光照和盐度对海水介质中磷化氢转化的影响

通过室内模拟实验,研究了光照和盐度对海水介质中磷化氢转化的影响。结果表明,不同光照条件下磷化氢转化率有明显差异,按对磷化氢转化促进作用由大到小排列依次为：UVC〉UVB〉日光〉UVA〉避光条件,单位辐照强度的UVC比UVB更能促进磷化氢的转化。在实验体系中加入臭氧、过碳酸钠的实验进一步验证自由基反应对磷化氢转化有促进作...     

一种海洋环境中易被忽略的磷化合物——磷化氢

根据国内外最新研究进展 ,对以往海洋环境研究中往往忽略的一种磷化物———磷化氢 (Phosphine)的存在形式、分布特征、与其他形态之间的相互转化以及在磷的生物地球化学循环中的作用和地位等进行了综合评述。认为磷化氢是磷在海洋环境中普遍存在的一种形式 ,与磷的其他氧化形态之间存在着相互转化的关系 ,尽管目前对其转化机制、在磷循环中的地位和作用等方面尚不清楚 ,但磷化氢对海洋生物可利用性磷的贡献应是一个不可忽视的因子 ,在磷循环过程中应是重要的一环 ,在将来进一步深入讨论磷的生物地球化学过程、揭示其循环机制中应予以重视     

海水中萘的光化学降解研究

系统研究了在高压汞灯或天然日光照射下萘在天然海水、人工海水和蒸馏水中的光降解情况。萘的光降解过程受到包括光源、溶液介质、溶解氧、重金属离子、光敏剂在内的各种因素的影响。实验证明，高压汞灯较天然日光更能有效地激发萘的光反应。开始的90min之内，萘的浓度慢慢下降，在照射90－120min后，萘的浓度迅速下降，这是整个萘光解过程中最有效的部分，一级反应速率常数为0.0075-0.0203min^-1。萘在天然海水中的光解速率大于在人工海水和蒸馏水中的光解速率，其主要原因是天然海水中存在天然光敏剂。同蒸馏水中的光反应相比，人工海水中的离子有助于提高萘的光解反应。然而，溶液中加入的重金属离子或光敏剂会改变萘的光解反应。此外，研究证明，溶解氧是必不可少的，它的存在大大加速了光反应。     

海洋石油光化学降解的研究

石油进入海水会发生各种物理、化学变化,以往的研究已证明光化学氧化在石油及其精炼产品风化过程中具有重要意义.光化学氧化机理主要在于接受日光照射的能量,以不同的方式与溶解氧结合,从而最终降解石油烃.生成的光氧化产物一般为羧酸、醇、醚、羰基化合物等几类,还有一些产物尚不能确定其结构.光氧化产物仍然存在毒性,对海洋生物等十分有害.在动力学方面,针对其某一组分已证实为一级反应动力学行为,并定量地得出了速率常数.光降解速率会受到光照条件、溶解氧、金属离子等因素的影响.目前的研究表明,对石油光化学进行深入探讨具有较高的研究价值和现实意义.     

海洋石油光化学降解的研究

石油进入海水会发生各种物理、化学变化,以往的研究已证明光化学氧化在石油及其精炼产品风化过程中具有重要意义。光化学氧化机理主要在于接受日光照射的能量,以不同的方式与溶解氧结合,从而最终降解石油烃。生成的光氧化产生一般为羧酸、醇、醚、羰基化合物等几类,还有一些产物尚不能确定其结构。光氧化产物仍然存在毒性,对海洋生物等十分有害。在动力学方面,针对其某一组分已证实为一级反应动力学行为,并定量地得出了速率常     

海洋环境中氧化还原敏感性微量元素的地球化学行为及环境指示意义

依据国内外最新研究成果,初步讨论了氧化还原敏感性微量元素(RSE)Re、Cd、Mo、U、V等的地球化学行为,其中包括海洋沉积物中RSE的来源、RSE在缺氧和无氧海区的沉淀富集机理及其环境指示意义。在此基础上讨论了利用RSE研究氧化还原环境时应注意的一些问题。RSE的沉淀富集机制不尽相同,但具有以下共同特点:①对底层海水的溶解氧浓度敏感。在正常溶解氧条件下,氧化还原敏感性微量元素在海水中呈溶解态稳定存在,而当底层海水处于缺氧或无氧条件时容易发生还原。②当底层海水处于缺氧或无氧条件时,经过沉积物—海水界面过程,受缺氧程度不同的制约,海水中呈溶解态的RSE依次在沉积物中沉淀,出现不同程度的富集。③持续还原条件下,RSE在沉积物中稳定存在;受氧化作用后,容易在沉积物中发生二次迁移和重新富集。不同的RSE其氧化还原电位不同,在氧化还原序列中的位置不同,Re在U之后Mo之前发生还原。因此,RSE在海洋沉积物中的不同富集特征和富集程度可作为还原程度指标研究底层海水的缺氧程度和底质的氧化还原环境。研究RSE的氧化还原环境指示意义,必须对RSE陆源碎屑来源组分进行剔除,同时,还应充分注意到还原沉积区发生氧化后,RSE在沉积物中会发生重新迁移和二次富集。     

