首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 46 毫秒
1.
Seasonality in coastal benthic ecosystems   总被引:1,自引:0,他引:1  
For historical reasons, knowledge about seasonality in the dynamics of marine benthic suspension feeders from temperate areas comes mainly from studies of cold temperate seas. Recent surveys of Mediterranean taxa show different patterns from those observed in cold temperate seas, which are characterized by winter dormancy. In the Mediterranean, summer dormancy predominates among taxa and appears to be related to energetic constraints. Temperature and food availability are crucial to the dynamics of benthic suspension feeders. However, because these factors tend to be positively correlated in cold temperate seas, it is difficult to distinguish between their effects. Such correlation does not occur in Mediterranean ecosystems. The contrast between recent studies in the Mediterranean and in other areas can help to disentangle confounded environmental controls.  相似文献   

2.
In the present paper we suggest an effect of seasonal variations in food availability on two ecophysiological parameters in a warm temperate benthic suspension feeder: the tissue concentrations of proteins, carbohydrates and lipids on the one hand, and the expression of stress proteins (HSP 70 and 90, inducible and/or constitutive) on the other hand. The concentrations of biomacromolecules have already been used to describe bentho-pelagic and reproductive processes, but this is the first time that stress protein expression is suggested to be directly related with food constraints in marine organisms. Paramuricea clavata (Cnidaria: Gorgonacea) express HSP 70 and 90 (constitutive and/or inducible) throughout the seasonal cycle, and HSP 70 levels are twice as high as the levels of HSP 90. In summer and autumn, when seston availability to suspension feeders was low, P. clavata showed low levels of carbohydrates and lipids, but high levels of HSPs expression. The levels of HSP 70 and 90 expression fit with negative exponential functions of carbohydrate and lipid concentrations. We suggest a direct effect of food availability on the studied ecophysiological parameters while the effect of temperature may be rather indirect. HSP expression as well as the tissue concentrations of carbohydrate and lipids may be used as biomarkers of environmental changes and seston availability to benthic suspension feeders.  相似文献   

3.
Diatoms in the food of krill caught in the summer in coastal waters close to the South Shetland Islands and in the summer and three winters in Admiralty Bay, King George Island were investigated. The diatoms were used as indicators of sources of krill food. Principal component analysis divided the diatom taxa into two groups, one being pelagic diatoms and from the food of krill in coastal waters, and the other being benthic diatoms and taxa from the food of krill in Admiralty Bay. All pelagic taxa of diatoms were consumed by krill. In the summer in coastal waters, benthic diatoms in krill food originated from the sublittoral. In the summer in Admiralty Bay, besides phytoplankton, diatoms were noted from the sublittoral and littoral in the food of krill. However, in the winter mostly sublittoral and epiphytic diatoms were present in krill food. Accepted: 20 March 2000  相似文献   

4.
Massive outbreaks are increasing all over the world, which are likely related to climate change. The North Adriatic Sea, a sub-basin of the Mediterranean Sea, is a shallow semi-closed sea receiving high nutrients inputs from important rivers. These inputs sustain the highest productive basin of the Mediterranean Sea. Moreover, this area shows a high number of endemisms probably due to the high diversity of environmental conditions and the conspicuous food availability. Here, we documented two massive mortalities (2009 and 2011) and the pattern of recovery of the affected biocoenoses in the next two years. Results show an impressive and fast shift of the benthic assemblage from a biocoenosis mainly composed of slow-growing and long-lived species to a biocoenosis dominated by fast-growing and short-lived species. The sponge Chondrosia reniformis, one of the key species of this assemblage, which had never been involved in previous massive mortality events in the Mediterranean Sea, reduced its coverage by 70%, and only few small specimens survived. All the damaged sponges, together with many associated organisms, were detached by rough-sea conditions, leaving large bare areas on the rocky wall. Almost three years after the disease, the survived specimens of C. reniformis did not increase significantly in size, while the bare areas were colonized by fast-growing species such as stoloniferans, hydrozoans, mussels, algae, serpulids and bryozoans. Cnidarians were more resilient than massive sponges since they quickly recovered in less than one month. In the study area, the last two outbreaks caused a reduction in the filtration efficiency of the local benthic assemblage by over 60%. The analysis of the times series of wave heights and temperature revealed that the conditions in summer 2011 were not so extreme as to justify severe mass mortality, suggesting the occurrence of other factors which triggered the disease. The long-term observations of a benthic assemblage in the NW Adriatic Sea allowed us to monitor its dynamics before, during and after the mortality event. The N Adriatic Sea responds quickly to climatic anomalies and other environmental stresses because of the reduced dimension of the basin. The long-term consequences of frequent mass mortality episodes in this area could promote the shift from biocoenoses dominated by slow-growing and long-lived species to assemblages dominated by plastic and short life cycle species.  相似文献   

