东海大陆架鱼类群落的空间结构

根据1997～2000年东海大陆架水深30～200米海域4个航次的底拖网调查资料,运用多元分析(聚类分析和非度量多维标度(NMDS))、SIMPER以及BIO-ENV方法分析了东海鱼类群落的空间格局以及与非生物环境因子之间的关系。结果表明,东海大陆架海域鱼类群落在空间上可分为3个群落类型,分别为东海近海群落、东海大陆架外缘群落以及这两个群落之间的东海大陆架混合群落。东海大陆架鱼类群落的种类组成沿着水深梯度的变化明显,每种鱼类均有一定的水深范围。不同的流系具有不同的温盐特征,影响了鱼类的分布及其洄游,从而控制了不同鱼类群落类型的种类组成。东海大陆架鱼类群落类型中,大陆架外缘群落类型各调查季节在空间分布和种类组成上相对稳定,而东海近海群落类型和东海大陆架混合群落类型在夏季融合在一起,其它季节保持各自的空间结构。同时东海陆架区只在一种群落类型中出现的鱼类相对较少,多数鱼类同时出现在两个群落类型中或3个群落类型中,但是它们相对较集中的区域明显不同,在不同群落类型中的生物量和出现频率有很大的差异,这些鱼类在其不同的生长发育阶段由于对海洋环境的不同需求,它们根据繁殖或摄食需求而在东海陆架区范围内洄游以寻找最适的海洋环境,因此对3个群落类型定义是相对的,很难严格确定一个永久的鱼类群落地理区域,以形成相互隔离的鱼类群落,而且鱼类群落之间的边界随着季节不同发生变化。     

Variation in the diet of Arctic Cod (<Emphasis Type="Italic">Boreogadus saida</Emphasis>) in the Pacific Arctic and Bering Sea

Arctic cod, Boreogadus saida (Lepechin, 1774), is a nodal species in Arctic marine foodwebs as an important prey of many birds, marine mammals, and other fishes, as well as an abundant predator of zooplankton and epibenthic fauna. We examined the summer diet of Arctic cod across a latitudinal gradient extending from the southern limit of their distribution in the eastern Bering Sea to the northern margins of the eastern Chukchi Sea (ECS) continental shelf. Specimens were collected from demersal and pelagic trawls conducted between 1999 and 2012, and across a range of predator sizes (3–26 cm). Arctic cod diets vary with body size and between regions within the study area, and appear to vary between years in the eastern Bering Sea, indicating opportunistic feeding habits. Constrained Analysis of Principal Coordinates was conducted on ECS demersal samples and revealed consumption of fish and decapod crustacea were positively correlated with Arctic cod length while consumption of euphausiids and copepods had the opposite relationship. The demersal Arctic cod diet in the northern latitudes of the ECS was dominated by copepod consumption (47% by weight, %W), but copepods were less important (12–26%W) in the central and southern latitudes of the ECS and in the northern and eastern Bering Sea—areas where diets were more varied in their composition. High levels of variation in the diet of Arctic cod highlights the need to monitor Arctic cod diets to identify consistently dominant prey types and potential future changes to trophic relationships related to climate change or increasing anthropogenic activity.     

The “Grey Area” in the Northern Bay of Bengal: A Note on a Functional Cooperative Solution

The judgments in maritime delimitation cases involving Bangladesh and Myanmar (2012) and between Bangladesh and India (2014) have resulted in a “Grey Area” in the northern Bay of Bengal involving intersecting and overlapping rights and responsibilities in terms of the exclusive economic zone (EEZ) and continental shelf regimes. This article seeks to identify a functional solution for this Grey Area.     

