Crustacean plankton community (Crustacea: Copepoda and Cladocera) in gypsum karst lakes and their relation to abiotic parameters

Two gypsum karst lakes and one non-gypsum karst lake were studied for copepod and cladoceran species composition in relation to specific habitat characteristics. The investigation was conducted from March to June 2007. Four copepod and six cladoceran species were recorded. Gypsum karst lakes are characterized as sulphate lakes and they show significant differences from non-gypsum karst lakes in conductivity, TDS, alkalinity, calcium and sulphates. Data on environmental variables and zooplankton were analyzed using redundancy analysis (RDA). The model explained 65.73% of the variance of the crustacean zooplankton and environmental data by the first two axes. The analysis confirmed that the major environmental variables influencing zooplankton in gypsum karst lakes are conductivity, TDS, calcium and sulphates. In the non-gypsum karst lake, on the contrary, the major variables were oxygen concentration and alkalinity. Specific habitat characteristics of gypsum karst lakes influence the zooplankton community by reducing the number of species and leading to the dominance of one of them.     

Diversity of the free-living marine and freshwater Copepoda (Crustacea) in Costa Rica: a review

The studies on marine copepods of Costa Rica started in the 1990’s and focused on the largest coastal-estuarine systems in the country, particularly along the Pacific coast. Diversity is widely variable among these systems: 40 species have been recorded in the Culebra Bay influenced by upwelling, northern Pacific coast, only 12 in the Gulf of Nicoya estuarine system, and 38 in Golfo Dulce, an anoxic basin in the southern Pacific coast of the country. Freshwater environments of Costa Rica are known to harbor a moderate diversity of continental copepods (25 species), which includes 6 calanoids, 17 cyclopoids and only two harpacticoids. Of the +100 freshwater species recorded in Central America, six are known only from Costa Rica, and one appears to be endemic to this country. The freshwater copepod fauna of Costa Rica is clearly the best known in Central America. Overall, six of the 10 orders of Copepoda are reported from Costa Rica. A previous summary by 2001 of the free-living copepod diversity in the country included 80 marine species (67 pelagic, 13 benthic). By 2009, the number of marine species increased to 209: 164 from the Pacific (49% of the copepod fauna from the Eastern Tropical Pacific) and 45 from the Caribbean coast (8% of species known from the Caribbean Basin). Both the Caribbean and Pacific species lists are growing. Additional collections of copepods at Cocos Island, an oceanic island 530 km away of the Pacific coast, have revealed many new records, including five new marine species from Costa Rica. Currently, the known diversity of marine copepods of Costa Rica is still in development and represents up to 52.6% of the total marine microcrustaceans recorded in the country. Future sampling and taxonomic efforts in the marine habitats should emphasize oceanic environments including deep waters but also littoral communities. Several Costa Rican records of freshwater copepods are likely to represent undescribed species. Also, the biogeographic relevance of the inland copepod fauna of Costa Rica requires more detailed surveys.     

The mammals of the Mongolian People's Republic

The mammals of the Mongolian People's Republic are reviewed, their current status and distribution are summarized and distribution maps are provided.     

Antennule shape and body size of <Emphasis Type="Italic">Bosmina</Emphasis>: key factors determining its vulnerability to predacious Copepoda

Cyclopoid copepods are common in lakes and ponds, and they have a significant predation impact on the communities of the small zooplankton species. To reduce the predation risk, some cladoceran zooplankters develop protuberant (defensive) morphologies in the presence of the copepods. In the case of the small cladoceran Bosmina, they elongate their appendages (antennule and mucrone) and change the antennule morphotype. However, information about the effectiveness of these defensive devices against copepod predation is still insufficient. In our study, to find the compositive effects of these appendages on the vulnerability of Bosmina, we exposed two bosminid species (B. longirostris and B. fatalis) of different body sizes and with appendages of different lengths and shapes to copepod (Mesocyclops) predation. The experiment revealed that the shape of the antennule is a main factor determining the bosminid’s vulnerability to copepod predation and indicated that the protection of the opened ventral carapace must be a key strategy by which Bosmina avoids copepod predation.     