盐度及保存时间对牙鲆精子活力的影响

人工授精是鱼类养殖过程中的一项重要技术,获取具有受精能力的精子是这一活动中的重要步骤。环境因子对于海产鱼类精子生理状态的影响国内已有初步研究［１,２］,但环境因子对牙鲆精子的作用还需进一步研究。本实验着重研究了牙鲆精子于室温条件下贮存不同时间后,这些精子在不同盐度条件下的活力,以及室温条件下,于精液中保存了不同时期后的精子在天然海水中（盐度为３２）使卵子受精的能力。１材料与方法１．１精、卵的获取实验中所用的牙鲆亲鱼取自山东荣成市寻山养鱼场的亲鱼池。卵子和精子系采用人工挤压的方法获得。挤压过程中防…     

海洋环境中甲烷好氧氧化过程的研究进展

海洋环境中微生物驱动的甲烷好氧氧化作用是甲烷迁移转化过程的关键环节之一,在降解甲烷方面的贡献不容忽视,能够有效降低甲烷大气通量、影响海洋碳循环。本文系统调研了国内外文献资料,认识到海洋环境中甲烷好氧氧化的赋存范围十分广泛,可赋存于超过3 000 m水深的深海环境、热液喷口等极端环境,其中海底高压、渗漏甲烷的动态运移等是甲烷好氧氧化所面临的特殊环境,在该赋存环境下,好氧甲烷氧化菌主要以Ⅰ型氧化菌为主。Ⅰ型与Ⅱ型氧化菌对甲烷、微量金属元素等环境条件具有一定偏向性,并且在水体和沉积物两种赋存环境下氧化菌的类型也不尽相同。同时,在该赋存环境下甲烷好氧氧化强度存在时间或空间上的差异,受温度、甲烷浓度、氧浓度、微量金属元素等环境因子影响显著,但目前对压力以及甲烷渗漏运移状态对好氧氧化过程的影响规律认识不清。随着深海科研探索不断发展,甲烷氧化菌菌群多样性研究将更加丰富。此外,还需进一步针对海底高压渗漏状态下的好氧氧化过程开展精细研究工作,进一步理解海洋环境中甲烷的好氧氧化规律,这对深刻揭示甲烷迁移转化机制、科学评估甲烷生态环境效应具有重要意义。     

一氧化氮的海洋生物地球化学研究进展

一氧化氮(NO)是影响全球气候和环境的重要污染气体之一,同时也是影响生物生长的重要调控因子。本文综述了海水中NO的测定方法,海洋中NO的来源和分布、迁移和转化,NO在海洋生态系中的作用,以及NO在大气中的转化和作用,并对海洋中NO的进一步研究提出了展望。目前围绕海洋中NO的研究刚刚起步,本文有助于了解海洋中NO的生物地球化学循环及在海洋生态系统中起到的重要作用。     

有机改性黏土对海水中营养盐及主要水质因子的影响

为了阐明黏土方法治理有害赤潮的生态环境效应，研究了有机改性黏土对海水中营养盐和溶解氧、化学耗氧量、pH等主要水质因子的影响。结果表明，有机改性黏土对营养盐，尤其是磷酸盐有一定的吸附作用，吸附量随水体中磷酸盐浓度的增加而增大，不同有机改性黏土对海水中磷酸盐的吸附能力为：有机改性黏土Ⅰ〉有机改性黏土Ⅱ〉有机改性黏土Ⅲ。通过有机改性黏土对磷酸盐的吸附再释放作用研究，进一步探讨了磷酸盐释放作用对赤潮异弯藻（Heterosigma akashiwo）、东海原甲藻（Prorocentrum donghaiense）等赤潮生物生长的影响。实验结果表明，经过有机改性的黏土有利于提高其对磷酸盐的吸附能力，降低对磷酸盐的解吸率，缓解海水富营养化程度，虽然少量被吸附的磷酸盐能缓慢释放，但仍不足以维持赤潮生物的正常生长。同时利用有机改性黏土治理赤潮能显著改善溶解氧、pH、化学耗氧量等水质指标，有利于治理赤潮后的环境修复。     

