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851.
André Chiaradia Yan Ropert-Coudert Akiko Kato Thomas Mattern Julija Yorke 《Marine Biology》2007,151(4):1535-1542
Little Penguins, Eudyptula minor, breed in several small colonies in New Zealand and Australia. In this study, we compare the birds’ diving performances at
different sites situated throughout their breeding range. Environmental conditions and breeding success vary drastically amongst
colonies, but all birds feed on similar types of prey and face similar limitations on their foraging range. We examined several
diving parameters and calculated the proportion of foraging zone available during breeding to examine whether oceanographic
and geographic factors in the foraging zone can explain variations in diving behaviour and fledging success among the different
colonies. In colonies with high fledging success, Penguin Island and Oamaru, penguins made shallow dives <50 m depth and had
lower diving effort. More than 90% of the foraging zone was in waters <50 m depth in these colonies. Motuara Island also has
shallow waters with 95% <50 m depth, but the fledging success was low. Phillip Island has only 42% of waters <50 m and comparatively
low fledging success. Thus, penguins dived deeper and showed a higher diving effort in colonies with lower fledging success
(Motuara Island and Phillip Island), indicating that they were disadvantaged compared to conspecifics from other colonies
that dived shallower and with a lesser diving effort. We concluded that bathymetry is an important factor, but not the only
one, which influences fledging success. 相似文献
852.
Information about foraging speeds is particularly valuable when the impact of a predator species upon a community of prey has to be defined, as in the case of great cormorants. We measured the swim speed of 12 (six males and six females) free-ranging great cormorants Phalacrocorax carbo, foraging off the Greenland coast during the summer of 2003, using miniaturized data-loggers. Although mean body mass of males was 27% greater than that of females, and mean swim speed of males were 29–57% higher than that of females during foraging phases (but not descent phases) of dives, these differences in speeds were not significant due to high variances. Birds descended to the mean maximum depth of 4.7 m at an average speed of 1.6±0.5 m s−1, a speed similar to that measured in captive cormorants in previous studies. Although bursts of up to 4 m s−1 were recorded, speed usually decreased during the deepest (foraging) phase of dives, being on average 0.8±0.6 m s−1. Speeds measured here should be taken with caution, because the large propeller loggers used to measure speed directly decreased descent speeds by up to 0.5 m s−1 when compared to smaller depth-only loggers. Cormorants in Greenland seem to combine two searching strategies, one requiring low speed to scan the water column or benthos, and one requiring high speed to pursue prey. These two strategies depend on the two main habitats of their prey: pelagic or demersal. 相似文献
853.
Weiguo Luo Shihe Wang Juan Huang Lu Yan Jun Huang 《Frontiers of Environmental Science & Engineering》2007,1(3):316-319
To determine the impact of photosynthesis and transpiration on nitrogen removal in wetlands, an artificial wetland planted with reeds was constructed to treat highly concentrated domestic wastewater. Under different meteorological and hydraulic conditions, the daily changes of photosynthesis and transpiration of reeds, as well as nitrogen removal efficiency were measured. It was found that net photosynthesis rate per unit leaf area was maintained on a high level (average 19.0 μmol CO2/(m2·s)) from 10:00 to 14:00 in July 2004 and reached a peak of 21.1 μmol CO2/(m2·s) when Photon Flux Density was high during the day. Meanwhile, TN and NH4 +-N removal efficiency rose to 79.6% and 89.6%, respectively—the maximum values observed in the test. Correlation coefficient analysis demonstrated a positive correlation among photon flux density, net photosynthetic rate, transpiration rate, and TN and NH4 +-N removal efficiency. In contrast, there was a negative correlation between stomatal conductance and TN and NH4 +-N removal efficiency. Results suggest that the photosynthesis and transpiration of wetland plants have a great impact on nitrogen removal efficiency of wetlands, which can be enhanced by an increase in the photosynthesis and transpiration rate. In addition, the efficiency of water usage by reeds and nitrogen removal efficiency could be affected by the water level in wetlands; a higher level boosts nitrogen removal efficiency. 相似文献
854.
磷肥施用量对缺锌土壤上水稻生长的影响李延,潘伟彬(福建农业大学土化系,福州350002)(闽西职业大学,龙岩364021)EffectofPhosphaticFertilizeronGrowthofRiceonZincDeficientSoil¥Li... 相似文献
855.
本文对化学品登记时所要求的部分健康效应数据一急性毒性和急性刺激做了解释.涉及到的测试参数包括:急性经口毒性、急性经皮毒性、急性吸入毒性、急性皮肤刺激/腐蚀和急性眼睛刺激/腐蚀. 相似文献
856.
857.
巢湖流域不同土地利用类型地表径流污染特征研究 总被引:31,自引:2,他引:29
巢湖是我国五大淡水湖之一,目前正面临着严重的环境污染与水体富营养化问题。通过对巢湖流域塘西地区大豆地,水稻田,菜地,山芋地,小麦地,集镇街道,山坡地,饲养场地,农村道路,湖滩芦苇地,荒地等11种土地利用类型地表径流污染现状的详细调查与分析,建立了巢湖流域不同土地利用类型地表径流污染研究的一般程序与方法。 相似文献
858.
对极大螺旋藻(Spirulina maxima)和钝顶螺旋藻(S.platensis),在接种后第1~7 d通过不同时间添加Na2TeO3来施加Te(IV)胁迫,5种Te(IV)胁迫实验组的累计加Te浓度均为250 mg/L,结果表明:两种螺旋藻的最终生物量,从I~V组均呈增加趋势;其中IV、V组对S.platensis的生长有促进作用。利用动力学方程并结合胁迫强度的概念,对实验结果进行了合理的解释。 相似文献
859.
860.