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1.
近海的生态环境问题态势严峻。在机制上，普遍认为富营养化是导致近海环境恶化的主导因子，但实际上，营养盐的结构失衡对近海生态环境问题的产生可能起到了更重要的作用。目前关于营养盐结构失衡的主导因素和机制尚缺乏全面系统的研究。本文基于对已有数据和文献资料的整合分析发现，由于存在强烈的人类活动影响，中国近海营养盐结构失衡问题较过去更为突出，且可能引发潜在“磷消耗”问题，其影响在某种程度上较传统意义上的磷限制要强，并进而产生深远的生态环境效应。据此提出，今后相关的研究应该特别关注河流流域-近海环境变化和它们之间的内在关联，阐明控制近海营养盐浓度、形态、分布和结构的关键生物地球化学过程，量化近海氮与磷的滞留机制与效率，揭示浮游植物群落结构变化与营养盐结构失衡和磷消耗的耦合关系及其生态效应等，最终制定中国入海河流与近海氮磷协同控制的适应性管理措施。 相似文献
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陈能汪 《海洋地质与第四纪地质》2018,(1)
河流-河口系统是陆地与海洋物质循环的重要通道。人类活动和气候变化已显著改变营养盐循环并产生一系列生态环境效应(富营养化、有害藻华、缺氧、酸化等)。本文基于现场观测、实验模拟和模型分析结果,总结亚热带中小型河流——九龙江河流-河口系统的营养盐(氮、磷、硅)含量和通量的长期变化及主控因素、水体反硝化作用、梯级电站水库对营养盐的滞留、气候变化(暴雨事件、升温)影响营养盐输送与循环等方面的研究进展,讨论营养盐变化的潜在生态环境效应。与大型河流相比,中小型河流对人类活动与气候变化的干扰更为敏感。最后提出全球变化下流域-近海生物地球化学过程研究的若干重点方向:(1)在不同时空尺度上捕捉营养盐变化信号,基于多学科交叉与综合研究,揭示复杂的营养盐循环过程与驱动机制。(2)评估中小型河流的独特性及其对全球或区域尺度气候与环境变化的影响。(3)深入研究河流水坝滞留、滨海湿地净化对近海生态系统的影响。 相似文献
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富营养化是指氮、磷等营养物质大量进入流动缓慢的水体,引起藻类及其他浮游生物大量繁殖和生长,使水中溶解氧含量迅速下降,最终导致鱼类和其他水生生物死亡。近年来,沿海赤潮频发,对海洋生态环境和水产养殖带来不利影响,如何有效地控制赤潮的发生已成为当前研究的热点之一。文章简要介绍水体富营养化的现状,包括引起水体富营养化的原因、富营养化防治措施,引出利用浒苔化感物质即浒苔生物抗藻剂进行生物防治赤潮的想法,治标治本,且不会对环境造成污染,为浒苔资源化利用及赤潮防治开辟新的方向。 相似文献
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以1997年8月中旬和2011年10月中旬对三门湾附近海域开展的海域水质现状调查为依据,分析了近15 a间该海域水体环境氮、磷营养盐的分布现状及变化特征。结果表明:近15 a来,三门湾海域的无机氮和活性磷酸盐含量均成倍增长,水体营养程度由轻度富营养化逐步上升为重度富营养化;从营养结构来看,活性磷酸盐仍为限制性富营养化因子;大量的海水养殖是导致该海域营养盐大幅提高的直接原因。因此,为控制三门湾的富营养化现象进一步加剧,建议适度控制海水养殖规模,调整海水养殖结构,加强对三门湾沿岸排污控制,以获得养殖经济效益和生态环境效益的协调、可持续发展。 相似文献
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同位素在确定物质来源、指示生物地球化学循环路径、定量生物地球化学过程速率等方面具有独特的优势,本文以近海生态环境变化研究中常用的稳定同位素（13C、15N、18O）和放射性核素（14C、234Th、232Th、230Th、228Th、210Po、210Pb、137Cs、226Ra、228Ra、224Ra、223Ra）为对象,介绍它们在揭示海洋有机质来源、食物网结构、水体缺氧机制、氮循环过程、颗粒动力学、海底地下水输入、有机地球化学过程、沉积年代学等方面的应用,侧重于总结我国近海生态环境研究中同位素示踪取得的进展。伴随着我国经济的发展,近百年来我国近海生态环境也发生了明显的变化,基于同位素示踪揭示的近海富营养化和沉积环境的演变规律表明,我国近海生态环境自20世纪50年代起经历持续的变化,特别是在过去20~30年时间里,近海生态环境的变化尤为剧烈,反映出人类活动是我国近海生态环境变化的主要驱动力。未来需要通过发展新的同位素技术及拓展更广泛的应用,围绕近海海洋生态环境变化的突出问题,重点揭示近海生态环境变化的响应特征、变化速率和作用机制,从而系统地掌握近海生态环境的时空变化规律。 相似文献
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水体富营养化的生化防治机理——污水深度处理与脱氮除磷 总被引：4，自引：0，他引：4
由于人类生活生产活动的范围日益扩大 ,大量高含氮、磷的生活废水和工业污水排入江河、湖泊及海域中 ,引起水体富营养化 ,从而导致赤潮等灾害频繁发生。因此分析富营养化机理 ,探索污水的处理方法 ,减少水体的富营养化已成为迫切的问题。１富营养化危害与藻类形成１．１富营养化危害水体富营养化作用 (ｅｕｔｒｏｐｈｉｃａｔｉｏｎ)是指含大量氮、磷(含Ｎ＞０．２～０．３ｍｇ／Ｌ,含Ｐ＞０．０１～０．０２ｍｇ／Ｌ)的工业污水或生活废水排入江河、湖泊或海域中时 ,水体出现的富营养状态。当富营养水体有适当的生物、水文、气象条件时 ,水… 相似文献
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近年来快速城镇化和人类活动导致沿海地区营养盐含量显著增加,导致海湾富营养化现象日趋严重。了解水体营养盐含量分布特征与陆源污染之间的关系,是对海湾进行有效环境管理的前提。本研究以2010—2019年福建省厦门湾近岸海域水质监测数据为基础,分析长期性、季节性水质空间分布特征,并利用富营养化指数法对海湾富营养化状态进行评价,为氮、磷污染物治理提供措施建议。结果表明：厦门湾自2013年以来无机氮、无机磷含量波动降低,但同安湾无机磷含量近年来有明显增加。春季和秋季无机氮、无机磷含量明显高于夏季,不同季节氮、磷含量均呈现由湾内向湾外递减的分布趋势,反映出典型的陆源输入特征。硝酸盐氮是厦门湾无机氮的最主要成分,其与无机磷的比值普遍高于Redfield比值。无机氮、无机磷是导致九龙江口、西海域、同安湾富营养化指数较高的主要因子,受径流调控明显,无机磷在秋季还受到沿岸排污口的显著影响。厦门湾亟需加强对所有入海河流氮、磷污染的总量控制,建议强化沿岸排污口的管控。 相似文献
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作为近海海洋系统中最大的氮储库,溶解有机氮(DON)是营养物质循环的一个重要环节,不仅可与溶解无机氮之间相互转化,且可被浮游植物直接利用利用,对近海富营养化形成具有重要贡献。本文综述了近海DON对浮游植物的生物可利用性研究进展,包括近海DON的主要化学组成和浓度分布、DON生物可利用性评价方法、浮游植物对DON的吸收利用特性以及DON丰度和构成对浮游植物种群演替的潜在影响等;并指出,系统研究DON在近海生态生态系统中迁移转化的动力学过程及其控制机制,确定DON构成与生物有效之间的耦合关系,是今后需要深入研究的问题。 相似文献
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The ecosystem model ERSEM II has been used to hindcast the development of the ecosystem of the North Sea during the years 1955 to 1993. The simulation was driven by the box-aggregated output from a general circulation model of the North Sea of corresponding duration; radiation, river inputs, atmospheric input and boundary conditions at the borders to the Atlantic Ocean and to the Baltic Sea were applied as realistically as possible. The general features of the eutrophication process are reproduced in the hindcast: the coastal areas show strong changes in nutrient concentrations in the hindcast as well as in the observations. Eutrophication not only shows up in the nutrient concentrations, but also in primary production. The simulated spatial distributions of phosphate, nitrate