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1.
The magnitude and seasonality of organic carbon exchange was estimated for two basin mangrove forests in Rookery Bay, Florida. Runoff and tidal inundation in the forests were seasonal with half the annual total of each occurring from August to October. In each forest there were 152 tides yr?1 with a cumulative depth of about 12 m. Total organic carbon increased in bay waters exporting from the mangroves following a flood tide and peak concentrations were associated with export due to rainfall. The amount of net export from each basin forest was similar, although the concentration of organic carbon in each were different. Monthly net organic carbon export was proportional to the cumulative tidal amplitude within the forest. Total organic carbon export was 64 gC m?2 yr?1 and DOC was 75% of the total. A comparison of organic carbon export among riverine, fringe and basin mangroves suggests that tidal hydrology influences the proportion of litter fall that is exported from mangroves; and the magnitude of this organic carbon export from mangroves is related to the cumulative tidal amplitude within the forests.  相似文献   
2.
Seasonal samples from Shark Bay on the west coast of Australia were used to determine (1) the habitats occupied by the juveniles and adults of Acanthopagrus latus in this large subtropical marine embayment and (2) the extent to which the dietary composition of this sparid is influenced by habitat type, body length and season. Sampling was undertaken in two habitat types in which A. latus was known to be abundant, namely mangrove (Avicennia marina) creeks and nearby rocky areas, the latter comprising sandstone boulders and/or limestone reefs. The mean total length ±95% CLs of A. latus was far lower in mangrove creeks, 126 ± 6.1 mm, than in rocky areas, 313 ± 4.7 mm. As A. latus attains maturity at ca. 245 mm, the juveniles of this species typically occupy mangrove areas and then, with increasing body size, move to nearshore rocky areas, where they become adults. The species composition of the food ingested by juvenile A. latus in mangrove creeks differed markedly from that of large juveniles and adults in rocky areas. Based on analyses of data for both habitat types combined, this difference was far greater than that between size classes and season, which was negligible. There were indications, however, that, overall within each habitat, the dietary composition did change seasonally, although not with body size. Acanthopagrus latus fed predominantly on mangrove material, sesarmid crabs and small gastropods in mangrove habitats, and mainly on Brachidontes ustulatus in rocky areas, where this mytilid bivalve is very abundant. The mangrove material, which contributed nearly 40% of its overall dietary volume in mangrove creeks, consisted mainly of lateral root primordia. This apparently unique food source for a teleost is presumably ingested through subsurface nipping, which would be facilitated by the mouth and dentitional characteristics of sparids. The almost total lack of correspondence in the dietary compositions of fish in the length class that was well represented in both mangrove and rocky areas illustrates the extent to which this sparid is capable of opportunistic feeding behaviour.  相似文献   
3.
On the basis of an investigation on the mangroves in Fujian from November 1998 to January 1999, the species composition, area, distribution, artificial afforestation of mangroves and the factors restricting the development of mangroves in Fujian are discussed in the paper. Some suggestions on how to develop mangroves in Fujian have been put forward.  相似文献   
4.
海桑属红树植物遗传多样性和引种关系研究   总被引:8,自引:2,他引:8  
周涵韬  林鹏 《海洋学报》2002,24(5):98-106
以海南东寨港红树林自然保护区内无瓣海桑(Sonneratia apetala)、海南海桑(S.hainanensis)、拟海桑(S.paracaseolaris)、杯萼海桑(S.abla)、大叶海桑(S.ovata)、海桑(S.caseolaris)等6种海桑属红树植物为材料,对15个有效引物进行RAPD分析,共扩增出512条带,其中多态性条带为297,占总扩增条带的58.01%.Nei指数法分析和UPGMA统计分析表明,6种海桑属红树植物分为A,B,C3个组,平均遗传距离为0.38.A组包括无瓣海桑、海南海桑、大叶海桑、怀萼海桑,其中无瓣海桑、海南海桑、大叶海桑处于同一个亚组.B组包括拟海桑.C组包括海桑.对海南和福建无瓣海桑种群进行RAPD分析.对Shannon表型多样性指数统计结果表明,福建种群为0.669,海南种群为0.671,各种群遗传变异较大,这与无瓣海桑种群广泛的适应性相一致.对种群间的Shannon表型多样性指数分析表明,种群内的遗传变异占整个遗传变异的93.3%,而种群间的遗传变异仅占6.7%.这表明无瓣海桑种群的大部分遗传变异存在于种群内,而种群间的遗传变异较小.由此可见,无瓣海桑基因组丰富的多样性,是使其由海南成功引种到福建的重要因素.  相似文献   
5.
Variations in elemental and isotopic ratios of suspended particulate matter (SPM) were investigated in the Guayas River Estuary Ecosystem (GREE) that empties into the Gulf of Guayaquil, Ecuador. Detritus in the system was identified on the basis of extremely high carbon:chlorophyll aratios (>1000). This material had mean δ13C of −26·4±0·3, δ15N of +4·8±0·2, and (C:N)atomicof 14·1±0·9. The isotopic data were comparable to measurements reported for fresh and degrading mangrove leaves, whereas the elemental ratio was comparatively enriched in nitrogen. Isotope measurements of SPM throughout the GREE were more similar to values for riverine material and detritus compared with that for the coastal end-member. Values indicative ofin situproduced algae, sewage and shrimp pond effluent were only found at selected sites. Bacterial bioassays, which were used to document potential sources of dissolved organic matter in the GREE, were isotopically similar to SPM. This correspondence coupled with the relatively low (C:N)aof SPM could be explained by bacterial immobolization of nitrogen onto detritus. Finally, tidal variations of (C:N)aand δ13C at a brackish mangrove site were similar in magnitude to spatial variations encountered throughout the GREE. Based on these results, the authors caution that care must be taken when samples are taken for food-web studies in these systems.  相似文献   
6.
