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1.
微塑料污染目前成为海洋污染普遍关注的一个研究热点。本文在实验室内将青岛近海常见的海洋桡足类猛水蚤暴露于不同浓度的微塑料尼龙6中,研究了猛水蚤的摄食、排泄以及生殖的变化。研究结果表明,微塑料尼龙6对猛水蚤的摄食、排泄、生殖均产生不利的影响,并且存在剂量-效应关系。微塑料尼龙6对猛水蚤摄食率、滤水率、排粪率的24 h·EC 50分别为67.7、62.2、84.1 mg·L^-1,对猛水蚤抱卵率的144 h·EC 50为30.3 mg·L^-1。“饱食感”造成猛水蚤摄食率降低,从而能量和营养摄入不足可能是导致猛水蚤抱卵率降低的原因。猛水蚤对微塑料的摄食,导致猛水蚤排泄的粪便颗粒小型化,由长椭球体变为短小椭球体,可能与其粘度或物理结构的改变有关。暴露于尼龙6的猛水蚤的粪便体积和沉降速率显著低于未暴露微塑料的对照组。本实验结果对于研究微塑料对海洋桡足类以及滤食性浮游动物的生态毒理影响具有一定的帮助。 相似文献
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2000—2002年6月在黄海西南侧、山东半岛南部鳀鱼产卵场专项调查中,由底至表垂直拖网获得浮游生物中网(网孔径160μm)浮游动物样品,作者就该产卵场内四种主要小型桡足类(体长<1mm)双刺纺锤水蚤、小拟哲水蚤、拟长腹剑水蚤和近缘大眼剑水蚤的数量分布进行分析。在连续三年的6月,测区内均以小拟哲水蚤和拟长腹剑水蚤数量最多。四种小型桡足类的数量空间分布虽有一定的种间、年间差异,但总体上来说,四种小型桡足类的密集中心大多分布于山东半岛沿岸或近苏北浅滩沿岸水域。相关性分析表明,双刺纺锤水蚤和近缘大眼剑水蚤与底层水温呈正相关,与盐度呈负相关,拟长腹剑水蚤与底层水温呈负相关,与盐度呈正相关。小拟哲水蚤与温度的相关性较大。双刺纺锤水蚤和小拟哲水蚤与鳀鱼仔、稚鱼的数量分布有着较为显著的正相关。 相似文献
4.
《Journal of Oceanography》2007,63(6):983-994
A mesoscale iron-enrichment study (SEEDS II) was carried out in the western subarctic Pacific in the summer of 2004. The iron
patch was traced for 26 days, which included observations of the development and the decline of the bloom by mapping with
sulfur hexafluoride. The experiment was conducted at almost the same location and the same season as SEEDS (previous iron-enrichment
experiment). However, the results were very different between SEEDS and SEEDS II. A high accumulation of phytoplankton biomass
(∼18 mg chl m−3) was characteristic of SEEDS. In contrast, in SEEDS II, the surface chlorophyll-a accumulation was lower, 0.8 to 2.48 mg m−3, with no prominent diatom bloom. Photosynthetic competence in terms of F
v/F
m for the total phytoplankton community in the surface waters increased after the iron enrichments and returned to the ambient
level by day 20. These results suggest that the photosynthetic physiology of the phytoplankton assemblage was improved by
the iron enrichments and returned to an iron-stressed condition during the declining phase of the bloom. Pico-phytoplankton
(<2 μm) became dominant in the chlorophyll-a size distribution after the bloom. We observed a nitrate drawdown of 3.8 μM in the patch (day 21), but there was no difference in silicic acid concentration between inside and outside the patch. Mesozooplankton
(copepod) biomass was three to five times higher during the bloom-development phase in SEEDS II than in SEEDS. The copepod
biomass increased exponentially. The grazing rate estimation indicates that the copepod grazing prevented the formation of
an extensive diatom bloom, which was observed in SEEDS, and led to the change to a pico-phytoplankton dominated community
towards the end of the experiment. 相似文献
5.
Annual Cycle of Zooplankton Biomass, Abundance and Species Composition in the Neritic Area of the Balearic Sea, Western Mediterranean 总被引:7,自引:0,他引:7
Abstract. Seasonal changes in zooplankton biomass, abundance and species composition were studied at a neritic station in the Balearic Sea between April 1993 and May 1994. Sampling was carried out every 10 days in a zone influenced by the main current circulating through the Mallorca channel. Three main peaks of zooplankton biomass and abundance were observed: (1) at the beginning of summer when the thermocline developed, (2) in autumn when the thermocline broke down, and (3) in early spring. The smaller zooplankton fraction (100–250 μm) comprised on average 32 % of the total biomass and 73 % of total abundance. Copepods were the predominant group (64 % of the total abundance) with Clausocalanus, Oithona and Paracalanus being the most abundant genera. Paracalanus parvus, Clausocalanus furcatus, Acartia clausi, Oithona plumifera, Temora stylifera, Centropages typicus and Oncaea mediterranea were found to be the most important species in the area. Other abundant groups were cladocerans (15 %) and meroplankton larvae (12 %), both of which were particularly numerous during the stratified period. The copepod community was characterized by the above‐cited perennial species, which were abundant during the cycle studied. However, the influence of the hydrological conditions of the Balearic Sea, such as the Atlantic water influx and the physical structure of the water column (stratification and mixing), promoted the observed variability in zooplankton as well as the appearance of characteristic species during the annual cycle. 相似文献
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7.
