The marine macrobenthic communities of Wallis and Smiths Lakes,New South Wales

The shallow macrobenthic communities of Wallis and Smiths Lakes on the central N.S. W. coast have been studied by replicate grab samples. Wallis Lake is a coastal marine lagoon constantly open to the sea, whereas Smiths Lake, also a coastal lagoon, is periodically closed to the sea for several months at a time. The benthic communities were described using indices of dominance and diversity. Between site communities were compared using MULTBET and a GOWER ordination. Generally, sites in Wallis Lake had a more diverse fauna than those in Smiths Lake. Weed beds supported more species and individuals than sandy substrates. The benthic fauna of these two lakes is compared with other coastal rivers and lagoons which have been studied in temperate eastern Australia.     

The barnacles (Cirripedia: Thoracica) collected by the Viking expedition in chemobiotic benthic communities of the Norwegian and Barents Seas

The barnacles (Cirripedia Thoracica) collected by the Viking expedition in chemobiotic benthic communities of Arctic Ocean-Nyegga area in Norwegian Sea and Håkon Mosby Mud Volcano area in the Barents Sea are investigated. The species (Weltnerium nymphocola in Håkon Mosby Mud Volcano area and Hamatoscalpellum hamatum in Nyegga area) that were found are common inhabitants of the Barents and Norwegian sea benthic communities. The absence of obligatory barnacle fauna that was revealed in investigated chemobiotic benthic communities of the Arctic Ocean shows they are similar to corresponding communities of the Atlantic Ocean, while the specific obligatory barnacle fauna is noted for chemobiotic benthic communities of the Pacific and Indian oceans.     

IDENTIFYING DIURNAL FORAGING HABITAT OF ENDANGERED HAWAIIAN MONK SEALS USING A SEAL-MOUNTED VIDEO CAMERA

The Hawaiian monk seal ( Monachus schauinslandi ) is thought to be a foraging generalist, preying on numerous species in diverse habitats of the subtropical Northwestern Hawaiian Islands. At the atoll of French Frigate Shoals, recent evidence of emaciation and low survival in monk seals prompted a search for their specific prey communities and foraging habitat.
A video camera (National Geographic Television's CRITTERCAM) fitted to 24 adult male seals documented benthic and demersal foraging on the deep slopes (50-80 m) of the atoll and neighboring banks. The number of bottom searches for prey was compared by year, time of day, type of bottom, individual seal, and length of bottom time. Analysis of variance identified a significant interaction of seal and bottom type, explaining 65% of the total variance. Seals fed on communities of cryptic fauna (fish and large invertebrates) in transitional "ecotone" regions of low relief where consolidated substrate, rubble, and talus bordered areas of sand. Independent areal surveys of bottom types throughout the atoll and neighboring banks suggest that the type of bottom selected as foraging habitat represents a relatively small percentage of the total benthic area available.     

Drifting algal mats as an alternative habitat for benthic invertebrates: Species specific responses to a transient resource

Patchy occurrences of benthic drift algae (i.e. loose lying macroalgal mats) may increase habitat complexity on normally bare soft bottoms, but at the same time, extensive amounts of drifting algal mats are known to stress the benthic fauna. This paper presents results of the first detailed study of the fauna associated with drift algal mats in the northern Baltic Sea. In order to assess the importance of drifting algae as an alternative habitat for benthic fauna, benthic drift algal mats were sampled on shallow (2-9 m) sandy soft bottoms in the outer archipelago of the ?land Islands (Finland). Species composition, abundance and biomass of the macrofauna associated with algal mats were recorded. The results show that drifting algae at times can harbour very high abundances of invertebrates (up to 1116 individuals/g algal dryweight), surpassing invertebrate densities recorded in seagrass communities. The algal fauna varied between sites and over time, and factors such as ambient benthic fauna, exposure to wind-wave disturbance, depth, and algal coverage and condition influenced the invertebrate community composition of the algal mats. Abundance increased while individual biomass of the animals decreased over time (summer season; July-October). A series of laboratory experiments were conducted in order to test the ability of a few important benthic species to move up into, and survive in a drifting algal mat. Macoma balthica, Hydrobia spp., Nereis diversicolor and Bathyporeia pilosa were used in the experiments, and significant differences in their survival and mobility within drifting algae were recorded. This study shows that benthic species differ significantly in their ability to utilise the algal mats, with mainly opportunistic and mobile taxa such as Hydrobia spp., Chironomidae and Ostracoda benefiting from the algae, whereas infaunal species such as M. balthica and B. pilosa are negatively affected. The occurrence of eutrophication induced drifting macroalgal mats has increased significantly during the last decade in the northern Baltic Sea. Hence, the importance of drifting algae as a stress factor and as an alternative habitat for benthic fauna increases.     