5.
In boreal lakes, temperature and photoperiod are important environmental cues affecting reproduction, growth and feeding rates of benthic invertebrates; however, how invertebrates cope with seasonal changes in the availability of their food sources has rarely been addressed. In this study, where temperature and light conditions were controlled, we aimed at assessing whether Hyalella azteca amphipods from the littoral zone of boreal lakes adjust their feeding rates in response to the dynamics of their food sources and their population structure. Using a gravimetric approach, we compared the ingestion and absorption rates of amphipods from a natural population collected periodically during the ice-free season. Amphipods were fed in the laboratory with conditioned leaf detritus. Feeding rates increased regardless of seasonal variations of temperature and photoperiod in the lake. Field data suggest this increase could be linked to seasonal changes in the population structure or in the diet of amphipods. This suggests that H. azteca amphipods adjusted their feeding rates with their energy and nutrient requirements and/or developed a compensatory feeding trade-off to cope with the dynamics of their different food sources in lakes.  相似文献   

6.
SUMMARY. 1. The life history of the benthic harpacticoid paracamptus schmeili (Crustacea: Copepoda) in the oligotrophic lake Pääjärvi, South Finland, was described from quantitative field data of all developmental stages. The generation time of P. schmeili was exceptionally long for a meiobenthic animal and varied with depth from 1 year in the littoral (depths of 1 and 2m) to 2 years in the upper profundal (13 and 14 m). and to 3 years in the lower profundal (40 m).
2. In the littoral, egg-bearing females were found from April to October, with peaks in spring and late summer, while in the profundal a single summer egg peak was present.
3. In the littoral and in the lower profundal there were three, in the upper profundal) probably four, simultaneous parallel cohorts over-wintering as adults, medium-sized (at 13 m also large) copepodids and medium-sized nauplii. Reproductive isolation of the parallel cohorts was possible at all depths.
4. The between-depth variation in the life history of P. schmeili was probably mainly a phenotypic response to the changing level and seasonal course of temperature and food supply. Growth and reproduction were confined to summer months, and the lengthening generation times with depth accompanied decreasing summer temperatures.
5. The cessation of growth in winter was probably due to a shortage of food, which may also have accentuated the size differences of the overwintering groups through intraspecific competition.  相似文献   

7.
We investigated how establishment of invasive dreissenid mussels impacted the structure and energy sources of the littoral benthic food web of a large temperate lake. We combined information about pre- and postdreissenid abundance, biomass, and secondary production of the littoral benthos with results of carbon and nitrogen stable isotope analysis of archival (predreissenid) and recent (postdreissenid) samples of all common benthic taxa. This approach enabled us to determine the importance of benthic and sestonic carbon to the littoral food web before, and more than a decade after dreissenid establishment. Long term dreissenid presence was associated with a 32-fold increase in abundance, 6-fold increase in biomass, and 14-fold increase in secondary production of the littoral benthos. Dreissenids comprised a large portion of the post-invasion benthos, making up 13, 38, and 56% of total abundance, biomass, and secondary production, respectively. The predreissenid food web was supported primarily by benthic primary production, while sestonic material was relatively more important to the postdreissenid food web. The absolute importance of both sestonic material and benthic primary production to the littoral benthos increased considerably following dreissenid establishment. Our results show drastic alterations to food web structure and suggest that dreissenid mussels redirect energy and material from the water column to the littoral benthos both through biodeposition of sestonic material as well as stimulation of benthic primary production.  相似文献   