Distribution of fishes on the Cretan shelf

Information on the abundance of demersal fishes on the shelf of Crete has been collected through a 3-year bottom trawl survey carried out at fixed sampling stations. Cluster analysis identified three major station-groups delimited by the nature of the substrate. Two of the identified substrate zones were situated on the continental shelf while the beginning of the third zone coincided with the start of the continental slope. Discriminant analysis applied to the abiotic variables defined that depth was the most important variable in discriminating between the identified groups. Discriminant analysis also identified that the most important species in discriminating among station-groups were Capros aper (Linnaeus, 1758), Gadicuh argenieus argenteus Guichenot, 1850, Merluccius merluccius (Linnaeus, 1758), Mullus surmuletus Linnaeus, 1758 and Spicara flexuosa Rafinesque, 18 10. Association analysis revealed few species pairs having significant associations which in most cases seem to be related to the reproductive migration of these species. The results demonstrate that there is a pronounced change with the substrate and by extension with depth in the ichthyofaunal composition of the shelf of Crete. It has also been suggested that there may be a particular relationship between the fish communities of the two zones of the continental shelf.     

中国东海微型鞭毛虫群落的分布特征及其环境影响因子

海洋微型鞭毛虫是海洋原生生物中一类高度异质化的类群,物种多样性高,具有多种营养方式,在全球海洋生态系统中占据广阔的生态位,在生物地球化学循环中发挥着关键作用。然而关于其生物多样性和群落结构的认识十分有限,特别是有关环境因子与其生物地理分布关系的研究更为罕见。为了探究微型鞭毛虫群落多样性、群落结构以及影响其生物地理分布格局的环境因素,将高通量测序技术与传统的显微镜观测方法相结合,全面调查了中国东海春季和秋季微型鞭毛虫的群落特征,并深入探讨了与环境因子之间的关系。结果表明：东海微型鞭毛虫的丰度平均为2.27×10~3个/mL,表现为近岸处较高、随离岸距离的增加而下降的趋势;Shannon多样性指数呈现表层低于底层、近岸区低于陆架区的特征,反映了生物群落的稳定程度以及对环境条件的适应程度;不同类群的鞭毛虫具有各自独特的营养模式和相对固定的粒级,表现出对温度、盐度、溶解氧等环境因素的不同响应,从而使群落的物种组成和分布模式呈现明显的季节变化和生境差异。研究结果可为深入认识东海海洋微型鞭毛虫的群落结构、分布格局以及环境影响因素提供理论依据。     

Innocent,transit, and archipelagic sea lanes passage

Abstract

Norway is involved in two maritime boundary disputes with the Soviet Union. In relation to Svalbard, the Soviet Union argues that the archipelago has a continental shelf and an exclusive economic zone (EEZ) of its own to which all parties to the Svalbard Treaty have equal access. This is disputed by Norway, which maintains that such a view of the matter implies an expansive interpretation of the Svalbard Treaty for which there is no support in international legal practice. In the Barents Sea there is a continuing dispute between Norway and the Soviet Union over the proper location of the continental shelf and EEZ boundaries. This article sets out some of the reasons behind the different arguments on which the two base their respective cases, and the reasons why Norway in the absence of a delineated boundary has refused to accept Soviet proposals for economic cooperation in the disputed ocean area. Major emphasis is placed on the confluence of several circumstances inter alia, geopolitical and historical factors, a strongly asymmetrical power relationship, and legal ambiguity.     

Submarine Elevations and Ridges: Wild Cards in the Poker Game of UNCLOS Article 76

Submarine elevations and ridges present an array of definitional uncertainties to coastal states that are engaged in the high-stakes process of delimiting extended continental shelves. Faced with the imprecise terminology of Article 76, with the nonspecific wording of the Scientific and Technical Guidelines of the Commission on the Limits of the Continental Shelf (CLCS), and with the Commission's rules of confidentiality that hamper the open exchange of information concerning ridge and elevation assessments in previous continental shelf implementations, a coastal state needs to develop its own evaluations of what might and might not pass the “test of appurtenance.” Significant components of a continental shelf submission might thus be formulated on the basis of these national evaluations, only to have the CLCS question them, which could necessitate a potentially expensive and time-consuming reworking of the submission. This article outlines the ramifications of this wild card effect.     

