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Grazing of Salpa thompsoni on phytoplankton in summer in the Prydz Bay region, Antarctica
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作者 李超伦 孙松 +1 位作者 张光涛 吉鹏 《Chinese Journal of Polar Science》 2001年第1期63-68,共6页
During the CHINARE ⅩⅤ cruise in austral summer of 1998/1999, the abundance and feeding activity of Salpa thompsoni were investigated in the Prydz Bay region. Salps samples were collected by vertical tows from t... During the CHINARE ⅩⅤ cruise in austral summer of 1998/1999, the abundance and feeding activity of Salpa thompsoni were investigated in the Prydz Bay region. Salps samples were collected by vertical tows from the depth of 200 m to the surface with a conical net of 330 μm mesh size. At ⅤⅠ 3 station, the grazing rates were studied by the gut fluorescence method and culture experiments. S. Thompsoni was mainly distributed in the northern part of the survey area, and its maximum densities reached to 2795 ind.·1000 m -3 . A dramatic decrease in salp stock was observed at the Marginal Ice Zone. The results of the feeding experiments at the ⅤⅠ 3 show that the gut pigment contents of S. thompsoni ranged from (0.14 1.27) μg ind. -1 (average 0.98 μg ind. -1 ). The individual ingestion rate is 7.9 μg ind. -1 ·day -1 , and the filtration rate is 28 L ind. -1 ·day -1 . Through the daily grazing rate of S. thompsoni , which takes account of less than 1% of the phytoplankton standing stock, it shows a relatively higher grazing impress on the primary production (72.2%). 展开更多
关键词 salpa thompsoni gut pigment GRAZING Prydz Bay.
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The impact of salps(Salpa thompsoni)on the Antarctic krill population(Euphausia superba):an individual-based modelling study
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作者 Bruno Walter Pietzsch Aaron Schmidt +3 位作者 Jürgen Groeneveld Dominik Bahlburg Bettina Meyer Uta Berger 《Ecological Processes》 SCIE EI CSCD 2023年第1期680-695,共16页
Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ecosystem.However,due to differing habitat requirements,both species previously exhibited little spat... Background Krill(Euphausia superba)and salps(Salpa thompsoni)are key macrozooplankton grazers in the Southern Ocean ecosystem.However,due to differing habitat requirements,both species previously exhibited little spatial overlap.With ongoing climate change-induced seawater temperature increase and regional sea ice loss,salps can now extend their spatial distribution into historically krill-dominated areas and increase rapidly due to asexual reproduction when environmental conditions are favorable.Understanding the potential effects on krill is crucial,since krill is a species of exceptional trophic significance in the Southern Ocean food web.Negative impacts on krill could trigger cascading effects on its predators and prey.To address this question,we combined two individual-based models on salps and krill,which describe the whole life cycle of salp individuals and the dynamic energy budget of individual krill.The resulting new model PEKRIS(PErformance of KRIll vs.Salps)simulates a krill population for 100 years under varying chlorophyll-a concentrations in the presence or absence of salps.Results All of the investigated krill population properties(abundance,mean length,and yearly egg production)were significantly impacted by the presence of salps.On the other hand,salp density was not impacted if krill were present.The medians of krill population properties deviated during variable maximum chlorophyll-a density per year when salps were introduced by−99.9%(−234 individuals per 1000 m3)for krill density,−100%(−22,062 eggs per 1000 m3)for krill eggs and−0.9%(−0.3 mm)for mean length of krill.Conclusions If both species compete for the same food resource in a closed space,salps seem to inhibit krill populations.Further simulation studies should investigate whether this effect prevails if different phytoplankton sizes and consumption preferences of krill are implemented.Furthermore,direct predation of the two species or consumption of krill fecal pellets by salps could change the impact size of the food competition. 展开更多
关键词 Euphausia superba salpa thompsoni Individual-based model Food competition Population dynamics DEB theory
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基于ABMSSA的PP算法分布式自动驾驶轨迹跟踪控制策略
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作者 周正阳 潘树国 +2 位作者 蔚保国 高旺 陈宗良 《电子测量与仪器学报》 CSCD 北大核心 2024年第6期50-57,共8页
针对在轨迹跟踪控制中横向纯追踪控制算法前视距离的选取受车辆速度影响较大的问题,本文设计了一种改进樽海鞘优化算法对纯追踪控制中的前视距离进行实时调整优化。首先在纯追踪控制模型的基础之上,采用横向误差作为主要决策参数,设计... 针对在轨迹跟踪控制中横向纯追踪控制算法前视距离的选取受车辆速度影响较大的问题,本文设计了一种改进樽海鞘优化算法对纯追踪控制中的前视距离进行实时调整优化。首先在纯追踪控制模型的基础之上,采用横向误差作为主要决策参数,设计了改进樽海鞘优化算法的目标函数,同时还在算法中引入布朗运动和自适应权重以防止陷入局部最优解和提高算法的收敛速度。其次本文还设计了纵向双环PID控制算法用于实现智能体车辆对于参考速度的跟踪。最后在智能体车辆实际平台上对所提出的基于分布式纵向双环PID控制算法、横向前视距离优化的纯追踪控制算法进行实验验证,并且设置多组对比实验。结果表明采用基于前视距离优化的纯追踪轨迹跟踪控制控制算法具有最优控制性能,其中最大横向误差为0.068 m,平均横向误差为0.014 m,相较于模糊优化其控制精度提升了24.73%。 展开更多
关键词 轨迹跟踪 纯追踪控制 双环PID速度控制 改进樽海鞘优化算法
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南黄海梭形纽鳃樽昼夜垂直移动的初步研究
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作者 刘永芹 孙松 张光涛 《海洋与湖沼》 CAS CSCD 北大核心 2013年第5期1200-1207,共8页
本文对2006年12月、2007年5月和6月在南黄海两个连续站S1-4和S3-3采集的梭形纽鳃樽的昼夜垂直移动进行了研究。结果表明,在不同季节不同海域该种昼夜垂直移动行为略有差异。在S1-4站位,12月份梭形纽鳃樽复体从未到达底层(50—70m),在0—... 本文对2006年12月、2007年5月和6月在南黄海两个连续站S1-4和S3-3采集的梭形纽鳃樽的昼夜垂直移动进行了研究。结果表明,在不同季节不同海域该种昼夜垂直移动行为略有差异。在S1-4站位,12月份梭形纽鳃樽复体从未到达底层(50—70m),在0—50m的水层中表现出不规则的昼夜垂直移动。从中午(12:00)到傍晚(18:00)主要分布在表层,之后移动到较深的水层(10—30m),而单体由于数量较少而未进行昼夜垂直移动分析;5、6月份,该种单体和复体都出现了明显的反向昼夜垂直移动,即白天迁移到表层,夜间向底层迁移,5月份尤为明显。在S3-3站位,12月份和5月份梭形纽鳃樽的单体和复体几乎在整个水层都有分布。12月份梭形纽鳃樽复体在夜间有向下移动的趋势,在06:00时到达最底层,白天主要分布在20m以上的水层中。5月份梭形纽鳃樽单体和复体昼夜垂直移动不明显,但主要分布在10—20m的水层中。 展开更多
关键词 南黄海 梭形纽鳃樽 垂直分布 昼夜垂直移动
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