and primary production compare well with the observed ones. In addition, the hindcast simulates considerable trend-like changes of the nutrients in the southern part of the North Sea, where the nutrients are transported from the continental coastal strip to the southern central North Sea. The line from the river Humber to southern Norway separates the region of noticeable anthropogenic influence of riverine and atmospheric input from the northern area, which is mainly influenced by the Atlantic nutrient inflow. The observed annual cycles in the central and northern North Sea are quite well reproduced by the hindcast. The comparison of the hindcast with the long-term observations at two sites in the continental coastal zone of the North Sea shows that the long-term behaviour of phosphate, nitrate and silicate is simulated well. Primary production is increased in summers during the main period of eutrophication, 1975 to 1989, in the hindcast and in the observations. The flagellates at Helgoland, however, experience much more pronounced annual cycles with much less interannual variability in the hindcast than in the observations. 相似文献
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Jan E. Vermaat Abigail McQuatters-Gollop Marieke A. Eleveld Alison J. Gilbert 《Estuarine, Coastal and Shelf Science》2008
Comprehensive, aggregate nutrient budgets were established for two compartments of the North Sea, the shallow coastal and deeper open regions, and for three different periods, representing pre-eutrophication (∼1950), eutrophication (∼1990) and contemporary (∼2000) phases. The aim was to quantify the major budget components, to identify their sources of variability, to specify the anthropogenic components, and to draw implications for past and future policy. For all three periods, open North Sea budgets were dominated (75%) by fluxes from and to the North-East Atlantic; sediment exchange was of secondary importance (18%). For the coastal North Sea, fluxes during the eutrophication period were dominated by sediment exchange (49% of all inputs), followed by exchange with the open sea (21%), and anthropogenic inputs (19%). Between 1950 and 1990, N-loading of coastal waters increased by a factor of 1.62 and P-loading by 1.45. These loads declined after 1990. Interannual variability in Atlantic inflow was found to correspond to a variability of 11% in nutrient load to the open North Sea. Area-specific external loads of both the open and coastal North Sea were below Vollenweider-type critical loads when expressed relative to depth and flushing. External area-specific load of the coastal North Sea has declined since 1990 from 1.8 to about 1.4 g P m−2 y−1 in 2000, which is close to the estimate of 1.3 for 1950. N-load declined less, leading to an increase in N/P ratio. 相似文献
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River discharges of water and nutrients to the Mediterranean and Black Sea: Major drivers for ecosystem changes during past and future decades? 总被引：2，自引：0，他引：2
Wolfgang Ludwig Egon Dumont Michel Meybeck Serge Heussner 《Progress in Oceanography》2009,80(3-4):199-217
Rivers are important sources of freshwater and nutrients for the Mediterranean and Black Sea. We present a reconstruction of the spatial and temporal variability of these inputs since the early 1960s, based on a review of available data on water discharge, nutrient concentrations and climatic parameters. Our compilation indicates that Mediterranean rivers suffer from a significant reduction in freshwater discharge, contrary to rivers of the Black Sea, which do not have clear discharge trends. We estimate this reduction to be at least about 20% between 1960 and 2000. It mainly reflects recent climate change, and dam construction may have reduced discharge even further. A similar decrease can also be expected for the fluxes of dissolved silica (Si), strongly controlled by water discharge and potentially reduced by river damming as well. This contrasts with the fluxes of nitrogen (N) and phosphorus (P) in Mediterranean and Black Sea rivers, which were