Life cycle strategies of Northern krill (Meganyctiphanes norvegica) for regulating growth, moult, and reproductive activity in various environments: the case of fjordic populations     

Cuzin-Roudy  J; Tarling  G.A; Stromberg  J.-O 《ICES Journal of Marine Science》2004,61(4):721-737

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三门湾夏季浮游植物现存量和初级生产力   总被引：1，自引：0，他引：1  

刘镇盛  张经  蔡昱明  张志道  刘诚刚 《海洋学研究》2003,21(3):24-33

该海区的生物、化学、水文等项目进行调查。用HQM-1型有机玻璃采水器采集水样,大面观测站仅采集表层(0～1m)水样,用于测定叶绿素a质量浓度和光合作用速率。在N2和N11两个连续观测站,每隔3h采集表层和5m层的水样,用于分析叶绿素a质量浓度及营养盐浓度。同时,用浅 型浮游生物网由近底层向表层垂直拖网采集浮游植物样品,所采样品被装入容积为600cm3的塑料瓶中,并加入20cm3的福尔马林溶液固定保存,供对浮游植物细胞计数和种属鉴定之用。营养盐样品用经酸预清洗过的孔径为0.45μm的醋酸纤维膜过滤,滤液用饱和HgCl2溶液固定后,低温避光保存。图…  相似文献   

深圳湾北岸泥滩大型底栖动物次级生产力研究   总被引：8，自引：2，他引：8  

金亮  蔡立哲  周细平  徐华林 《台湾海峡》2007,26(3):415-421

根据2005年3、6、9月和12月在深圳湾北岸泥滩9个取样站采集的大型底栖动物4个季度的定量样品,运用Brey(1990)的经验公式进行了大型底栖动物栖息丰度、生物量、次级生产力和P/B值的研究计算.整个研究区域大型底栖动物年次级生产力平均值(去灰干重)为54.55g/(m2.a),其中观鸟屋附近泥滩(A断面)较高,为68.85g/(m2.a),凤塘河口附近泥滩(H断面)为50.62g/(m2.a)次之,沙嘴码头附近泥滩(F断面)较低,为44.18g/(m2.a),深圳湾北岸泥滩大型底栖动物年平均P/B为2.95.可见,大型底栖动物次级生产力越靠近深圳河河口越低,这与越靠近深圳河河口,大型底栖动物个体越小、生活史更短的结果是一致的.  相似文献   

南黄海和东海毛颚类生态特征的研究Ⅱ.群落特征          下载免费PDF全文

戴燕玉  林茂 《海洋学报》2007,29(3):90-97

在对南黄海和东海毛颚类生态特征的研究数量分布特征后的续篇.重点探讨调查区毛颚类群落性质和群落结构的特征及与海区环境因子的相关性.结果表明,本区共记录毛颚类28种,种类季节变化不明显,周年共有种达64.3%;但群落优势种则有季节差异与区域差异.毛颚类群落多样性指数(H')和均匀度(J')年均值分别为1.68和0.64.H'的平面分布表现出外部海区大于近岸海区的分布格局.在群落中存在4个生态类群,其中近海暖温带类群和广盐暖水类群可分别指示黄海水、浙江沿岸流和东海陆架混合水在南黄海和东海这两个海区的相互推移和消长过程.此外,从不同侧面的计算分析也表明,影响群落特征值(H')的主要因子是温度和盐度.群落性质是以近岸暖温带低盐种和暖水广布种为主,近岸暖水种和大洋暖水种占一定比例的暖温带-亚热带群落结构的特点.  相似文献   

Particulate barium fluxes and export production in the northwestern Mediterranean   总被引：1，自引：0，他引：1  

Erika Sternberg  Catherine Jeandel  Juan-Carlos Miquel  Beat Gasser  Marc Souhaut  Roseanna Arraes-Mescoff  Roger Francois 《Marine Chemistry》2007,105(3-4):281-295

Biogenic barium, mostly in the barite (BaSO₄) form, has been proposed as a tracer for export production in the ocean. Here we report on biogenic barium (Ba_xs) and particulate organic carbon (POC) fluxes from sediment traps deployed at the DYFAMED site in the Northwestern Mediterranean Sea. Ba_xs fluxes display average values of 37 ± 45 and 50 ± 58 μg/m²/d at 200 and 1000 m respectively, and are linearly correlated to POC fluxes (mean values of 7.9 ± 9.3 and 6.8 ± 6.8 mg C/m²/d at 200 and 1000 m). Export production estimates, calculated using published Ba_xs- or POC-based algorithms, all fall below or close to the lower limit of potential export values proposed in the literature. This work clearly demonstrates the usefulness of Ba_xs as a tracer of oceanic export production in the Northwestern Mediterranean Sea. However, development of a quantitative export production proxy requires a clear understanding of the underlying cause(s) for the observed spatial variations in the relationship between Ba_xs and POC fluxes. The present study confirms that the processes leading to barite formation differ between margin and open-ocean sites and probably account for much of the regional variability in the POC/Ba_xs ratio.  相似文献   

Multi-scale spatial variability in fish assemblages associated with Posidonia oceanica meadows in the Western Mediterranean Sea     

Joan Moranta  Miquel Palmer  Gabriel Morey  Ana Ruiz  Beatriz Morales-Nin 《Estuarine, Coastal and Shelf Science》2006,68(3-4):579

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Atmospherically-promoted photosynthetic activity in a well-mixed ecosystem: Significance of wet deposition events of nitrogen compounds   总被引：1，自引：0，他引：1  

C. Boulart  P. Flament  V. Gentilhomme  K. Deboudt  C. Migon  F. Lizon  M. Schapira  A. Lefebvre 《Estuarine, Coastal and Shelf Science》2006,69(3-4):449