红树林植被对大型底栖动物群落的影响

大型底栖动物是红树林生态系统的重要组成部分,从红树林大型底栖动物种类、红树林与其周边生境大型底栖动物群落的比较,以及生境变化对动物群落的影响等方面阐述了红树林植被与大型底栖动物群落的关系.从物种数量上看,软体动物和甲壳类动物构成了红树林大型底栖动物的主要部分.影响大型底栖动物分布的环境因素包括海水盐度、潮位和土壤特性等,但在小范围区域,林内动物的分布更多地与红树林植被特性和潮位有关.因此,由于红树林植被破坏或者恢复引起的生境变化,将导致大型底栖动物群落和常见物种种群的变化,尤其对底上动物影响明显;随着人工恢复红树林的发育,林内底栖动物的多样性相应增加,优势种也发生变化.相比位于相同潮位的无植被滩涂,红树林可促进潮间带生物多样性.     

Macrozoobenthic Communities of the Piedmont and Lowland Watercourses of the Lower Amur Region

On the basis of 120 original stations, macrozoobenthic communities of rivers from two adjacent areas of the Lower Amur Region (Khabarovsk krai) have been described. Rivers basins are characterized by contrasting landscape conditions: the Anyuy River basin in the piedmonts of the Sikhote-Alin mountain range and the Simmi River basin on the Amur Lowland. About 250 taxa of macroinvertebrates have been found; 16 types of communities have been described. The principal differences in both benthic fauna and macrozoobenthic communities in the basins of the Anyuy River (cold-water rheophilic fauna as well as ritral and crenal communities predominate) and the Simmi River (warm-water limnophilic fauna and phytal communities predominate) are shown. We discuss the reasons for these differences, specific features of the fauna and communities of the whole region, and the biogeographical position of the region.     

Benthic community response (primarily Chironomidae) to nutrient enrichment and alkalinization in shallow,soft water humic lakes

A comparison of the benthic fauna found in two shallow lakes in the New Jersey Pinelands (USA) illustrated the impact of elevated pH and nutrients caused by residential and agricultural disturbance on a naturally acidic, poorly buffered aquatic environment. Detailed community analysis suggested that change in community composition was a better indicator of response to disturbance than biological diversity indices. Chironomidae (insecta) were the predominant components of the benthic macroinvertebrate assemblage of both undisturbed Oswego Lake (low pH, low nutrients) and Nescochague Lake (fluctuating pH, elevated nutrients). The genera Procladius, Tribelos, and Pagastiella dominated Oswego Lake, where as Zalutschia zalutschicola, Procladius, Dicrotendipes, and Tanytarsus dominated Nescochague Lake. Glyptotendipes was a common and unique member of the Nescochague Lake assemblage. Cluster analysis indicated that the chemical differences between lakes were the most important community determinants, although, within each lake, depth and substrate affected the local communities. Oswego Lake exhibited a depauperate nonchironomid benthic fauna typical of low nutrient, acid lakes. In turn, Nescochague Lake exhibited an enriched nonchironomid fauna including mollusks and planaria which were not found in Oswego Lake.     