Population Structure of Pacific Cod <Emphasis Type="Italic">Gadus macrocephalus</Emphasis> in the Southern Part of the Range Based on the Microsatellite Analyses

The population structure of Pacific cod Gadus macrocephalus in the southern part of the range and adjacent regions is studied on the basis of the results of microsatellite analyses. Collected data indicate heterogeneity of this species population within the studied area. According to the obtained F_ST values, Pacific cod from the waters of the Republic of Korea (Yellow Sea side) and northwestern part of the Sea of Okhotsk significantly differ from all other studied regions (Table 4). Significant differentiation was also revealed between samples from the waters of the Tatar Strait and all other regions except for South Kurils Pacific cod (both Sea of Okhotsk and Pacific Ocean sides). These two latter sample collections were similar to each other as well. A low level of differentiation was also shown for the Peter the Great Bay and the East Sea/Sea of Japan waters of the Republic of Korea.     

Gasteromyzeten aus der Mongolischen Volksrepublik

18 species of Gasteromycetes are known from the Mongolian People's Republic by Pilát (1972) and the present communication which indicates 11 species, represented by 15 collections, from this territory. Lycoperdon asiaticum sp. nov. and 6 more species are reported for the first time from Mongolia. The 18 species are arranged in relation to vegetation belts. Two species are endemic after actual knowledge, 15 species occur in similar vegetation types in Europe, and one is doubtful. Only 5 of the 18 species are represented also in the well-known Gasteromycete flora of Nepal. Consequently, the Gobi desert forms an important mycofloristic limit between the European-Centralasiatic and the Southeastasiatic Gasteromycete flora.     

Recovery of copepod, but not cladoceran, zooplankton from severe and chronic effects of multiple stressors

In the mid‐twentieth century, many lakes near Sudbury, Canada, were severely contaminated by acid and metal emissions from local smelters. For example, in the early 1970s, Middle Lake had pH of 4.2, and Cu and Ni levels both >0.5 mg L^?1 . To determine if crustacean zooplankton could recover from such severe and chronic damage, Middle Lake was neutralized in 1973. A comparison of its zooplankton with that of 22 reference (pH > 6) lakes indicates that the planktonic Copepoda completely recovered by 2001. In contrast, the cladoceran assemblage improved but did not recover. Colonist sources existed – Cladocera and Copepoda occurred with equal frequency in area lakes – but six separate colonizations by cladoceran species failed. We argue that local factors, metal toxicity and predation by yellow perch, have, to date, prevented cladoceran recovery. Nonetheless, the complete copepod recovery is encouraging, given the severity and duration of pre‐neutralization stress.     

Zooplankton species composition is linked to ocean transport in the Northern California Current

In the Northern California Current (NCC), zooplankton communities show interannual and multiyear shifts in species dominance that are tracked by survival of salmon populations. These zooplankton community changes correlate with the Pacific Decadal Oscillation (PDO) index: a ‘warm‐water’ copepod species group is more abundant during warm (positive) phases of the PDO and less abundant during cold (negative) phases; the reverse occurs for a ‘cold‐water’ species group. The observed relationship led to the hypothesis that the relative dominance of warm/cold‐water copepods in the NCC is driven by changes in the horizontal advection of surface water over different phases of the PDO. To test this hypothesis, variation in surface water advection to coastal regions of the NCC over the period of 1950–2008 was investigated using a Regional Ocean Modeling System (ROMS) and passive tracer experiments, then was compared with zooplankton collected off Oregon since 1996. Results showed that surface water advection varied with the phase of the PDO; the low‐frequency component of advection anomalies strongly correlated with copepod species composition (R>0.9). During positive phases of the PDO, current anomalies were northward and onshore, resulting in transport of warmer waters and the associated copepods into the region. During negatives phases, increased equatorward current anomalies led to a copepod community that was dominated by cold‐water taxa. Our results support the hypothesis that climate‐driven changes in basin‐scale circulation controls copepod community composition in the NCC, and demonstrate that large‐scale climate forcings downscale to influence local and regional ecosystem structure.     