8.
Hans-U. Dahms 《Hydrobiologia》1995,306(3):199-211
Dormancy affects copepods in their anatomy, physiology, genetics, population biology, community ecology, evolution and local and geographic distribution. It is known from freeliving representatives of three copepod taxa, namely the Harpacticoida, Cyclopoida and Calanoida. Species showing dormancy occur in various realms and habitats, both freshwater and marine, being benthic, planktic or ice-dwelling. Depending on the taxon, dormancy occurs at various times of the year, prevailing in higher and temperate latitudes. Copepod dormancy is expressed in various ontogenetic stages, such as resting eggs, arrested larval development, juvenile and adult encystment, or arrested development of nonencysted copepodids or adults. Ecologically, dormancy is an energy saving trait, allowing the individual to bridge periods of environmental harshness. Adverse environmental conditions could be abiotic (e.g. desiccation, temperature, oxygen availability) or biotic in nature (e.g. food availability, predation). Diapause s. str. is initiated, maintained and terminated by triggering factors (e.g. photoperiod, temperature, chemical cues, population density/physiological factors). The dormant state and emergence patterns directly affect reproduction, population dynamics, community composition, coexistence and distribution of copepods, as well as the phenology of their predators and living food items. Populations having dormancy, in most cases belong to and affect communities of two realms: the water column and the bottom. Dormant stages may provide means for dispersal as well as for staying in special localities. The variability of dormancy permits flexible and complex life histories. Dormancy is subjected to and on the other hand affects copepod evolution.  相似文献   

9.
Summer phytoplankton blooms on the West Antarctic Peninsula (WAP) shelf result in episodic deposition of labile food material for benthic detritivores. This summer deposition is thought to enhance benthic recruitment of macro- and megafauna. To explore seasonality in benthic recruitment, juvenile invertebrates (>100 μm) were collected in a seasonal time series at three stations on the WAP continental shelf. 4,098 juveniles were collected (average densities 2,000–7,000 m−2), with polychaetes dominant (2,581 individuals). The majority of polychaetes showed evidence of enhanced recruitment prior to the summer bloom, although patterns varied across stations. Additional taxa showed recruitment peaks in summer, but again, patterns varied among stations. Based on observed patterns, polychaete taxa are classified as “seasonal”, “marginally seasonal”, and “non-seasonal” recruiters, with the latter two patterns predominating. The year-round presence of small juveniles in most taxa suggests that recruitment occurs continuously, with periodic enhancement. Year-round recruitment is consistent with the presence of a persistent “food bank” of labile organic material in WAP shelf sediments, allowing recruitment to be largely decoupled from seasonal bloom dynamics.  相似文献   

10.
The Arctic system is one of the regions most influenced by ongoing global climate change, but there are still critical gaps in our knowledge regarding a substantial number of biological processes. This is especially true for processes taking place during the Arctic winter but also for seasonal processes, such as the dynamics of intra-annual meroplankton occurrence. Here, we report on a 1-year study of meroplankton seasonal variability from a fjordic system in the Arctic Archipelago of Svalbard. The study combines an examination of phytoplankton, zooplankton, and hard bottom benthic settlement with measurements of environmental parameters (e.g., water temperature, particulate organic matter, and dissolved organic carbon). Samples were taken on a bi-weekly or monthly basis, and a total of 11 taxa representing six phyla of meroplankton were recorded over a 1-year period from January to December 2007. The occurrence of benthic larvae varied between the seasons, reaching a maximum in both abundance and taxon richness in late spring through early summer. Meroplanktonic larvae were absent in winter. However, settlement of benthic organisms was also recorded during the winter months (February and March), which indicates individual trade-offs related to timing of reproduction and competition. In addition, it suggests that these larvae are not relying on higher summer nutrient concentrations, but instead are dependent on alternative food sources. In parallel with meroplankton abundance, all other measured parameters, both biological (e.g., phyto- and zooplankton abundance and diversity) and physical (e.g., particulate organic matter), exhibited seasonal variability with peaks in the warmer months of the year.  相似文献   

11.
We document invertebrate benthic and drift dynamics in a regulated river in central Spain at two temporal scales: seasonal (for both benthos and drift) and daily (for drift). The benthic abundance of individuals and taxon richness generally increased in the summer. Drift abundance showed no seasonal or daily variation, but taxon richness of drifting individuals was higher in the spring. Both ben‐thos and drift showed clear seasonal changes in taxonomic composition. Interestingly, some benthic taxa showed their highest abundances in the spring, while others were more abundant in the summer. In contrast, most drifting taxa were more abundant in the spring. Different functional feeding groups showed different patterns of variation throughout the year, both in the benthos and the drift. Daily variations in drift were present in very few taxa and functional feeding groups, and only in some seasons. (© 2005 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)  相似文献   