不同类型底栖动物对表面流人工湿地系统水质净化的影响

研究以表面流人工湿地为研究对象,探讨不同类型底栖动物在夏季和冬季对人工湿地系统氮磷去除效果的影响,并通过人工湿地系统运行前后不同介质氮磷含量变化及不同介质微生物丰度变化进行水质净化机理分析。结果表明,夏季添加河蚌和添加田螺均能增强人工湿地系统NO3-N和TN去除效果,其中添加河蚌使得系统NO3-N和TN平均去除率较对照组分别提升37.19%和24.32%,添加田螺使得系统NO3-N和TN平均去除率较对照组分别提升22.98%和12.46%。冬季添加摇蚊幼虫使得表面流人工湿地NO3-N、TN和TP平均去除率分别在37.8%、54.0%和94.8%,与对照组相比分别增加了29.51%、15.16%和37.62%,添加河蚌和田螺受底栖动物半冬眠活动和代谢降低影响没有显著水质提升效果。这表明通过添加底栖动物可以增强表面流人工湿地运行效果,选取适合的底栖动物种类组合可能在全年提升人工湿地水质净化效果。机理研究结果表明,底栖动物通过增强底泥和基质中微生物硝化反硝化作用、植物氮吸收和基质氮吸附等促进人工湿地氮去除,通过增强下层基质磷吸附沉淀和植物磷吸收提升水质磷去除。研究结果将为底栖动物在人工湿地的...     

Numerical Abundance and Biomass of Bacteria,Algae and Macrobenthos of a Large Northern River,the Athabasca

The benthic flora and fauna of a large, turbid, northern river was sampled in autumn. Macroinvertebrate communities on bedrock resembled those of smaller streams but specialized Chironomidae larvae dominated sandy substrates. Bacterial densities on rocks were within the ranges reported from smaller streams. Benthic primary production is probably limited by high turbidity so that most of the energy available to benthic communites is probably allochthonous in origin.     

Impacts of introduced brown and rainbow trout on benthic invertebrate communities in shallow New Zealand lakes

1. Brown and rainbow trout have been introduced to many inland waters in New Zealand, but research on the impacts on native communities has focused mainly on streams. The purpose of this study was to compare the benthic communities of trout and troutless lakes. Based on previous studies in North America and Europe, we predicted that the benthic biomass, and especially the abundance of large invertebrates, would be lower in lakes with trout as compared to those without. We surveyed the invertebrate fauna of 43 shallow, high‐elevation lakes (26 with and 17 without trout) in four geographic clusters on the central South Island and then conducted a detailed quantitative study of invertebrate biomass and community structure in 12 of these lakes. 2. Benthic community composition and diversity of lakes with and without trout were nearly identical and biomass was as high or higher in the lakes with as without trout. There was no evidence that trout have caused local extinctions of benthic invertebrates. Although the proportional abundance of large‐bodied aquatic was slightly lower in lakes with than without trout, the abundance of several groups of large‐bodied benthic taxa (dragonflies, caddisflies and water bugs) did not differ. 3. Our findings are in contrast to those in North American and Europe where trout introductions into previously troutless lakes have led to declines in the abundance of benthic invertebrates, especially large‐bodied taxa. We propose that the modest effects of trout in New Zealand could be explained by (i) the high areal extent of submergent vegetation that acts as a benthic refuge, (ii) low intensity of trout predation on benthic communities and/or (iii) characteristics of the benthic invertebrates that make them relatively invulnerable to fish predation. 4. Regardless of the relative importance of these hypotheses, our results emphasise that the same invertebrates occurred in all of the lakes, regardless of size, elevation and presence of trout, suggesting habitat generalists dominate the benthic fauna in shallow New Zealand lakes.     

The barbs (Barbus spp.) of Lake Tana: a forgotten species flock?