Transition zones in small lakes: the importance of dilution and biological uptake on lake-wide heterogeneity

Community structure and diversity patterns of pelagic copepods were investigated for the coastal areas and in the marine lakes of the Palau islands in the West Pacific. We conducted field surveys during 2004–2007 and collected zooplankton samples from eight coastal areas and 16 marine lakes. The marine lakes in the islands of Palau are limnologically classified into two types, meromictic and holomictic lakes. Species diversity indices (Margalef’s species richness d′, Shannon–Wiener index H′, and Simpson’s dominance) were measured at each sampling site. The copepod community structure was analyzed using multivariate analyses, hierarchical cluster analysis, and non-metric multidimensional scaling (MDS) from the PRIMER package. A total of 36 copepod taxa were identified to the genus or species level from Calanoida, Cyclopoida, Harpacticoida, and Poecilostomatoida. Multivariate analysis based on the Bray–Curtis similarity index revealed that copepod assemblages could be classified into three different groups according to their habitat: (I) meromictic lakes, (II) holomictic lakes with an exceptionally shallow and flat basin (type A holomictic lakes), (III) holomictic lakes with a deep basin (type B holomictic lakes), and all coastal areas. The meromictic lakes were characterized by markedly decreased species diversity (d′ = 0.15, H′ = 0.41) in which only two brackish-water species, Bestiolina similis and Oithona dissimilis, were dominant. Type A holomictic lakes were characterized by relatively low levels of species diversity (d′ = 1.25, H′ = 1.35). In contrast, type B holomictic lakes were characterized by relatively high levels of species diversity, which was comparable to that of coastal areas. This result indicated that zooplankton assemblages in the type B holomictic lakes were closely related to a coastal community. The present study showed that the species diversity of pelagic copepods varies according to the level of isolation and the local environmental conditions for each marine lake.     

Characteristic features of ecology of the Pacific saury Cololabis saira (Scomberesocidae, Beloniformes) in open waters and in the northeast Pacific ocean

The results of long-term studies of the spatial distribution, size composition, and spawning intensity of the Pacific saury Cololabis saira in open waters of the North Pacific Ocean and the northeastern part of the Pacific Ocean off the west coast of North America are presented. In the open waters of the Pacific Ocean, saury forms aggregations early in summer; intraseasonal changes in their distribution pattern have been identified. Migrations of Pacific saury stocks in the northeastern part of the Pacific Ocean were considered, and assumptions about their causes were made. The differences in the size composition of Pacific saury in different parts of the range are associated with the peculiarities of occurrence of favorable conditions for the formation of aggregations. Intensive spawning of Pacific saury in the northeastern part of the Pacific Ocean is observed in winter and spring, and that in open waters is observed in summer. The distribution of the early progeny of Pacific saury is associated with the systems of currents; its findings in the extreme northern regions in the 1980s are explained.     

Micro-evolutionary processes in sablefish Anoplopoma fimbria,based on polymorphism of the two sites of mitochondrial DNA

Sablefish Anoplopoma fimbria is a deep-sea fish, endemic to the North Pacific Ocean, with continuous range from southern California to the central part of Honshu Island, including the Bering and Okhotsk Seas. It is an important commercial species and a promising object for aquaculture [1, 2]. Compared to the eastern part of the range [3, 4] the population structure of sablefish in Asian waters is poorly studied. It is believed that sablefish goes to the Bering Sea and Pacific waters of Kamchatka and the Kuril Islands from the northeastern Pacific, and Asian waters are its eviction zone [5]. Other authors suggest that replenishment of sablefish off the eastern Kamchatka and the Kuril Islands is not only due to migration of the adult fish from the Bering Sea along the continental slope, but also due to the drift of yearlings by Aleutian current over the American coast [6].     

