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鉴于红树林生态系统对气候变化背景下海平面上升和极端台风事件有高度敏感性,应用1980—2018年的海洋大气观测资料和实地调查数据,分析了海口东寨港地区的海平面、温度和台风最大风速的变化特征,并基于IPCC气候变化综合风险的理论框架,构建了"暴露度-敏感性-适应性"的脆弱性评价指标体系和估算方法,评估了海平面上升和台风事件背景下东寨港红树林生态系统的脆弱性主要特征。结果显示:①东寨港红树林生态系统的致灾影响因子主要为该地区沿海海平面的快速上升,其上升速率可达4. 6 mm/a,远高于全球和中国沿海平均值;其次为1993年之前和2006年之后,在海口地区250 km范围内出现的热带气旋或台风事件;②东寨港红树林脆弱性指数的平均值为0. 31,属于中度脆弱等级,其中三江片区的红树林脆弱性相对最高,演丰片区最低。构建的评价指标体系可较好地反映出海平面快速上升和热带气旋或台风影响下红树林生态系统的脆弱性特征。 相似文献
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依托2017年8月23日至2017年9月6日在长江口及邻近海域连续走航测得的二氧化碳分压(pCO2)值,结合温度、盐度、溶解氧等数据,阐述该海域pCO2的分布特征,并利用一次大风事件前后一个断面的重复观测数据,讨论天气事件对长江口海-气CO2通量的影响。夏季长江口及邻近海域表层海水pCO2范围为145~929 μatm,总体呈近岸高远岸低的分布特征,在受长江冲淡水影响的区域,海表pCO2较低,整体表现为大气CO2的汇。大风事件(最大风速达9.7 m·s-1)加强了水体的垂直混合,导致近岸区域从大气CO2的弱源变为强源(CO2通量从0.2±1.9上升到 55.0±12.4 mmol·m-2·d-1),而远岸区域的碳汇略有加强(CO2通量从-12.7±2.3变为-16.8±2.5 mmol·m-2·d-1)。因此,在估算东海海-气CO2通量时,台风、冷空气等短时间尺度天气事件的影响也不容忽视。 相似文献
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海岛森林生态系统受地理位置特殊和数据源较少等因素影响,其碳通量动态监测及碳汇功能评估鲜见报道。该文以南麂岛森林生态系统为研究对象,基于涡度相关技术探讨了2020—2021年净生态系统碳生产力(net ecosystem productivity, NEP)、总初级生产力(gross primary productivity, GPP)和生态系统呼吸(ecosystem respiration, Reco)的变化特征及其影响因素。结果显示,南麂岛森林生态系统表现为碳吸收,2020和2021年CO2净吸收量分别为516 g C·m-2·a-1和598 g C·m-2·a-1,Reco分别为1 037 g C·m-2·a-1和1 646 g C·m-2·a-1,GPP分别为1 552 g C·m-2·a-1和2 244 g C·m-2 相似文献
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探究海气CO2交换有助于解析全球碳循环和全球气候变化。由于海水和大气的直接接触,研究表层海水碳酸盐系统变化成为探究海气碳交换的关键。基于已有热带西太平洋表层海水碳酸盐系统研究成果,本文总结了有孔虫壳体B/Ca和δ11B指标重建碳酸盐系统参数的原理、方法及优缺点。然后,从厄尔尼诺-南方涛动(El Ni?o-Southern Oscillation, ENSO)、东亚季风以及大气桥梁和海洋隧道三方面综述了晚第四纪热带西太平洋海气CO2交换影响因素的研究现状。结果显示,类ENSO通过横向平流和垂向变化分别影响热带西太平洋东端和西端的海气碳交换。东亚夏季风对热带西太平洋海气碳交换具有较强的调控作用,而东亚冬季风的调控作用较弱或不明显。冰消期南大洋深部流通状况增强,可通过大气桥梁(大气CO2)和海洋隧道(南极中层水)影响热带西太平洋海气碳交换。然而,为了更准确清晰地了解全球碳循环变化,还需针对指标记录的可靠性、覆盖范围以及海气碳交换在更长时间尺度的变化机理等方面开展更多研究。 相似文献
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河口红树林湿地CH4通量的日变化研究 总被引：10，自引：0，他引：10
甲烷(CH4)是大气中除CO2外最为丰富的含碳组分,其浓度以每年0.7%-1.1%的速率递增[1,2].尽管大气CH4含量仅为CO2的二百分之一,但却对预计的全球变暖约有20%的贡献率,而CO2的贡献率约为50%[3,4],由这些数据推算得一个分子的CH4比一个分子的CO2(目前最重要的温室气体)的增暖潜值高约80倍.很多研究者对全球大气CH4的预算结果均表明,湿地是大气CH4最重要的生物源[5,6],约占全球CH4源的40%～50%[7].湿地CH4通量的日变化研究是正确估算大时间尺度下CH4排放量(如平均年排放量和季节排放量)的基础,因而具有相当的重要性. 相似文献
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太平洋中低纬海水中的二氧化碳分布特征及其与海洋环境条件的关系 总被引：3，自引：0，他引：3
根据1986年11月至1990年6月进行的中美热带西太平洋海-气相互作用(TOGA)联合考查和1995年10月至1996年6月“中日副热带联合调查”期间获得的14个航次大气和海水CO2的观测资料,给出了主要观测海区CO2的源与汇的分布特征:在赤道地区5°N~5°S,130°~165°E观测到的表面水中二氧化碳分压的值超过了大气中二氧化碳分压1.5~4.5 Pa,结果表明该海区对大气CO2而言是源,但是该值远小于在中赤道测到的+9.1 Pa和在东赤道太平洋所测的+15 Pa的值.由此表明热带太平洋CO2源的强度是向西减弱的.副热带海区在秋季对大气CO2而言是较强的源,春季是汇.对影响海水CO2变化的主要因素温度、盐度等进行了讨论,表明CO2的分布变化直接受海流、水团、黑潮和ENSO事件影响. 相似文献
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XU Qingyan WANG Jianfeng HUANG Yaojian ZHENG Zhonghui SONG Siyang ZHANG Yongmin SU Wenjin 《海洋学报(英文版)》2004,23(3):541-547
Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts. They prove to be a natural microorganisms and new metabolites storage. In the study of mangrove endophytic fungi metabolites, four new compounds, Compounds 1, 2, 3 and 4, as well as a known octaketide, cytosporone B (5), are isolated from an endophytic fungus, Dothiorella sp., HTF3. They all show cytotoxic activities. The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses. 相似文献