Spatial and temporal variability of the ratios between the nitrate and phosphate concentrations in the Sea of Okhotsk

The relation between the nitrate and phosphate concentrations in the Sea of Okhotsk and the bordering waters of the Pacific Ocean were studied. The surveys were carried out in the autumn, spring, and summer of 2001–2002. For the deepwater part of the sea, the relation [NO^? ₃] = ((14.88 ± 0.07) × [PO^3? ₄] ? 5.46 ± 0.17) was found. The coefficients in the equation given are statistically different from those in the similar equation for the Pacific waters: [NO^? ₃] = (16.05 ± 0.15) × [PO^3? ₄]-(7.23 ± 0.36). In the northern part of the sea; on the shelf; in the slope area; and, especially, in the deep waters of the TINRO Depression, the linear dependence between the phosphate and nitrate concentrations was distorted. This feature was described in terms of nitrate deficiency. The maximum values of this deficiency were found in the near-bottom waters. The principal processes that might cause the nitrate deficiency were considered: the difference in the oxidation rates of the nitrogen and phosphorus organic compounds, the matter transfer between the continent and the sea, the different efficiency of the biogenic burial of nitrogen and phosphorus in the bottom sediments, and the denitrification in the upper layer of the bottom sediments. It was shown that the most probable cause of the nitrate deficiency was the denitrification. The loss of inorganic nitrogen owing to the supply of the waters of the Sea of Okhotsk to the Pacific Ocean was estimated as ～2.5 × 10¹¹ mol N/year.     

不同磷源对米氏凯伦藻生长和碱性磷酸酶活性的影响

为了解米氏凯伦藻(Karenia mikimotoi)赤潮形成的磷营养机理,作者研究了不同磷源[三磷酸腺苷二钠盐(Adenosine disodium triphosphate,ATP)、甘油磷酸钠(sodium glycerophosphate,G-P)、卵磷脂(lecthin,LEC)和Na H2PO4·2H2O]对其生长和藻细胞碱性磷酸酶活性(alkaline phosphatase activity,APA)的影响。结果表明:(1)米氏凯伦藻可以有效利用无机磷(Na H2PO4·2H2O),对有机磷源如三磷酸腺苷二钠盐(ATP)、甘油磷酸钠(G-P)也能有效利用,但不能有效利用卵磷脂(LEC);(2)米氏凯伦藻碱性磷酸酶的检测中,在起始阶段,不同磷源(ATP,G-P,LEC和Na H2PO4·2H2O)的米氏凯伦藻APA达到最大值,米氏凯伦藻的APA分别为6.0,10.5,8.0和0.4 pmol/(个·h)。随培养时间的持续,各有机磷培养基中米氏凯伦藻的APA均表现出先逐渐减小,而后增强,最后在最大值维持的趋势,而以Na H2PO4·2H2O为磷源的米氏凯伦藻的APA没有明显的增加;(3)单个细胞的米氏凯伦藻的APA位点分布明显,大致位于细胞表面。通过研究发现,米氏凯伦藻在外界环境无机磷限制的条件下,能够较好地吸收利用有机磷维持生长,印证了近年来米氏凯伦藻赤潮频繁地发生在磷限制海域的事实。     

Silicate correction in the colorimetric determination of phosphate in seawater

An improved Strickland and Parsons' method, in which silicate correction is made, is described for the colorimetric determination of phosphate in seawater. Silicate correction is made by subtracting the value of 0.025 (C/100)², whereC is silicate concentration (µg atoms 1^?1), from the observed phosphate concentration. The relative standard deviations are 2 % at the 1 µg atom PO ₄ ^3? ?Pl^?1 level and less than 1 % at the 3 µg atoms PO ₄ ^3? ?Pl^?1 level in seawater.     