Synopsis All living species occupy an ecological niche, and are positioned within a trophic hierarchy. Extinct organisms presumably held similar behavioral and coevolutionary characteristics in the past, and were susceptible to the same kinds of natural ecological pressures operating today. Paleoecological investigations are limited by the incompleteness of the fossil record, and particularly by a lack of behavioral data that are so fundamental to ecological studies of living communities and habitats. Opportunities to examine the coevolutionary structure of ancient communities from empirical data are extremely rare. One such opportunity is provided by the Lower Cretaceous Santana Formation of north-eastern Brazil, a series of richly fossiliferous strata approximately 110 million years old. Many fossil fishes from the Santana Formation contain identifiable prey, including decapod crustaceans and fishes. A trophic hierarchy of these organisms is reconstructed here, and their ecological relationships are discussed. Comparison is made with a similar fish fauna from the Upper Jurassic Solnhofen Limestone of Germany. Low-level, intermediate and high-level predators are identified in each fauna. Predator-prey relationships in the Santana fauna are strongly hierarchical, and are more focussed at the intermediate predator level than in Solnhofen. Comparison with a model of predator-prey relationships between fishes and benthic fauna of the Baltic Sea (which like the Araripe Basin represents a semi-enclosed environment) suggests that heavy predation on teleosts such asRhacolepis, occupying an intermediate trophic level, may have permitted benthic decapods to proliferate and exclude other benthic organisms. Less intense predation on fishes at the intermediate trophic level would allow their numbers to increase, thereby increasing the intensity of predation on the benthos at the base of the trophic hierarchy.     

The role of chironomid larvae in the structure of river benthic communities of the upper and middle Kama River basins

The paper represents results of long-term studies of riverine benthic fauna of Upper and Middle Kama River basins, a region with highly heterogeneous hydrologic conditions. The role of chironomid larvae in rheophilic benthic communities is assessed. Quantitative parameters of typical chironomid complexes are provided.     

Spatial distribution of zoobenthos in the watercourses of the Biya River basin (Altai)

The composition and spatial distribution of macrozoobenthos were studied in 26 watercourses of the Biya River basin from 1997 to 2004. The bottom fauna of the basin’s rivers includes 382 species, 217 genera, 81 families, 21 orders, 11 classes, and 7 types of invertebrates. Species common in the northern and eastern Palearctic prevail, presumably evidencing the oriental origin of the rheophylic benthic fauna. Four basic and two intermediate types of benthic communities were revealed. These communities differ in the structures of the complexes dominant by biomass. The successive substitution of the communities from the upper reaches of Lake Teletskoye tributaries to the Biya mouth depends on factors related to the basin’s relief and corresponds to changes in the landscape and hydrological conditions. This substitution generally conforms to the concept of river continuum.     

Distribution of the macrobenthos fauna in the Ola River basin,northern coast of the Sea of Okhotsk

The taxonomic composition of the macrobenthos fauna and its distribution in the main stream and tributaries of the mid-size salmon Ola River, the northern coast of the Sea of Okhotsk, were investigated for the first time. In the Ola River basin, 253 taxa of benthic invertebrates belonging to 3 phyla (Plathelminthes, Annelida, and Arthropoda) and 5 classes (Turbellaria, Clitellata, Crustacea, Arachnida, and Insecta) were revealed. Mayflies (Ephemeroptera), stoneflies (Plecoptera), caddisflies (Trichoptera), and midges (Chironomidae, Diptera) showed the highest species richness and dominated the benthic communities. Chironomidae comprised most of the fauna: 140 species and species groups, or more than 55% of the total diversity. The shares of identified species of mayflies, stoneflies, and caddisflies were subequal. Analysis of hydromorphological characteristics and the composition of aquatic insect families showed that all the areas surveyed in the Ola River basin were rhithral while the macrobenthos fauna represented there belonged to rhithron. The classification obtained by cluster analysis showed spatial heterogeneity in the distribution of the benthic fauna along the Ola River, related to changes in water temperature, slope, and altitude. The heterogeneous fauna distribution and the corresponding change in stable hydromorphological features indicated the existence of the typical epi-, meta-, and hyporhithral subzones whose boundaries were difficult to distinguish. However, the rhithral subzones selected were characterized by the habitat selectivity of certain taxa and by peculiar species richness values, thus emphasizing their individuality.     

