Comparison of the growth rates of two stocks ot snapper (Chrysophrys auratus) in south‐east Australian waters using capture‐recapture data     

M. J. Sanders  D. G. M. Powell 《新西兰海洋与淡水研究杂志》2013,47(2):279-284

Between 1957 and 1962, 4155 snapper, Chrysophrys auratus (Bloch & Schneider), were tagged and released at a number of sites in Victoria. By the end of June 1972, 210 had been recaptured, and knowing their lengths at release and recapture and the periods at liberty, we determined the von Bertalanffy growth parameters K and L ₈ ^. The values (with 95% confidence limits) were: eastern stock ‐ K = 0.071 ± 0.040, L₈ = 968 ± 325 mm; western stock ‐ K = 0.068 ± 0.023, L₈ = 1079 ± 209 mm; combined stocks ‐ K = 0.062 ± 0.019, L ₈ = 1119 ± 215 mm. No difference between the stocks was apparent when we compared the estimates of K and L ₈ separately; however, when the estimates of K and L ₈ were compared together, a Wilcoxon's test gave a significance probability of 1.5%, indicating a difference in growth rate between the stocks. For the range of lengths of snapper recaptured, this difference was evidently caused by faster growth of snapper from the western stock.  相似文献   

Nitrogen and phosphorus in the Ngongotaha Stream     

R. A. Hoare 《新西兰海洋与淡水研究杂志》2013,47(3-4):339-349

This paper gives the data and methods used to calculate the nitrogen and phosphorus loads of the Ngongotaha Stream, near Rotorua, New Zealand. The variations in concentration with time and with flow rate are given in some detail, as examples of what may happen in other streams of the central volcanic plateau, and a novel way to define a flow‐concentration curve is described. Nitrate, ammonia, dissolved reactive phosphorus (DRP), total phosphorus (TP), and total Kjeldahl nitrogen (TKN) concentrations were measured, and mean concentrations in 1976 base flow were found to be 527, 25, 32, 48, and 162 mg m^‐3 respectively. Nitrate concentrations showed seasonal variations, and although changes occurred during floods, they were not correlated with flow rate. DRP concentrations showed little variation, except that they dropped at the peak of the largest floods. TP was strongly correlated with flow rate during floods, and TP loads could best be calculated by allowing for a curvilinear relationship between concentration and flow rate. The logarithms of the TP load carried by a flood and the peak flow rate of the flood were highly correlated (R = 0.984). The annual loads of nitrate, ammonia, DRP, TP, and TKN were estimated to be 34, 1.3, 2.9, 6.0, and 26 tonnes in 1976.  相似文献   

Nitrogen and phosphorus in Rotorua urban streams     

R. A. Hoare 《新西兰海洋与淡水研究杂志》2013,47(4):451-454

Nitrate concentrations in urban streams at Rotorua are much higher than those in nearby rural streams. The loads of nitrogen are consistent with the loads discharged to septic tanks in the stream catchments. Phosphorus concentrations are no higher than in rural streams, and phosphorus loads in the streams are less than 2% of the load on the septic tanks. Nitrate in the streams is slowly decreasing now that the sewerage reticulation system is almost complete.  相似文献   

Water quality of a lowland stream in a New Zealand dairy farming catchment   总被引：3，自引：2，他引：1  

Robert J. Wilcock  John W. Nagels  Harvey J. E. Rodda  Michael B. O'Connor  Bruce S. Thorrold  James W. Barnett 《新西兰海洋与淡水研究杂志》2013,47(4):683-696

A small stream in a predominantly dairying catchment in the Waikato region of New Zealand was monitored for 2 years at three sites. Total nitrogen (TN) concentrations were up to 7.09 g m^‐3 in winter, with the bulk comprising nitrate nitrogen (NO^‐ ₃‐N). During summer NO^‐ ₃‐N was near zero and TN mostly comprised organic nitrogen. Maximum concentrations of total phosphorus (TP) and dissolved reactive phosphorus (DRP) were 1.64 and 0.555 g m^‐3, respectively, and peaks coincided with spring and autumn applications of phosphorus fertiliser. Ammoniacal nitrogen concentrations exceeded 1 g m^‐3 on several occasions and mean concentrations at the three sites were 0.165–0.272 g m^‐3. Faecal coliform and enterococci bacteria concentrations were 64–26000 and 7–23000 cfu per 100 ml, respectively. Specific yields of TN and NO^‐ ₃‐N (35.3 and 30.7 kg ha yr^‐1, respectively) were much greater than any previously reported for New Zealand pasture catchments, whereas TP and DRP yields (1.16 and 0.54 kg ha yr^‐1, respectively) were more in accord with other studies. Greater use of land treatment of liquid wastes will reduce stream inputs of faecal organisms, NH₄‐N and P.  相似文献   

Land use effects on habitat,water quality,periphyton, and benthic invertebrates in Waikato,New Zealand,hill‐country streams   总被引：2，自引：2，他引：0  

John M. Quinn  A. Bryce Cooper  Robert J. Davies‐Colley  J. Christopher Rutherford  R. Bruce Williamson 《新西兰海洋与淡水研究杂志》2013,47(5):579-597

