微量元素锰对底栖甲藻热带库里亚藻(Coolia tropicalis)生长及叶绿素荧光特性的影响

以热带库里亚藻(Coolia tropicalis)为研究对象, 在不同锰浓度(0、1、5、10、50μmol·L ^-1)的人工海水培养15d, 利用叶绿素荧光动力学技术研究了其生长和光合作用对不同锰环境的响应。结果表明: 1)比生长速率(μ)和最大相对电子传递速率(rETR_max)与锰浓度均呈指数关系且对锰胁迫具有相同程度的响应; 2)锰浓度至少大于1μmol·L ^-1才能维持热带库里亚藻正常的光合作用活性, 当锰浓度低于该浓度时, 光合作用活性(F_v/F_m)在6d后开始下降, 而单位反应中心吸收光能(ABS/RC)和热能耗散(DI₀/RC)升高; 两个反应中心之间的电子传递(φ_E0)及生长并未受影响, 表明此阶段锰缺乏只影响活性光反应中心数量并提高热耗散途径; 当锰缺乏延长至15d时, 胁迫作用显现(F₀上升)并且电子传递(φ_E0)和生长受到抑制, 这阶段锰缺乏使光反应中心关闭且电子传递受阻; 3)锰缺乏的修复损伤比(r/k)并未降低, 表明锰缺乏并未影响热带库里亚藻的光保护能力。     

Annual Variation of Benthic Nutrient Fluxes in Shallow Coastal Waters (Gulf of Trieste, Northern Adriatic Sea)

Abstract. Benthic fluxes of dissolved N. Si and P nutrients, alkalinity, dissolved inorganic C (DIC), and O₂ from sediments in the Gulf of Trieste (northern Adriatic, Italy) were measured monthly for 16 months, using laboratory incubated flux chambers at in siru temperatures in the dark. The annual average fluxes were: 02 = -19.3 ± 8.2, DIC = 13.7 ± 9.6, NO3 = -0.04 ± 0.16, NH4 = 0.3 ± 0.4. PO₄= 4.001 ± 0.01, Si = 0.9 ± 0.1 mmol m-² d^-1, with strong temporal fluctuations. The highest effluxes of all nutrients and DIC were observed in the summer. Small effluxes of DIC and NH4 and influxes of Si and PO4 were observed in late winter. Only NH₄ (ca. 50%) and Si (ca. 70%) fluxes were significantly correlated with temperature. This correlation suggests that the rate of downward input and the quality of sedimented organic matter (autochthonous and allochthonous) were superimposed on the temperature fluctuations. High DIC, NH₄ and Si effluxes observed in May 1993 during low temperature were due to the degradation of sedimentary organic matter produced by an early spring bloom of benthic microalgae which occurred about 6 weeks earlies while the autumn phytoplankton bloom was simultaneously reflected in enhanced benthic fluxes due to higher temperature. The role of benthic biological advection in this transport across the sediment-water interface, evaluated by comparison between measured benthic and calculated diffusive fluxes from nutrient pore water concentrations, was of minor importance. This is probably due to low infaunal activity throughout the year it was localized mostly in the narrow surficial layer. The annual average diffusive fluxes of NH4 and PO4 were higher than those measured, probably due to the presence of nitrificationdenitrifi-cation processes and redox-dependent chemical reactions at the oxic sediment-water interface, respectively. Only during bottom-water hypoxia in September 1993 did strong PO₄ effluxes prevail. Calculations based on the Redfield stoichiometry of oxic decomposition of organic N to NH4 and NO3, and differences between diffusive and measured NH₄ fluxes showed that denitrifkation averaged 0.8 mmol m^-2 d^-1. Significant correlations between NH₄ and PO₄ DIC and Si, and NH4 and Si fluxes suggested their parallel regeneration and utilization at the sediment-water interface. The nutrient fluxes observed were not significantly linked to O₂ consumption, suggesting also that anaerobic oxidation processes were important at the sediment-water interface in the gulf. The N, P and Si nutriqnts released from sediment pore waters are probably utilized in benthic microalgal and bottorn-hater primary production. This indicates that pelagic and benthic communities in the central part of the Gulf of Trieste function relatively independently of each other.     