长江水体溶解态无机氮和磷现状及长期变化特点

于2006年2、5、8和11月对长江从攀枝花至河口和上游的两条支流雅砻江和嘉陵江的溶解态无机氮(NO-3-N、NO-2-N和NH+4-N)和磷酸盐(PO43--P)进行了取样调查,同时结合长江营养盐的历史数据,分析了长江水体中溶解态无机氮、磷的长期变化特点。结果表明,长江NO-3-N、NH+4-N、DIN(包括NO-3-N、NO-2-N和NH+4-N)和PO3-4-P浓度从上游到下游显示出增加趋势,但存在季节差异;NO2-N浓度总体较低,在长江中下游(武汉—南京)浓度较高。长江从上游到下游DIN通量的变化主要受径流量的影响,从上游到下游单位面积年产N量逐渐升高;PO3-4-P输送通量从上游往下游呈增加趋势,也主要受径流量控制,但从季节变化来讲,PO3-4-P的月输送通量受其浓度的控制更加明显。自20世纪60年代来,长江水体中NO3--N、NO2--N、DIN和PO3-4-P的浓度都处于缓慢上升趋势,但到80年代上升速度明显加快;不同阶段DIN和34PO-P的季节变化特点也不尽相同,反映了其来源的差异。目前,长江水体中溶解态无机氮、磷浓度与国内及国际河流相比处于中等水平。     

Nutrient Concentrations are High in the Turbid Waters of the Colorado River Delta

We studied the seasonal change of the spatial distribution of nitrite (NO^-₂), nitrate (NO^-₃), reactive phosphate (PO^3-₄), and silicate (SiO₂) in the Colorado River Delta. We also generated 24-h time series at one location to study their short-period variability. The delta is a negative estuary. During summer, salinity may be as high as 40. Amplitude of spring tides is as large as 9 m, and this causes great water turbidity by sediment resuspension. Nutrient concentrations were high throughout the whole year, with lower values towards the oceanic region. Maximum nutrient values in the river delta were 15, 53, 11·5 and 92 μM, for NO^-₂, NO^-₃, PO^3-₄, and SiO₂, respectively. Most values were under 2, 40, 5, and 60 μM, for NO^-₂, NO^-₃, PO^3-₄, and SiO₂, respectively. Our nutrient data show no clear seasonal pattern. Possibly, high NO^-₃ values in the delta are due to groundwater input, mostly at the internal extreme, and high NO^-₂, PO^3-₄, and SiO₂ values are due to resuspension of sediments and mixing of porewaters with the water column, caused mainly during spring tides. In the case of NO^-₂, oxidation of NH⁺₄ in the water column would be part of the mechanism. This would explain the high negative correlation between NO^-₃ and sea-level, and the relatively low correlation between the other nutrients and sea-level, for the time series generated at a single location.     

Cadmium and phosphate in coastal Antarctic seawater: Implications for Southern Ocean nutrient cycling

Cadmium is a biologically important trace metal that co-varies with phosphate (PO₄³⁻ or Dissolved Inorganic Phosphate, DIP) in seawater. However, the exact nature of Cd uptake mechanisms and the relationship with phosphate and other nutrients in global oceans remain elusive. Here, we present a time series study of Cd and PO₄³⁻ from coastal Antarctic seawater, showing that Cd co-varies with macronutrients during times of high biological activity even under nutrient and trace metal replete conditions. Our data imply that Cd/PO₄³⁻ in coastal surface Antarctic seawater is higher than open ocean areas. Furthermore, the sinking of some proportion of this high Cd/PO₄³⁻ water into Antarctic Bottom Water, followed by mixing into Circumpolar Deep Water, impacts Southern Ocean preformed nutrient and trace metal composition. A simple model of endmember water mass mixing with a particle fractionation of Cd/P (α_Cd–P) determined by the local environment can be used to account for the Cd/PO₄³⁻ relationship in different parts of the ocean. The high Cd/PO₄³⁻ of the coastal water is a consequence of two factors: the high input from terrestrial and continental shelf sediments and changes in biological fractionation with respect to P during uptake of Cd in regions of high Fe and Zn. This implies that the Cd/PO₄³⁻ ratio of the Southern Ocean will vary on glacial–interglacial timescales as the proportion of deep water originating on the continental shelves of the Weddell Sea is reduced during glaciations because the ice shelf is pinned at the edge of the continental shelf. There could also be variations in biological fractionation of Cd/P in the surface waters of the Southern Ocean on these timescales as a result of changes in atmospheric inputs of trace metals. Further variations in the relationship between Cd and PO₄³⁻ in seawater arise from changes in population structure and community requirements for macro- and micronutrients.     

