Bryozoans

1. Habitat-forming bryozoans are here defined as extant, heavily-calcified species which regularly attain sizes over 50 mm in three-dimensions and which contribute significantly to benthic habitat structure as living colonies.
2. Records of habitat-forming bryozoans were collated and mapped, together with information about the location, environment, habitat-forming species, the nature and size of the habitat formed, any associated fauna, and relevant threats and/or conservation measures.
3. Records collated here indicated that habitat-forming bryozoans occurred from ~59 N to 77 S, but that they did not occur frequently in the tropics, being found most commonly in temperate continental shelf environments, on stable substrata in places where water movement was relatively fast and consistent.
4. Habitat-forming bryozoans are particularly abundant and diverse in New Zealand, where 27 species, a quarter of which are cyclostomes, provide habitat over hundreds of square kilometres of seafloor. Other areas where they are particularly rich and/or abundant include Antarctica (Weddell, Lazarev and Ross Seas), the North Pacific around Japan, the northern Mediterranean and Adriatic, and along the southern edge of the North Sea, through the English Channel and around the United Kingdom.
5. Large bryozoans provide habitat for diverse associated assemblages, particularly for other bryozoans, molluscs, annelids, arthropods, cnidarians, sponges, echinoderms and macroalgae.
6. Protected areas which include habitat-forming bryozoans occur throughout the distribution of this frequently unrecognized habitat type, but despite this they are prone to damage by anthropogenic impacts including pollution and bottom fishing.

Factors related to depth have the potential to provide an analogue for future changes in the skeletal mineralogy of calcifying marine organisms and communities, given that oceanic pH decreases with depth, with a minimum pH of < 7.7, which corresponds to the predicted pH of shallow waters in the next 85 yr. Antarctic bryozoans are often characterized by surprisingly broad bathymetrical ranges, and thus have potential for the study of depth-related environmental changes. This study addressed depth-related changes in the levels of magnesium (Mg)-calcite in Antarctic bryozoan skeletons for the first time in order to facilitate predictions of ocean acidification effects. Specimens (n = 103) belonging to 4 bryozoan species (3 cheilostomes and 1 cyclostome) were collected at various depths in East Antarctica (Terre Adelie and George V Land) during the CEAMARC cruise (December 2007 to January 2008), and Mg-calcite contents from their calcareous skeletons were studied using X-ray diffraction. A dataset was compiled from existing environmental data for both sampling and neighboring sites. All 4 species were found to be entirely calcitic with low or intermediate Mg-levels. The predicted negative correlation between pH and Mg-calcite was not evident. Higher Mg levels were found in Fasciculipora ramosa from the George V Basin, suggesting that high salinity shelf water creates favorable conditions for this species, although alternative environmental and biological factors influencing Mg-calcite in skeletons are also discussed for this species.

In 1931, Borg distinguished five ‘‘varieties’’ as morphologically differing from what he perceived as the ‘typical form’ of Electra crustulenta (Pallas, 1766). Taxonomic status has not been resolved for all of those morphotypes. One of them was recently recognized as a separate species, E. arctica; two are considered as species in other genera. In the present study the remaining three of Borg’s subdivisions, ‘‘forma typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’, were analyzed to evaluate their status and reconstruct phylogenetic relationships within the whole species group based on ribosomal 16S
mtDNA and 18S nDNA. All known E. crustulenta-like species and forms with unresolved status were included: E. crustulenta (including ‘‘f. typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’), E. arctica, E. korobokkura, and Electra moskvikvendi sp. nov. A well-supported phylogeny fully concordant for both genetic markers was obtained with maximum parsimony, neighbor-joining, maximum likelihood, and Bayesian methods. Statistical parsimony was applied to the 16S dataset. Only four species were revealed regardless of the method or gene fragment, with E. crustulenta as a single species. There was no evident correlation between the morphotypes ‘‘f. typica’’, ‘‘var. baltica’’ and ‘‘var. fossaria’’ and haplogroups found in E. crustulenta populations. The E. crustulenta species group consisted of two subgroups: E. crustulenta–E. korobokkura and E. moskvikvendi–E. arctica. Divergence of the mitochondrial lineages within the group was dated using a Bayesian relaxed-clock approach. Most probably the diversification of the lineages examined started in the Early Miocene. Electra arctica and E. moskvikvendi sp. nov. are two young species, having diverged during the Pliocene–Pleistocene. The new species described here was found in the Western Baltic Sea, Kiel Bay. An identification key for the E. crustulenta species group is given, based on morphology, morphometry, and geographical and ecological ranges. Additionally, reference sequences of 16S and 18S DNA for each species, which can be used for DNA-based barcoding, have been published.

Recent advances in sampling and novel techniques in drug synthesis and isolation have promoted the discovery of anticancer agents from marine organisms to combat this major threat to public health worldwide. Bryozoans, which are filter-feeding, aquatic invertebrates often characterized by a calcified skeleton, are an excellent source of pharmacologically interesting compounds including well-known chemical classes such as alkaloids and polyketides. This review covers the literature for secondary metabolites isolated from marine cheilostome and ctenostome bryozoans that have shown potential as cancer drugs. Moreover, we highlight examples such as bryostatins, the most known class of marine-derived compounds from this animal phylum, which are advancing through anticancer clinical trials due to their low toxicity and antineoplastic activity. The bryozoan antitumor compounds discovered until now show a wide range of chemical diversity and biological activities. Therefore, more research focusing on the isolation of secondary metabolites with potential anticancer properties from bryozoans and other overlooked taxa covering wider geographic areas is needed for an efficient bioprospecting of natural products.

The bryozoan genus Watersipora includes
rapidly invading species that are becoming common
globally. We used paired-end Illumina sequencing to
identify thousands of potentially amplifiable microsatellite
loci, enabling researchers to track patterns of the invasive
spread, and to facilitate ecological and evolutionary question
setting. We describe variability of nine loci within
recently introduced populations of two Watersipora species
in California.