Wet atmospheric deposition of dissolved N, P and Si species is studied in well-mixed coastal ecosystem to evaluate its potential to stimulate photosynthetic activities in nutrient-depleted conditions. Our results show that, during spring, seawater is greatly depleted in major nutrients: Dissolved Inorganic Nitrogen (DIN), Dissolved Inorganic Phosphorus (DIP) and Silicic acid (Si), in parallel with an increase of phytoplanktonic biomass. In spring (March–May) and summer (June–September), wet atmospheric deposition is the predominant source (>60%, relative to riverine contribution) for nitrates and ammonium inputs to this N-limited coastal ecosystem. During winter (October–February), riverine inputs of DIN predominate (>80%) and are annually the most important source of DIP (>90%). This situation allows us to calculate the possibility for a significant contribution to primary production in May 2003, from atmospheric deposition (total input for DIN ≈300 kg km⁻² month⁻¹). Based on usual Redfield ratios and assuming that all of the atmospheric-derived N (AD-N) in rainwater is bioavailable for phytoplankton growth, we can estimate new production due to AD-N of 950 mg C m⁻² month⁻¹, during this period of depletion in the water column. During the same episode (May 2003), photosynthetic activity rate, considered as gross primary production, was estimated to approximately 30 300 mg C m⁻² month⁻¹. Calculation indicates that new photosynthetic activity due to wet atmospheric inputs of nitrogen could be up to 3%.  相似文献   

Cycladophora davisiana (Radiolaria) in the Okhotsk Sea: A key for reconstructing glacial ocean conditions     

Yusuke Okazaki  Osamu Seki  Takeshi Nakatsuka  Tatsuhiko Sakamoto  Minoru Ikehara  Kozo Takahashi 《Journal of Oceanography》2006,62(5):639-648

Cycladophora davisiana, a radiolarian species dwelling at mesopelagic depths, is known as a representative glacial fauna due to its unique distribution during glacial periods. In the present ocean, abundant production of C. davisiana is only observed in the Okhotsk Sea, indicating an adaptation of C. davisiana for seasonal sea-ice covered conditions. We found pronounced abundant production of C. davisiana during the early to middle Holocene in the Okhotsk Sea, suggesting more favorable conditions for C. davisiana than the present Okhotsk Sea. In order to clarify the reason, oceanographic conditions during the Holocene were reconstructed based on biomarkers, lithogenic grains including ice-rafted debris (IRD), biogenic opal, and total organic carbon (TOC) in two sediment cores from the Okhotsk Sea. These indicators suggest that the pronounced C. davisiana production may be attributed to: 1) a supply to mesopelagic depths under intensified stratification of fine organic particles derived from coccolithophorids, bacteria, and detrital materials; and 2) cold, well-ventilated intermediate water formation.  相似文献   

Spatial and temporal variations of mesozooplankton in the Pearl River estuary, China   总被引：10，自引：0，他引：10  

K.Z. Li  J.Q. Yin  L.M. Huang  Y.H. Tan   《Estuarine, Coastal and Shelf Science》2006,67(4):543-552

This paper examines spatial and temporal variations of mesozooplankton abundance, biomass and community structure during three cruises of July 2002 (summer), January 2003 (winter), and April 2003 (spring) in the Pearl River estuary, China. Zooplankton abundance and biomass fluctuated widely and showed distinct heterogeneity in the Pearl River estuary. A total of 154 species were identified during three surveys. The number of zooplankton species richness was strongly linked to salinity. Hierarchical cluster analysis identified three zooplankton groups during this study. Estuarine, neritic and pelagic groups corresponded to the upper, middle and lower reaches in the Pearl River estuary. The difference among groups could be mainly ascribed to changes in the relative contributions of the dominant species. The fluctuations in the zooplankton abundance, biomass and community structure were determined by the interactive effects of freshwater inflow, tidal and coastal currents, chlorophyll a, salinity and temperature. Significant spatial variability in the distribution of zooplankton species, abundance and biomass can be ascribed to the virtual presence of a horizontal gradient in salinity.  相似文献   

Sustainable shellfish aquaculture in Saldanha Bay,South Africa     

A Santa Marta  JG Ferreira  GC Pitcher  J Lencart e Silva 《African Journal of Marine Science》2020,42(2):151-166

The carrying capacity for bivalve shellfish culture in Saldanha Bay, South Africa, was analysed through the application of the well-tested EcoWin ecological model, in order to simulate key ecosystem variables. The model was set up using: (i) oceanographic and water-quality data collected from Saldanha Bay, and (ii) culture-practice information provided by local shellfish farmers. EcoWin successfully reproduced key ecological processes, simulating an annual mean phytoplankton biomass of 7.5 µg Chl a l^–1 and an annual harvested shellfish biomass of about 3 000 tonnes (t) y^–1, in good agreement with reported yield. The maximum annual carrying capacity of Small Bay was estimated as 20 000 t live weight (LW) of oysters Crassostrea gigas, or alternatively 5 100 t LW of mussels Mytilus galloprovincialis, and for Big Bay as 100 000 t LW of oysters. Two production scenarios were investigated for Small Bay: a production of 4 000 t LW y^–1 of mussels, and the most profitable scenario for oysters of 19 700 t LW y^–1. The main conclusions of this work are: (i) in 2015–2016, both Small Bay and Big Bay were below their maximum production capacity; (ii) the current production of shellfish potentially removes 85% of the human nitrogen inputs; (iii) a maximum-production scenario in both Big Bay and Small Bay would result in phytoplankton depletion in the farmed area; (iv) increasing the production intensity in Big Bay would probably impact the existing cultures in Small Bay; and (v) the production in Small Bay could be increased, resulting in higher income for farmers.  相似文献