Water quality, habitat, and biota were compared during spring amongst c. 100 m reaches on 11 streams draining pasture, native (podocarp‐broadleaf) forest, and exotic pine forest established on pasture 15 years previously. Differences were greatest between the pasture and native forest streams. Only 1–3% of incident light reached native and pine forest streams whereas 30% reached pasture streams. Pasture streams had 2.2°C higher mean temperature than the native streams, and 5‐fold higher nitrate, 30‐fold higher algal biomass, and 11‐fold higher gross photosynthesis. Native streams were 60% wider than pasture, with pine streams intermediate. Pine and pasture streams had 3‐fold higher suspended solids and fine sediment stored in the streambed than native streams. Woody debris volume was 17‐fold greater in pine than pasture streams, with native streams intermediate. Invertebrate taxa richness did not differ between land uses. Community composition differed most between pasture and native forest, with pine forest streams intermediate. Invertebrate densities were 3‐fold higher in pasture than native streams, mainly because of more chironomids and snails, but mayflies, stoneflies, and caddisflies densities were 2–3‐fold higher in forest streams than pasture.  相似文献   

Foraging across ecosystems: diet diversity and social foraging spanning aquatic and terrestrial ecosystems by an invertebrate     

Mark E. Laidre 《Marine Ecology》2013,34(1):80-89

Ecosystems are fundamentally connected to one another, although empirical documentation of the links between them, especially the links between marine and terrestrial ecosystems, has been limited. This study examined the foraging behavior and ecology of an understudied invertebrate, the hermit crab Coenobita compressus, which is remarkably abundant at the nexus of marine, terrestrial, and freshwater ecosystems. Data collected between 2008 and 2011 in the Osa Peninsula of Costa Rica revealed that C. compressus plays a generalist scavenger role across ecosystems. Beach almond fruits (Terminalia catappa) were a staple of the crabs’ diet, but the crabs also commonly consumed a variety of other fruit species and various parts of plants (nuts, seeds, flowers, husk, stems, buds) as well as algae, fungus, animal feces, and the carcasses of insects, jellyfish, conspecifics, other crustacean species, freshwater and saltwater fish, sea turtles (eggs and adults), and mammals. The crabs fed on these resources in prominent social aggregations, also forming such aggregations as they exchanged the aquatically derived gastropod shells that they use as homes while roaming the land. The size of the crabs’ aggregations around plant versus animal resources and around terrestrial versus aquatic resources did not differ, underscoring the species’ generalist foraging behavior. Broadly, these results suggest that C. compressus has one of the most diverse diets of any crustacean and plays a critical role in recycling organic matter and nutrients. This species might also mediate the passage of resources across different ecosystems, although further research is needed to explore this possibility.  相似文献   

微型异养鞭毛虫摄食选择性的研究进展     

黄凌风  林施泉  熊源  陆家昌  吴林南 《海洋学报》2013,35(2):1-8

微型异养鞭毛虫(HNF)是海洋微微型浮游生物的重要摄食者,通过摄食作用对后者的种类(或类群)组成、粒径分布、数量结构和营养价值等属性具有重要的影响,而这与HNF的摄食选择性有直接关系。对HNF摄食选择性的研究有助于深入了解HNF在海洋微食物环乃至整个海洋生态系统中的作用。就国际上已开展的HNF摄食选择性相关研究进行了回顾,分析和总结了影响HNF选择性摄食的关键因素,如食物大小、游动性、营养价值及食物细胞表面的生化结构特征等,并重点介绍了HNF摄食选择性形成的主要机制以及HNF的选择性摄食在调节海洋微微型浮游生物群落结构中的作用。  相似文献   

夏季南黄海主要环境因子对微微型浮游生物分布影响   总被引：2，自引：1，他引：1  

屈佩  王宗灵  庞敏  傅明珠  蒲新明  孙萍  徐宗军 《海洋学报》2013,35(4):176-187

利用流式细胞技术, 获取南黄海夏季微微型浮游生物丰度数据, 分析了其组成和分布规律, 并探讨了主要的影响因子。2011年夏季, 聚球藻、微微型真核藻、异养细菌在整个调查海区的平均丰度分别在1×104、1×103、1×106 cells/mL数量级上。在全调查海区, 聚球藻和微微型真核藻受温度和光照的限制明显, 主要集中分布在温跃层及其以上水层;而营养盐的限制较小, 它们的影响只有在沿岸流影响明显的西部海区才能较为明显的体现出来。结果表明在该海域浓度较高的营养盐能够促进微微型浮游生物的生长, 但不是其限制因素;异养细菌受环境因子限制较小, 即使在深海也保持着较高的丰度。  相似文献   

渤海水环境无机氮污染风险研究   总被引：2，自引：0，他引：2  

兰冬东  李冕  梁斌  鲍晨光  马明辉 《海洋科学》2013,37(11):59-63

渤海海域污染日趋严重, 无机氮是主要的污染因子, 对无机氮未来趋势的预测及风险空间分布的分析可为减缓和管理渤海海域污染提供依据。本文基于2000 到2011 年渤海无机氮的趋势性监测数据, 用IDW 插值和回归分析方法对其发展趋势进行预测, 并根据其发展趋势预测今后5 年渤海海域无机氮含量, 划分了渤海无机氮污染的高、中、较低和低风险区, 为渤海无机氮污染控制提供科学依据。  相似文献   

Microscale Response of Sediment Variables to Benthic Disturbance in the Central Indian Ocean Basin     

Shanta Nair  C. Mohandass  P. A. Loka Bharathi  G. Sheelu  Raghukumar Chandralata 《Marine Georesources & Geotechnology》2013,31(3):273-283

Abstract

The response of sediment bacteria and biochemical variables to benthic disturbance was investigated in the Central Indian Ocean Basin from cores at nine stations. Generally, bacterial density and biochemical variables declined vertically with depth in the upper layers of the cores. Mechanical disturbance caused by a hydraulic disturber brought about a substantial decrease in total bacterial numbers. However, the numbers of retrievable bacteria increased by two orders of magnitude. The biochemical parameters decreased in quantity with a shift in the linear relationship. The data suggest that abiotic artifacts will directly affect the biomass and biochemistry of the sediment.  相似文献