区位和管理政策对海岸带土地利用变化的影响--以昌黎黄金海岸地区为例

本文在RS和GIS支持下研究了河北昌黎黄金海岸地区1985年至2000年的土地利用变化格局及其影响因子。该区域的海岸区位对海岸带土地利用变化具有重要影响作用,近岸带变化较剧烈,远岸带变化较小,且具有不同的变化特点。海岸带管理政策对土地利用变化的程度和特征存在重要影响,开发区土地利用变化较剧烈,其变化类型受开发方式及其目标影响;保护区主要是大片沙丘转变为林地和草地。     

Distribution and composition of phytoplankton in northeastern coastal waters of the United States

Results are given from collections made during eight cruises over the northeastern continental shelf. Seasonal phytoplankton assemblages are noted, which include a variety of ultraplankton components. Areas of greatest cell concentrations were at near shore stations, Georges Bank, and at scattered sites over the shelf. Dominant species included Skeletonema costatum, Asterionella glacialis and Leptocylindrus danicus.     

Characteristics of resuspended sediment from Georges Bank collected with a sediment trap

A sediment trap was deployed 3 m from the bottom at a water depth of 62 m on the southern flank of Georges Bank (41°02·2′N, 67°33·5′W) from 30 September 1978 to 10 March 1979 to qualitatively determine the size of sediments resuspended from the bottom by winter storms and to determine if seasonal changes in the phytoplankton could be observed in the trapped sediment.Bulk X-ray analyses of the trapped sediment showed layers of distinctly different textures preserved in the collection vessel. The median grain size of sampled layers ranged from 2·7 to 6·5 φ (fine sand to silt), but all layers contained a pronounced mode in the 3 φ (fine sand) range. Nine layers containing relatively large amounts of sand were present. The sand content was 75% in the coarest layers and about 32% in the fine layers. The median grain size of bottom sediments at the deployment site was considerably coarser than the trap samples, although the dominant grain size was also 3 φ.Average bottom-current speeds during the deployment period were about 30 cm s^?1 with a range of 10 to 50 cm s^?1. Bottom stress, computed from the observed currents and waves, suggest that 11 storms caused sufficient stress to resuspend 3 φ-sized sediments, in good agreement with the nine layers of relatively coarse sediments collected in the trap. Surface waves had to be included in the calculation of bottom stress because the bottom currents alone were insufficient to cause the resuspension of 3 φ-sized sediment.The trapped sediments contain numerous diatoms and coccoliths that are typical of late fall and winter assemblages. No clear seasonal difference in the flora was noted among sampled layers, probably due to the large influx of resuspended material and a reduced primary flux during this period. An undescribed species of Thalassiosira (G. Fryxell, personal communication), and siliceous scales of unknown systematic position were observed at all levels.     

The dynamics of a bathymetrically arrested estuarine front

The mixing and circulation associated with a bathymetrically arrested estuarine front was studied using hydrographic and current data. A quasisteady front, exhibiting strongly convergent surface flows, is formed along the steeply sloping inner margins of the flood tide delta during each semidiurnal tide cycle. This front separates the brackish ambient water within a deep estuarine basin from the incoming oceanic tidal water. The position of the front is dependent on the local water depth and the difference in density between the two water masses. Beneath the surface there is an inclined frontal interface where static stability is very low and vertical mixing intense. A vertically integrated horizontal momentum equation was derived for flow in the upper layer and an estimate made as to the value of the associated entrainment coefficient.     