Encystment and excystment of <Emphasis Type="Italic">Gyrodinium instriatum</Emphasis> Freudenthal et Lee

In the present study, we have investigated the conditions influencing encystment and excystment in the dinoflagellate Gyrodinium instriatum under laboratory conditions. We incubated G. instriatum in modified whole SWM-3 culture medium and in versions of modified SWM-3 from which NO₃ ⁻, PO₄ ³⁻, NO₃ ⁻ + PO₄ ³⁻, or Si had been omitted and observed encystment. Percentage encystment was high in the media without N and without P, while the percentage encystment in the medium lacking both N and P was highest. Moreover, to investigate N or P concentration which induced the encystment, Gyrodinium instriatum was also incubated in media with different concentrations of inorganic N and P; the concentrations of NO₂ ⁻ + NO₃ ⁻ and PO₄ ³⁻ were measured over time. The precursors of cysts appeared within 2 or 3 days of a decrease in NO₂ ⁻ + NO₃ ⁻ or PO₄ ³⁻ concentration to values lower than 1 μM or 0.2 μM, respectively. When cysts produced in the laboratory were incubated, we observed excystment after 8–37 days, without a mandatory period of darkness or low temperature. We incubated cysts collected from nature at different temperatures or in the dark or light and observed excystments. Natural cysts excysted at temperatures from 10 to 30°C, in both light and dark, but excystment was delayed at low temperatures. These studies indicate that G. instriatum encysts in low N or P concentration and excysts over a wide temperature range, regardless of light conditions, after short dormancy periods.     

Early diagenetic redistribution and burial of phosphorus in the sediments of the southwestern East Sea (Japan Sea)

This study was carried out in order to understand the early diagenetic redistribution of phosphorus and relevant mass balance in the sediments of the East Sea. In two cruises during May 1993 and October 1995, 11 box cores were collected in the southwestern part of the East Sea. Dissolved phosphorus and iron were analyzed in the porewater from the cores. Sediment samples were analyzed for solid-phase P species and solid-phase Fe oxyhydroxide by sequential extraction.Phosphorus speciation results show that organic P is the major chemical form of phosphorus in young sediments within the upper 50 cm of sediment. However, the authigenic fraction of total P increases with depth, indicating the precipitation of carbonate fluorapatite (CFA) in the sediments. The authigenic CFA (Ca₅(PO₄)_2.6(CO₃)_0.4F) was formed and buried at rates of 11–110 μmol cm⁻² kyr⁻¹. The main source of dissolved phosphorus for the precipitation of CFA is organic P. Dissolved phosphorus, released from the decomposition of organic P, diffuses upward to return to bottom water, or is sorbed to iron oxides in the oxidized sediments. As sedimentation proceeds, the iron oxide-bound P is released in the reduced layer and enters the dissolved phase, which contributes P to the formation of CFA in addition to that contributed by the organic P.The burial flux of reactive P (iron oxide-bound P+authigenic P+organic P) is 0.09–0.53 g P m⁻² yr⁻¹ that accounts for 18–58% of the reactive P arriving at the sediment/water interface. The burial flux of reactive P is high in the upper and lower continental margin sediment. The burial flux of reactive P in the Ulleung Basin sediment is less than those in the continental margin sites by a factor of 6, indicating that the reactive P burial flux is mainly dependent on sedimentation rate.     

Tidal time-scale variation in nutrient flux across the sediment–water interface of an estuarine tidal flat

We determined the range of the tidal variations in nutrient flux across the sediment–water interface and elucidated mechanisms of the flux variation in two estuarine intertidal flats (one sand, one mud) in northeastern Japan. Nutrient flux was measured using in situ light and dark chambers, which were incubated for 2 h, 2–6 times per day. Results showed that nutrient concentration in overlying water varied by tide and was also affected by sewage-treated water inflow. The nutrient fluxes responded quickly to the tidal variation in overlying water chemistry and the range of the variation in flux was as large as the seasonal-scale variation reported in previous studies. In the sand flat, salinity increase likely enhanced benthos respiration and led to increases in both O₂ consumption and PO₄³⁻ regeneration under low illumination, while benthic microalgae were likely to actively generate O₂, uptake PO₄³⁻ and suppress PO₄³⁻ release under high illumination (>900 μmol photons m⁻² s⁻¹). Also in the mud flat, PO₄³⁻ flux was related with O₂ flux, although the range of temporal variation in PO₄³⁻ flux was small. In both the flats, NH₄⁺ flux was always governed by NH₄⁺ concentration in the overlying water; either an increase in NH₄⁺ uptake or a decrease in NH₄⁺ release was observed as the NH₄⁺ concentration rose due to inflow of river water or input of sewage-treated water. Although NO₃⁻ tended to be released in both tidal flats when low NO₃⁻ concentration seawater dominated, their relationship was likely to be weakened under conditions of low oxygen consumption and suppressed denitrification. It is likely that tidal variation in nutrient flux is governed more by the nutrient concentration than other factors, such as benthic biological processes, particularly in the case where nutrient concentration in the overlying water is relatively high and with wide amplitude.