The role of continental shelf width in determining freshwater phylogeographic patterns in south‐eastern Australian pygmy perches (Teleostei: Percichthyidae)

Biogeographic patterns displayed by obligate freshwater organisms are intimately related to the nature and extent of connectivity between suitable habitats. Two of the more significant barriers to freshwater connections are seawater and major drainage divides. South‐eastern Australia provides a contrast between these barriers as it has discrete areas that are likely influenced to a greater or lesser extent by each barrier type. We use continental shelf width as a proxy for the potential degree of river coalescence during low sea levels. Our specific hypothesis is that the degree of phylogeographic divergence between coastal river basins should correspond to the continental shelf width of each region. This predicts that genetic divergences between river basins should be lowest in regions with a wider continental shelf and that regions with similar continental shelf width should have similar genetic divergences. Pygmy perches (Nannoperca australis and Nannoperca ‘flindersi’) in south‐eastern Australia provide an ideal opportunity to test these biogeographic hypotheses. Phylogeographic patterns were examined based on range‐wide sampling of 82 populations for cytochrome b and 23 polymorphic allozyme loci. Our results recovered only limited support for our continental shelf width hypothesis, although patterns within Bass clade were largely congruent with reconstructed low sea‐level drainage patterns. In addition, we identified several instances of drainage divide crossings, typically associated with low elevational differences. Our results demonstrate high levels of genetic heterogeneity with important conservation implications, especially for declining populations in the Murray–Darling Basin and a highly restricted disjunct population in Ansons River, Tasmania.     

Individual foraging site fidelity in lactating New Zealand fur seals: Continental shelf vs. oceanic habitats

Wide‐ranging marine central place foragers often exhibit foraging site fidelity to oceanographic features over differing spatial scales (i.e., localized coastal upwellings and oceanic fronts). Few studies have tested how the degree of site fidelity to foraging areas varies in relation to the type of ocean features used. In order to determine how foraging site fidelity varied between continental shelf and oceanic foraging habitats, 31 lactating New Zealand fur seals (Arctocephalus australis forsteri 1 ) were satellite tracked over consecutive foraging trips (14–108 d). Thirty‐seven foraging trips were recorded from 11 females that foraged on the continental shelf, in a region associated with a coastal upwelling, while 65 foraging trips were recorded from 20 females that foraged in oceanic waters. There were no significant differences in the mean bearings (to maximum distance) of individual's consecutive foraging trips, suggesting individual fidelity to foraging areas. However, overlap in area and time spent in area varied considerably between continental shelf and oceanic foragers. Females that foraged on the continental shelf had significantly greater overlap in consecutive foraging trips when compared to females that foraged in oceanic waters (overlap in 5 × 5 km grid cells visited on consecutive trips 55.9%± 20.4% and 13.4%± 7.6%, respectively). Females that foraged on the continental shelf also spent significantly more time within the same grid cell than females that foraged in oceanic waters (maximum time spent in 5 × 5 km grid cells: 14%± 5% and 4%± 2%, respectively). This comparatively high foraging site fidelity may reflect the concentration of productivity associated with a coastal upwelling system, the Bonney Upwelling. Lower foraging site fidelity recorded by seals that foraged in oceanic waters implies a lower density/larger scale habitat, where prey are more dispersed or less predictable at fine scales, when compared to the continental shelf region.     

Winter lipid depletion of juvenile walleye pollock Theragra chalcogramma in the Doto area, northern Japan

Seasonal variation in body size and nutritional condition of juvenile walleye pollock Theragra chalcogramma was examined to elucidate the mechanism underlying their first-winter survival on the continental shelf of the Doto area, northern Japan, based on monthly samples collected over 2 years. Stored lipid mass was highest during autumn, but 93% (2004) and 80% (2005) of lipids were exhausted by the onset of winter. Lipid levels in the winter of 2004 remained low (7–14% of the autumnal maximum), and there was reduced growth rate until the spring, whereas in 2005 lipid levels were higher and more variable (10–46% of the maximum) and some growth occurred. An analysis of the allometric relationships between body size and stored energy showed that larger individuals accumulated disproportionately more energy in the autumn, but the advantage disappeared prior to the winter. In January 2004, stored lipid energy was low throughout the Doto continental shelf relative to the continental slope area. These results suggest that winter feeding opportunities on the shelf are severely limited but not completely absent. Previous studies have shown that winter temperatures on the shelf are lower than those in the slope area. It is possible that juvenile T. chalcogramma survive winter on the shelf without a high level of pre-winter lipid storage because the occasional feeding in the cold shelf water benefits energy conservation.     