Lake construction has facilitated calanoid copepod invasions in New Zealand

Aim We tested the hypothesis that construction of lakes and ponds has facilitated both inter‐ and intracontinental invasions of calanoid copepod species. Location North Island, New Zealand. Methods We sampled both natural and constructed lakes, ponds and reservoirs for calanoid copepods in the North Island, New Zealand. Species records were supplemented by examining historically collected samples and literature review. Distributions of non‐indigenous calanoid copepod species were compared between constructed and natural waters. Species distributions of native species were compared with the basement terranes (microplates) of the North Island to determine if they possess ‘natural ranges’, and to assess whether construction of new water bodies had altered these distributions. Results Ten calanoid copepod species have been recorded. At least four, and possibly five, of these species are non‐indigenous and were restricted to constructed water bodies. Occurrences in constructed water bodies were not restricted to dammed valleys, but also included ponds constructed on farms, ornamental ponds, disused quarries and retired mines. Four Boeckella species had distributions in natural waters closely related to the North Island basement terranes, and therefore possess ‘natural ranges’ on the island. One species, Boeckella propinqua, was found in natural lakes over a small geographical range only, but has spread with construction of new water bodies to now be widely distributed over the island. Main conclusions Construction of lakes and ponds has facilitated the invasion of calanoid copepod species at both inter‐ and intracontinental scales. Our findings suggest that resident native calanoid copepod species may reduce the risk of invasion to natural water bodies, as similar‐sized species are commonly unable to co‐occur. Spread of the non‐indigenous representatives from constructed into natural waters is inevitable, with established populations providing local propagule supplies for regular introductions.     

Microbial attachment to particles in marine and freshwater ecosystems

Scanning electron microscopy observations ofin situ suspended marine and freshwater particles show diverse but similar modes of bacterial and fungal attachment. A survey of Sierra Nevada mountain lakes and pelagic and near-shore waters in the Pacific Ocean indicates that attachment is most noticeable in the near-surface waters where fresh dissolved and particulate input of carbon from phytoplankton and elevated temperatures favor microbial growth. The most common modes of attachment are: adhesive stalk formation, growth on adhesive webs, attachment by the use of pili-like appendages and slimy capsular secretions, and molecular or chemical sorption without the use of visualized structural appendages. Attached microbial growth is accelerated when particulate substrates are supplied, even when they are not rich in organic nutrients. This is the case in the Lake Tahoe basin, where microflora attached to eroded silts can significantly modify the organic carbon and nutrient content of such minerogenous particles.     

PHYLOGENETIC RELATIONSHIPS OF BRYDE'S WHALES IN THE WESTERN NORTH PACIFIC AND ADJACENT WATERS INFERRED FROM MITOCHONDRIAL DNA SEQUENCES1

To clarify phylogenetic relationships of Bryde's whales, we examined the nucleotide sequence of the mitochondrial control region and cytochrome b gene in 33 animals: 12 from offshore waters of the western North Pacific, five from off the Solomon Islands, and 16 from the East China Sea and coastal waters of Kochi in southwestern Japan. For reference purposes, homologous sequences from four Balaenoptera species including four Bryde's whales collected in the eastern Indian Ocean were added. We found whales from the three sampling areas to be genetically distinct. The control region sequences suggested that the whales from the three areas separate at higher than the populational level from one another. The cytochrome b data indicated that genetic differences between whales off the Solomon Islands and animals in the other two areas are equivalent to values found among recognized Balaenoptera species, although such a relationship was not observed between the other two areas. We conclude that whales in the East China Sea and coastal waters of Kochi separate from Bryde's whales in offshore waters of the western North Pacific at higher than the populational level but lower than the specific level (i. e., at the subspecific level) and that whales off the Solomon Islands do not belong genetically to the Bryde's whale as previously recognized.     

Collection and culture of live foods for aquaculture in Taiwan

Collection and culture of live foods to be used instudies of feeds for rearing finfish and shellfishlarvae in Taiwan began in 1982. Today, 31 species (49strains) of microalgae, three species (nine strains)of rotifers, one cladoceran and one copepod are holdas start culture. Microalgae are collected from localwaters and obtained from foreign collection centers.The most common genera are Chlorella,Nannochloropsis, Tetraselmis, Chaetoceros, Skeletonema, Isochrysis, and Pavlova. Someinteresting genera such as Ellipsoidion,Nannochloris, Synechococcus, and Alexandriumare also included. Three types of rotifers, i.e. L, S,and SS-type, which are classified as Brachionusplicatilis, B. rotundiformis, and Brachionus sp. are found in Taiwan waters. Among therotifers, six strains have been isolated and cultured.Another L-type strain and two SS-type strains wereobtained from foreign sources. The cladoceran Diaphanosoma aspinosum and copepod Apocyclopsroyi are the most common species used in aquaculture.Studies of live foods including their morphology,culture techniques, fatty acid composition andnutritional value as feeds have been undertaken.     