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Mangroves can not only provide multiple ecosystem service functions, but are also efficient carbon producers,capturers, and sinks. The estimation of the organic carbon accumulation rate(OCAR) in mangrove sediments is fundamental for elucidating the role of mangroves in the global carbon budget. In particular, understanding the past changes in the OCAR in mangrove sediments is vital for predicting the future role of mangroves in the rapidly changing environment. In this study, three dated sediment cores from interior and fringe of mangroves in the Yingluo Bay, China, were used to reconstruct the spatiotemporal variations of the calculated OCAR since 1900 in this area. The increasing OCAR in the mangrove interior was attributed to mangrove flourishment induced by climate change characterized by the rising temperature. However, in the mangrove fringe, the strengthening hydrodynamic conditions under the sea level rise were responsible for the decreasing OCAR, particularly after the1940 s. Furthermore, the duration of inundation by seawater was the primary factors controlling the spatial variability of the OCAR from the mangrove fringe to interior, while the strengthened hydrodynamic conditions after the 1940 s broke this original pattern. 相似文献
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调查了广东红树林区水质的时空变化, 分别采集了红树林区表层水体水样旱季30个样点(2017年10月至2018年1月)和湿季20个样点(2018年7月至8月)进行分析。利用单一营养状态指数(TSI Chl a)评价红树林水质特征和营养状态, 评价标准: 050为富营养, >70为高营养。红树林区环境参数的时空变化为: 盐度(2.15‰~27.14‰)、pH (6.18~8.65)、电导率(10.87~90.52µs·cm-1)、浊度(0.0975~21.61FTU)、硝酸盐(0~127.2mg·L-1)、亚硝酸盐(0~12.0mg·L-1)、磷酸盐(0~34.5mg·L-1)、硅酸盐(1.22~2.88mg·L-1)和叶绿素a (0.19~38.08mg·m-3)。聚类分析表明, 丰水期横跨雷州半岛右侧至广东沿海东部的水质相对较好, 而左侧则处于中营养化状态。同时, 在枯水期, 红树林区水质较差, 从雷州半岛周围的高中营养化状态, 到广东沿海东部的富营养化状态。主成分分析表明, 营养盐、盐度、pH、电导率(electrical conductivity, EC)和浊度对红树林区水质状况贡献显著, 进而影响红树林生态系统中藻类群落的变化。 相似文献
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红树林(Mangroves)是生长在热带和亚热带海岸潮间带的木本植物群落。老鼠簕(Acanthus ilicifolius)是我国红树林林下灌丛的主要物种,是林下植被碳库的主要构成成分。本研究选取深圳福田红树林区的林下、林窗、林缘和光滩等不同生境下自然生长的老鼠簕植株,测定植株生物量和光合特性等相关指标。研究表明,林窗生境下的老鼠簕植株的光合能力、光合固碳速率和地上生物量累积均达到最大;林下生境最不利于老鼠簕植株固碳;光滩的老鼠簕植株具有较高的地下生物量累积,但由于其蒸腾速率高、水分利用率低下,其固碳较低。光照强度是决定不同生境老鼠簕植株固碳的关键因子。在未来我国红树林造林中,老鼠簕可作为林下植被构建,以提高红树林生物量总碳库,但最适宜老鼠簕固碳的光照约为40%~80%。本文研究结果将为红树林造林实践中的物种选择和林分构建提供理论参考。 相似文献
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文章以福建省漳江口国家级红树林自然保护区为研究区, 提出了一种联合星载光学和合成孔径雷达(SAR)影像的红树林与互花米草分布的自动提取算法, 提取研究区内红树林和互花米草的空间分布。本研究选择2016年、2017年和2018年各一景低潮时的Sentinel-2 A光学影像数据, 获取植被和其他地物的光谱和纹理信息。算法首先基于归一化植被指数、增强型植被指数、地表水分指数以及数字高程模型的相关规则计算红树林和互花米草的潜在分布区; 通过随机森林分类算法区分红树林和互花米草, 2016年、2017年和2018年影像的分类总体精度和Kappa系数分别为98.53%和0.980、96.52%和0.952、98.71%和0.978, 分类效果良好; 使用当年所有Sentinel-1 A/B的SAR影像获得研究区的常年海水分布范围, 使用与海水交界的判据, 实现红树林、互花米草提取范围的优化。研究表明, 研究区2016年、2017年和2018年红树林总面积分别为56.85hm2、59.88hm2和58.61hm2, 互花米草总面积分别为109.23hm2、124.00hm2和142.39hm2, 与前人的研究成果在红树林和互花米草的空间分布和面积量级上有较好的一致性。 相似文献
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Macrofauna along the Sudanese Red Sea coast: potential effect of mangrove clearance on community and trophic structure 
