Annotated list of new records of marine macroalgae for Kenya and Tanzania, since Isaac's and Jaasund's publications

48 species of Rhodophyta, 10 species of Phaeophyta and 38 species of Chlorophyta, newly reported since Isaac's publications on seaweeds from Kenya and Jaasund's papers on macroalgae fiom Tanzania, are listed with bibliograpbic, taxonomic and biogeographic comments. Some of these species were previously published in more detailed taxonomic studies by this paper's authors

Hunting for nuclear markers in green algal lineages: molecular evolution of glucose-6-phosphate isomerase

The Chlorophyta exhibit a remarkable cytological diversity ranging from unicellular microscopic algae with a single nucleus, over multicellular filaments and foliose blades, to coencytic and even siphonous life forms that are essentially composed of a giant cell containing thousands of nuclei. Unravelling the evolutionary history of this diverse and evolutionary old group is a difficult task due to the antiquity of the major lineages and considerable rate variation between those lineages for the commonly used 18S ribosomal DNA sequences and chloroplast markers (Lewis et al., Therefore different genes with known function and sequence data available are tested and more recently a cDNA library is screened to search for new useful genes.Glucose-6-phosphate isomerase (G6PI) is one of the genes we are testing. It is an important enzyme of the carbohydrate biosynthesis pathway in photosynthetic organisms and of the glycolysis in all organisms. Little is known about copy number of the gene in the Chlorophyta. The complete genome sequences of Chlamydomonas reinhardtii and Ostreococcus taur revealed that both have a single copy of G6PI. In plants however within a single genus there are species with one G6PI gene and other species with two G6PI (e.g. Arabidopsis, Actinidia,…) and up to thre copies are observed in Zea mays. It always concerns recent duplication within one genus.To investigate if the G6PI gene(s) is useful as a phylogenetic marker in the Chlorophyta, primers were made based on the G6PI genome sequences of Arabidopsis thaliana, Oryza sativa, Chlamydomonas reinhardtii and Ostreococcus tauri. The primers were tested on DNA and RNA of a variety of green algae.Following conclusions can be drawn from these preliminary results: 1. epiphytic or endophytic bacteria interfere with the direct amplification of nuclear genes; 2. the G6PI gene is informative on several taxonomic levels: for deep phylogenies we have to use a codon substitution model, for species level relationships introns may offer opportunities towards studies at the interspecific level; 3. most likely only one (functional) copy of the G6PI gene is present in the tested taxa

The Change in Macroalgal Assemblages through the Saldanha Bay/Langebaan Lagoon Ecosystem (South Africa)

Saldanha Bay and Langebaan Lagoon form together one of the few sheltered habitats within the Benguela Marine Province; a wide gradient in environmental factors is found here. The West Coast National Park was established to protect this unique ecosystem, but at the same time an industrially expanding harbour marks this area. In an effort to understand the biological composition of the Saldanha/Langebaan ecosystem, the intertidal macroalgal assemblages were studied in relation to the relatively well-known South African West Coast flora. Three distinct floral entities were identified using various analytical techniques (similarity coefficients, CCA and TWINSPAN): (i) the species poor, though distinct, salt marshes; (ii) the Lagoon sites; and (iii) the Bay and West Coast sites. The transition between the latter two is located at the mouth of the Lagoon. The species richness of the Bay/West Coast entity is larger than in the Lagoon. The change in algal composition can be explained in terms of the environmental variables of which wave exposure is the most significant. Other important environmental parameters are water surface temperature and salinity, which were found to be negatively correlated with wave exposure. Biogeographical affinities of the different algal entities of the Bay/Lagoon system were also determined in relation to the entire South African shoreline. The Bay/West Coast entity supports a typical West Coast flora, with some noticeable effects of uplift of subtidal species into the infralittoral fringe and morphological variation in less exposed areas. The algal flora of the Lagoon is also dominated by West Coast species, but is typified by species characteristic of sheltered habitats, and with a number of species which otherwise only occur on the geographically distant South Coast (east of Cape Agulhas). The algae from the salt marshes occur widely in tropical mangroves and warm temperate salt marshes

Evaluating environmental drivers of spatial variability in free-living nematode assemblages along the Portuguese margin

Understanding processes responsible for shaping biodiversity patterns on continental margins is an important requirement for comprehending anthropogenic impacts in these environments and further management of biodiversity. Continental margins perform crucial functions linked to key ecological processes which are mainly structured by surface primary productivity and particulate organic matter flux to the seafloor, but also by heterogeneity in seafloor characteristics. However, to what extent these processes control local and regional biodiversity remains unclear. In this study, two isobathic parallel transects located at the shelf break (300-400 m) and upper slope (1000 m) of the western Iberian margin were used to test how food input and sediment heterogeneity affect nematode diversity independently from the spatial factors geographical distance and water depth. We also examined the potential role of connectedness between both depth transects through molecular phylogenetic analyses. Regional generic diversity and turnover were investigated at three levels: within a station, between stations from the same depth transect, and between transects. High variability in food availability and high sediment heterogeneity at the shelf-break transect were directly linked to high diversity within stations and higher variation in community structure across stations compared to the upper slope transect. Contrastingly, environmental factors (food availability and sediment) did not vary significantly between stations located at the upper slope, and this lack of differences were also reflected in a low community turnover between these deeper stations. Finally, differences in nematode communities between both transects were more pronounced than differences within each of the isobathic transects, but these changes were paralleled by the previously mentioned environmental changes. These results suggest that changes in community structure are mainly dictated by environmental factors rather than spatial differences at the western Iberian margin. Furthermore, phylogenetic relationships revealed no evidence for depth-endemic lineages, indicating regular species interchanges across different depths