海南儋州海域造礁石珊瑚种类组成及动态变化研究          下载免费PDF全文

廖宝林  肖宝华  覃业曼  谢子强  谢勇琪  朱鸣 《海洋开发与管理》2020,37(7):55-61

文章通过断面法调查分析了儋州海域海花岛沿岸、南华墟沿岸和磷枪石岛沿岸造礁石珊瑚的种类组成与群落分布，结果表明：儋州海域造礁石珊瑚共有12科25属55种，相较于此前的研究增加了10个种，优势种为斯氏角孔珊瑚、澄黄滨珊瑚、柱角孔珊瑚；活造礁石珊瑚覆盖率急剧下降，由2012年的42.92%下降至现在的22.24%，降幅高至48.18%；造礁石珊瑚死亡率高居不下，长期维持在35%左右；初级群落以团块状造礁石珊瑚为优势种的趋势愈发明显，且单一绝对优势种的情况频繁出现，说明该海域造礁石珊瑚群落受到了较为严重的破坏，导致群落退化演替，分析认为这种破坏是由自然因素和人为活动共同造成的。  相似文献   

Late Quaternary climate and environmental change derived from glacial deposits in the Parlung Zangbo Valley,southeastern Tibetan Plateau     

Renrong Chen  Yingkui Li  Zhongping Lai  Xianjiao Ou  Xiaoyu Lu 《自然地理学》2020,41(2):99-125

ABSTRACT

This study investigated the late Quaternary climate and environmental characteristics of two tributary valleys (Xingmu and Depu Valleys) in the Parlung Zangbo Valley, southeastern Tibetan Plateau. Optically stimulated luminescence (OSL) samples collected from moraines at the mouth of Xingmu Valley produce a wide age range from 13.9 ka to 76 ka. The ages measured from the lenticular sand are consistent with the relative geomorphic sequence of the landforms. Lenticular sand layers below the moraine were dated to 37.9 ka and 44.7 ka, indicating that fluvial processes were likely dominant in the valley during Marine Isotope Stage (MIS) 3. The outer moraine ridges at the valley mouth were formed during 13.9 ka and 26.5 ka, corresponding to MIS2. At Depu Valley, OSL samples from two sets of lateral and terminal moraines close to the modern glacier, provide ages from 1.4 ka to 29.2 ka. The paleosol layer widely developed during 2.6 cal ka BP and 8.7 cal ka BP in the study area, reflecting a relatively warm condition during the mid-Holocene.  相似文献   

Space Changes in the Rural Tourism Area of Mufu Town,Hubei Province,China     

TAO Hui  GAO Jing  CHEN Kaiqiang 《资源与生态学报(英文版)》2020,11(6):633-644

In a society dominated by tourism consumption, space changes occurring in rural areas can generally reflect their social changes. On the theoretical basis of flow, regeneration and adaptation of rural tourism space, this paper originally and creatively proposes that the spatial elements in a rural tourist area can be classified into three categories: Attractions (A), Towns (T) and Villages (V). By analyzing the spatial transformation characteristics of A, T and V, five types of rural spatial transition modes are found, the types of heritage, theme park, those serving as scenic spots, leisure industrial clusters and ecotourism areas. These different classes emerge due to their geographical differentiation. They show the same spatial evolution trend: The Attractions are distributed throughout the whole area and characterized by diversification; supporting services facilities gather in the Towns; and the Villages are landscape images. In this area the traditional rural benefit trends toward that of compound development. Mufu Town, Hubei province, is taken as a study case, and the changing characteristics of A, T and V from 2006 to 2016 are described. Problems in the process of establishing the new spatial order are considered. In order to realize the synergy between production space, living space and ecological space, the interactive development between Attractions, Towns and Villages is recommended. The perspective of Attraction-Town-Village (ATV) can lead to a better understanding of the situation of tourism space in rural areas and provide directions for thinking about the reconstruction path for the modernization of traditional societies.  相似文献   

气候变化对东北大西洋渔获物组成、多样性和营养级的影响     

陈爽  陈新军 《海洋学报》2020,42(10):100-109

东北大西洋是世界上重要的捕捞海域，气候变化对该海域捕捞产生了重要的影响。本文基于联合国粮农组织所提供的1982?2016年东北大西洋渔获产量数据，对该海域渔获物组成、多样性、平均营养级及主成分变化特征进行时间序列上的分析，并结合东北大西洋海域气候、环境因子，应用广义可加模型探究渔获物组成与气候变化之间的关系。结果显示:渔获物多样性的变化总体上呈下降趋势，2002?2010年间处于较低水平；平均营养级在2002年之前呈平缓下降的趋势，2002年之后开始波动上升，相关性分析表明这两个指标与海域环境因子的变化较为相关。对渔获物组成进行主成分分析显示，第一主成份变化的方差解释率达到35.3%，且与海域气候、环境因素有较高的相关性，第一主成分变化能够较好地表征气候影响下渔获物组成变化的情况。广义可加模型分析结果显示，渔获物组成变化的影响因素按解释率由高到低分别为:海表温度、海平面高度、盐度、海冰和北大西洋涛动指数。该研究有助于认识气候变化对海洋渔业资源及其结构组成的影响。  相似文献   

