河北省近海有害藻华灾害分级、时空分布和优势藻华生物变化特征     

安鑫龙  李雪梅  李志霞 《海洋技术学报》2015,34(1):69-75

为研究1989—2013年河北省近海有害藻华灾害分级、时空分布和优势肇事生物变化特征,对河北省近海累计58次有害藻华记录的发生时间、位置与范围、面积和优势有害藻华生物种类进行了统计分析。结果表明:小型(面积0~100 km2)、中型(100~1 000 km2)、大型(≥1 000 km2)和面积不详的有害藻华中,小型藻华为多发性藻华,发生次数占全省海域累计发生次数的60.35%;5-8月份是藻华多发期,发生次数占累计发生次数的86.21%;2000年后藻华发生频率大增,由原来年均发生1次演变为年均发生4次;秦皇岛海域发生藻华次数最多,占全省海域累计发生次数的57.14%,沧州海域次之,唐山海域最少;秦皇岛海域发生藻华累计面积最大,占全省海域累计发生面积的64.25%,沧州海域次之,唐山海域最小。河北省优势海洋有害藻华生物共计15种,易发性藻华生物夜光藻Noctiluca scintillans引发藻华次数最多,占全省海域累计发生次数的44.83%,2009年前是河北省近海最主要的藻华肇事生物;高发性藻华生物抑食金球藻Aureococcus anophagefferens引发有害藻华累计面积最大,占全省海域累计发生面积的55.57%,2009年后该藻和夜光藻共同成为河北省近海优势藻华肇事生物。  相似文献   

气象条件对滇池水华分布的影响   总被引：3，自引：1，他引：2  

李蒙  谢国清  鲁韦坤  戴丛蕊 《气象科学》2011,31(5):639-645

使用MODIS卫星资料,利用假彩色合成法和归一化植被指数法对滇池蓝藻水华进行监测,得到滇池水华的分布特征是：初现于5月,7月最盛,5—10月均有分布,盛时滇池水华分布区域直至南部海口一线。滇池水华分布总体北部最多,湖岸高于中心湖区,西岸高于东岸和南岸。在营养盐条件满足的条件下,高温对水华有促进作用,但不是决定因素。充足的日照是水华形成的必要条件。降水通过改变水温及日照对水华有抑制作用。小风（小于3 m/s）利于水华形成,大风对水华尤其是稀薄水华分布影响较大。气象条件通过相互影响,共同作用对水华产生影响。  相似文献   

Air-sea CO₂ exchange of beach and near-coastal waters of the Chukchi Sea near Barrow, Alaska     

Hiroki Ikawa  Walter C. Oechel 《Continental Shelf Research》2011,31(13):1357-1364

Partial pressure of CO₂ in equilibrium with sample water (pCO₂) for the coastal water in the Chukchi Sea was continuously observed in summer, 2008. Average daily CO₂ flux calculated from the pCO₂ and gas transfer coefficients ranged from −0.144 to −0.0701 g C m⁻² day⁻¹ depending on which gas transfer coefficient was used. The pCO₂ before the landfast ice sheets melted appeared to be highly biologically controlled based on the following information: (1) the diurnal pattern of pCO₂ was strongly correlated with Photosynthetic Photon Flux Density (PPFD); (2) high chlorophyll density was observed during periods of peak uptake; and (3) the day-to-day variation in the pCO₂ strongly correlated with the presence or absence of near-shore ice sheets. The lowest pCO₂ of 35 ppm together with the highest PPFD of 1362 μmol E m⁻² s⁻¹ were observed in the afternoon on June 28 in the presence of sea ice. The very low pCO₂ observed in late June was likely caused by high photosynthetic rates related to high phytoplankton densities typically observed from spring to early summer near the ice edge, and by water low in salinity and CO₂ released by melting sea ice early in the season.  相似文献   

高温微风条件下太湖流域风场时空特征分析   总被引：3，自引：2，他引：1  

王成林  黄娟  钱新 《湖泊科学》2011,23(1):122-128

适宜太湖蓝藻水华大面积形成的诸多因素中,气象因素主要是高温、微风.据此对太湖周边17个常规气象观测站的7年报文资料进行筛选,选择的17个站点同时满足时间为14点、气温大于2590、风速小于等于4m/s的风场进行分析,研究发现太湖流域风场空间特征以东南风居多,而且不同风向的背景风场吹过水面后.在下风向湖面及湖岸附近都存在...  相似文献   

广东省高州水库春季蓝藻水华成因初步探讨   总被引：12，自引：3，他引：9  

姚玲爱  赵学敏  周广杰  完颜华  蔡立梅  胡国成  许振成 《湖泊科学》2011,23(4):534-540

高州水库为广东省茂名市重要的饮用水源地,2009年和2010年春季相继出现蓝藻水华,给居民饮水带来安全隐患.对高州水库2009年和2010年春季水华情况进行分析,结果表明:两年浮游藻类细胞密度最高分别达4.08×107 cel1s/L和1.47 x 108cells/L,其中蓝藻所占比例分别为98.2%和98.7%,优...  相似文献   

