小尺度海洋生态功能分区指标体系与技术方法研究——以长兴岛近海海域为例

以辽宁省长兴岛海洋生态系统为研究对象,在分析长兴岛自然环境特征和海洋生态系统基础上,依据生态功能区划原则,建立海洋生态功能分区的技术方法体系,运用 GIS 技术将长兴岛海域划分为生态保护区、生态维护区和开发利用区三个生态功能区,所占比例分别为47.17%、18.04%和34.78%。根据区内的主导生态功能及目前各区存在的生态环境问题,提出长兴岛近海海域未来生态保护与建设的重点和目标及区域产业结构与布局的调整方向。     

舟山东极岛潮间带贝类生态学初步研究

为了解东极岛潮间带贝类生态状况,为浙江海洋生态系统基本群落结构提供基础资料,于2010年4月至2011年4月的大潮期间,在舟山东极岛潮间带采集贝类,调查了解贝类的种类组成、数量分布、生态特点、多样性情况。研究分析发现,东极岛潮间带贝类33种,隶属3纲7目20科。根据温度适应性质分,东极岛潮间带贝类属于3个类群：广温广布种15种,占45.5%;温带种4种,占12.1%;亚热带种14种,占42.4%。东极岛潮间带贝类四季平均生物量为1541.8 g/m2,由高潮带向低潮带呈递增趋势;四季平均栖息密度为925.2个/m2,以中潮带最高,向高潮带和低潮带递减。季节变化中生物量由大到小依次为夏季、春季、冬季、秋季,栖息密度由大到小依次为夏季、秋季、冬季、春季。多样性指数(H′)为0.9~3.0,均匀度指数(J)为0.2~0.8。结果表明东极岛种类丰富,生物量和栖息密度较高,说明东极岛地理环境较好,适宜贝类生存;物种分布均匀,生态环境稳定。     

枸杞岛贻贝养殖区大型底栖动物群落结构及与环境因子的关系

大型底栖动物物种组成及其群落结构能间接反映贻贝养殖区底栖生态状况。基于2021年4月和8月枸杞岛贻贝养殖区现场调查数据,开展了大型底栖动物群落结构、季节差异及主要驱动因子的系统解析。调查共鉴定大型底栖动物172种,隶属14纲40目84科,物种季节更替率为83.14%。丰度等级分布(Rank abundance)曲线表明,夏季物种更丰富,但均匀度相对较低。春、夏季大型底栖动物Shannon-Wiener多样性介于1.61～2.95之间,季节间差异显著。Simpson指数与盐度、沉积物中值粒径(D50)存在显著正相关关系;生物量与沉积物中值粒径、总有机碳(TOC)存在显著负相关关系;物种数、Chao1指数、生物量、丰富度均与TOC显著负相关。聚类分析将春季分为四个组别,夏季分为三个组别,NMDS分析表明,春季分组物种分离不显著,夏季分组物种分离显著,相似性分析(ANOSIM)印证了这种差异。应用相似百分比(SIMPER)分析表明,季节平均相异率为87.57%,分歧种为丝异须虫(Heteromastus filiformis)。CCA分析表明,溶解氧、TOC和硝酸盐是驱动贻贝养殖区大型底栖动...     

海洋工程对觉华岛国家级海洋公园海域生态环境影响研究

文章根据2016—2019年觉华岛周边海域生态环境监测结果,并结合期间大规模海洋开发活动,分析了觉华岛国家级海洋公园海域环境变化趋势。结果表明:2016—2019年,觉华岛周边海域水质要素监测结果均符合《海水水质标准》中的二类标准,沉积物要素监测结果均符合《海洋沉积物质量》中的一类标准。水质与沉积物大部分监测要素的平均含量年际变化呈先降低再上升的变化趋势,生物环境状况整体水平变化情况与水质和沉积物的变化趋势有良好的对应关系,说明海洋工程建设对觉华岛国家级海洋公园海域生态环境造成了一定的负面影响,但影响程度不大。     

Source and magmatic evolution of ocean island basalts from the Pohnpei Island,Northwest Pacific Ocean: Insights from olivine geochemistry

