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Francesco CARUSO Leigh HICKMOTT Joseph D. WARREN Paolo SEGRE Gustavo CHIANG Paulina BAHAMONDE Sonia ESPAÑOL-JIMÉNEZ Songhai LI Alessandro BOCCONCELLI 《Integrative zoology》2021,16(4):594-611
The northern Chilean Patagonia region is a key feeding ground and a nursing habitat in the southern hemisphere for blue whales (Balaenoptera musculus). From 2014 to 2019, during 6 separate research cruises, the dive behavior of 28 individual blue whales was investigated using bio-logging tags (DTAGs), generating ≈190 h of data. Whales dove to significantly greater depths during the day compared to nighttime (day: 32.6 ± 18.7 m; night: 6.2 ± 2.7 m; P < 0.01). During the night, most time was spent close to the surface (86% ± 9.4%; P < 0.01) and at depths of less than 12 m. From 2016 to 2019, active acoustics (scientific echosounders) were used to record prey (euphausiids) density and distribution simultaneously with whale diving data. Tagged whales appeared to perform dives relative to the vertical migration of prey during the day. The association between diurnal prey migration and shallow nighttime dive behavior suggests that blue whales are at increased risk of ship collisions during periods of darkness since the estimated maximum ship draft of vessels operating in the region is also ≈12 m. In recent decades, northern Chilean Patagonia has seen a large increase in marine traffic due to a boom in salmon aquaculture and the passenger ship industry. Vessel strike risks for large whales are likely underestimated in this region. Results reported in this study may be valuable for policy and mitigation decisions regarding conservation of the endangered blue whale. 相似文献
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H. LAUDELOUT L. GERMAIN P. F. CHABALIER C. N. CHIANG 《European Journal of Soil Science》1977,28(2):329-339
An estimate is given of nitrogen losses which could occur through chemical decomposition of nitrite formed by nitrification of ammonium in acid tropical soils. Experiments on the rate of disappearance of nitrite were carried out in acid buffers as well as in soil samples. Numerical solutions of a system of differential equations describe the nitrification process and the chemical denitrification reaction. Up to 50 per cent of added ammonium nitrogen may be lost in an acid soil when nitrification occurs at temperatures prevailing in the humid tropics. 相似文献
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新疆維吾爾自治區伊犂專區鞏乃斯羊場培育成的新疆毛肉兼用細毛羊(簡稱新疆細毛羊或新疆羊,舊名蘭哈羊),是我國第一個育成的細毛羊品種。截至1956年4月初止,鞏乃斯羊場有大羊14,821只,羔羊7,977只。自1949-1955年間,已出場公母羊16,479只,其中大部份為公羊,供該自治區以及關內各地充改良品種之用。1956年推廣範圍更大。目前分佈地區除新疆外,包括內蒙古自治區、甘肅、青海、陝西、山西、河北、四川、江西、吉林等省,全國純種新疆細毛羊已達70,000只左右,已雜交母羊160餘萬只,對我國綿羊品種改良工作影響極大。故作者認為將有關新疆細毛羊在鞏乃斯羊 相似文献
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土壤有机-无机复合体是土壤肥力的物质基础之一,不仅依随成土过程而发生变化,人类耕作利用也可产生影响。 相似文献
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降雨是导致土壤冲蚀的主要原因,而通用土壤流失公式(USLE)为目前世界上应用最广泛的土壤流失模式,式中之降雨冲蚀指数直接反映了降雨对土壤侵蚀的程度,为评估土壤侵蚀状况的重要因子之一.研究以基隆、新竹、嘉义、高雄、宜兰、花莲、台东等雨量测站资料之历年雨量记录建立各月之降雨冲蚀指数,所采用之记录为1975-2000年之降雨资料,并建立月降雨冲蚀指数及月降雨量关系式.由于气候变迁导致的降雨变化将影响土壤冲蚀之估算,而不同时间之雨量资料所推估的降雨冲蚀指数精度不同,又必须配合气候变迁模拟之时间尺度,故本研究以月雨量及月降雨冲蚀指数为基础探讨之.采用IPCC公告之B2情境下的大气环流模型(GCMs)模拟基隆、新竹、嘉义、高雄、宜兰、花莲、台东等测站未来降尺度月雨量变化.推估基隆、新竹、嘉义、高雄、宜兰、花莲、台东等测站未来短期、中期、长期之月降雨冲蚀指数,以供推估土壤流失量,可以发现各模型之平均值未来土壤冲蚀量在B2情境约-80%～+60%. 相似文献
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1.设计了一个在田间直接测定水稻土的电导的电导池,用以鉴别水稻土的肥力状况。根据条件试验,在水稻生长期间通常变动的水分含量范围以内,水分含量的差别可以不予考虑。土壤胶体本身的电荷在电导上的贡献也很小,所以一般也不必考虑。土壤含砂粒较多时,应该加以适当的改正值。2.根据大量的田间测定结果,在酸性的水稻土中,电导与肥力水平成明显相关。施肥的数量和种类对土壤电导发生显著的影响。由于水稻对养分的吸收,所以根际土壤的电导较根外为低,并且随着水稻的生长,而使土壤电导降低。3.酸性水稻土的干土渍水后电导的增加数值与土壤的肥力水平成正相关。这种电导的增加,基本上是由于有机质的分解所致。4.根据与化学分析的对照结果,土壤溶液的电导与阳离子的浓度成明显相关。在引起酸性水稻土电导的阳离子中,钙镁占90—95%,钾占2—8%,铁和铵的数量都在1%以下。5.作者根据研究结果,认为电导可以作为鉴别酸性水稻土的肥力水平的一个简便的综合性参考指标。 相似文献
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几种水稻土对铵离子的吸附特性 总被引：5，自引：4，他引：5
根据两年来水稻丰产的研究结果,在水稻所需的氮磷钾营养元素中,氮素最为活跃,而且敏锐地受到人为措施的影响.水稻的氮素营养问题,不仅在于氮素的供应容量,土壤的氮素供应强度及其持续时间,也同时深刻地影响水稻器管的协调生长. 相似文献