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1.
Studies on island intertidal benthic ecology in Fujian   总被引：1，自引：0，他引：1  
lNreomicrlowIntertidal zone is an important type of wetIand easystem on the earth as it is in the tranai-tion zone between 1and and the and subject to frequent human interferences. Since the inter-tidal sone is subject to a1ternative physical and chemical actions of land and as, the intertidalzone has a compticated and changeable environment. The studies on intertidal zon ecobeyhave always attracted much attention for the past decades (Stephensons, l972; MOrtons,l983: Huang and Zhu, l998; Y…  相似文献   

2.
The reproductive ecology of the mudskipper Boleophthalmus pectinirostris was investigated during the spawning season in the Funing Bay, Fujian, China. The fish burrows were basically Y-shaped and had two openings onto the mudflats. Part of the intersection at the center of the burrow was dilated to form a "spawning chamber". The dissolved oxygen concentrations (0.40~0.65 mg/dm3)of water 15 cm deep inside the burrows were much lower than those (5.96~6.19 mg/dm3) of intertidal pool water. Water temperatures inside the burrows were much lower than those of intertidal pools. Field investigations indicated that eggs were laid on the inner wall and ceiling of the spawning chamber by means of filamentous attachments, and a male stayed inside the burrows to guard it. Field investigations also suggested that fish of both sexes constructed mud burrows by themselves but that the spawning chamber was made only in the male burrow. The male attracted a female to his burrow for mating and spawning. There was no water in the spawning chamber, and thus the eggs were exposed to the air in the chamber. Changes in spawning readiness and gonadosomatic index indicated that synchronization of spawning was related to the semi-lunar periodicity, and this is the first report of this relationship in the mudskippers.  相似文献   

3.
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4.
This study is based on 172 planktonic samples collected by vertical hauls of planktonic net from the bottom to the surface in the Western Taiwan Strait (116°40′～120°30′E, 22°22′. 9～26°43′N) in four seasonal months from May 1984 to February 1985.  相似文献   

5.
The Ebro catchment, the largest river basin in Spain, includes various heavily industrialized areas. Among these is the Flix site, where a chemical plant has been operating since the beginning of the 20th century. This extended operational period, together with the construction of a dam next to the factory around 1960, resulted in the accumulation of large amounts of heavily polluted sediments in the adjacent riverbed, many of which are contaminated by mercury. Pollutants from Flix are carried downstream by the Ebro River to its delta. In order to assess the transfer of mercury to the complex river estuary ecosystem, we studied the ecology of the tern community living there as these birds segregate into a range of habitats. For this purpose, first we used stable isotope analysis (SIA) (δ34S, δ13C, δ15N) of eggs to determine the trophic ecology and habitat partitioning of several tern species (Common, Sandwich, Little, Gull-Billed and Whiskered Tern) breeding sympatrically, in order to link their foraging ecology with habitat types. Next we measured mercury concentrations in eggs to monitor the input of this metal into the diverse habitats. With the exception of the Little Tern, the other terns used a restricted habitat range in the Ebro Delta, as shown by C and S isotopes; the Gull-Billed and Whiskered Tern foraged in freshwater habitats, while the Common and Sandwich Tern used marine habitats. This restricted feeding behavior of the Gull-Billed and Common Tern contrasts with previous reports in other breeding sites. The Little Tern, which showed a wide range of isotopic values, was found to be an opportunistic forager but fed mainly in saltpans, a feeding habitat not reported previously for this species in this area. We found that mercury concentrations are related to foraging habitat and diet, and are unexpectedly higher in species feeding on demersal prey in marine habitats and also higher in birds feeding in saltpans than in those feeding in freshwater habitats. The mercury concentrations found in the Little and Common Tern eggs sampled in “Punta de la Banya” may be sufficiently high to endanger breeding success.  相似文献   

6.
From May to July, 1985, foulers on eleven navigation buoys have been surveyed in Shuidongand Bohe Harbours of Dianbai, Guangdong. Foulers on different parts of buoys (side, bottom and in-side tail tube) were sampled. The thickness and cover area of foulers were measured in the field andall the foulers on an area of 30×30 cm~2 were taken back for lab. identification. Thirty-four quatita-tive samples and several qualitative samples have been got and five hundred and twenty-four sampleshave been classified.  相似文献   