The compositional variability of ocean island basalts (OIBs) is thought to reflect partial melting of a lithologically-heterogeneous mantle source dominated by either pyroxenite or peridotite. The Pohnpei Island in Micronesia, which is associated with the Caroline hotspot, is suggested to have been generated from partial melting of a pyroxenite-rich mantle. To examine this hypothesis, we present new major- and trace-element compositions of olivine phenocrysts in basalts from the island. The olivines exhibit large systematic inter- and intra-crystalline compositional variability. In Sample DS1, olivines record compositional zonation, in which cores have relatively high Fo (77–85), Ni (550×10?6–2 392×10?6), and Fe/Mn ratios (66–82), whereas rims have lower Fo (71–78), Ni (526×10?6–1 537×10?6), and Fe/Mn ratios (51–62). By contrast, olivines within other samples preserve no clear compositional zonation, exhibiting similar or slightly lower Fo values (66–78), Ni contents (401×10?6–1 268×10?6), and Fe/Mn ratios (53–69) as the rims of zoned crystals. The distinct chemical contrast between the two different types of olivine suggests they formed in magma chambers at different depths. Analysis using forward petrological modeling and multi-element indicators (Fe/Mn, Zn/Fe, FC3MS (FeOT/CaO?(3×MgO/SiO₂)), Mn/Zn, and Ni/(Mg/Fe)) of whole-rock samples and high-Fo olivines is inconsistent with a pyroxenite-rich mantle source. We suggest these inconsistencies reflect an influence on the partition coefficients of Ni and Mn between olivine and liquid during melting at variable pressures and temperatures. In addition, magma recharge and mixing within the magmatic plumbing system can change the composition of olivine. We suggest that identification of the mantle source of OIBs in volcanic islands such as the Pohnpei Island using olivine geochemistry should be treated with caution.     

崇明岛"闸控型"河网水体富营养化特征及其影响因素

为研究崇明岛"闸控型"河网水体富营养化特征及其与环境因子的相互作用,以2010年各季节崇明岛河网水质数据为基础,探讨了环境因子与藻类的变化规律及其相互作用机制.结果表明:崇明岛河网水环境中营养盐水平较高,氮污染尤为严重.长江引水进入岛内河网水环境后,营养盐(除SiO₃-Si)、Chl.a含量和营养状态都出现了明显的升高.与长江引水相比,河网内藻类群落Chl.a贡献比例的变化主要表现为硅藻比例的下降以及蓝藻和绿藻比例的上升.尽管水温、pH、浊度以及营养盐中的TN、TP、NO₃^--N、DOC的变化均与Chl.a含量显著相关,但藻类群落对环境因子的响应关系存在较大差异.蓝藻的增加主要与水温和TP含量的升高有关;绿藻与TN、NO₃^--N的关系最为密切;硅藻的变化只与浊度存在明显正相关,营养盐并不是硅藻生长的促进因子.     

三亚蜈支洲岛热带海洋牧场渔业资源现状及季节变动

蜈支洲岛海洋牧场为海南省首个国家级海洋牧场示范区,为评估蜈支洲岛海洋牧场的资源养护效果,进而为下一步海洋牧场的渔业资源科学管理提供依据。采用渔业资源水声学调查方法,对蜈支洲海洋牧场近岛人工鱼礁区及海棠湾湾区的渔业资源现状及其季节变动进行了研究。2019年4月、8月、12月进行了3次调查,结果显示：4月近岛人工鱼礁区域共捕获游泳生物63种,平均资源量密度为63.71 t/km²,8月、12月海棠湾湾区共捕获游泳生物68种和120种,平均资源量密度分别为8.29 t/km²和7.21 t/km²。4-12月物种多样性指数（H''）均值分别为3.532、3.478、4.414。三次调查中,鱼类优势种中多齿蛇鲻（Saurida tumbil）、短鳄齿鱼（Champsodon snyderi）、宽条鹦天竺鯛（Ostorhinchus fasciatus）均出现2次,其余种类均只出现一次。4-12月重要经济生物占总资源量的比重依次为72.46%、64.74%、57.59%。综上所述,蜈支洲岛海洋牧场近岛人工礁区及海棠湾湾区渔业资源丰富、物种多样性高,尤其是海洋牧场建设对于渔业资源的聚集起到了积极的作用,但仍存在重要经济鱼类少,个体较小等问题。     