12.
1. The assemblage of suspension‐feeding microcrustaceans in lakes changes along a habitat gradient from nearshore to offshore. This gradient of microcrustaceans was explored in relation to differences in macrophytes and the associated changes in water chemistry, food resources and types of predators.
2. Some microcrustacean species were littoral or limnetic specialists, while others changed their distribution along this horizontal habitat gradient on a diel or seasonal basis. Distribution patterns were similar in a lake and a pond which differed in extent of macrophyte habitat.
3. There was a large shift in the composition of sestonic food, indicating heterotrophic seston nearshore and more autotrophic seston offshore. Sit‐and‐wait predators of microcrustaceans (e.g. Enallagma spp.) dominated nearshore and cruising predators (e.g. Leptodora kindtii Focke) were more common offshore.
4. A reciprocal transplant experiment revealed that littoral specialists could survive equally well when fed littoral or limnetic seston, while limnetic specialists performed poorly when fed littoral seston. Food resources may be important in determining where some microcrustacean species live along this horizontal habitat gradient.  相似文献   

13.
《Marine Micropaleontology》2010,74(3-4):207-225
The distribution of recent shallow-water benthic foraminifera in surface sediment samples from cool-water carbonate environments of the Oran Bight, Alboran Platform and Mallorca Shelf in the Western Mediterranean Sea was studied. Multivariate statistical analyses resulted in the identification of species assemblages, representing different environmental settings. In all three regions the assemblages show a distinct bathymetric zonation that is mainly attributed to the distribution of rhodoliths and related substrates, but also to water turbulence and the availability of food at the sea floor. The live assemblages (Rose Bengal stained individuals) are characterised by rather low diversity and low standing stocks, likely reflecting seasonal population dynamics. In the Oran Bight, elevated standing stocks of “high food”-taxa suggest the impact of anthropogenic eutrophication on the near-coastal benthic ecosystems of this area. The diversity of the dead assemblages is higher than in siliclastic shelf ecosystems of the Mediterranean Sea but lower when compared to carbonate environments of the Levantine Sea. This regional difference is mainly attributed to lower sea surface temperatures and the lack of Lessepsian invaders in the western Mediterranean Sea. In all study areas, a distinct faunal change occurs between approximately 80–90 m water depth. This change coincides with the lower distribution limit of living rhodoliths at the shelf of Mallorca, providing coarse-grained substrates that are dominated by attached taxa. Below this depth interval, the fauna shows regional differences depending on the grain-size and related accumulation of organic material. Fine-grained substrates with infaunal niches are restricted to low-energy environments on the deeper shelf southwest off Mallorca.  相似文献   

14.
Nutrient stoichiometric ratios are primary driving factors of planktonic food web dynamics. Ecological stoichiometry theory postulates the elemental ratios of consumer species to be homeostatic, while primary-producer stoichiometry may vary with ambient nutrient availability. The notion of phytoplankton intracellular storage is far from novel, but remains largely unexplored in modeling studies of population dynamics. We constructed a seasonally-unforced, zero-dimensional, nutrient–phytoplankton–zooplankton–detritus (NPZD) model that considers dynamic phytoplankton phosphorus reserves and quasi-dynamic zooplankton stoichiometry. A generic food quality term is used to express seston biochemical composition, ingestibility, and digestibility. We examined the sensitivity of the planktonic food web patterns to light and nutrient availability, zooplankton mortality, and detritus food quality as well as to phytoplankton intracellular storage and zooplankton stoichiometry. Our results reinforce earlier findings that high quality seston exerts a stabilizing effect on food web dynamics. However, we also found that the combination of low algal and high detritus food quality with high zooplankton mortality yielded limit cycles and multiple steady states, suggesting that the heterogeneity characterizing seston nutritional quality may have more complicated ecological ramifications. Our numerical experiments identify resource competition strategies related to nutrient transport rates and internal nutrient quotas that may be beneficial for phytoplankton to persevere in resource-limiting habitats. We also highlight the importance of the interplay between optimal stoichiometry and the factors controlling homeostatic rigidity in zooplankton. In particular, our predictions show that the predominance of phosphorus-rich and tightly-homeostatic herbivores in nutrient-enriched environments with low seston food quality can potentially result in high phytoplankton abundance, high phytoplankton-to-zooplankton ratios, and acceleration of oscillatory dynamics. Generally, our modeling study emphasizes the impact of both intracellular/somatic storage and food quality on prey–predator interactions, pinpointing an important aspect of food web dynamics usually neglected by the contemporary modeling studies.  相似文献   

