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A large-scale enigmatic mound structure (M1) has been discovered in middle Miocene strata of the Norwegian–Danish Basin, c. 10 km east and updip of the Central Graben. It is located about 1 km beneath the seabed and clearly resolved by a 3D seismic data set focused on the deeper, remobilised, sand-filled Siri Canyon. M1 comprises two culminations, up to 80 m high and up to 1400 m long, constituting a sediment volume of some 5.3 × 107 m3. It is characterized by a hard reflection at the top, a soft reflection at the base, differential compaction relative to the surrounding sediments, and 10 ms TWT velocity pull up of underlying reflections, indicating a relatively fast mound fill, attributed to the presence of sand within the mound. Internal seismic reflections are arranged in an asymmetric concentric pattern, suggesting a progressive aggradation to the NW, downstream to a mid-Miocene contour current system. Numerous elongated pockmarks occur in the upper Miocene succession close to the mound and indicate that the study area was influenced by gas expulsion in the mid- and late Miocene.The reflection configuration, velocity, dimensions, regional setting, and isolated location can best be explained by interpreting the mound as a giant sand volcano extruded >1 km upward from the Siri Canyon during the middle Miocene (c. 15 Ma). The likely causes of this remarkable structure include gas charge and lateral pressure transfer from the Central Graben along the Siri Canyon reservoir. While this is the first such structure described from this part of the North Sea, similar-aged sand extrudites have recently been inferred from seismic observations in the North Viking Graben, thus suggesting that the mid-Miocene was a time of widespread and intense sediment remobilization and fluid expulsion in the North Sea. 相似文献
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Yamaguti 1934年建立的二囊属Bivesicula,原划入独睾科Monorchiidae,以后(1939)因其无腹吸盘以及阴茎囊构造、卵黄腺形状和分布等特征,另立新科——二囊科Bivesiculid-ae。除以二囊属为模式属外,尚包括Bivesiculoides Yamaguti,1938和W.H.Coil,1965发表的Paucivitellosus属,H.W.Manter 1961发表了Treptodemus属,但Yamaguti, 相似文献
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Effect of temperature on an alga‐grazer trophic transfer: A dual stable isotope (13C, 15N) labeling experiment
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In this study, we examined the impact of temperature on the carbon and nitrogen trophic transfers from a macroalga to a macro‐grazer by the use of dual 13C‐ and 15N‐labeling. Using an experimental approach in mesocosms, individuals of the urchin Psammechinus miliaris were maintained for 1 month at 17°C (mean summer temperature in the Bay of Brest) and at 20°C (maximum summer temperature) and fed with 13C‐ and 15N‐labeled Solieria chordalis. The results showed that the urchins’ 13C uptake was 0.30 µg13C g dry weight (DW)?1 at 17°C and 0.14 µg13C g DW?1 at 20°C at the end of the experiment. The lower uptake at the higher temperature may be attributed to a decrease in metabolic activity at 20°C, involving lower feeding and/or respiration rates. Conversely, no significant effect of temperature was detected on 15N uptake. At the end of the experiment, the urchins’ 15N uptake was 0.04 µg15N g DW?1 at 17°C and 0.03 µg15N g DW?1 at 20°C. This suggests that temperature may affect carbon and nitrogen trophic fluxes differently. The use of dual isotope labeling offers interesting prospects and needs to be further extended in order to better understand trophic interactions in marine communities and the consequences of current environmental changes, such as global warming. 相似文献
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《Marine Policy》2016
This paper proposes a new network-based approach to analyse intergroup relations in fishing ports. The technique of clustered graphs is applied to the case of the Andalusian fishing ports to assess the balance between intra and inter-professional relationships. The patterns of sociability in Mediterranean and Atlantic fishing enclaves in the southern region of Spain were compared, examining their implications for participatory governance of marine resources. The personal networks of 53 fishermen, ship owners or skippers and key individuals of 18 Andalusian fisheries were analysed. The personal networks were compared in terms of fishing ground (Atlantic versus Mediterranean) and port type (by size and form of participation). The data of 45 individuals with whom each respondent usually interacts in the harbour was summarised in clustered graphs of intra-group and inter-group relationships between 8 professional roles in the harbour. Results show primarily that personal networks of Mediterranean ports are overall denser, in comparison with those of the Atlantic, which are more centralised and have a higher average betweenness. Secondly, in the Atlantic a clear difference of roles between ship owners and skippers is observed. A strong link between ship owners and the crew was found, and also between the ship owner and commercial roles in the Mediterranean. Small ports seem to be more apt for the artisanalisation of fisheries, as well as for the European Union’s Common Fisheries Policy. 相似文献
