Decadal changes in a NW Mediterranean Sea food web in relation to fishing exploitation

We analysed changes in the ecological roles of species, trophic structure and ecosystem functioning using four standardized mass-balance models of the South Catalan Sea (North-western Mediterranean). Models represented the ecosystem during the late 1970s, mid 1990s, early 2000s, and a simulated no-fishing scenario. The underlying hypothesis was that ecosystem models should quantitatively capture the increasing exploitation in the ecosystem from the 1970s to 2000s, as well as differences between the exploited and non-exploited scenarios. Biomass showed a general decrease, while there was an increase in biomass at lower trophic levels (TL) from the 1970s to 2000s. The efficiency of energy transfer (TE) from lower to higher TLs significantly increased with time. The ecosystem during the 1990s showed higher biomass and flows than during the 1970s and 2000s due to an increase in small pelagic fish biomass (especially sardines). Exploited food webs also showed similarities in terms of general structure and functioning due to high intensity of fishing already in the 1970s. This intensity was highlighted with low trophic levels in the catch, high consumption of production by fisheries, medium to high primary production required to sustain the catches and high losses in secondary production due to fishing. Significant differences on ecosystem structure and functioning were highlighted between the exploited and no-fishing scenarios. Biomass of higher TLs increased under the no-fishing scenario and the mean trophic level of the community and the fish/invertebrate biomass ratios were substantially lower in exploited food webs. The efficiency of energy transfer (TE) from lower to higher TLs was lower under the no-fishing scenario, and it showed a continuous decrease with increasing TL. Marine mammals, large hake, anglerfish and large pelagic fish were identified as keystone species of the ecosystem when there was no fishing, while their ecological importance notably decreased under the exploited periods. On the contrary, the importance of small-sized organisms such as benthic invertebrates and small pelagic fish was higher in exploited food webs.     

“Protecting coastal zones in the Mediterranean: an economic and regulatory analysis”

This paper examines existing measures taken to protect the coastal zones of the Mediterranean Sea and assesses their success. A summary of the main pressures facing this region is given, followed by an analysis of the legislation covering coastal zone development in ten countries: Algeria, Croatia, Egypt, France, Israel, Italy, Malta, Spain, Tunisia and Turkey. The paper finds that not all of these States have legislation specifically covering coastal zones, but there is concern in all areas that existing legislation is not working. The costs and benefits of controlling coastal development are examined. Firstly, a literature review of valuation studies identifies a range of values placed on the developed and undeveloped coastline for both users and local property owners. These values were then used in a model to evaluate policy options to control development of a stretch of coastline. The model indicates that a stricter control regime of coastal development may provide significant benefits.

渤海海冰Modis影像中"伪海冰像元"消除方法的探讨

"伪海冰像元"对渤海海冰范围分布信息的提取产生影响,消除伪海冰像元需要得到一些传感器、大气状况等参数,但往往很难全部得到满足.本文研究了在不知道传感器、大气状况等参数的条件下,通过对数字影像进行实验分析,提取传感器、大气状况引起的脉冲响应函数,并利用该函数结合频域逆滤波和维纳滤波器求解消除非理想脉冲响应的反卷积函数,在空域利用反卷积函数对图像进行逆处理的"伪海冰像元"消除方法.试验结果表明,该方法能够达到降低"伪海冰像元"与其邻域海水像元之间分离度的目的,从而较好的在渤海海区Modis影像中实现分离出"伪海冰像元"的效果.     

南海水域不同深度非光合微生物的固碳潜能及其对不同电子供体的响应

通过对南海水域多个区域不同深度的海水分别以H2、Na2S2O3、Na NO2为电子供体经过一定时间的驯化培养后,测定其中非光合微生物的固碳潜力,并统计南海水域不同深度非光合微生物在不同电子供体条件下固碳潜力的差异性,最后结合不同深度海水的主要固碳基因丰度差异,分析南海水域不同深度海洋非光合微生物在不同电子供体条件下固碳潜能差异的原因.结果发现以Na NO2为电子供体时,海洋非光合微生物固碳能力普遍较低,各深度之间没有显著差异;以H2为电子供体时,表层海水中的非光合微生物的固碳潜力显著高于深层海水中的;而以Na2S2O3为电子供体时,深层海水中的非光合微生物的固碳潜力显著高于表层海水中的.基因分析结果表明,固碳基因cbb L在表层海水中的丰度高于深层海水,而cbb M基因在深层海水中的丰度高于表层海水.硫细菌大多以拥有cbb M基因为主,而氢细菌大多以拥有cbb L基因为主.因此不同海洋深度非光合微生物对不同电子供体响应的差异性可能和优势菌群结构的差异有关.海洋表层和深层溶解氧、无机碳含量的差异是导致菌群结构差异,乃至固碳潜力差异的重要原因.     