太湖水体理化指标在夏季短时间尺度上的分层及其控制因素   总被引：5，自引：4，他引：1  

赵林林  朱梦圆  冯龙庆  刘笑菡  朱广伟  陈元芳  秦伯强 《湖泊科学》2011,23(4):649-656

通过连续9d(2010年7月24日至2010年8月1日)对太湖水体理化指标垂向分层的高频率观测,揭示太湖多指标垂向分层规律.观测表明:(1)太湖中各水质指标频繁出现分层现象,但不稳定;(2)分层的主要控制因素包含气温的日变化、蓝藻水华堆积与风浪扰动等;(3)气温和太阳辐射日变化影响水温分层,水温垂向变幅可达3.94℃,...  相似文献   

赤潮影响因素研究进展   总被引：13，自引：1，他引：12  

曾江宁  曾淦宁  黄韦艮  郑平  周青松  陈全震  高爱根 《海洋学研究》2004,22(2):40-47

通过对赤潮发生的生物、化学、物理等影响因素研究现状的分析,认为赤潮生物是引发赤潮的内在因素,化学因素是赤潮发生的物质基础,而物理因素则是提供赤潮发生的环境条件。在赤潮生物存在的前提下,化学和物理因素都可以限制赤潮的发生,所以,将生物学、化学与物理海洋学耦合仍旧是赤潮研究需要解决的问题。在分析了现有研究状况的基础上,从不同角度提出了赤潮的研究方向。  相似文献   

Holocene cool‐water carbonate and terrigenous sediments from southern Spencer Gulf,South Australia     

M. K. Fuller  Y. Bone  V. A. Gostin  C. C. Von Der Borch 《Australian Journal of Earth Sciences》2013,60(4):353-363

Holocene sediments from southern Spencer Gulf are cool‐water carbonate‐rich gravels and sands, dominated by molluscs and Bryozoa. Five sedimentary fades are recognized: (i) molluscan gravel; (ii) branching coralline‐algal gravel, associated with shallow partially protected environments; (iii) molluscan‐biyozoan sand; (iv) mixed bioclastic sand, representative of the deeper central region of the lower gulf; and (v) bryozoan gravel, an isolated fades developed in a semi‐protected micro‐environment. The southern gulf is characterized by complex oceanographic conditions together with variations in water depth and substrate. The sediments share the characteristics of both the southern shelf and upper Spencer Gulf. Grain‐size distribution and sedimentary facies are controlled by a combination of all the above processes. Past sea level fluctuations are recognized from sea floor strand‐line deposits. The relic component of the palimpsest sediments has eroded from the Pleistocene aeolianite dunes. The sediments, therefore, reflect both the modern marine and past environments.  相似文献   

The effects of trophic interactions and spatial competition on algal community composition on Hawaiian coral reefs     

Mark J. A. Vermeij  Meghan L. Dailer  Sheila M. Walsh  Mary K. Donovan  Celia M. Smith 《Marine Ecology》2010,31(2):291-299

Much of coral reef ecology has focused on how human impacts change coral reefs to macroalgal reefs. However, macroalgae may not always be a good indicator of reef decline, especially on reefs with significant sea urchin populations, as found in Kenya and Hawaii. This study tests the effects of trophic interactions (i.e. herbivory by fishes and sea urchins) and spatial competition (between algae and coral) on algal community structure of reefs surrounding two Hawaiian Islands that vary in their level of human impacts. Reef‐building organisms (corals and crustose coralline algae) were less abundant and turf algae were more abundant on Maui as compared to Lanai, where human impacts are lower. In contrast to previous studies, we found no evidence that macroalgae increased with human impacts. Instead, low turf and macroalgal abundance were best explained by the interactive effects of coral cover and sea urchin abundance. Fishing sea urchin predators appeared to have cascading effects on the benthic community. The absence of sea urchin predators and high sea urchin densities correspond to a disproportionately high abundance of turf and crustose coralline algae. We propose that high turf algal abundance is a better indicator of reef decline in Hawaii than high macroalgal abundance because turf abundance was highest on reefs with low coral cover and few fish. The results of this study emphasize that understanding changes in community composition are context‐dependent and that not all degraded reefs look the same.  相似文献   

Food web structure within kelp holdfasts (Laminaria): a stable isotope study     

Gauthier Schaal  Pascal Riera  Cédric Leroux 《Marine Ecology》2012,33(3):370-376

Kelp holdfasts are highly reticulated structures which host a large diversity of small fauna. These microhabitats have been reported to play a crucial role in the biodiversity associated to kelp forest ecosystems. This study aimed at identifying trophic links and the main food sources sustaining food webs within communities associated with kelp holdfasts, through a stable isotope (δ¹³C and δ¹⁵N) approach. Sampling of the main invertebrates inhabiting Laminaria digitata holdfasts, and of their potential food sources, took place in February and May 2007. Stable isotope results reveal that most of the primary consumers, including filter-feeders and deposit-feeders, rely on the particulate organic matter sedimented within kelp holdfasts. Only three grazers departed from this general pattern. The correspondence between the stable isotope ratios of predators and sediment consumers indicated that this source is at the base of the main pathway through which energy and matter transit in the food web. δ¹⁵N ranges found for consumers revealed that the food web associated with kelp holdfasts is composed of 3.5 levels. In spite of the low diversity of food sources at the base of the food web, these microhabitats can therefore be considered micro-scale ecosystems, from a functional perspective.  相似文献