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The South Pacific freshwater ecosystems have never been investigated systematically. Although their ecological value has long been recognized and recommended for protection, little action has been taken so far. Here, we present results of 39 lentic water bodies on 18 islands belonging to seven countries. Temperature, conductivity, and pH were measured and samples of aquatic organisms were collected. Freshwater algae, nematodes, rotifers, ostracods, copepods, cladocerans, and aquatic oribatid mites were identified to genus or species level. Sixty-six percent of all taxa recorded have a cosmopolitan distribution, 14% are circumtropical/tropicopolitan species, and for 20% a restricted distribution predominantly in Australasia has previously been reported. Eleven new copepod and three new ostracod taxa were discovered. Out of 39 water bodies we found at least 17 stocked with nonindigenous fish species. Salinization and uncontrolled introduction of alien fish species may lead to reduced species richness in these remote freshwater ecosystems. The highest species richness was recorded in old, shallow, fish-free softwater lakes at high altitude., THE SOUTH PACIFIC islands harbor some of the most isolated freshwater lakes of the world. Most of them fill volcanic craters that formed thousands of kilometers away from the next [...]

In order to understand Chamaesiphon spp. evolution and ecological diversification, we investigated the phylogenetic differentiation of three morphospecies from field samples by means of single colony genetics. Individual colonies of three different morphospecies (C. starmachii, C. polonicus, C. geitleri,) were isolated from lotic gravel streams and their 16S rDNA nucleotide variability was analyzed. For a number of individual colonies, microscopical and ultrastructural analysis was also performed. A phylogenetic tree of all major lineages of the phylum of Cyanobacteria assigned all Chamaesiphon genotypes (1149-1176 bp) most closely with the family of Gomontiellaceae of the order Oscillatoriales. The sequences obtained from colonies assigned to C. starmachii (n = 21), C. polonicus (n = 9), and C. geitleri (n = 17) were found to reveal high average (3.5%) nucleotide diversity. No phylogenetic sub-branching in correspondence with morphology was observed suggesting that the three Chamaesiphon morphospecies did not represent monophyletic taxa. We could not attribute specific thylakoid ultrastructure to phylogenetic sub-branches; however, the observed parietally and loosely arranged thylakoids indicate that for the genus Chamaesiphon, the variability in thylakoid ultrastructure might have been underestimated. In summary, the high nucleotide diversity of the 16S rDNA gene implies phylogenetic diversity that corresponds little to morphological classification. [ABSTRACT FROM AUTHOR]

To expand on the biodiversity study of the eastern Alpine region of North Tyrol, we investigated silica-scaled chrysophyte flora of unexplored high-altitude Alpine sites. We concentrated mostly on lakes that were 1000-2500 m above sea level; some of them were still partly ice covered. Overall, 27 taxa were recorded at 12 sites, despite 21 sites being sampled altogether. In general, the sites were oligotrophic and species poor. Due to a restricted data set, an extensive analysis was not possible. However, altitude and pH were found to be important variables for explaining species distribution. We described the new species Mallomonas pechlaneri from two of the sampled sites. Mallomonas pechlaneri most closely resembles Mallomonas striata var. striata and M. striata var. serrata; these three taxa are clearly distinguished by bristle morphology and scale shape. The bristles of M. pechlaneri terminate in a bifurcated tip consisting of unequal diverging branches. Scale shape was captured my means of landmark-based geometric morphometries (GM) and evaluated using multivariate statistical analyses. GM methods proved to be an efficient tool to be employed in chrysophycean taxonomy. [ABSTRACT FROM AUTHOR]