The Spratlys: Are They Rocks or Islands?

The South China Sea is a multilateral battlefield of conflicting claims to sovereignty over island features and vast areas of maritime jurisdiction. In the middle of the South China Sea lies the Spratly archipelago - some 150 small island features to which six states have made claims. The core of the SCS dispute is access to natural resources, and the rivalling claims to sovereignty over islands are largely based on the assumption that whoever has sovereignty to the features can also claim large areas of ocean space attached to them. The United Nations Convention on the Law of the Sea has codified the regimes of the continental shelf and the exclusive economic zone, and it is accepted that islands, as well as continental territory, generate such zones of maritime jurisdiction. However, one category of islands cannot generate these extensive maritime zones. Article 121(3) of the convention states that "rocks which cannot sustain human habitation or economic life of their own shall have no exclusive economic zone or continental shelf." This provision, if applied to certain features, has the potential to significantly change the scope of the conflict in the Spratlys.     

Third Party Intervention in the Commission on the Limits of the Continental Shelf Regarding a Submission Involving a Dispute

The Commission on the Limits of the Continental Shelf (CLCS) was established in accordance with Article 76 of the Law of the Sea Convention. CLCS has the mandate to consider data submitted by coastal states concerning the outer limits of their continental shelf in areas where those limits extend beyond 200 nautical miles and to make recommendations to the submitting state on matters related to the establishment of the limits. For third parties that have actual or potential disputes, unresolved borders, or unresolved land or maritime disputes with the submitting state, the recommendations of the CLCS can be very sensitive. The focus of this article is on the practice of third parties in responding to submissions and how third parties have constructed their Notifications.     

Insights into Diversity and Imputed Metabolic Potential of Bacterial Communities in the Continental Shelf of Agatti Island

Marine microbes play a key role and contribute largely to the global biogeochemical cycles. This study aims to explore microbial diversity from one such ecological hotspot, the continental shelf of Agatti Island. Sediment samples from various depths of the continental shelf were analyzed for bacterial diversity using deep sequencing technology along with the culturable approach. Additionally, imputed metagenomic approach was carried out to understand the functional aspects of microbial community especially for microbial genes important in nutrient uptake, survival and biogeochemical cycling in the marine environment. Using culturable approach, 28 bacterial strains representing 9 genera were isolated from various depths of continental shelf. The microbial community structure throughout the samples was dominated by phylum Proteobacteria and harbored various bacterioplanktons as well. Significant differences were observed in bacterial diversity within a short region of the continental shelf (1–40 meters) i.e. between upper continental shelf samples (UCS) with lesser depths (i.e. 1–20 meters) and lower continental shelf samples (LCS) with greater depths (i.e. 25–40 meters). By using imputed metagenomic approach, this study also discusses several adaptive mechanisms which enable microbes to survive in nutritionally deprived conditions, and also help to understand the influence of nutrition availability on bacterial diversity.     

Disputed Areas and the 10-Year Time Frame: A Legal Lacuna?

Where a coastal state intends to delineate, in accordance with Article 76 of the 1982 Law of the Sea Convention, the outer limits of its continental shelf beyond 200 nautical miles, it is to submit scientific and technical data of such proposed limits to the Commission on the Limits of the Continental Shelf within 10 years of the entry into force of the Convention for that state. This obligation has subsequently been subject to a general de facto amendment by which the commencement of the 10-year time frame has been postponed to May 13, 1999, for the states for which the Convention had entered into force prior to the above date. This article discusses whether any provision in the Convention, any subsequent agreement, or any subsequent practice render inoperative the 10-year time frame with regard to those parts of the outer continental shelf that are disputed areas. It is concluded that nothing in the Convention, no subsequent agreements, and no subsequent practice allow for derogation of the 10-year time frame with regard to disputed areas.     