Substrate specificity,environmental degradation and disturbance structuring macroinvertebrate assemblages in neotropical streams

Structure and composition of benthic macroinvertebrate assemblages were investigated in seven sampling sites with a gradient of environmental integrity and water quality conditions. Composite samples of the four most representative substrates were collected in order to characterize the riffle-pool dynamic in each sampling site. Spatial and temporal variability of macroinvertebrate assemblages were analyzed at two scales: using substrates and grouping samples for comparing sampling sites. Distribution of macroinvertebrates was influenced primarily by substrate type, but also by environmental integrity, water quality and sampling period. Species occurrence was highly dependent on substrate type. At local spatial scale, environmental degradation measured by the Riparian Channel Environmental Inventory and water chemistry were the determinants of assemblage patterns. We evaluated to which extent the substrates were influenced by environmental integrity and water chemistry, and we found that degradation influenced significantly the macroinvertebrate fauna on the four substrate types, although they were not responding to the same variables. Our results show that qualitatively communities were not influenced by seasonal changes, but abundance was stochastically dependent on rainfall.     

The inshore marine ecosystem off the Vestfold Hills,Antarctica

The planktonic, ice/water interface, and benthic communities at three sites off the coast of the Vestfold Hills, Antarctica, were examined over a complete year.The planktonic flora and fauna were composed predominantly of oceanic species with diatoms and copepods the numerically dominant groups. Primary production was largely restricted to the summer months except for epontic algae which developed in spring. The zooplankton exhibited a similar seasonal cycle but lagged some months behind that of the phytoplankton.The ice/water interface (epontic) fauna consisted of species from the plankton and benthos. Copepods were major contributors; however, two amphipod species dominated. Seasonality of the fauna in this habitat was determined by ice formation and breakout, and development of ice algae.Each of the benthic substrates supported a characteristic macrofaunal assemblage, although infaunal amphipods and tanaids were similar at each site. Infauna exhibited a distinct seasonal cycle related to that of the primary producers whereas macrofauna showed no seasonal changes in abundance.Species composition of each community in this coastal antarctic region was comparable with that of similar habitats in other antarctic coastal areas, supporting the circumpolarity of antarctic marine communities.     

Response of Antarctic benthic communities to disturbance: first results from the artificial Benthic Disturbance Experiment on the eastern Weddell Sea Shelf, Antarctica

The long-term benthic disturbance experiment (BENDEX) was started on the eastern Weddell Sea shelf off Austasen (Antarctica) during ‘Polarstern’ cruise ANT XXI/2 in December 2003 to simulate the impact of grounding icebergs on the seabed and follow the steps and timescales of recovery of disturbed benthos and demersal fish communities. Here, we report the basic approach and first results for this experimental field study. By means of 11 densely-placed hauls with a modified bottom trawl, a seabed area of approximately 100 × 1000 m was artificially scoured to inflict a similar damage to the benthic habitats as a grounding iceberg. Before the disturbance event and 11 days after it, the seafloor communities were sampled (invertebrate assemblages by multibox corers, the fish fauna by trawl hauls) and comparatively analyzed. Sediment texture and chemistry was not significantly altered by the heavy disturbance inflicted by repeated trawling, whereas the fauna was negatively affected. Invertebrate benthic biomass was drastically reduced by a factor of 10, while mean abundances were only slightly reduced. Demersal fish biomass and abundance were slightly but not significantly smaller after the disturbance. Effects of disturbance became more evident in the composition of the fish fauna, with Trematomus pennelli and T. hansoni being dominant at disturbed sites, whereas Chionodraco myersi was the dominant species in trawl catches from undisturbed stations.     

Evaluation of a vector-control strategy of haemorrhagic thelohanellosis in carp,caused by Thelohanellus hovorkai (Myxozoa)