This study examined the phenology and ecological consequences of a benthic filamentous cyanobacterial bloom (Lyngbya majuscula) in Deception Bay (Moreton Bay, Queensland, Australia). Bloom initiation occurred in mid December 1999 and expanded to encompass an 8 km2 area by April 2000. Small fish and penaeid prawns (<25 cm total length) were quantitatively sampled through periods designated as before, during and after the bloom using a combination of pop-netting within mangroves and beam trawling over adjacent seagrass beds. Data on larger-bodied fish were compiled from daily fishing logs provided by local commercial fishers. Changes in dry mass of bloom material caught in nets and changes in water chemistry were also measured. Mean concentrations of ammonia-N in residual water within mangroves were several orders of magnitude higher in the affected area than in the control and dissolved oxygen was markedly lower in affected areas. Across the study area, mean density, live mass and number of species declined during the bloom, with fish assemblages using mangroves showing greater decline than assemblages using seagrasses. Response at the species level was highly variable; generally, epibenthic species showed a more sustained decline than demersals. Mean monthly fish catch was significantly lower in bloom than non-bloom years. This study has also demonstrated that throughout the bloom, the affected area continued to support a highly diverse and abundant fish and prawn assemblage, and probably maintained its function as an important nursery habitat for many species.  相似文献   
7.
Georg  Ribi 《Marine Ecology》1982,3(1):13-19
Abstract. The frequency of parasitism of free ending prop roots of the red mangrove, Rhizophora mangle, by the wood boring isopod Sphaeroma terebrans, increased with increasing distance of the endings to established roots. In a field experiment, in which isolated endings were, surrounded by wooden sticks, the endings were colonized by S. terebrans at a lower rate than control endings, thus indicating that the wooden structures in the vicinity of the ending tended to reduce colonization rate by S. terebrans. It is concluded that S. terebrans may cause mangrove root density to increase by colonizing peripheral endings more readily than endings which are near established roots.  相似文献   
8.
A review of the world oceans in three volumes by 365 scientists, provides scope for several ‘meta-analyses' of the main problems affecting over 100 areas in the year 2000. This article summarises the main issues affecting a sub-set of the reviewed areas, covering Asian, African and Arabian countries dealt with in Volume 2, which included over 50 articles. From all issues raised, assessment is made of the nature of the major ones, including evaluation of reasons why so many of them remain important issues after so much attention to them. These include long standing problems, several problems more newly flagged as becoming particularly important, the issue of global warming and no less than three related issues connected with fishing and over exploitation. One or two issues such as industrial pollution and sewage, previously considered of almost universal concern, almost traditional pollution issues even, continue to feature strongly for some countries, but while these were almost always referred to in Seas chapters, by and large these categories appear not to be the most pressing of issues today, except in localized areas (albeit areas where huge numbers of people live). Perhaps other issues have simply taken over. They are excluded from this article.  相似文献   
9.
红树林海岸的沉积物输运和碳沉降特征   总被引:1,自引:0,他引:1  
Mangroves play an important role in sequestering carbon and trapping sediments. However, the effectiveness of such functions is unclear due to the restriction of knowledge on the sedimentation process across the vegetation boundaries. To detect the effects of mangrove forests on sediment transportation and organic carbon sequestration, the granulometric and organic carbon characteristics of mangrove sediments were investigated from three vegetation zones of four typical mangrove habitats on the Leizhou Peninsula coast. Based on our results, sediment transport was often "environmentally sensitive" to the vegetation friction. A transition of the sediment transport mode from the mudflat zone to the interior/fringe zone was often detected from the cumulative frequency curve. The vegetation cover also assists the trapping of material, resulting in a significantly higher concentration of organic carbon in the interior surface sediments. However, the graphic parameters of core sediments reflected a highly temporal variability due to the sedimentation process at different locations. The sediment texture ranges widely from sand to mud, although the sedimentary environments are restricted within the same energy level along the fluvial-marine transition zone. Based on the PCA results, the large variation was mainly attributed to either the mean grain size features or the organic carbon features. A high correlation between the depth and δ13C value also indicated an increasing storage of mangrove-derived organic carbon with time.  相似文献   
10.
The Sonneratia apetala artificial mangroves in the intertidal zone of Da Wei Bay at Qi’ao Island of Zhu-hai, South China were chosen as the macrofauna succession plots while bare tidal flats of the same size were established as control plots in surrounding interference-free areas. Conventional change indicators of community structure, such as biomass and biodiversity, and indicators, such as exergy and specific exergy, which reflect the information change of overall communities, were used to analyze the succession of macro-fauna communities inS. apetala artificial mangroves. The similarities and differences in variation tendency of the different ecological indicators and their reflected ecological principles were compared. The results showed that from D-1 to D-1275 after plantingS. apetala, the biomass of the macrofauna communities first increased, which was then followed by an increase in the network relationship between the macrofauna communities (analysis of the Pielou evenness index and Shannon-Wiener diversity index). The system in-formation (specific exergy) increased the slowest. Between D-1460 and D-2370 after plantingS. apetala, there was a decrease in biomass, network structure, and system information in the succession plots. After the decrease in the system information (the specific exergy), there was a decline in the network relationships (Pielou evenness index and Shannon-Wiener diversity index). Biomass was the last indicator to decrease. The similarities and differences among the different ecological indicators varied during the succession pro-cess, which reflected the relativity and differences among the indicators. This study suggested that, although the species diversity index can be an effective indicator of two types of changes (network structure and system information), it was quite clear that species diversity measurement was not suitable for expressing the changes in biomass during the succession process. While exergy and specific exergy can provide useful information  相似文献   
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