Paleocurrent and paleoslope — A case study

The relationship between the paleocurrent pattern and the paleoslope in several continental and marine environments has been reviewed. This relationship in shelf sediment is not adequately established, and appears to be more complex than is now understood. The paleocurrent pattern of the Mississippian Loyalhanna—Trough Creek Limestone (a shelf calcarenite) is presented here as a case study. The study shows that the sediment dispersal system and the current pattern are independent of the paleoslope, and that the vector orientation is polymodal. It is, however, argued that before a precise paleocurrent model for shelf carbonate is formulated, more investigation in recent and ancient rocks is necessary.     

Submarine Ridges and Elevations of Article 76 in Light of Published Summaries of Recommendations of the Commission on the Limits of the Continental Shelf

Several of the summaries of recommendations of the Commission on the Limits of the Continental Shelf contain recommendations involving the application of the provisions of Article 76 of the 1982 UN Convention on the Law of the Sea with respect to a class of morphological features that can best be described as seafloor highs. The application of these provisions requires the classification of such features into one of the three categories of seafloor highs: oceanic ridges of the deep ocean floor, submarine ridges, and submarine elevations that are natural components of the continental margin. The summaries of the CLCS recommendations provide guidance on the approach that has been adopted for the application of these provisions. Furthermore, the summaries give insight into the principles by which the CLCS is guided in considering the submerged prolongation of the landmass of a coastal state and the delineation of the outer limits of its continental shelf beyond 200 nautical miles, and the importance of determining the foot of the continental slope at its base in this connection.     

Morphological features of the gorgonian Paramuricea macrospina on the continental shelf and shelf edge (Menorca Channel,Western Mediterranean Sea)

Morphological variability in gorgonians is frequent and commonly associated with habitat variability, often resulting in segregated morphotypes. Paramuricea macrospina is an endemic Mediterranean gorgonian species found on rocky bottoms between 40 and 160?m depth and has recently been reported as one of the most abundant species in continental shelf and shelf edge environments. Three different chromatic forms of P. macrospina were observed in the Menorca Channel: a yellow form and a light purple form occurring on maërl beds of the continental shelf, and a dark purple form occurring on rocky substrates of the shelf edge. The objective of the present work is to verify if these P. macrospina forms may represent distinct taxonomic units by analysing differences in colony morphology and sclerite size and shape of the three chromatic forms. No significant differences were found in colony shape, suggesting that environmental variability between the continental shelf and the shelf edge is not influential enough to significantly alter colony morphology. Significant differences in sclerite size and shape were found amongst all forms, suggesting that sclerites may be influenced by environmental conditions. However, the co-occurrence of the yellow and light purple forms side by side on the continental shelf may indicate a certain degree of genetic differentiation.     

Phylogeny and spatio‐temporal diversification of Prunus subgenus Laurocerasus section Mesopygeum (Rosaceae) in the Malesian region

The goals of this study were to reconstruct the phylogeny of Prunus subgenus Laurocerasus section Mesopygeum and to provide a preliminary assessment of its spatio‐temporal diversification in the Malesian region. We inferred the phylogeny using nuclear ITS and ETS and plastid psbA‐trnH, rps16, rpl16, and trnC‐petN sequences. Our analyses support the monophyly of sect. Mesopygeum. Within sect. Mesopygeum, we identified four main subclades: (i) Prunus lancilimba from continental Asia; (ii) Prunus ruthii from Malay Peninsula; (iii) a subclade comprising species from areas centered on the Sunda shelf and also a few species from continental Asia and Wallacea; and (iv) a subclade composed of species from areas of the Sahul shelf, with a small number of taxa also from areas of the Sunda shelf, continental Asia, and the Philippines. We estimated that sect. Mesopygeum originated in continental Asia at c. 44.71 Mya (95% HPD: 31.66–46.90). Nine dispersals between major geographic areas were inferred. From continental Asia, three and two dispersals were inferred to the Sunda shelf and the Sahul shelf in the mid‐Oligocene, respectively. Two dispersals were inferred from the Sahul shelf region to the Sunda shelf in late Oligecene and early Miocene, respectively. There were also two dispersals inferred from the Sunda shelf region, one to the Philippines and one to Wallacea, in the middle and late Miocene, respectively. The diversification in sect. Mesopygeum was likely driven by active geologic events and orogenies in the Neogene in the Malesian region.     