15.
Food quality of the natural food (seston) from Lake Monte Alegre was evaluated throughout a series of life-table experiments with cladocerans from the same lake carried out in summer and autumn. Experiments were performed using cohorts of newborns originated from ovigerous females cultured for several generations in the lab or taken directly from the lake. For these tests of food limitation, juveniles of different species were submitted to one of the following treatments: (1) lake seston and (2) lake seston + green algae. The age at first reproduction, mean clutch size, total offspring and the intrinsic rate of natural increase (r) were estimated. Cladocerans responded to both seasonal changes in food resources and to additions of green algae. In summer, food levels were higher and cladocerans grew better than in autumn. The low fecundity and population growth rates of Daphnia gessneri, together with high C:P ratios (>500) in the seston in summer, suggested P limitation. The other cladocerans (Moina micrura, Ceriodaphnia cornuta and Simocephalus mixtus) were apparently less sensitive than D. gessneri to P-limitation in summer. However, energy limitation cannot be disregarded even in summer, although in a lower degree compared to autumn. In this season, the predominance of large diatoms and dinophyceans of low nutritional value and the low food concentration suggested both quantitative and qualitative food limitation. Phytoplankton composition, nutritional value and particle size appeared to be important factors in determining cladocerans reproduction rates with seston diets.  相似文献   

16.
1. Subarctic ponds are seasonal aquatic habitats subject to short summers but often have surprisingly numerous planktonic consumers relative to phytoplankton productivity. Because subarctic ponds have low pelagic productivity but a high biomass of benthic algae, we hypothesised that benthic mats provide a complementary and important food source for the zooplankton. To test this, we used a combination of fatty acid and stable isotope analyses to evaluate the nutritional content of benthic and pelagic food and their contributions to the diets of crustacean zooplankton in 10 Finnish subarctic ponds. 2. Benthic mats and seston differed significantly in total lipids, with seston (62.5 μg mg?1) having approximately eight times higher total lipid concentrations than benthic mats (7.0 μg mg?1). Moreover, the two potential food sources differed in their lipid quality, with benthic organic matter completely lacking some nutritionally important polyunsaturated fatty acids (PUFA), most notably docosahexaenoic acid and arachidonic acid. 3. Zooplankton had higher PUFA concentrations (27–67 μg mg?1) than either of the food sources (mean benthic mats: 1.2 μg mg?1; mean seston: 9.9 μg mg?1), indicating that zooplankton metabolically regulate their accumulation of PUFA. In addition, when each pond was evaluated independently, the zooplankton was consistently more 13C‐depleted (δ13C ?20 to ?33‰) than seston (?23 to ?29‰) or benthic (?15 to ?27‰) food sources. In three ponds, a subset of the zooplankton (Eudiaptomus graciloides, Bosmina sp., Daphnia sp. and Branchinecta paludosa) showed evidence of feeding on both benthic and planktonic resources, whereas in most (seven out of 10) ponds the zooplankton appeared to feed primarily on plankton. 4. Our results indicate that pelagic primary production was consistently the principal food resource of most metazoans. While benthic mats were highly productive, they did not appear to be a major food source for zooplankton. The pond zooplankton, faced by strong seasonal food limitation, acquires particular dietary elements selectively.  相似文献   

17.
1. Generalist fish species are recognised as important couplers of benthic and pelagic food‐web compartments in lakes. However, interspecific niche segregation and individual specialisation may limit the potential for generalistic feeding behaviour. 2. We studied summer habitat use, stomach contents and stable isotopic compositions of the generalist feeder Arctic charr coexisting with its common resource competitor brown trout in five subarctic lakes in northern Norway to reveal population‐level and individual‐level niche plasticity. 3. Charr and trout showed partial niche segregation in all five lakes. Charr used all habitat types and a wide variety of invertebrate prey including zooplankton, whereas trout fed mainly on insects in the littoral zone. Hence, charr showed a higher potential to promote habitat and food‐web coupling compared to littoral‐dwelling trout. 4. The level of niche segregation between charr and trout and between pelagic‐caught and littoral‐caught charr depended on the prevailing patterns of interspecific and intraspecific resource competition. The two fish species had partially overlapping trophic niches in one lake where charr numerically dominated the fish community, whereas the most segregated niches occurred in lakes where trout were more abundant. 5. In general, pelagic‐caught charr had substantially narrower dietary and isotopic niches and relied less on littoral carbon sources compared to littoral‐caught conspecifics that included generalist as well as specialised benthivorous and planktivorous individuals. Despite the partially specialised planktivorous niche and thus reduced potential of pelagic‐dwelling charr to promote benthic–pelagic coupling, the isotopic compositions of both charr subpopulations suggested a significant reliance on both littoral and pelagic carbon sources in all five study lakes. 6. Our study demonstrates that both interspecific niche segregation between and individual trophic specialisation within generalist fish species can constrain food‐web coupling and alter energy mobilisation to top consumers in subarctic lakes. Nevertheless, pelagic and littoral habitats and food‐web compartments may still be highly integrated due to the potentially plastic foraging behaviour of top consumers.  相似文献   

