Genetic techniques were employed to investigate the archaeal, bacterial and eukaryotic communities associated with the Antarctic sponges Kirkpatrickia varialosa, Latrunculia apicalis, Homaxinella balfourensis, Mycale acerata and Sphaerotylus antarcticus. The phylogenetic affiliation of sponge-derived bacteria was assessed by 16S rRNA sequencing of cloned DNA fragments. Denaturing gradient gel electrophoresis (DGGE) was used to determine the stability of bacterial associations within each sponge species and across spatial scales. Of the 150 archaeal clones from L. apicalis, K. varialosa and M. acerata screened by restriction fragment length polymorphism (RFLP) analysis, four unique operational taxonomic units (OTUs) were observed and all clustered closely together within the Crenarchaeota. Of the 250 sponge-derived bacterial clones screened by RFLP analysis, 61 were unique OTUs that were not detected during examination of 160 seawater-derived clones. Rarefaction analysis indicated that the clone libraries represented between 44 and 83% of the total estimated diversity. Phylogenetic analysis of sequence data revealed that the bacterial communities present in Antarctic sponges primarily clustered within the Gamma and Alpha proteobacteria and the Cytophaga/Flavobacterium of Bacteroidetes group. Bacterial DGGE analysis for replicate sponge and seawater samples at each Antarctic site revealed that bacterial communities were consistently detected within a particular species regardless of the collection site, with six bacterial bands exclusively associated with a single sponge species. Phylogenetic analysis of sequence data from eukaryotic DGGE analysis revealed that the communities present in Antarctic sponges fell into diatom and dinoflagellate clusters with many sequences having no known close relatives. In addition, seven eukaryotic sequences that were not detected in seawater samples or other sponge species were observed in K. varialosa.

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Shotgun cloning into E. coli of genomic DNA from Prochloron sp., symbiont of the seasquirt Lissoclinum patella, resulted in the heterologous expression of the patellamide gene cluster and subsequent production of patellamide D (1) and ascidiacyclamide (2) at levels of 80–100 ng mL−1.

Intraspecific variation in the composition of three cytotoxic secondary metabolites from the New Zealand marine sponge Mycale hentscheli collected at two sites in central New Zealand was quantified by 1H NMR techniques. A total of 275 sponges were analyzed bimonthly over 15 mo to compare intersite (approximately 100 km) and intrasite (approximately 100 m) spatial and temporal variations in the metabolites. Biological and physical characteristics of sponge size, morphology, depth, and temperature were recorded at each site. Metabolite concentrations were found to vary in space and time. Metabolite composition was site-specific; mycalamide A, pateamine, and peloruside A were present at Pelorus Sound, whereas pateamine was absent from sponges at Kapiti Island. Pateamine and peloruside A concentrations in sponges at Pelorus Sound varied seasonally; no such patterns were observed at Kapiti Island. Relationships of compound concentration with volume and depth were complex. High levels of peloruside A in Pelorus Sound sponges from between 8 and 10 m depth coincided with a density boundary layer and chlorophyll a maximum.

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