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51.
52.
Abstract. Food preferences of six dominant salt marsh invertebrates were studied to identify detritivores and to assess differences in their diets. Animals fed on agar suspensions of dead and live foods in petri dishes with four compartments. Only two foods were included in each dish. Relative palatability was assessed by measuring the amount of suspension removed or by counting the number of feeding marks left on the surface of the suspensions.
Feeding marks reflected differences in mouth parts and feeding mechanisms of the six invertebrates. Melampus bidentatus, Orchestia grillus , and Philoscia vittata preferred dead litter over live tissues of marsh graminoids, blue-green algae, and sulfur bacteria. No preference for detritus from different graminoids was shown by M. bidentatus. Orchestia grillus fed preferentially on Spartina patens detritus. Philoscia vittata preferred detritus from S. alterniflora and S. patens. Blue-green algae and sulfur bacteria were preferred over detritus by Littorina saxatalis , but detritus was preferred over live graminoids. Littorina saxatalis fed preferentially on Juncus gerardi detritus. Blue-green algae, sulfur bacteria, and live graminoids were preferred over detritus by L. littorea. Talorchestia longicornis also preferred blue-green algae.
On the basis of their food preferences, Littorina saxatalis, Melampus bidentatus, Orchestia grillus , and Philoscia vittata were classified as detritivores. Feeding on detritus from different plant species could result in a partitioning of this food resource in the detritus-based food chains of the salt marsh ecosystem. 相似文献
Feeding marks reflected differences in mouth parts and feeding mechanisms of the six invertebrates. Melampus bidentatus, Orchestia grillus , and Philoscia vittata preferred dead litter over live tissues of marsh graminoids, blue-green algae, and sulfur bacteria. No preference for detritus from different graminoids was shown by M. bidentatus. Orchestia grillus fed preferentially on Spartina patens detritus. Philoscia vittata preferred detritus from S. alterniflora and S. patens. Blue-green algae and sulfur bacteria were preferred over detritus by Littorina saxatalis , but detritus was preferred over live graminoids. Littorina saxatalis fed preferentially on Juncus gerardi detritus. Blue-green algae, sulfur bacteria, and live graminoids were preferred over detritus by L. littorea. Talorchestia longicornis also preferred blue-green algae.
On the basis of their food preferences, Littorina saxatalis, Melampus bidentatus, Orchestia grillus , and Philoscia vittata were classified as detritivores. Feeding on detritus from different plant species could result in a partitioning of this food resource in the detritus-based food chains of the salt marsh ecosystem. 相似文献
53.
Concentrations of total recoverable inorganic tin (TRISn), monomethyltin (MeSn3+), dimethyltin (Me2Sn2+), trimethyltin (Me3Sn+) and (3-dimethylsulphonio)propionate (DMSP) were determined in leaves of Spartina alterniflora from three sites in the Great Bay estuary (NH) from 8 May to 15 September 1989. Total methyltin concentration increased from 8·9 ng g−1 (fresh weight) on 8 May to 472 ng g−1 on 23 May, decreased to 52 ng g−1 on 7 June and 16ng g−1 on 20 June, and remained low until the last sample on 18 September. Statistical calculations showed that methyltin concentrations varied significantly with sampling week, but not with site. DMSP concentrations showed very different behaviour. During the same sampling period DMSP concentrations varied only from 7·5 to 26 μmol g−1 (fresh weight). DMSP concentrations varied significantly for site, but not sampling week. 相似文献
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利用三维高分辨率有限体积的近海海域模型FVCOM来分析2001年秋季期间风作用对坦帕湾区域盐度平衡的影响。为了区分风的影响,分别设计了两个实验:一个由潮汐和河流作为驱动,另一个由潮汐、河流以及风场共同驱动。结论如下:首先,风作用会使盐度产生变化,能够明显地使坦帕湾内的盐度增加,并导致水平和垂直方向上盐度梯度的减少;随后,本文分析了坦帕湾区域内的盐度平衡,主要的盐度平衡来自于全部(水平和垂直方向上)平流的盐度流量分歧以及除去海峡底部的垂直方向上盐度流量分歧;最后,对由风引起的盐度变化进一步进行分析,结果表明风作用不能改变盐度平衡地位的相对重要性,由风引起的盐度平衡改变高度依靠于特殊的地形,除此之外,全部平流盐度流量分歧和垂直散布盐度通量分歧能够抵消,并且两者都远大于水平散步盐度流量分歧。 相似文献
55.