山东蓬莱沿海的贝类

本文报导了蓬莱沿海的贝类１１１种,隶属４９科８６属 ,并对它们的生态类型,区和纱分布特点作了初步分析。     

The biology of the catfish Cnidoglanis macrocephalus (Plotosidae) in an Australian estuary

This paper describes the age structure, growth, diet and aspects of gonadal development in the cobbler, Cnidoglanis macrocephalus (Valenciennes), in the large Swan estuary in south-western Australia between August 1982 and June 1984. Analysis of otolith annuli showed that while the 0+ to 3+ age classes were regularly represented in monthly samples, the 4+ and more particularly the 5+ and 6+ were much less abundant. The weighted means for the back calculated lengths at the end of the first to fourth years of life were 181 mm (≡ 26 g), 314 mm (≡ 156 g), 418 mm (≡ 410 g) and 518 mm (≡ 833 g) respectively. The mean length at the end of the second year of life was similar to the minimum legal size for capture by commercial fishermen (320 mm). The von Bertlanffy growth curve calculated from the back calculated lengths was L_t = 917 [1 − e^{−0·20(t + 0·11)}]. The relative weight of mulluscs, crustaceans and polychaetes in the intestine varied markedly between small and large fish, apparently reflecting differences in the size of these prey. The large mean diameter of mature eggs ( ) was correlated with a low mean absolute fecundity (2078). Trends shown by egg size, gonadosomatic index and time of appearance of spent females indicate that spawning takes place between October and December. The attainment of sexual maturity is both age- and size-dependent. Although sexually maturing and occasionally spent fish were found in the lower estuary, meristic values, commercial catch statistics and other data indicate that the cobbler found in the Swan estuary are part of a population which typically spawns at sea.     

Annual cycle and composition of the phytoplankton in the Quempillen River Estuary,southern Chile

Phytoplankton species and abundance were studied in the Quempillen River Estuary, from August 1979 to July 1980 in addition to some important environmental factors: salinity, temperature and dissolved oxygen. In order to determine the seasonal variations in cell density and biomass of the phytoplankton in this brackish aquatic environment, phytoplankton data obtained by the Uthermöhl (1958) technique were analysed.A total of 109 phytoplankton species were identified within the samples. Throughout the year there were two periods of population maxima, September and May, and one period of high biomass, February. The phytoflagellates were always present but only dominated the flora when diatoms were extremely reduced, especially during low tide periods.     

华南沿海地质灾害类型、发育规律和防治对策

本文系统和全面地论述华南沿海地质灾害的类型和发育规律。从宏观控制因素划分出岩石圈、大气圈、水圈及生物圈控制的四大地质灾害类型,阐明各类型发灾特点,论述主要地质灾害类型的分布和发育规律,提出灾害的总体防治对策。     

Rethinking Precolonial Plant Cultivation on the Northwest Coast of North America

The indigenous peoples of the Northwest Coast of North America are widely believed to have been true “hunter-fisher-gatherers,” lacking plant cultivation of any kind. This depiction of the region's indigenous inhabitants emerged within early colonial accounts and was perpetuated within the literatures of geography, anthropology, and archaeology. Still, there is ample evidence of plant cultivation available from archival, archaeological, and ethnographic sources. In particular, the peoples of coastal British Columbia created large gardens of edible estuarine plants, using sophisticated indigenous technologies. The oversight of these practices in written representations of the region reveals consistent patterns of bias, emanating from the agendas of colonial agents and early academics alike. In turn, this bias has undermined aboriginal traditions of cultivation and indigenous land claims.     

海峡西岸城市群旅游经济网络演化的动力机制与因果组合配置

以海峡西岸城市群为例,通过修正引力模型构建旅游经济网络,依托“增长极”理论,运用QAP和地理探测器分析方法,探讨旅游经济网络驱动因素,并运用fsQCA方法探讨其因果组合配置策略。结果如下：(1)海峡西岸城市群旅游经济网络空间结构呈东部沿海地区网络相对密集、中西部网络稀疏特征。(2)地区经济水平、对外开放程度是其核心驱动因素;各影响因子对促进旅游经济空间发展的影响强度均较高。(3)地理探测器分析结果显示,各影响因素在旅游经济网络系统中处相对优势地位,旅游经济空间发展核心驱动因素明显,其中,以地区GDP、对外开放程度最为突出,这也体现为旅游需求不断提升以及旅游供给向高质量方向发展的趋势。研究最终识别出两种因果组合配置方案。本研究有助于实现区域旅游经济空间发展优化及管理。