Benthic Nutrient Recycling in Port Phillip Bay, Australia

Benthic chamber measurements of the reactants and products involved with biogenic matter remineralization (oxygen, ammonium, nitrate, nitrite, phosphate, silicate, TCO₂and alkalinity) were used to define solute exchange rates between the sediment and overlying water column of Port Phillip Bay, Australia. Measurements at various sites throughout the bay, conducted during the summers of 1994 and 1995, indicate that the variability in flux values within a site is comparable to year-to-year variability (±50%). Four regions of the bay were distinguished by sediment properties and the northern region was identified as having 3–30 times greater nutrient regeneration rates than the other regions. Benthic recycling accounted for 63 and 72% of the annualized N and P input, respectively, to the entire bay as determined by summing benthic, dissolved riverine, atmospheric and dissolved effluent sources. However, bay-wide sedimentary denitrification accounted for a loss of 63% of the potentially recyclable N. This fraction is higher than many other coastal regions with comparable carbon loading. Denitrification efficiency is apparently not enhanced by benthic productivity nor by bio-irrigation. The rate of bio-irrigation is negatively correlated with denitrification efficiency. Bio-irrigation was studied using radon-222 and CsCl spike injection chamber measurements. Radon fluxes from sediments in Port Phillip Bay were enhanced over the diffusive flux by 3–16 times. The modelled rate of loss of Cs from chamber water was positively correlated with radon flux enhancement results. Both methods identify regions within Port Phillip Bay that have particularly high rates of non-diffusive pore-water overlying water solute exchange.     

渤海底栖桡足类群落结构的研究

渤海1998年9月航次的调查结果.小型底栖生物总平均丰度为(8688±5097)个/m2,底栖桡足类居第2位,平均丰度为(663±569)个/m2,占总数量的76%.根据77种底栖桡足类丰度所做的聚类和标序分析将渤海20个站位划分为4个组合.根据11种环境因子数据所做的聚类和主成分分析将研究海域划分为两个生境、4个亚区.对研究海域进行的分区与自然分区是基本一致的.支配研究海域底栖桡足类群落结构的主要环境因子是水深和沉积物粒度.     

南麂列岛潮间带的微小型底栖藻类

本文首次记录南麂列岛国家级海洋自然保护区潮间带的微小型底牺藻类。经初步鉴定南麂列岛潮间带共有微小型底栖藻类４门５４属１５５种，以硅藻类占优势（４１属１２５种）。其优势种在岩礁为附生性的海生斑条藻，沙滩为附生性的小形舟形藻和翼茧形藻，泥滩为底栖性的圆筛藻和斜纹藻。不同生境其种类组成差异显著，在各生境均出现的共有种仅６种。微小型底栖藻类年平均丰度：岩礁为７０９４．６１个／ｇ，沙滩为４６８２１．６３个／ｇ，泥滩为４５６．５个／ｇ，岩礁和沙滩以春季最高；泥滩以夏季最高；秋、冬季各生境的丰度均较低。     

大型多元统计软件PRIMER的方法原理及其在底栖群落生态学中的应用

本文阐述大型多元统计分析软件 PRIMER的原理及其在底栖生态学中的应用。PRIMER是处理生态和环境多元数据的重要数值分析工具 ,本文从实用的角度对其中包括的技术方法和相应的子程序如 :等级聚类 (CLUSTER)、非度量多维标度 (MDS)、主分量分析 (PCA)、相似性分析检验(ANOSIM)、相似性百分比分析 (SIMPER)、生物 -环境连接的逐步分析和相关检验 (BIOENV/BVSTEP)等作了较为系统的介绍。     

