Phytoplankton biomass and size fractions in surface waters of the Australian sector of the southern ocean     

Wendy Ehnert  C. Peter McRoy 《Journal of Oceanography》2007,63(2):179-187

We collected surface water along the 142nd E meridian from Tasmania to Antarctica in December 1999. We measured temperature, salinity and total chlorophyll a; additionally, we collected suspended particle size fractions and used fluorometric analysis to determine the quantity of chlorophyll a in each of four cell size classes: picoplankton (<3 μm), two nanoplankton fractions (3–10 μm and 10–20 μm) and microplankton (> 20 μm). Changes in temperature and salinity show that we crossed 6 water masses separated by 5 fronts. We found low abundance (<0.2 mg m⁻³) of chlorophyll in all size classes, with the exception of higher values near the continent (0.2 to 0.4 mg m⁻³). Lowest chlorophyll values (<0.1 mg m⁻³) were found in the Polar Frontal Zone (51° to 54°S). Microplankton made up the largest portion of total chlorophyll throughout most of the region. We conclude that biomass of all phytoplankton fractions, especially pico-and nanoplankton, was constrained by limiting factors, most probably iron, throughout the region and that ecosystem dynamics within a zone are not circumpolar but are regionalized within sectors.  相似文献   

海洋平台复杂节点阴极保护电位分布的有限元法计算   总被引：1，自引：0，他引：1  

王爱萍  杜敏  陆长山  曹圣山  王庆璋 《中国海洋大学学报(自然科学版)》2007,37(1):129-134

了解阴极保护电位分布是合理设计阴极保护工程的必要条件和评价阴极保护效果的重要依据。本文应用有限元素法(FEM)计算海洋平台复杂节点表面的阴极保护电位分布。在实验室通过边界条件试验建立数学模型,计算海水中被保护的I,Y,K型复杂节点电位分布情况。计算结果与测量结果吻合得很好,说明FEM能够应用于海洋平台复杂节点阴极保护电位分布的计算,所获得的边界条件合理。  相似文献   

Microhabitat preferences and depth distribution of combtooth blennies (Blenniidae) in the Gulf of Trieste (North Adriatic Sea)     

Martina Orlando-Bonaca  & Lovrenc Lipej 《Marine Ecology》2007,28(3):418-428

The microhabitat preferences and depth distribution of blenniid species (Blenniidae) in the Gulf of Trieste (North Adriatic Sea) were surveyed using the all‐occurrence sampling method, a non‐destructive visual census method, aided by SCUBA diving. Fourteen species were identified during the entire survey. Four species showed to be indiscriminate in their microhabitat choice while 10 species were classified as infrequent in the surveyed coastal area. A statistically significant correlation was found between the blenniid assemblage and nine microhabitat variables. The blenniid assemblage was divided in two main groups, by the use of canonical correspondence analysis, electivity index, and the depth distribution analysis. The first group comprises species that dwell in surface waters and show a high positive correlation with boulders, the presence of Mytilus galloprovincialis, cirripeds and empty holes bored by Lithophaga lithophaga. The second group includes species that mostly inhabit deeper waters and show a high positive correlation with rocks covered by precoralligenous bioformations.  相似文献   

Distribution and abundance patterns of two parapagurid hermit crabs (Crustacea: Decapoda: Anomura) along the west and south coasts of South Africa     

AG Wright  TP Fairweather 《African Journal of Marine Science》2020,42(2):177-183

A series of over 6 000 research-trawl samples collected along the west and south coasts of South Africa between 1987 and 2014 were analysed for the presence and biomass of two parapagurid hermit crabs, Sympagurus dimorphus and Parapagurus bouvieri. The percentage of trawls that landed S. dimorphus and P. bouvieri and the mean caught biomass were higher on the west than on the south coast for both the more-abundant S. dimorphus (30.59 vs 5.81% success and 287.88 vs 31.37 kg km^–2, respectively) and for the less-abundant P. bouvieri (13.76 vs 3.58% success and 38.56 vs 16.32 kg km^–2, respectively). Very few parapagurids were caught shallower than 150 m; thereafter, the proportion of trawls containing hermit crabs increased, peaking over the depth range 201–250 m for S. dimorphus (54%) and 401–450 m for P. bouvieri (51%), and declining steadily thereafter. On the west coast, the relative caught biomass of S. dimorphus increased significantly from north to south, but there was no apparent latitudinal trend in relative biomass for P. bouvieri. Similarly, there was a significant decline in caught biomass of S. dimorphus with increasing longitude along the south coast, but no apparent trend for P. bouvieri. Although this represents by far the most comprehensive global analyses of distribution and abundance patterns for parapagurids to date, extremely little remains known about the biology and ecological relationships of these species, or indeed of other members of the group.  相似文献   

Analysis, synthesis and modelling of high-resolution observations of salt-marsh eco-geomorphological patterns in the Venice lagoon   总被引：1，自引：0，他引：1  

Marco Marani  Enrica Belluco  Sergio Ferrari  Sonia Silvestri  Andrea D'Alpaos  Stefano Lanzoni  Alessandra Feola  Andrea Rinaldo   《Estuarine, Coastal and Shelf Science》2006,69(3-4):414

