularly over the southern portion of the shelf. Populations of northern fur seals (Callorhinus ursinus) and seabirds such as kittiwakes (Rissa spp.) at the Pribilof Islands have declined, most probably in response to a diminished prey base. The available evidence suggests that these changes are unlikely the result of a decrease in total annual new primary production, though the possibility of reduced post-bloom production during summer remains. An ecosystem approach to management of the Bering Sea and its fisheries is of great importance if all of the ecosystem components valued by society are to thrive. Cognizance of how climate regimes may alter relationships within this ecosystem will facilitate reaching that goal.