赤道西太平洋末次盛冰期以来的浮游有孔虫氧碳稳定同位素记录

对西太平洋暖池核心区MD01—2386柱状样最上部5m进行了高分辨率的浮游有孔虫Globigerinoides ruber和Pulleniatina obliquiloculata的氧、碳稳定同位素分析,结合AMS^14C测年,研究表明其属于末次盛冰期-全新世的沉积。赤道西太平洋海区末次盛冰期以来δ^18O值显著降低,但有几次回返事件。表层浮游有孔虫G．ruber比次表层温跃层属种P．obliquiloculata对于环境变化的响应要快,但后者变化的幅度较大。这两个种的氧、碳同位素差值反映出温跃层深度自末次盛冰期以来逐渐加深,并存在周期性的回返事件,说明西太平洋暖池晚第四纪冰期旋回存在气候不稳定性。     

底栖生物生产力现场测试系统(BCSPM)的建立及其初步实验结果

为对生态系统的健康评估及底栖生物资源的开发利用提供技术支撑,在胶州湾筏式养殖水域,建立了底栖生物生产力现场测试系统(BCSPM),并在光照和黑暗条件下测定了沉积物海水界面溶解氧随时间的变化、计算了氧通量、估算了底栖总初级生产力和群落呼吸。在光照较强的中午时刻测定的群落总生产力为20．76mgCm^-2h^-1;养殖水域沉积物中的群落呼吸要高于邻近水域。BCSPM整体运转良好,初步结果为系统的改进和进一步实验提供了依据。     

夏季珠江口外近海沉积物/水界面营养盐的交换通量

基于2002年夏季(7月)对珠江口外近海的生态环境调查,获取了该海域沉积物间隙水的营养盐剖面资料,估算了沉积物/水界面的营养盐交换通量,并且与实验测定的沉积物/水界面交换通量进行了对比。结果表明,沉积有机质在厌氧环境下降解大大提高了间隙水中的铵盐、磷酸盐和硅酸盐含量,导致这些营养盐总体上从沉积物内部向沉积物/水界面转移。但在该界面附近,铵盐被不同程度地硝化,所形成的硝酸盐又被不同程度地反硝化;磷酸盐和硅酸盐交换通量则受到自生矿物沉淀与溶解、吸附与解吸作用的影响,因此营养盐的净交换通量是各种物理、化学和生物作用的综合结果。模拟实验研究显示,该海区NH4+、NO3-、NO2-、PO43-和SiO44-的沉积物/水界面交换通量分别为-0.197—1.93、-0.558—0.178、-0.064—-0.009、-0.079—0.126和-6.89—7.00 mmol.(m2.d)-1。根据营养盐剖面资料计算的交换通量不仅很小,交换通量方向也往往与实验结果不符。     

浙江6个列岛大型底栖藻类分类多样性

本文基于对七星列岛大型底栖藻类的实地调查,结合浙南3个列岛(七星列岛、南麂列岛和洞头列岛)和浙北3个列岛(渔山列岛、中街山列岛和马鞍列岛)大型底栖藻类物种组成的有关文献,构建大型底栖藻类基础数据库。采用平均分类差异指数△~+、分类差异变异指数∧~+、G-F多样性测度指数和相似性系数开展分类多样性研究。结果显示:6个列岛藻类在目级和科级的相似性很高,其值均在0.800以上;洞头列岛的△~+值最高(77.42),中街山列岛最低(72.65),这表明洞头列岛大型底栖藻类类群间的亲缘关系较远,中街山列岛藻类类群间的亲缘关系较近;七星列岛的∧~+值最高,达942.00,南麂列岛最低,仅865.12,这表明南麂列岛大型底栖藻类在不同分类阶元分布最均匀,七星列岛的藻类分布较集中;南麂列岛无论是F指数、G指数还是G-F指数的值均比其他5个列岛高,依次为18.62,4.40和0.76,这说明南麂列岛藻类的生态位分化程度较高。本研究构建了6个列岛大型底栖藻类资源与分类多样性基础数据库,为有效保护和管理大型底栖藻类提供了理论依据。