早渐新世钙质超微化石演变与营养盐及二氧化碳关系     

马瑞罡  杨海长  金晓波  赵钊  张功成  刘传联 《海洋学报(英文版)》2020,39(10):70-80

南海北部早渐新世发生明显的营养供给和二氧化碳浓度的变化，相关地质记录为研究颗石藻的生理机制提供了理想的自然实验室。在本研究中，我们建立了一个新的颗石藻群落演化的指标，定义为E*比值。该比值由富营养属种和中等-贫营养属种的相对丰度计算而得（E^*=e/(e+c)×100，e代表富营养属种，c代表中等-贫营养属种）。其中富营养属种包括小Reticulofenestra， Reticulofenestra lockeri组，Reticulofenestra bisecta组和Coccolithus pelagicus组，而中等-贫营养属种包括Cyclicargolithus spp.。E^*指标与早渐新世营养盐指标具有较强的相关性，但在不同二氧化碳浓度的条件下表现不同的公变趋势。将群落组合与已发表的二氧化碳浓度数据对比，我们提出颗石藻可能在二氧化碳持续降低的环境下改变其对碳源和营养盐的利用方式，指示颗石藻的碳浓缩机制可能开始于早渐新世。  相似文献   

基于大数据分析下的气候模型     

张宸豪  冯曦  冯卫兵  刘涛  丁坤 《海洋科学》2020,44(10):1-11

为研究全球变暖与极寒天气间的关系，对加拿大13个省代表性测站10年的观测数据进行时空变化趋势分析，采用经验正交函数（EOF）寻找海洋表面温度历史数据的变化规律。另外利用BP神经网络建立了年平均温度、日降水量与地球吸热、散热、海表面温度、当地纬度间的关系，预测未来25年气候的变化，并建立了“极寒天气”与气候变化的关系模型。研究表明：高纬度地区温度、降水量普遍较低，同经度地区的温度差异较小且降水量变化不大；加拿大地区温度呈周期性变化，符合北半球的季节变化特征；北大西洋的东部与其他海洋的温度是反相关的，西太平洋南北回归线附近的海洋表面温度升高；“极寒天气”出现频率与气候变化有一定关系，局地极寒现象与全球变暖的大趋势并不矛盾。本研究为人们认识和理解“全球变暖”提供了一个新的思路。  相似文献   

2016—2017年夏季舟山近岸海域富营养化程度与浮游植物多样性          下载免费PDF全文

金敬林  蔡丽萍  余健涛 《海洋开发与管理》2020,37(1):51-55

文章根据2016-2017年夏季的调查资料,对2016-2017年夏季舟山近岸海域富营养化状态及浮游植物进行分析。结果表明:2016-2017年夏季舟山近岸海域富营养化程度较高,且由近岸至外海递减;浮游植物群落主要由硅藻和甲藻组成,其密度、多样性指数均由近岸至外海递增;受其他因素影响,富营养化程度与浮游植物多样性关系的规律性不显著。  相似文献   

Modelling tropical cyclone risks for present and future climate change scenarios using geospatial techniques     

Muhammad Al-Amin Hoque  Stuart Phinn  Chris Roelfsema  Iraphne Childs 《International Journal of Digital Earth》2018,11(3):246-263

Tropical cyclones and their devastating impacts are of great concern to coastal communities globally. An appropriate approach integrating climate change scenarios at local scales is essential for producing detailed risk models to support cyclone mitigation measures. This study developed a simple cyclone risk-modelling approach under present and future climate change scenarios using geospatial techniques at local scales, and tested using a case study in Sarankhola Upazila from coastal Bangladesh. Linear storm-surge models were developed up to 100-year return periods. A local sea level rise scenario of 0.34?m for the year 2050 was integrated with surge models to assess the climate change impact. The resultant storm-surge models were used in the risk-modelling procedures. The developed risk models successfully identified the spatial extent and levels of risk that match with actual extent and levels within an acceptable limit of deviation. The result showed that cyclone risk areas increased with the increase of return period. The study also revealed that climate change scenario intensified the cyclone risk area by 5–10% in every return period. The findings indicate this approach has the potential to model cyclone risk in other similar coastal environments for developing mitigation plans and strategies.  相似文献   

Modelling coastal land use change by incorporating spatial autocorrelation into cellular automata models   总被引：1，自引：0，他引：1  

Yongjiu Feng  Qianqian Yang  Zhonghua Hong  Li Cui 《国际地球制图》2018,33(5):470-488

This paper presents a spatial autoregressive (SAR) method-based cellular automata (termed SAR-CA) model to simulate coastal land use change, by incorporating spatial autocorrelation into transition rules. The model captures the spatial relationships between explained and explanatory variables and then integrates them into CA transition rules. A conventional CA model (LogCA) based on logistic regression (LR) was studied as a comparison. These two CA models were applied to simulate urban land use change of coastal regions in Ningbo of China from 2000 to 2015. Compared to the LR method, the SAR model yielded smaller accumulated residuals that showed a random distribution in fitting the CA transition rules. The better-fitting SAR model performed well in simulating urban land use change and scored an overall accuracy of 85.3%, improving on the LogCA model by 3.6%. Landscape metrics showed that the pattern generated by the SAR-CA model has less difference with the observed pattern.  相似文献   

Soil salinity and vegetation cover change detection from multi-temporal remotely sensed imagery in Al Hassa Oasis in Saudi Arabia     

Amal Allbed  Lalit Kumar  Priyakant Sinha 《国际地球制图》2018,33(8):830-846

Detecting soil salinity changes and its impact on vegetation cover are necessary to understand the relationships between these changes in vegetation cover. This study aims to determine the changes in soil salinity and vegetation cover in Al Hassa Oasis over the past 28 years and investigates whether the salinity change causing the change in vegetation cover. Landsat time series data of years 1985, 2000 and 2013 were used to generate Normalized Difference Vegetation Index (NDVI) and Soil Salinity Index (SI) images, which were then used in image differencing to identify vegetation and salinity change/no-change for two periods. Soil salinity during 2000–2013 exhibits much higher increase compared to 1985–2000, while the vegetation cover declined to 6.31% for the same period. Additionally, highly significant (p < 0.0001) negative relationships found between the NDVI and SI differencing images, confirmed the potential long-term linkage between the changes in soil salinity and vegetation cover.  相似文献