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The paper by Schito et al. (2017) contains many misquotations of the regional literature on the Holy Cross Mountains, that may confuse the reader. Present comment suggests more appropriate references related to the stratigraphic, tectonic and palaeothermal aspects of the commented paper. The burial-thermal history as interpreted by Schito et al. is based on doubtful, poorly documented or even unsubstantiated thermal maturity and stratigraphical data, ignoring important regional evidence, such as Caledonian (sub-Devonian) unconformity and Permian thermal anomaly. The 1-D modeling study performed by Schito et al. (2017) did not consider published alternative concepts of the temporal and spatial heat flow patterns. The resulting models, assuming uniformly low heat flow between the Ordovician and the earliest Cretaceous, are inconsistent with independent regional data pointing to a hotter Variscan (Carboniferous-Permian) thermal regime. 相似文献
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《Marine Policy》2017
In a recent commentary, Pauly and Zeller disagreed with the Food and Agriculture Organization's interpretation of its global capture fishery production records, arguing that trends were distorted by unreliable statistics in some countries. They criticized FAO for not having used their “catch reconstructions” in the 2016 State of the World Fisheries and Aquaculture (SOFIA) report and questioned the interpretation and significance of FAO's aquaculture production statistics. In this paper, we refute their claims and demonstrate that their critique is based on fundamental misunderstandings caused by mixing up statistical metrics and using simple normative explanations to interpret highly complex datasets. We explain how FAO maintains, curates and updates the only validated source of global fisheries landings, describe our capacity building projects and activities underpinning the annual updates for the over 231 different sources of fisheries data, and clarify such updates include dialogues with member countries to improve and revise present and historical records. FAO will continue to work closely with member states, IGOs, NGOs, academia and civil society, to further improve fishery and aquaculture databases, while calling on states to make renewed efforts to improve data quality. It also welcomes research efforts that contribute to the improvement of statistical data which are critical to the sustainable management of fisheries and aquaculture. 相似文献
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J. A. Colman 《新西兰海洋与淡水研究杂志》2013,47(4):693-697
The unique holotype of Arnoglossus boops Hector is compared with specimens of Arnoglossus scapha (Schneider). It is concluded that the two species are identical, and that A. boops is therefore a junior synonym of A. scapha. 相似文献
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The long-term studying of the reproduction of the spotted seal Phoca larga and the analysis of the oceanological conditions in Peter the Great Bay of the Sea of Japan have shown that the ice situation
is not right for the successful parturition and breeding of pups due to the impossibility of synchronization of the reproduction
processes with the dynamics and properties of the ice substratum. A major factor promoting the spotted seal’s coastal reproduction
in this area is the existence of an archipelago of small islands with a specific geomorphological structure. Being the historical
norm, the coastal reproduction has a number of advantages in comparison with ice reproduction and, as a whole, allows the
existence in Peter the Great Bay of local groupings of the spotted seal with extremely small numbers of members. 相似文献