Estimating denitrification in North Atlantic continental shelf sediments

A model of coupled nitrification/denitrification was developed for continental shelf sediments to estimate the spatial distribution of denitrification throughout shelf regions in the North Atlantic basin. Using data from a wide range of continental shelf regions, we found a linear relationship between denitrification and sediment oxygen uptake. This relationship was applied to specific continental shelf regions by combining it with a second regression relating sediment oxygen uptake to primary production in the overlying water. The combined equation was: denitrification (mmol N m^–2 d^–1)=0.019^* phytoplankton production (mmol C m^–2 d^–1). This relationship suggests that approximately 13% of the N incorporated into phytoplankton in shelf waters is eventually denitrified in the sediments via coupled nitrification/denitrification, assuming a C:N ratio of 6.625:1 for phytoplankton. The model calculated denitrification rates compare favorably with rates reported for several shelf regions in the North Atlantic.The model-predicted average denitrification rate for continental shelf sediments in the North Atlantic Basin is 0.69 mmol N m^{– 2} d^–1. Denitrification rates (per unit area) predicted by the model are highest for the continental shelf region in the western North Atlantic between Cape Hatteras and South Florida and lowest for Hudson Bay, the Baffin Island region, and Greenland. Within latitudinal belts, average denitrification rates were lowest in the high latitudes, intermediate in the tropics and highest in the mid-latitudes. Although denitrification rates per unit area are lowest in the high latitudes, the total N removal by denitrification (53 × 10¹⁰ mol N y^–1) is similar to that in the mid-latitudes (60 × 10¹⁰ mol N y^–1) due to the large area of continental shelf in the high latitudes. The Gulf of St. Lawrence/Grand Banks area and the North Sea are responsible for seventy-five percent of the denitrification in the high latitude region. N removal by denitrification in the western North Atlantic (96 × 10¹⁰ mol N y^–1) is two times greater than in the eastern North Atlantic (47 × 10¹⁰ mol N y^–1). This is primarily due to differences in the area of continental shelf in the two regions, as the average denitrification rate per unit area is similar in the western and eastern North Atlantic.We calculate that a total of 143 × 10¹⁰ mol N y^–1 is removed via coupled nitrification/denitrification on the North Atlantic continental shelf. This estimate is expected to underestimate total sediment denitrification because it does not include direct denitrification of nitrate from the overlying water. The rate of coupled nitrification/denitrification calculated is greater than the nitrogen inputs from atmospheric deposition and river sources combined, and suggests that onwelling of nutrient rich slope water is a major source of N for denitrification in shelf regions. For the two regions where N inputs to a shelf region from onwelling have been measured, onwelling appears to be able to balance the denitrification loss.     

Coastal States in the South China Sea and Submissions on the Outer Limits of the Continental Shelf

The purpose of this article is to examine the outer continental shelf submissions made by the coastal states of the South China Sea and their potential impact on legal and political developments in the South China Sea. In accordance with the United Nations Convention on the Law of the Sea of 1982 and the guidelines of the Commission on the Limits of the Continental Shelf, coastal states are to establish the outer limits of their continental shelf where it extends beyond 200 nautical miles. Meeting this obligation is complicated in enclosed or semienclosed seas where there are maritime disputes such as in the South China Sea.