Planktonic copepod Calanus sinicus is the dominant meso-zooplankton in the Northwest Pacific Ocean. To better understand its population dynamics and phylogeographic patterns, 243 C. sinicus individuals were collected from seven locations across the shelf waters of China and its population genetics was studied by mitochondrial DNA cytochrome oxidase I(mtCOI) sequences analyses. Thirty-nine different sequences, or haplotypes, were detected with moderate haplotype diversity(h=0.749) and low nucleotide diversity(π=0.003) for all populations. The evolutionary divergence between geographic populations varied from 0.24% to 0.37%, indicative of very limited genetic differentiation. Visualized minimum spanning network(MSN) and phylogenetic analysis of all the detected haplotypes did not reveal any clear phylogeographic pattern. Furthermore, AMOVA data showed no significant spatial population differentiation existed among the individuals collected across China shelf waters. Pairwise FST values showed that population collected from northwest of the East China Sea(ECS) displayed a low difference to other populations. Mismatch distribution analyses and neutrality tests indicated that C. sinicus might undergo a demographic/population expansion. No significant population genetic structuring was detected, indicating an extensive gene flow among the C. sinicus populations. Our results provide molecular evidence for the hypothesis that C. sinicus in the northwestern South China Sea in winter is transported from the East China Sea and the Yellow Sea by the China Coastal Current during the northeast monsoon period. 相似文献
8.
Seasonal change in body length of important small copepods and relationship with environmental factors in Jiaozhou Bay,China 总被引:1,自引:0,他引:1
Differences among species in prosome length and in species’ response to environmental factors do exist. Therefore, it is useful to examine prosome length for different copepod species in variable environments. Seasonal variations in prosome length of four small copepods and their copepodite stages in the Jiaozhou Bay were compared and the relative influence of temperature, salinity, and chlorophyll concentration were examined. Two peaks were found in the mean prosome length of Paracalanus parvus (in early winter and May). For Acartia bifilosa, the maximum values of all copepodites occurred mainly from February to April, and decreased to the bottom in July. Prosome length of Acartia pacifica peaked when it first appeared in June, then reached to the minimum in July. Parvocalanus crassirostris only appeared from late summer to autumn and the mean prosome length showed no clear changes. Correlations of adult prosome length with environmental factors were evaluated. For the four species, temperature was negatively correlated to prosome length except for P. crassirostris. But the different species varied markedly in their responds to temperature. A. bifilosa showed a more definite trend of size variation with temperature than P. parvus and A. pacifica. Correlations of prosome length with salinity were significantly positive for almost all the small copepods. The relationship between chlorophyll concentration and prosome length was complicated for these copepods, but for P. parvus, chlorophyll concentration was also an important affecting factor. Furthermore, investigation needs to be done on food quality for some copepod. These results are essential to estimate the biomass and the production, and to understand these small copepods’ population dynamics in this human-affected bay. 相似文献
9.
Pierre-Yves Pascal John W. Fleeger Fernando Galvez Kevin R. Carman 《Marine pollution bulletin》2010,60(12):2201-2208
Increased atmospheric CO2 concentrations are causing greater dissolution of CO2 into seawater, and are ultimately responsible for today’s ongoing ocean acidification. We manipulated seawater acidity by addition of HCl and by increasing CO2 concentration and observed that two coastal harpacticoid copepods, Amphiascoides atopus and Schizopera knabeni were both more sensitive to increased acidity when generated by CO2. The present study indicates that copepods living in environments more prone to hypercapnia, such as mudflats where S. knabeni lives, may be less sensitive to future acidification. Ocean acidification is also expected to alter the toxicity of waterborne metals by influencing their speciation in seawater. CO2 enrichment did not affect the free-ion concentration of Cd but did increase the free-ion concentration of Cu. Antagonistic toxicities were observed between CO2 with Cd, Cu and Cu free-ion in A. atopus. This interaction could be due to a competition for H+ and metals for binding sites. 相似文献
10.
In this study,the authors investigated the effects of residual chlorine on mortality,grazing and respiration of Labidocera euchaeta in laboratory.The grazing rate was evaluated by subtraction method of food concentration and respiration rate was measured using oxygen electrode.It was found that the lethal effect of residual chlorine on L.euchaeta increased with enhanced concentration and prolonged duration.The medium lethal concentration (LC 50 ) of chlorine for L.euchaeta in 24 h was about 0.58 mg/L and the safe concentration was about 0.21 mg/L.However,the grazing and respiration of L.euchaeta decreased by 32.6% and 18.9% when exposed to 0.2 mg/L residual chlorine for 4 h.It indicated that the physiological activities of zooplankton could be suppressed by the residual chlorine less than the safety concentration.Therefore,both survival and physiological activities of the organisms living in the thermal (nuclear) power plant discharging waters should be considered when carrying out the ecological risks assessment. 相似文献