南海东沙海域网状沙丘的发现及其成因探讨

基于多波束测深和高分辨率多道反射地震数据,以及遥感资料研究南海北部东沙海域深水沙丘,总结底形形态分布特征,分析其水动力成因.按照空间分布形态将沙丘分为平行沙丘、波状沙丘和网状沙丘,本文首次发现水下网状沙丘,重点讨论网状沙丘的特征分布和形成机制.网状沙丘发育在东沙环礁东北部水深约352~420 m之间,研究发现其延伸方向共有三个走向：NS、NE-SW和EW,前两个方向为西向传播的内波所致,而最后一个则很有可能是由洋盆西向传播的内波遇到东沙环礁后形成衍射,向北传播的内波引起了向南的近海底底流,冲刷海底底层,剥蚀出足够的沉积物颗粒,从而形成EW走向的水下沙丘.值得一提的是,在多边形网状沙丘的上方,反射地震剖面揭示水层中发育与下方沙丘相当波长的高频震荡内波,并且在遥感资料上也发现相关的衍射和内波干涉区域,而内波干涉很有可能导致高频震荡,从而形成网状沙丘.本研究丰富了水下沙丘形态类型,探讨了新型水下沙丘的形成机制,在陆坡底沙运动及工程应用中具有重要的价值.     

Evidence on the Koseda coast of Yakushima Island of a tsunami during the 7.3 ka Kikai caldera eruption

Previous research indicates that Yakushima Island, southwestern Japan, may have been struck by a huge tsunami before or soon after the arrival of the Koya pyroclastic flow during the 7.3 ka caldera‐forming Kikai eruption, but this has not yet been confirmed. This paper describes sedimentological and chronostratigraphic evidence showing that Unit TG, one of three gravel beds exposed on the Koseda coast of northeast Yakushima Island and investigated here, is a tsunami deposit. Unit TG is a poorly sorted, 30 cm thick gravel bed overlying a wave‐cut bench and underlying a Koya pyroclastic flow deposit. Sparse wood fragments in Unit TG were dated at 7 416–7 167 cal year BP. The constituent gravel clasts of Unit TG are similar in composition to those of modern beach and river deposits along the Koseda coast. Unit TG also contains pumice clasts whose chemistry is identical to that of pumice derived from the 7.3 ka eruption at Kikai caldera. The long‐axis orientations and composition of gravel clasts in Unit TG suggest that they were transported by a landward‐travelling high‐particle‐concentration flow, which suggests that Unit TG was deposited by a tsunami run‐up flow during the 7.3 ka Kikai caldera eruption, just before the arrival of the major Koya pyroclastic flow at the Koseda coast. Whether the 7.3 ka tsunami was caused by a volcanic eruption or an earthquake remains unclear, but Unit TG demonstrates that a tsunami arrived immediately before emplacement of a Koya pyroclastic flow.     

Reindeer Herders Without Reindeer. The Challenges of Joint Knowledge Production on Kolguev Island in the Russian Arctic

Kolguev Island in the Russian Arctic has a unique tundra ecosystem and an indigenous Nenets population whose livelihood is traditionally based on reindeer herding. The Nenets faced a major crisis in 2013–2014 when the reindeer population collapsed. Widely different explanations for this collapse were put forward. This lack of a shared perspective points at the failure of genuine joint knowledge production (JKP) in the island’s UNEP–GEF’s ECORA project (2004–2009). The ECORA project aimed to achieve integrated ecosystem management by stimulating dialog and mutual learning among indigenous people, state agencies, and scientists. This paper analyses the failure of ECORA’s JKP, using a recently developed framework of conditions for successful JKP. The results suggest that ECORA met none of these conditions. It failed at bringing the scientific and indigenous knowledge systems together, and the produced knowledge did not resonate with indigenous people’s perception of living in Kolguev.