The life cycle of Thelohanellus hovorkai (Myxozoa), the causative agent of haemorrhagic thelohanellosis of carp Cyprinus carpio, involves the alternate oligochaete host Branchiura sowerbyi, which plays the role of vector in the parasite's transmission. Field investigations in carp farms suggested that oligochaete fauna were closely associated with the substrate type of the pond. The pond bottom in the enzootic farm consisted of clay soil and soft sediments comprised of organic mud, in which B. sowerbyi dominated in high densities, with a maximum of 5.6 ind. kg(-1) soil. In another case, in a carp farm with no previous history of the disease, the pond bottom was sandy soil, in which small-sized oligochaetes, composed mainly of Limnodrilus socialis, dominated. Laboratory studies on the substrate preference of oligochaetes proved that B. sowerbyi prefers mud to sand, whereas L. socialis has no tendency to substrate tropism. The delicate body surface of B. sowerbyi was subject to damage by rugged-edged sand particles, which inflicted severe injuries to the worms. Transmission experiments showed that L. socialis, which are non-susceptible to T. hovorkai, suppressed the production of T. hovorkai actinospores in B. sowerbyi in a mixed assemblage of oligochaetes. Field and experimental evidence in this study imply that substrate replacement in culture ponds might regulate the benthic oligochaete communities, resulting in minimization of the impact of haemorrhagic thelohanellosis. We propose that ecological control of oligochaete fauna by environmental management is a promising strategy against myxozoan diseases.     

Two modified Breder traps for quantitative studies of tropical amphidromous migration

Amphidromy is a life cycle of fauna found throughout the tropics and subtropics, including representatives from three phyla. Amphidromy involves a life cycle of oceanic larval development, with postlarval migration into streams where growth and reproduction take place. With increasing industrial and urban development in tropical regions, demands for freshwater are continuously growing, resulting in the construction of dams and diversions that break the freshwater continuum necessary for the amphidromous life cycle; thus, jeopardizing many populations of native and endemic tropical stream fauna. Because of this, more quantitative studies are needed to better understand this unique life cycle, which heretofore, has been relatively little studied compared to tropical terrestrial communities. As such, new and quantitative methods are needed to study the immature stages (e.g., postlarvae) associated with amphidromy. In this paper, we introduce two modifications of the original Breder trap that have been designed specifically for standardized, quantitative monitoring of amphidromous postlarval migration. In addition, the two modified traps can be used in a variety of stream settings from natural bed substrates to modified channels with little heterogeneity. The first modification is made of acrylic, with a flat bottom useful in channelized streams or streams with relatively flat, unnatural benthic substrate (e.g., concrete). The second modification is an affordable trap made from polyvinylchloride (PVC) compression couplings, to be used in streams with natural benthic substrates, particularly those with large, embedded and immovable boulders and bedrock outcrops. Both traps were designed for continuous water flow through the traps, providing the necessary rheotactic cue for migrating amphidromous postlarvae, and ameliorating deficiencies of earlier traps not intended for tropical amphidromous fauna. We also make recommendations for standardized use of these traps to facilitate data comparisons among studies.     

Two modified Breder traps for quantitative studies of tropical amphidromous migration

Amphidromy is a life cycle of fauna found throughout the tropics and subtropics, including representatives from three phyla. Amphidromy involves a life cycle of oceanic larval development, with postlarval migration into streams where growth and reproduction take place. With increasing industrial and urban development in tropical regions, demands for freshwater are continuously growing, resulting in the construction of dams and diversions that break the freshwater continuum necessary for the amphidromous life cycle; thus, jeopardizing many populations of native and endemic tropical stream fauna. Because of this, more quantitative studies are needed to better understand this unique life cycle, which heretofore, has been relatively little studied compared to tropical terrestrial communities. As such, new and quantitative methods are needed to study the immature stages (e.g., postlarvae) associated with amphidromy. In this paper, we introduce two modifications of the original Breder trap that have been designed specifically for standardized, quantitative monitoring of amphidromous postlarval migration. In addition, the two modified traps can be used in a variety of stream settings from natural bed substrates to modified channels with little heterogeneity. The first modification is made of acrylic, with a flat bottom useful in channelized streams or streams with relatively flat, unnatural benthic substrate (e.g., concrete). The second modification is an affordable trap made from polyvinylchloride (PVC) compression couplings, to be used in streams with natural benthic substrates, particularly those with large, embedded and immovable boulders and bedrock outcrops. Both traps were designed for continuous water flow through the traps, providing the necessary rheotactic cue for migrating amphidromous postlarvae, and ameliorating deficiencies of earlier traps not intended for tropical amphidromous fauna. We also make recommendations for standardized use of these traps to facilitate data comparisons among studies.