7.
The species distribution and diversity of zooplankton and the effects of hydrodynamic factors of Zhejiang coastal waters during the active period of upwelling are discussed.High dominance (low diversity), high biomass and short food chain were found in the landward margins of the central region of the upwelling. There were evident interactions between the distribution of zooplankton and the environmental factors. The expression of these interactions is that different ecotypes of zooplankton adapt to different hydrological situations. There is significant positive correlation between the diversity indices of zooplankton and the mean water temperature in the survey area. It is noted that the vertical distribution of Calanus sinicus indicates to a certain extent the colder water environment of the upwelling (Fig. 7, Table 2, Reference (Hargreaves, 1981).  相似文献   

8.
The dispersion patterns and feeding behaviour of intertidal whelks were investigated in north‐eastern New Zealand. Aggregations of whelks feeding on clams occurred regularly, with an average of 15–20 individuals per aggregation. Death of clams was attributable to predation in up to 50% of the aggregations, although scavenging of dead and moribund animals was the main activity of whelks. Laboratory and field studies showed that Lepsiella scobina (generally not considered a soft shore species) was the main whelk predator at Lews Bay, Whangateau Harbour, drilling a small neat hole through the clam shell. The distinction between Cominella spp. as predators or scavengers is not so clear. Reseeding of intertidal clams, Austrovenus stutchburyi, has been proposed as a technique for reestablishing populations in some degraded New Zealand estuaries. The impact of whelk predation has many implications for A. stutchburyi reseeding. Both L. scobina and Cominella adspersa may potentially prey on newly reseeded clams as they preferentially attacked small clams in the laboratory. On‐growing to a larger size before reseeding may be advantageous although large size was not found to protect prey from predation. Additionally, no seasonal trend in whelk activity was found.  相似文献   

9.
The studied area is a shallow water area that belongs to the East China Sea continent shelf. The distribution of zooplankton biomass is higher inshore than offshore. The maximum abundance is in the inshore edge of the centre of upwelling, which is the superposed area of the salinity front and temperature front, due to the fact that the mixture of three different waters has brought about a concentration of nutrients. The herbivorous Euphausia, Copepoda and Tunicata are the major groups of the abundant area. Tunicata possess the possibility to compete against other kinds of herbivorous zooplankton. This means that there is negative correlation between the distribution of Tunicata and that of Copepoda and Euphausia. The positions of maximum areas of zooplankton biomass, phytoplankton individual and the concentration of phosphates and chlorophyll-a overlap one another. In the centre of upwelling, zooplankton can not adapt itself to the environment of lower temperature and less oxygen even with rich nutrient  相似文献   

10.
-Morphology, reproduction, ecology and isoenzyme electrophoresis of a Capitella complex in Qingdao were examined from 1983 to 1984. We determined that the Capitella complex in Qingdao was composed of at least three sibling species: Capitella cf capitata, Capitella sp. I and Capitella sp. IT. Although these three species are very similar in morphology, they differ in: three kinds of isoenzyme electrophoresis, staining reactions, developmental pattern, larval morphology and dispersal, reproductive strategies, breeding season and population ecology. In addition, they show a series of minor quantitative variations in adult morphology, especially in number and morphology of setae. Such differences can be detected only at the population level. Some ecological data such as density, growth rate, mortality and sex distribution are also provided in this paper.  相似文献   

11.
The feeding habits of the deep-sea blue–red shrimp Aristeus antennatus were determined based on the analysis of 1047 stomach contents, sampled in the Greek Ionian Sea (E. Mediterranean). The diet of this economically and biologically important decapod was studied in relation to the season, size class and sex. The diet of A. antennatus consisted of 54 different prey categories, and belonged mainly to smaller crustaceans (e.g. natantian decapods, euphausiids, tanaidaceans), molluscs, polychaetes, chaetognaths and, to a lesser extent, fishes. The above prey categories consisted of 71–82% of the relative abundance and total occurrence for males and 61–81% for females. Females seemed to be better fed than males (stomach fullness, food quality). A. antennatus displayed a highly diversified diet and the different feeding patterns were discussed. Diet composition showed slight seasonal fluctuations. The observed slight differences on A. antennatus diet among the western, central and eastern Mediterranean could be attributed to the more oligotrophic character of the eastern part of the basin. The principal factors driving the changes in the feeding strategy of this decapod among the seasons are the increased energy demands related to sexual requirements and the food availability in the marine environment. The ontogenetic changes in the shrimp's diet were relatively clear. Larger individuals exhibited selecting prey with a good swimming capacity (e.g. fishes), while the smaller individuals consumed prey with low mobility (e.g. copepods, ostracods).  相似文献   