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Cold filaments associated with Eastern Boundary Currents are typically narrower than 100 km but can be several hundred kilometers long, extending from the coast to the open ocean in upwelling areas. One such structure, observed off Península de Mejillones (23°S, Chile), was studied with both satellite images and two 5-days hydrographic cruises carried out during January 1997. The study used a coastal grid of 31 stations in an area of 165 ×155 km2, approximately. The spatial distribution of the filament and its change between cruises are described from the horizontal distributions of dynamic height, temperature, salinity and dissolved oxygen. The filament was a shallow feature (thickness <100 m) and extended at least 165 km toward the open ocean. A meandering northward current flowed at the borders of the filament, separating oceanic and coastal waters of different physical properties. Comparisons of cross sections of the filament near the coast and in the oceanic zone show the ascent of the shallow salinity minimum (SSM), and its extension toward the ocean, bound to the filament. It is concluded that Subantarctic Water ((SAAW) distinguish by low salinity, high dissolved oxygen) and Equatorial Subsurface Water ((ESSW) high salinity, low dissolved oxygen, high nutrient content) form this filament, and that their relative proportions depend on the strength of the coastal upwelling. Thus, the knowledge of the dynamics of these structures is fundamental to better understanding of the spatial distribution of important biological variables, such as nutrients and chlorophyll, in the coastal ecosystem. 相似文献
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Rogrio L. Ferreira Filipe R. Ceia Teresa C. Borges Jaime A. Ramos Alan B. Bolten 《Marine Ecology》2021,42(1):e12636
Within the same population, nesting green turtles (Chelonia mydas) might exploit different niches by exhibiting polymorphic foraging strategies and/or inhabiting geographically distinct foraging areas. This is crucial information for the conservation of this species. Here, we used stable carbon and nitrogen isotope ratios (δ13C and δ15N) to test for differences in a population of green turtles nesting on Príncipe Island (1°37′N; 7°24?′E), Central Africa. A total of 60 nesting females were sampled on the two main nesting beaches of the island in December 2012. Minimum curved carapace length (CCL) was recorded, and δ13C and δ15N values were measured in the epidermis of each individual. Overall, CCL varied from 87.0 to 108.0 cm (mean ± SD =100.0 ± 5.1), δ13C values from ?19.4 to ?8.6‰ (?17.3 ± 1.8) and δ15N values from 7.9 to 17.3‰ (13.6 ± 1.5). Despite the large variation in both isotopic ratios, their distributions were unimodal, showing an absence of polymorphic foraging strategies and isotopically distinct foraging areas. However, smaller females (< median, 100.8 cm) occupied a much larger isotopic niche (i.e., four times greater) than larger females. These results suggest that nesting green turtles may forage opportunistically on the resources available in each of their foraging home ranges, with smaller females venturing to more isotopic‐diversified areas and/or exhibiting broader foraging strategies than larger females. In addition, and in accordance with other studies, findings suggest that the foraging grounds used by the Príncipe green turtle nesting females are distributed mainly throughout the Gulf of Guinea. 相似文献
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During the past 5 years researchers from the University of Cádiz have carried out several studies on artisanal fishing in Andalusia, with the object of determining the state of the fleet and safety on board vessels. These studies have been financed largely with help from the European Union. In this third approach to the topic, the census of the fleet is updated and the changes that have taken place are considered from two perspectives: the influence of the policies implemented by the various governmental authorities, and the dynamic of the new commercial scenarios. For this study special emphasis is given to those communities in the SW of the province of Cádiz where the policies associated with the Treaties with the Kingdom of Morocco have had a decisive impact. 相似文献
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现代生物技术在紫菜属中的应用 总被引:2,自引:0,他引:2
本文综述了近十年来国内外紫菜生物技术的发展与研究。在细胞生物学方面,介绍了紫菜原生质体制备、组织培养和细胞融合等技术,及其在新种质创建,工业苗种生产、单细胞活饵料开发和基因组操作等研究中的广泛应用,而细胞分光光度技术(MSP)和流式细胞技术(FCM)的加盟使得对紫菜细胞DNA的了解达到量化,快速分选细胞并实现对其生理代谢动态 观测,在生物化学方法中,讨论了用同工酶电泳技术来评价紫菜群体遗传结构、鉴别种质和描述系统发育等研究,以及利用生化方法对糖类等其它化合物进行提纯与测定等工作,在分子生物学方面;总结了如何获得高纯度DNA,并将其应用于DNA分析研究,RFLP、RAPD和DNA-序列测定等分子标记技术所揭示的紫菜的多态性,以及利用DNA-指纹和消减DNA文库的技术来构建紫菜的质体基因图谱和cDNA文库,并进行紫菜比较基因组学的研究,此外还介绍了紫菜基因转移方面的工作。 相似文献
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C. G. Castro T. R. Baumgartner S. Bograd R. Castro F. P. Chavez C. A. Collins R. Durazo J. García G. Gaxiola-Castro T. Hayward A. Huyer R. Lynn A. S. Mascarenhas M. R. D. Robert R. L. Smith P. A. Wheeler F. A. Whitney 《Progress in Oceanography》2002,54(1-4)
Hydrographic data collected along the West Coast of North America between January 1997 and January 1999 have been compiled into a web-based Atlas of the 1997–8 El Niño event. This paper discusses the organization of the Atlas, describes the data that were incorporated into the Atlas and explains how vertical and horizontal distributions for the different properties were constructed. Examples of figures from the Atlas are shown. 相似文献