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下载免费PDF全文 Mangroves along the Sudanese Red Sea coast are under constant anthropogenic pressure. To better understand the influence of mangrove clearance on the intertidal benthic community, we investigated the composition, biodiversity and standing stock of the macrofauna communities at high‐, mid‐ and low‐water levels in three contrasting habitats: a bare sand flat, a cleared mangrove and an intact mangrove. In addition, a community‐wide metric approach based on taxon‐specific carbon and nitrogen isotope values was used to compare the trophic structure between the three habitats. The habitats differed significantly in terms of macrofaunal standing stock, community composition and trophic structure. The high‐ and mid‐water levels of the intact mangroves showed a distinct macrofaunal community characterized by elevated densities and biomass, largely governed by higher decapod and gastropod abundances. Diversity was similar for cleared and intact mangroves, but much lower for the bare sand flat. Community‐wide metrics indicated highest trophic diversity and community niche breadth in the intact mangroves. Differences between the cleared and intact mangroves can be partly attributed to differences in sediment characteristics resulting from mangrove clearance. These results suggest a significant impact of mangrove clearance on the macrofaunal community and trophic structure. This study calls for further investigations and management actions to protect and restore these habitats, and ensure the survival of this ecologically valuable coastal ecosystem. 相似文献
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Using mangroves as a geological indicator of coastal changes in the Bragança macrotidal flat,Brazilian Amazon: A remote sensing data approach 总被引：1，自引：0，他引：1
《Ocean & Coastal Management》2006,49(7-8):462-475
A mangrove ecosystem shows close links between geomorphology and vegetation assemblage. In addition, the vegetation can change over time as landforms can accrete or erode, which is a direct response to coastal sedimentary processes. This demonstrates that significant changes can occur on short time scales and mangroves provide an excellent register of these modifications. Therefore, mangrove morphology and sedimentation are good indicators of interactions between relative sea level changes, coastal processes and sediment supply. These interactions are responsible for landward migration of the shoreline (erosion) and seaward migration of the shoreline (accretion), which is possible to detect from multi-date satellite data and field observations. Mangroves are one of the best geo-indicators in global coastal change research and they are an excellent procedure to detect and quantify coastal modifications. 相似文献
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Remote Sensing of Mangrove Change Along the Tanzania Coast 总被引：1，自引：1，他引：0
Yeqiao Wang Gregory Bonynge Jarunee Nugranad Michael Traber Amani Ngusaru James Tobey 《Marine Geodesy》2013,36(1-2):35-48
This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania. 相似文献
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Yeqiao Wang Gregory Bonynge Jarunee Nugranad Michael Traber Amani Ngusaru James Tobey Lynne Hale Robert Bowen Vedast Makota 《Marine Geodesy》2003,26(1):35-48