The present paper describes observations, analyses and models of salt-marsh channel network and vegetation patterns with the aim of contributing to the development of predictive models of ecological and morphological co-evolution. Existing and new observations are described, with particular emphasis on remote sensing and ancillary field surveys, which are shown to allow reliable, accurate and repeatable quantitative characterizations of landform and vegetation properties over the spatial scales of interest. The observed channel network morphological characters are then used as the basis and validation of models describing the emergence of channel network and vegetation spatial patterns. In particular, with reference to observations performed in the Venice Lagoon, the note describes: (i) new, 2-cm resolution, characterizations of channel network geometry obtained from “proximal sensing” photographic observations; (ii) the reliable quantitative maps of salt-marsh vegetation which may be retrieved from hyperspectral remote sensing data and field ancillary observations; (iii) a synthesis of recent and new analyses of the statistical properties of vegetation and landform spatial organization, that may be inferred from the maps so derived; (iv) recent and new conceptual and quantitative ecological and geomorphic models developed and validated by remote-sensing and field observations. A coherent observational and theoretical eco-morphodynamic framework is then proposed.  相似文献   

The recovery of the Barents Sea capelin (Mallotus villosus) from a larval point of view     

Fossum  P. 《ICES Journal of Marine Science》1992,49(2):237-243

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秦皇岛昌黎黄金海岸的沙丘沉积和发育机理   总被引：7，自引：0，他引：7  

曾照爽  庄振业  祁兴芬  刘志杰 《海洋地质前沿》2003,19(7):23-27

昌黎黄金海岸长40km，分布1～1．5km宽的风成沙丘。主沙丘链高30～40m，顺岸线分布，与其斜交数列新月形横向沙丘链。沙丘以中细砂组成，分选极好，层理构造十分丰富。距今3～4ka以前，沙坝形成时就开始形成沙丘；1915年滦河新三角洲发育以来增加了风沙的输沙量，增高沙丘和扩宽了沙丘带。  相似文献   

Response of zooid size in Cupuladria exfragminis (Bryozoa) to simulated upwelling temperatures     

Aaron O'Dea  Felix Rodríguez  & Tania Romero 《Marine Ecology》2007,28(2):315-323

We investigate the effect of the temperature–size rule upon zooids of the tropical American bryozoan Cupuladria exfragminis. Results show that mean zooid length, zooid width and zooid area vary significantly between clonal replicates of C. exfragminis kept under different controlled temperature conditions. Significantly larger zooids are produced during times of lowered water temperature that are comparable with the temperatures that occur during seasonal upwelling along the Pacific coast of Panama where the animal lives in abundance. Interpolation of data suggests that a drop of 1 °C causes a 5% increase in zooid size, and that almost all variation in zooid size in natural populations can be explained by temperature. Results are discussed in context of the potential use of zooid size variation in cupuladriid bryozoans to measure the strength of seasonal upwelling in ancient seas by analysing zooid size changes in fossil colonies. The technique of cloning cupuladriid colonies by fragmentation is also discussed with reference to its benefits in experimental studies where genotypes need to be controlled or replicated.  相似文献   

Influences of Nutrient Outwelling from the Mangrove Swamp on the Distribution of Phytoplankton in the Matang Mangrove Estuary, Malaysia   总被引：1，自引：0，他引：1  

Katsuhisa Tanaka  Poh-Sze Choo 《Journal of Oceanography》2000,56(1):69-78

Distributions of dissolved nutrients and Chl. a were investigated in the Sangga Besar River Estuary in the well-managed Matang Mangrove Forest in West Malaysia. In the estuary, spring tide concentrations of ammonium, silicate and phosphate were higher than those in the neap tide, which suggests that these nutrients are flushed from the mangrove area by the inundation and tidal mixing of the spring tide. Ammonium comprised over 50% of the dissolved inorganic nitrogen in the spring tide, while nitrite tended to dominate in the neap tide, indicating the predominance of nitrification inside the estuary in neap tides. Nutrient concentrations in the creek water were higher than those of estuarine water, indicating the nutrient outwelling from the mangrove swamp and ammonium regeneration from mangrove litter in the creek sediments. The maximum concentration of Chl. a in spring tides reached 80 g/l while it was below 20 g/l in the neap tides. These variations in the phytoplankton biomass and nutrients probably reflect the greater nutrient availability in the spring tide due to outwelling from the mangrove swamp and creek.  相似文献   

东海海域海水中颗粒氨基酸(PAA)的组成与含量的分布调查研究     

李烈英  张星君  纪明侯 《海洋科学集刊》2004,46(46):100-105

海水中的有机物的含量微少，约为0.5~2.0 C mg/L，但其种类复杂。其中以溶解有机物(DOM)为主，而颗粒有机物(POM)所占比例则更少。大洋海水中的POM主要来源于浮游生物等的死骸及其分解碎屑；另外还有海水中受风浪影响所进行的DOM-POM的动力平衡产物。近岸海水还受河流和大气带入的陆源尘影响。POM主要由颗粒氨基酸(PAA)组成。即由Asp、Glu、Thr、Ser、Ala、Gly、Leu、Ile、Val、Met、Cys、Tyr、Lys、His、Arg、Phe、Pro等17种氨基酸组成。它们是食碎动物的主要食物，构成海洋食物链的一环，与该水域生产力有直接联系。纪明侯等(1992)于1983年和1984年首次对青岛胶州湾海水中的颗粒氨基酸的组成和含量的变化及其季节变化进行了调查研究。并且在1982年和1984年前后对渤海湾、黄河口和长江口附近水域同样调查研究了表层海水中PAA的组成与含量分布。他们还于1981年7、8月和1982年7、8月乘“科学一号”考察船进一步研究了长江口外东中国海，包括福建省外海、济州岛附近海域和黑潮流域26°00′-33°00′N、123°00′-129°00′E范围内海域的20余个站位的表层海水和部分站位上不同水深中的PAA的组成和含量。兹将调查研究结果报道如下。  相似文献