The fauna of athalassic saline waters in Australia and the Altiplano of South America: comparisons and historical perspectives

Similarities and differences between the fauna of inland saline waters in Australia and on the Altiplano are explored and explanations sought.Elements common to both continents include the calanoid copepod genus Boeckella (B. triarticulata in Australia, B. poopoensis and B. meteoris in South America) and the cladoceran genus Daphniopsis. Salinity data for Altiplano lakes are given for six species of Boeckella and for Daphniopsis.Ostracods have adapted to the open water of saline lakes in Australia but not in South America, a difference that may reflect past differences in the degree of predation by birds. In South America, diatoms are grazed by the flamingos Phoenicoparrus andinus and P. jamesi, while in Australia the main diatom grazer is probably the aquatic oniscoid isopod Haloniscus searlei. However, at least four species of flamingos were present in Australia during the late Cenozoic and one or more of these may well have grazed diatoms. The extinction of diatom-grazing or carnivorous flamingos, or both, in Australia may have been factors in the unique colonization of inland saline waters by H. searlei.     

Seasonal dynamics and composition of cladoceran and copepod assemblages in ponds of a Hungarian cutaway peatland

Seasonal dynamics of cladoceran and copepod zooplankton were studied over a one‐year period in five permanent ponds of a cutaway peatland, situated in the Danube−Tisza Interfluve, Central Hungary. 17 cladoceran, 11 cyclopoid copepod and 6 harpacticoid copepod species were identified and most of them were typical of small lowland ponds. Nevertheless, some taxa like Cyclops insignis, Ceriodaphnia setosa and Macrocyclops distinctus are considered to be rare in Hungary. The microcrustacean assemblages exhibited apparent seasonal succession with typical seasonal species. There appears to be at least two main successional patterns in the five ponds. After general cyclopoid copepod dominance in winter (Cyclops strenuus and Cyclops insignis), at sites with higher proportion of open water and submerged vegetation, spring was characterized by the dominance of the large cladoceran Daphnia curvirostris, which declined during summer, when microcrustacean assemblages composed mainly of smaller, littoral cladocerans. At these sites, species richness and diversity reached their maximum in autumn. In the case of duckweed covered ponds, succession led to less diverse autumn assemblages with fewer species, dominated by Simocephalus exspinosus. Our results draw the attention to the importance of long‐term investigations and the often neglected winter sampling in the accurate evaluation of species richness (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Cladoceran assemblages in a mineralization gradient

Cladoceran assemblages were studied in littoral samples from 44 water bodies in Central Spain, showing great differences in salinity and permanence of water. Principal component analyses (PCA) were performed with data on cladoceran relative abundances to identify the main groups of species. Five main groups of species were found, defining the following types of environments: (I) Small but deep hard water lakes (II) permanent but shallow hard water lakes fed by surface springs, rich in macrophytes (III) ephemeral and shallow soft waters lakes (IV) subsaline and hyposaline lakes in their lower range, specially the permanent ones and (V) saline lakes (salinities>6 mg l^–1) subject to short or long periods of dryness. The main species constituting these groups were: Group (I): Acroperus neglectus, Alona guttata, Pleuroxus truncatus, Daphnia longispina; group II: Phrixura leei, Latonura rectirostris, Eurycercus lamellatus; Alonella excisa, Daphnia pulicaria; group III: Ephemeroporus phintonicus, Macrothrix rosea, Moina micrura; group IV: Alona rectangula, Ceriodaphnia reticulata, Tetrocephala ambigua, Diaphanosoma mongolianum; group V: Alona salina, Pleuroxus letourneuxi, Dunhevedia crassa, Moina brachiata, Daphnia magna and Daphnia mediterranea. Sample scores from PCA extracted from the correlation matrix of cladoceran proportions were correlated with limnological measurements. Significant correlations with salinity, alkalinity anions and cations indicate that salinity is an important factor in the distribution of the species. However, species assemblages also reflect other factors, such as temporality and littoral development.