strongly enhanced by anthropogenic sources. Their total inputs to the Mediterranean Sea could have increased by a factor of >5. While N still remained at elevated levels in 2000, P only increased up to the 1980–1990s, and then rapidly dropped down to about the initial values of the 1960s. With respect to the marine primary production that can be supported by the riverine nutrient inputs, Mediterranean and the Black Sea rivers were mostly phosphorus limited during the study period. Their anthropogenic nutrient enrichment could only have had a fertilizing effect before the general decline of the P loads. When also considering Si as a limiting element, which is the case for siliceous primary producers such as diatoms, silica limitation may have become a widespread phenomenon in the Mediterranean rivers since the early 1980s. For the Black Sea rivers, this already started the late 1960s. Gross primary production sustained by rivers (PPR) represents only less than 2% of the gross production (PP) in the Mediterranean, and less than 5% in the Black Sea. Possible ecological impacts of the changing river inputs should therefore be visible only in productive coastal areas, such as the Gulf of Lions, where PPR can reach more than two thirds of PP. Reported ecosystem changes both in the Adriatic Sea and the Black Sea are concomitant with major changes in the reconstructed river inputs. Further work combining modelling and data collection is needed to test whether this may also have been the case for coastal ecosystems at other places in the Mediterranean and Black Sea. 相似文献
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长江口沉积记录反映的近80年陆源输入和营养盐变化特征 总被引：1，自引：1，他引：0
A variety of environmental problems have been observed in the Changjiang River Estuary and adjacent coastal area, including eutrophication, harmful algal blooms (HABs), and hypoxia in recent decades. A... 相似文献
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Phosphorus regeneration and burial in near-shore marine sediments (the Gulf of Trieste, northern Adriatic Sea) 总被引：1，自引：0，他引：1
According to bioassay studies and high dissolved nutrient N/P ratios in the seawater column, phosphorus (P) is thought to control marine productivity in the northern Adriatic Sea. P in near-shore marine sediments of the Gulf of Trieste, the northernmost part of the Adriatic Sea, was investigated using pore water P distributions, and benthic P flux studies under oxic and anoxic conditions. The data show that P regeneration is up to three-fold more extensive in sediments overlain by oxygen-depleted waters and proceeds in parallel with Fe and Mn enhanced benthic fluxes. It appears from the incubation experiments that degradation of sedimentary organic matter is the main contribution to the flux of P at the sediment–water interface, while the release of phosphate adsorbed on the iron oxide surface is of minor importance.It appears that about 50% of P in the Gulf of Trieste is retained within in the sediments, probably bonded to clay minerals and carbonate grains or precipitated as fluoroapatite. In these sediments total P (Ptot) is preserved preferentially over organic C (Corg). P regenerated from surficial sediments contributes about 1/3 of the P that is assimilated by benthic microalgae. The phytoplankton P requirement should be entirely supplied from fresh-water sources. These results suggest that oxygen depletion in coastal areas caused by eutrophication enhances P regeneration from sediments, providing the additional P necessary for increased biological productivity. The development of anoxic bottom waters in coastal areas enhances the recycling of P, exacerbating the nutrient requirement in the area. A geochemical record of P burial in a longer sedimentary sequence revealed an increasing trend of Ptot and organic P (Porg) contents occurring approximately 50 years BP (after 1950), probably due to increasing use of inorganic fertilizers and detergents in the area. 相似文献
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A. D. Tappin 《Estuarine, Coastal and Shelf Science》2002,55(6):885