宁波大榭岛邻近水域生态现状

通过对大榭岛附近海域水环境因子的调查和评价,发现该海域呈富营养化状态,无机氮、无机磷的含量已达发生赤潮临界条件,但与大榭岛开发前相比,浮游植物和浮游动物的结构组成及优势种并未发生明显变化,浮游植物和浮游动物的多样性指数H＇分别为0.97～3.00和1.98～2.75,平均值分别为2.27和2.35.     

中国近海沉积物在生源要素循环中的功能

中国近海沉积物中生源要素的含量与其粒度、河流输入等诸多因素有关。一般沉积物粒度由粗到细 ,有机质含量由低到高 ,OC ,N ,P的含量递增 ,S和Si含量递减。沉积物的生物地球化学环境涉及到Eh ,pH ,温度 ,OC含量 ,Fe3 /Fe2 值 ,水动力条件 ,沉积物的颗粒大小和间隙水的S体系 ,以及生物扰动等因素 ,它们影响着沉积物中生源要素的早期成岩过程和循环。一般而言 ,中国近海沉积物—海水界面S2 -,HS-,H4SiO4,PO43 -,NH4 的扩散通量是从沉积物向上覆水 ,而SO42 -,HCO3 -,NO3 -,NO2 -的扩散通量从上覆水向沉积物中扩散。生物扰动对沉积物—海水界面生源要素的循环起重要作用。     

我国东部沿海热带气旋演化特征研究

我国是遭受热带气旋灾害最为严重的国家之一.其年际年代际演化特征仍不清晰.采用中国气象局公布的1949?—?2018年的最佳路径数据集、登陆热带气旋名录以及HadlSST数据,探讨近70 a以来我国东部沿海热带气旋的时空演化特征及其与海表温度变化的内在关联.结果表明:(1)70 a间,热带气旋生成个数以及登陆我国东部沿海地区的个数略有波动,但超强热带气旋个数生成以及登陆我国的个数呈现明显增加趋势;登陆我国东部沿海地区的热带气旋大多生成于7、8、9月份,但4月以及11月也存在热带气旋生成并登陆现象.(2)登陆我国东部沿海地区的热带气旋主要生成于西北太平洋海域(432个)、南海海域(199个)和东海海域(28个),且主要在我国广东(220个)、海南(153个)、台湾(146个)、福建(47个)登陆.(3)热带气旋生成及登陆我国气旋与全球海表温度具有高度相关性;与西太平洋海温呈正相关,与东太平洋与印度洋海温呈负相关.     

黄河断流对三角洲附近海域生态环境影响的研究

本文根据多年调查监测数据研究成果，以及经济和社会统计资料，论述了黄河断流的历史与现状，定性定量地评价了黄河断流对三角洲附近海域生态环境的影响，并提出了缓解和预警对策。     

填海造地生态损害评估:理论、方法及应用研究

论文建立了一系列生态-经济模型,用于评估填海造地生态损害的价值以及被填海域作为生产要素的价值。用所建立的模型对厦门填海造地进行经验估算,得出在厦门每m²填海造地生态损害的价值为279元,远远高于现行的填海造地海域使用金征收标准。加上海域作为生产要素的价值,厦门工业用填海造地海域使用金征收标准应该为327.82元/m²,商业用填海造地的海域使用金征收标准应该为相邻土地价格的50%～55%。研究结果可以为制定填海造地规划和控制填海造地的经济手段提供强有力的科技支撑。     

北极沉积物中硫酸盐还原菌与生物地球化学要素的相关分析

对北极楚科奇海、白令海测区34个沉积物样品的硫酸盐还原菌(SRB)含量与CaCO3、Si、S、P、Cd、Fe、Ti、Pb、Hg等地球化学要素作了相关分析．同时分析了SRB与其所在沉积物粒度与底层水温间的关系．结果表明：SRB与Si、砂及底层水温为正相关；SRB与CaCO3、Fe、Ti、P、Pb、Hg、粉砂、粘土为负相关；而SRB与Cd、S的相关性因海区不同而不同．既有负相关．也有正相关．分析了这些相关状况及其原因．