18.
Among the few existing works on seasonal variation in metabolic rate of polar species, most have been conducted during summer due to logistic constraints and have been focused on species that cease feeding during winter. In this work, we present the first extensive data set on the seasonal variation in metabolic rate of G. antarctica, an abundant amphipod that feeds throughout the year, and its relationship with body size, potential food availability and temperature. We measured the resting metabolic rate (RMR) of groups of individuals during 6 months from late summer through winter at 4 experimental temperatures and for a wide range of body size. RMR had a negative allometric scaling with body size and showed a tendency to increase with temperature as expected. However, temperature and body size effects on RMR showed a significant temporal variation, and an increase in temperature decreased scaling exponents. RMR at the mean seawater temperature throughout the study showed a strong seasonal variation following food availability: RMR decreased from the end of summer through winter, coinciding with a reduction in microphytobenthos stock, but recovered summer values in August, when an epontic algae boom occurred. The seasonal factorial aerobic scope (×2.37) is lower than benthic Antarctic invertebrates that cease feeding during winter, in agreement with what is expected based on theoretical grounds. Results suggest that seasonal variation of RMR would allow G. antarctica to achieve a high efficiency in energy utilization, while maintaining the ability to exploit sudden changes in food supply.  相似文献   

19.
1. Research has often focused on the pelagic areas of lakes; the littoral zone has received less attention. The few studies concerning fish distribution in littoral habitats have concentrated on stands of submersed macrophytes, whereas other littoral habitat types have seldom been investigated. 2. This study aimed to predict the occurrence of juvenile fish in several littoral habitats of a shallow lake as a function of food availability, complexity of habitat structure, water depth and substrate. Habitats comprising reed, woody structures, and two open water areas differing in depth were sampled for fish and invertebrate biomasses on two shores, over 6 months and during both daylight and at night. 3. The juvenile fish community consisted almost exclusively of 0+ and 1+ roach and perch. There was a strong diel component in habitat use, with a predominant occurrence of fish in complex habitats (mainly woody structures) during the day, and a partial migration towards the open habitats at night, more strongly expressed in roach than in perch. 4. The diet of all fish groups was relatively constant over the seasonal cycle, and was independent of habitat. There was a higher degree of planktivory in roach than in perch, but both species fed on benthic macroinvertebrates to a substantial extent. 5. According to a logistic regression model, the biomass of potential food organisms in the different habitats had little predictive effect on the spatial distribution of the fish, whereas the structural complexity of the habitats combined with the diel cycle explained about 28% of the occurrence patterns in 0+ and 1+ perch and 1+ roach.  相似文献   

20.
Mass mortality events of benthic invertebrates in the temperate north‐western (NW) Mediterranean Sea have been observed in recent seasons. A 16 month in situ study in the Ligurian Sea (NW Mediterranean Sea) demonstrated that the occurrence of Paramuricea clavata mortality episodes were concomitant to a condition of prolonged high sea surface temperatures, low chlorophyll concentrations and the presence of culturable Vibrio spp. in seawater. The occurrence of Vibrio spp. at the seasonal scale was correlated with temperature; with few vibrios retrieved on specific media when the temperature dropped below 18°C and a sharp increase of vibrios abundance (up to 3.4 × 104 MPN l?1) when the temperature was greater than or equal to 22°C. Phylogenetic and phenotypic analysis of Vibrio isolates associated with healthy and diseased P. clavata colonies collected during a mortality episode showed that these bacteria were significantly more abundant in diseased than in healthy corals and were related to the V. harveyi, V. splendidus and V. coralliilyticus groups, the latter only identified in diseased organisms. Inoculation of bacterial isolates from these groups onto healthy P. clavata in aquaria caused disease signs and death in a range of Vibrio concentrations, temperature values and trophic conditions consistent with those recorded in the field. It is concluded that Vibrio infections may act as an additional triggering mechanism of mass mortality events in the coastal Mediterranean Sea and that their occurrence is climate‐linked. Predicted global warming leading to long‐lasting hot summer periods together with stratification resulting in energetic constraints represent a major threat to the survival of benthic invertebrates in the temperate NW Mediterranean Sea due to potential disease outbreak associated with Vibrio pathogens.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号