12.
Although the importance of the subsurface saturated interstitial zone (hyporheic zone) to the ecological functioning and maintenance of water quality of stream ecosystems is well known, there is little information on the impacts of different forms of land use upon this zone. Hyporheic physico‐chemistry and invertebrates were compared among small streams draining hill‐country catchments under pasture, exotic pine forest, and native forest near Hamilton, New Zealand. In streams draining native forest, the hyporheic zone harboured a relatively diverse invertebrate fauna comprising mostly taxa common in the surface benthos, although a few apparently obligate hyporheic taxa (ostracods, blind amphipods) were collected. Few individuals and taxa occupied the hyporheic zones of streams draining pasture with some groups such as water mites conspicuously absent. The hyporheos of the stream in exotic pine forest was similar in richness and abundance to that of the pasture streams. Hyporheic water temperatures were significantly higher in the pasture streams than those in pine or native forest. There were strong positive correlations between percentage saturation of dissolved oxygen in the hyporheic zones of all streams and both species richness and total invertebrate abundance. We suggest that land clearance for pasture leads to hill slumping and siltation that bury the lateral bars along the stream channels, rendering this habitat unsuitable for hyporheic invertebrates. Channel narrowing and incision may physically remove further hyporheic habitat, and the reduction of flushing flows to remove interstitial silt and clay leads to low hyporheic dissolved oxygen concentrations and reduced colonisation by surface benthos.  相似文献   

13.
Hypotheses regarding temperature, food abundance and food size were tested to explore niche separation between Calanoides carinatus, an abundant copepod in the cool and food-rich southern Benguela upwelling system, and Calanus agulhensis, the dominant copepod on the warmer, relatively food-poor Agulhas Bank off the south coast of South Africa. Under non-limiting food conditions, egg production by both species increased linearly with temperatures between 9°C and 18°C. Egg production by C. carinatus was relatively faster at 21°C, but was offset by greater mortality. Both species showed similar functional responses to food concentration in the field, reaching satiation at ～15mg Chl a m?3, or ～3–4ppm. Food abundance was the most important predictor of egg production, whether measured as Chl a or as particle volume. Both species preferred larger particles that dominated the biomass peak, but particle size appeared more important for C. carinatus, with increasingly faster rates of egg production as the proportion of large cells (>10μm) exceeded 50%, and slower ingestion of small (<10μm) cells. Omnivory may be more important to C. agulhensis. Niche separation between the two species appears unrelated to temperature, food abundance or diel vertical migratory behaviour, and is more likely a function of variability in food availability, although food size may also play a role.  相似文献   

14.
The purpose of this study is to detail the ecological characteristics of phytoplankton in waters around the Daya Bay Nuclear Power Station in Guangdong (GNPS) (Fig. 1) in spring, the bloom period of algae. The collections with a small temporal scale of every three days were made during 30 cruises from March to May in 1987. Such an investigation has never been carried out before in China except that the seasonal distribution and composition of phytoplankton in these regions were reported in  相似文献   

15.
The application of genomic approaches to marine biota has profoundly altered our understanding of life in the oceans, especially regarding concepts of adaptation, speciation and evolution. The avalanche of genomic data has provided an unbiased view of marine biology that has never been seen before. In particular, comparative and metagenomic approaches with microbes from different biogeochemical marine provinces provided the first insights into how they acquire and discard genes as needed, even across kingdom boundaries, in response to their environment. These data clearly reveal that marine microbes have remarkable abilities to change their genomes according to both environmental stresses and biotic interactions. Thus, it is most likely that the flux of energy and matter in the marine system is reflected by the presence or absence of genes and proteins in marine organisms, which could provide novel tools to understand biogeochemical processes of global significance. However, the challenge is to put the reductionistic knowledge gained by genomics and metagenomics into the larger contexts of cellular systems and ecosystems to identify emergent properties that could not have been predicted by breaking down the whole into its individual parts.  相似文献   

16.
The reproduction and feeding habits of giant isopods Bathynomus giganteus [range in body length (BL): 43–363 mm] from the continental slope of the Yucatán Peninsula, México, were studied from samples collected at depths of 359–1050 m during three research cruises conducted in winter, spring, and summer of different years. Samples taken in winter and spring yielded a large proportion of mancas and juveniles, as well as high percentages of adult females with functional oostegites and males with appendices masculinae, suggesting a peak in reproductive activity during these seasons. In contrast, the virtual absence in the summer samples of (a) mancas and small juveniles, (b) females with functional oostegites, and (c) small adult males (210–290 mm BL) with appendices masculinae, suggests a low reproductive activity of B. giganteus during summer. Stomach contents analyses were conducted on five life phases (mancas, small juveniles, large juveniles, adult females and adult males) in winter and summer. Mancas and juveniles had fuller stomachs than adults during winter, and all isopods had emptier stomachs during summer than during winter. The diet of B. giganteus was broad, but the most important food categories in all life phases were fish and squid remains, underlining the main scavenging habits of B. giganteus. However, the remaining food categories show that this species is a facultative rather than a strict scavenger and suggest some ontogenetic dietary shifts. These results were further supported by diet (Horn's) overlap indices. In the winter, high diet overlap occurred between all life phases. In the summer, adult males had a low diet overlap with adult females and large juveniles. Adult males also had a low diet overlap between summer and winter. Results from this and other studies suggest that the main reproductive activity of B. giganteus in the Yucatán slope occurs during winter and spring, when the food supply on the upper-slope is highest, particularly for the younger individuals.  相似文献   

