Assessment of spatial variation in carbon utilization by benthic and pelagic invertebrates in a temperate South African estuary using stable isotope signatures     

Nicole B. Richoux  P. William Froneman 《Estuarine, Coastal and Shelf Science》2007,71(3-4):545-558

Stable isotope analyses (δ¹³C and δ¹⁵N) were used to evaluate the spatial variations in carbon flow from primary producers to consumers at two sites in the temperate and permanently open Kariega Estuary on the southeastern coast of South Africa during October 2005 and February 2006. One site was located opposite a salt marsh while the second was upstream of the marsh. Except for significantly enriched δ¹³C values of Zostera capensis and surface sediments near the salt marsh, the δ¹³C and δ¹⁵N signatures of the producers were similar between sites. The invertebrates were clustered into groups roughly corresponding to the predominant feeding modes. The suspension feeders showed δ¹³C values closest to the seston, whereas the deposit feeders, detritivores and scavengers/predators had more enriched δ¹³C values reflecting primary carbon sources that were likely a combination of seston, Spartina maritima and Z. capensis at the upstream site, with an increased influence of benthic algae and Z. capensis at the salt marsh site. The δ¹⁵N signatures of the consumers showed a stepwise continuum rather than distinct levels of fractionation, indicating highly complex trophic linkages and significant dietary overlap among the species. Consumers exhibited significantly enriched δ¹³C values at the salt marsh site, an effect that was attributed to enriched Z. capensis detritus in this region in addition to increased phytoplankton biomass in their diets compared with invertebrates living upstream. The data reinforce the concept that between-site variations in the stable isotope ratios of consumers can result not only from dietary shifts, but also from alterations in the isotope ratios of primary producers.  相似文献   

南大洋普里兹湾基于234Th/238U不平衡法的POC输出通量研究   总被引：2，自引：0，他引：2       下载免费PDF全文

何建华  马豪  陈立奇  项宝强  曾宪章  尹明端  曾文义 《海洋学报》2007,29(4):69-76

中国第22次南极科学考察(2005年11月至2006年3月)期间,测定了南极普里兹湾海域5个站位的从表层至150 m水深的不同层位水样中溶解态和颗粒态234Th,238U的放射性比活度以及颗粒有机碳.利用234Th/238U在上层水体中的不平衡,计算了南极普里兹湾上层水体中234Th的平均停留时间和输出通量.结果显示,随着纬度的增加,上层水体中颗粒态和溶解态234Th的平均停留时间总体趋向减小,并在中纬度站位出现了最低值,分别为1~8和29~48 d,而颗粒态和溶解态234Th的输出通量则在中纬度站位出现了最大值,分别为21~38和26~39 dpm/(m3·d).运用箱型清除模式,利用两种不同的方法估算了各水柱中从真光层底部输出的POC通量,平均值分别达到104.7 mmol/(m2·d)(E法)和120.6 mmol/(m2·d)(B法),表明南极普里兹湾夏季存在很高的新生产力,它将会对该海域碳的生物泵过程产生重要作用.  相似文献   

东亚冬夏季风对热带印度洋秋季海温异常的响应   总被引：5，自引：0，他引：5  

李东辉  谭言科  张瑰  叶志敏 《热带海洋学报》2006,25(4):6-13

利用多年的Reynolds月平均海表温度资料和NCEP/NCAR全球大气再分析资料,分析了热带印度洋秋季海表温度距平(SSTA)与后期东亚冬夏季风强度变化的关系。结果表明,热带印度洋秋季SSTA的主要模态是全区一致(USB)型和偶极子(IOD)型,USB型模态主要代表热带印度洋秋季SSTA的长期变化趋势,而IOD型模态主要反映热带印度洋秋季SSTA的年际变化。热带印度洋秋季海温气候变率中既存在着明显的ENSO信号,也有独立于ENSO的变率特征,独立于ENSO的热带印度洋秋季SSTA变化的主要模态仍是USB型和IOD型。前期秋季USB模态与东亚冬季风及东亚副热带夏季风之间为负相关关系;与前期正(负)IOD模态相对应,南海夏季风强度偏弱(强),而东亚副热带夏季风强度偏强(弱)。USB型和IOD型模态对后期东亚冬、夏季风强度变化的影响是独立于ENSO的,但ENSO起到了调节二者相关显著程度的作用。  相似文献   

南海北部主要经济鱼类体长与体重关系   总被引：7，自引：1，他引：7  

王雪辉  杜飞雁  邱永松 《台湾海峡》2006,25(2):262-266

文中根据1997～1999年和2001～2002年期间在南海北部底拖网调查的43种共33 389尾鱼的体长（叉长、肛长）和体重数据,应用统计分析方法对各鱼种体长与体重关系进行分析.结果表明,43种鱼分别隶属于4目16科25属,相关系数R^2的范围为0.764～0.993,相关系数R^2值相对较高,其中58%的R^2值超过0.95.幂指数b值范围为2.50～3.44,平均2.90.盒须图分析表明,50%的b值在2.79～3.01范围.经初步分析,43种主要经济鱼类中,有16种为等速生长、22种负的异速生长和5种正的异速生长.  相似文献   