This article contributes to the understanding of the changes in distribution and total area of mangrove forests along the mainland Tanzania coast over the past decade. Mangroves are recognized as critical coastal habitat requiring protection and special attention. The Tanzania coastline forms a suitable habitat for establishment of mangrove forests. Mangrove forests are distributed from Tanga in the north to Mtwara in the south covering approximately 109,593 hectares from 1988-1990 and about 108,138 hectares in 2000. The largest continuous mangrove stands are found in the districts of Rufiji, Kilwa, Tanga-Muheza, and Mtwara. Comparison of data between these two time periods shows that the geographic coverage of mangroves has no dramatic change in the past decade. The Tanzania Mangrove Management Project and other closely related programs and efforts pertaining to mangrove conservation contribute to direct restoration and natural regeneration of mangroves. This study documents the changes of mangroves and demonstrates that remote sensing and GIS offer important data and tools in the advancement of coastal resource management and ecosystem monitoring. Application of geographic information technologies is critical for improved coastal resources management and decision making for sustainable development in Tanzania. 相似文献
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《Marine Policy》2014
Tropical fisheries are in decline around world as a result of diverse anthropogenic threats. These threats are intimately linked to biodiversity and conservation values because of the heavy dependence of both fisheries and high value marine and coastal wetlands on coastal ecosystem health. Consequently, if the widespread degradation of coastal ecosystems can be halted and remediated, there are substantial benefits to fisheries output, ecosystem resilience, food security, livelihoods, recreation and the protection of ecological assets of national and global significance. The extent, intactness and quality of Australia׳s tropical coastal ecosystems has declined markedly since European settlement, due to the cumulative impact of many small encroachments and local barrier construction on the extent and productivity of coastal wetlands, mangroves and seagrass meadows. Additionally, coastal ecosystem dependent biota has been excluded from large areas of critical habitats. Despite these changes, coastal fisheries show no clear declines that could not be explained by changes in effort. This lack of detectable decline is probably partly attributable to the short history of available fisheries catch data. However, it is also likely that it reflects the offsetting of lost natural productivity by greatly increased anthropogenic nutrient loads; a substantial problem as governments are committed to large scale, long term efforts to reduce discharges of nutrients to coastal waters. This possibility underlines the importance of rejuvenating lost coastal productivity. Evaluation of past remediation efforts show that documented success is rare, due to a complex of factors including ineffective prioritisation, a lack of necessary knowledge and resources, and inefficient monitoring and evaluation. Past experiences from Australia׳s tropics and around the world, together with current ecological understanding, suggests some generally desirable characteristics to enhance the likelihood of successful remediation and repair actions. 相似文献