In a number of regions of the world, enhanced flows of nitrogen (N) and phosphorus (P) from land to sea are of major concern because of the observable deterioration in the quality of many nearshore marine waters. Estuaries receive N and P from river and other runoff, from waste discharges, from the atmosphere and ocean and from exchange with coastal groundwaters (which in all likelihood results in a net input to the estuary). For rivers that do not discharge directly onto the continental shelf, seaward fluxes of N and P will be modified by within-estuary transformations of reactive species, the burial of particulate N and P in sediments (sub/intertidal, saltmarsh, mangrove) and the loss of gaseous N and P species by bacterial reduction.Driven by a desire to understand the effects of changing N and P loads on water quality, and to gain insights into the true modification of their fluxes within estuaries, much effort has been expended on providing quantitative estimates of the sources and sinks of these constituents. Yet, accurate and precise estimates on a global scale remain elusive. Riverine inputs of total N and P are calculated to be 35–64 and 22 Mt a−1, respectively. These inputs are dominated by particulate species, and because of this, are likely to be imprecise as overall sediment fluxes are disproportionately influenced by infrequent, poorly sampled, high flow events. Direct aeolian inputs of N to estuaries (P inputs are minor), at a minimum of 1–4 Mt a−1, are small but significant, although again good estimates are hampered by the apparent importance of infrequent, and thus under-sampled, deposition events. Indirect atmospheric inputs via deposition onto and runoff from catchments may be highly significant, at least in environments bounding the North Atlantic Ocean. Groundwater inputs are generally unknown, but, for N, may be 5–10 Mt a−1 (no data on P). Information on the global inputs of N and P from waste discharges and mariculture do not appear to be available. Denitrification, estimated to beca . 33 Mt a−1, may account for 52–94% of the currently estimated total N inputs; in contrast, the loss of P via venting of gaseous phosphine is unknown. The burial of N and P in sediments is about 7% and 30% of their total inputs, respectively. Nevertheless, reliable information on the modifying role of estuarine sediments appears far from complete.Globally, the inputs of N and P to the marine environment from all sources are expected to increase over the next few decades. The resulting effects of these increases on the marine environment, including any influences due to estuarine processing, may be partly assessed through the use of dynamic transport and transformation estuarine models for N and P. A further important development in this respect will be the linking of complementary models (e.g. catchment/river/estuarine/coastal zone) and their coupling to strategic large scale observations. 相似文献
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R.J. Gowen P. Tett K. Kennington D.K. Mills T.M. Shammon B.M. Stewart N. Greenwood C. Flanagan M. Devlin A. Wither 《Estuarine, Coastal and Shelf Science》2008
The question of whether the Irish Sea is eutrophic is addressed by reviewing the evidence for anthropogenic nutrient enrichment, elevated phytoplankton production and biomass and undesirable disturbance in the context of the EU and OSPAR definitions of eutrophication. Winter concentrations of dissolved available inorganic phosphate (DAIP), nitrogen (DAIN as nitrate and nitrite) and silicate (Si) in coastal waters and concentrations of DAIP and Si in offshore waters of the Irish Sea are elevated relative to winter Celtic Sea shelf break concentrations (0.5 μM DAIP, 7.7 μM DAIN and 2.7 μM Si). Significant, negative nutrient salinity relationships and analysis of the Isle of Man nutrient time-series indicate that the elevated Irish Sea levels of DAIP and DAIN are the result of anthropogenic enrichment with highest concentrations (≈2.0 μM DAIP, 30 μM DAIN and 17 μM Si) measured in near shore eastern Irish Sea waters. 相似文献