乳糖诱导重组别藻蓝蛋白(rAPC)在大肠杆菌(Escherichia coli)中的表达     

唐志红  葛保胜  林凡  任育红  秦松 《海洋与湖沼》2006,37(6):524-528

采用廉价的乳糖替代IPTG诱导重组别藻蓝蛋白(rAPC)在大肠杆菌(Escherichiacoli)JM109中表达,对诱导产物表达的培养基、培养条件、诱导剂的浓度和诱导时机进行了优化,将优化条件用于5L自控发酵罐进行高密度培养。结果表明,对rAPC表达的条件进行优化后,乳糖诱导rAPC的表达率可达26.8%,与IPTG的诱导结果接近;在高密度培养中,OD600最大达21.8。研究结果可为乳糖替代IPTG大规模生产rAPC奠定基础。  相似文献   

Ecological characteristics of Walleye pollock eggs and larvae in the southeastern Bering Sea during the late 1970s   总被引：1，自引：0，他引：1  

Kyung-Mi Jung  Sukyung Kang  Suam Kim  Arthur W. Kendall Jr. 《Journal of Oceanography》2006,62(6):859-871

Walleye pollock (Theragra chalcogramma) is an ecologically and economically important groundfish in the eastern Bering Sea. Its population size fluctuates widely, driving and being driven by changes in other components of the ecosystem. It is becoming apparent that dramatic shifts in climate occur on a decadal scale, and these “regime shifts” strongly affect the biota. This paper examines quantitative collections of planktonic eggs and larvae of pollock from the southeastern Bering Sea during 1976–1979. Mortality, advection, and growth rates were estimated, and compared among the years encompassing the 1970s’ regime shift. These data indicate that pollock spawning starts in late February over the basin north of Bogoslof Island. Over the shelf, most spawning occurs north of Unimak Island near the 100 m isobath in early or mid April. Pollock eggs are advected to the northwest from the main spawning area at 5–10 cm/sec. Larvae are found over the basin north of Bogoslof Island in April, and over the shelf between Unimak Island and the Priblof Islands in May. Compared to 1977, the spawning period appeared to be later in 1976 (a cold year) and earlier in 1978 (a warm year) in the study area. At the lower temperatures in 1976, egg duration would be longer and thus egg mortality would operate over a longer period than in the other years. Mean larval growth appeared to be lower in 1976 than in 1977 and 1979. Estimated egg mortality rate in 1977 was 0.6 in April and 0.3 in early May.  相似文献   

A simple method for comparing age-length keys reveals significant regional differences within a single stock of haddock (Melanogrammus aeglefinus)     

Gerritsen  Hans D.; McGrath  David; Lordan  Colm 《ICES Journal of Marine Science》2006,63(6):1096-1100

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东海浮游翼足类(Pteropods)数量分布的研究   总被引：10，自引：1，他引：10  

徐兆礼 《海洋学报》2005,27(4):148-154

根据1997～2000年东海海域23°30'～33°00'N,118°30'～128°00'E的4个季节海洋调查资料,运用定量、定性方法,探讨了东海浮游翼足类总丰度的平面分布、季节变化及变化的动力学机制.结果表明,东海翼足类总丰度和出现频率有明显的季节变化,均为秋季最高,夏季次之,春季最低;总丰度在各个季节基本上呈东海南部高于北部、外海高于近海的分布趋势;春季的尖笔帽螺(Creseis acicula)、夏季的锥笔帽螺(Creseis virgula)、秋季的蝴蝶螺(Desmopterus papilio)和冬季的马蹄螔螺(Limacina trochiformis)是导致总丰度季节变化的最主要的种类;冬、春和夏3个季节丰度变化及4季总丰度的变化同表层或10m层水温有非常显著的线性相关关系,与底层温度及盐度的相关关系不显著.夏季翼足类高丰度区位于台湾暖流与黑潮暖流的分支处;从夏季到秋季,翼足类随着台湾暖流向北扩展,并在与长江冲淡水,闽浙沿岸水团,黄海水团等交汇处形成高丰度(大于500×10-2个/m3)和较高丰度(250×10-2～500×10-2个/m3)分布区.水温和海流是影响东海翼足类总丰度分布的主要环境因素.  相似文献   

福建闽南沿海养殖贝类体中砷含量的分布   总被引：9，自引：0，他引：9  

钟硕良 《海洋学报》2005,27(6):116-122

通过2003~2004年对福建闽南沿海5种养殖贝类体砷含量的调查监测,对养殖贝类体中砷含量的分布进行了探讨.福建闽南沿海5种养殖贝类体总砷含量为0.65×10-6~4.80×10-6,总平均值为2.09×10-6,其中有机砷和无机砷占总砷含量的百分比分别为61.6%~98.2%和2.3%~38.4%,平均值分别为88.8%和11.2%.在相同养殖区,养殖贝类体总砷平均含量的种间分布差异较小.滩涂养殖底栖贝类体内总砷平均含量总体上高于浅海筏式养殖贝类体的平均含量.福建闽南沿海5种养殖贝类体内总砷含量在泉州湾、湄州湾、东山湾和九龙江口高,在诏安湾和围头湾低,在其余各湾相近.5种养殖贝类体内无机砷的污染指数和总平均值分别为0.05~0.76和0.23,总砷的污染指数和总平均值分别为0.06~0.48和0.21,总体符合国家食品卫生质量标准.养殖贝类体中砷含量与体长之间总体成正相关.  相似文献   

模糊化(拓扑)导算子的公理化     

安丰波  方进明 《中国海洋大学学报(自然科学版)》2005,35(4):583-586

将模糊化(拓扑)导算子进行了公理化，并且给出了若干模糊化(拓扑)导算子的刻画；同时建立了模糊化(拓扑)导算子和模糊化(拓扑)闭包算子之间的关系。  相似文献