17.
Short‐term effects of deposit feeding on benthic micro‐organisms are known from several marine environments, but longer‐term influences of deposit feeders have not been extensively investigated. The long‐term microbial response to deposit feeding by the gastropod Amphibola crenata was monitored in a 10‐month field study where deposit feeding intensity was controlled in artificial enclosures. The presence of the snail resulted in a minor decrease in bacterial numbers and a slight increase in heterotrophic activity relative to bacterial cell numbers. This effect may have been the long‐term signature of a previously reported pulse in bacterial production during the recolonisation of Amphibola faeces. Normal snail density had a strong inhibitory effect on primary productivity by the benthic microalgae, reducing CO2 fixation to 29–47% of levels that could be attained when snails were excluded. Variations in the effect of deposit feeding on micro‐organisms over the experimental period suggest that it may be modified by seasonal factors acting on benthic communities. In a similar interaction of influences, seasonal changes in microbial biomass and activity appeared to vary with snail density.  相似文献   

18.
The distributional ranges of Cape anchovy Engraulis encrasicolus and Natal anchovy Stolephorus holodon presently overlap at their eastern and western extremes, respectively, off South Africa’s east coast. These species might become more strongly sympatric as a consequence of changed distributions caused by climate change, possibly leading to intensified interspecific competition for trophic and other resources. A comparative analysis of the trophodynamics of the two species, which set out to assess elements of current niche partitioning between them, was conducted through morphological, dietary and stable-isotope analyses of specimens caught off South Africa’s east coast. Cape anchovy have larger gillraker spacing, gain the majority of their dietary carbon from large (>3 000 µm total length) planktonic crustaceans and occupy a higher trophic level than Natal anchovy, which have smaller gillraker spacing and gain the majority of their dietary carbon from planktonic crustaceans of two size classes (900–1 400 µm and 2 800–3 200 µm total length). These results indicate an element of trophic partitioning between the two species that will mitigate against interspecific competition.  相似文献   

19.
The black scabbardfish is a deep water species of high commercial interest in the NE Atlantic. Specimens were collected from commercial trawls to the west of the British Isles and from longliners operating near Madeira between September 2008 and May 2010. Stomach content analysis was confined to samples from the northern area, because of a high number of empty stomachs from Madeira. Stable isotope analyses identified that black scabbardfish feeds on species with epipelagic and benthopelagic affinities. For the west of British Isles, the δN values were significantly different between seasons suggesting a change in the diet throughout the year. Black scabbardfish have higher δN and δC values compared with other co-occurring benthopelagic feeders and lower nitrogen values than the true benthic predators and/or scavengers. Comparison with stable isotope analysis in samples from Madeira indicated that black scabbardfish feed at a similar trophic level and has the same trophic niche width in both areas, assuming similar baseline isotope compositions. The diet in the northern area comprised fish (68% N), crustaceans (22% N) and cephalopods (15% N) with blue whiting (Micromesistius poutassou) constituting 40% of the prey. Seasonal shift in diet was observed, with a predominance of blue whiting (70%) in the first quarter of the year, shifting to a more diverse diet in the remainder of the year. These results indicate that the diet of black scabbardfish is closely linked with the seasonal migration of blue whiting and that they likely select prey in proportion to availability. This study demonstrates that the combined used of both methods can elucidate the trophic ecology of black scabbardfish, in situations where conventional methods alone provide insufficient data.  相似文献   

20.
我国是世界上12个严重缺水国家之一,人均淡水占有量仅是世界人均占有量的四分之一。据有关部门统计,目前,我国668个大中城市中,就有400个缺水,100个严重缺水。华北、东北、西北地区,连年干旱缺雨;南方地区水体污染严重,使水源性缺水成为城市供水的突出问题。淡水资源短缺正严重制约着我国经济的发展。解决我国水资源短缺问题已是全国上下的共识;也是摆在全国人民面前亟待解决的重大课题,当前的问题是加快落实的步伐。  相似文献   

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