A Stable Carbon Isotope Study of the Food-web in a Freshwater-deprived South African Estuary, with Particular Emphasis on the Ichthyofauna 总被引:1,自引:0,他引:1
The importance of macrophytes as food sources for estuarine nekton is unclear. Previous carbon isotope investigations in the macrophyte-dominated, freshwater-deprived Kariega Estuary showed that the bivalveSolen cylindraceusdid not utilize the dominant estuarine macrophytes found within the estuary as a primary food source. This finding prompted questions as to what the nekton of this estuary utilize as primary energy sources. δ13C analyses of the principal autochthonous and allochthonous primary carbon sources, as well as the dominant invertebrate and fish species, indicate that there are two main carbon pathways within the Kariega Estuary. The littoral community, which incorporates the majority of crustaceans, gobies, mullet and a sparid, utilizes δ13C enriched primary food sources namelySpartina maritima,Zosteracapensis and epiphytes. The channel fauna, which includes the zooplankton, zooplanktivorous and piscivorous fish, utilizes a primary food source depleted in δ13C, which is most likely a mixture of phytoplankton, terrestrial plant debris and C4macrophyte detritus. The C3saltmarsh macrophytesSarcocornia perennisandChenolea diffusa, as well as benthic microalgae, appear to be less important as primary food sources to the nekton of the Kariega Estuary. 相似文献
56.
缢蛏(Sinonovacula constricta)是我国重要的水产经济贝类,开展耐高盐新品种选育对平衡不同地区缢蛏良种养殖意义重大。本研究对不同家系缢蛏幼贝进行高盐胁迫,运用统计学方法和相关性分析探究了缢蛏耐高盐性能及其与生长性状的相关性。结果显示,缢蛏家系间壳长、壳高、壳宽和体质量表型值差异较大,体质量变异系数达15.53%。不同家系对高盐耐受性差异较大,家系间死亡率范围在0~100%。胁迫实验共持续9 d,各家系缢蛏首粒死亡时间在第1~9 d之间,而且死亡率较高的家系内缢蛏死亡时间离散程度较大,说明不同个体间高盐耐受性差异也较大。缢蛏开始出现大量死亡的时间主要在胁迫后第8 d,第9 d部分家系死亡率高于80%,说明缢蛏对高盐耐受存在一个阈值,超过该阈值会开始或大量死亡。皮尔逊和斯皮尔曼相关性分析显示,缢蛏存活时间和生长性状为正相关,其中存活时间与缢蛏壳长、体质量相关性均达到显著水平(P<0.05)。缢蛏存活率与体质量、生长速度均显著正相关(P<0.05)。整体而言,壳长较长和体质量较重的缢蛏个体耐高盐性能较强,在高盐环境中具有生长优势。本研究揭示了缢蛏的高盐耐受性及... 相似文献
57.
58.
59.
Peri S.J. Coleman 《International Journal of Salt Lake Research》1998,7(1):25-40
Trials conducted at Dry Creek, a solar saltfield north of Adelaide, Australia, indicate that manganese, as manganous sulphate,
can increase both the purity and strength of salt crystals grown at an ambient or neutral-slightly acid pH range resulting
in a salt suitable for high purity uses. The improved load bearing strength of the crystals indicates that manganous sulphate
could also be useful in salt floor maintenance. However, the impact of an apparently slight rise in pH to 8.5 was significant.
Crystals produced at the higher pH from the manganese enriched brine were opaque with many tiny, almost colloidal crystals.
The salt did not drain well, had low load bearing strength and was notably impure. 相似文献
60.
卤水中的化学成分因受多种因素影响,使其在时间序列上的变化波动强烈而规律难循。灰色—马尔科夫过程预测是预测事物在时间序列上发展趋势的一种良好有效的统计分析手段,它将灰色系统预测法和马尔科夫过程预测法有效结合,既弥补了两种方法各自的缺点,又能充分考虑数据给予的信息,可以大大提高随机波动较大数据序列的预测精度。本文用灰色—马尔科夫过程预测法对吉兰泰盐湖卤水中几种主要离子浓度的变化进行了趋势分析,分析结果发现几种离子浓度的变化均有一定的规律性,而且这些离子在预测数据的变化规律同原始实测数据变化规律有很好的一致性。 相似文献