Sponges are ubiquitous components of various deep-sea habitats, including cold water coral reefs, and form deep-sea sponge grounds. Although the deep sea is generally considered to be a food-limited environment, these ecosystems are known to be hotspots of biodiversity and carbon cycling. To assess the role of sponges in the carbon cycling of deep-sea ecosystems, we studied the carbon budgets of six dominant deep-sea sponges of different phylogenetic origin, with various growth forms and hosting distinct associated microbial communities, in an ex situ aquarium setup. Additionally, we determined biomass metrics-planar surface area, volume, wet weight, dry weight (DW), ash-free dry weight, and organic carbon (C) content-and conversion factors for all species. Oxygen (O 2) removal rates averaged 3.3 ± 2.8 μmol O 2 g DW sponge h −1 (mean ± SD), live particulate (bacterio-and phytoplankton) organic carbon removal rates averaged 0.30 ± 0.39 μmol C g DW sponge h −1 and dissolved organic carbon (DOC) removal rates averaged 18.70 ± 25.02 μmol C g DW sponge h −1. Carbon mass balances were calculated for four species and revealed that the sponges acquired 1.3-6.6 times the amount of carbon needed to sustain their minimal respiratory demands. These results indicate that irrespective of taxonomic class, growth form, and abundance of microbial symbionts, DOC is responsible for over 90% of the total net organic carbon removal of deep-sea sponges and allows them to sustain themselves in otherwise food-limited environments on the ocean floor.

Study of the genetic basis of gene expression variation is central to attempts to understand the causes of evolutionary change. Although there are many transcriptomics studies estimating genetic variance and heritability in model organisms such as humans there is a lack of equivalent proteomics studies. In the present study, the heritability underlying egg protein expression was estimated in the marine mussel Mytilus. We believe this to be the first such measurement of genetic variation for gene expression in eggs of any organism. The study of eggs is important in evolutionary theory and life history analysis because maternal effects might have profound effects on the rate of evolution of offspring traits. Evidence is presented that the egg proteome varies significantly between individual females and that heritability of protein expression in mussel eggs is moderate to high suggesting abundant genetic variation on which natural selection might act. The study of the mussel egg proteome is also important because of the unusual system of mitochondrial DNA inheritance in mussels whereby different mitochondrial genomes are transmitted independently through female and male lineages (doubly uniparental inheritance). It is likely that the mechanism underlying this system involves the interaction of specific egg factors with sperm mitochondria following fertilization, and its elucidation might be advanced by study of the proteome in females having different progeny sex ratios. Putative identifications are presented here for egg proteins using MS/MS in Mytilus lines differing in sex ratio. Ontology terms relating to stress response and protein folding occur more frequently for proteins showing large expression differences between the lines. The distribution of ontology terms in mussel eggs was compared with those for previous mussel proteomics studies (using other tissues) and with mammal eggs. Significant differences were observed between mussel eggs and mussel tissues but not between the two types of eggs. Molecular & Cellular Proteomics 8:132-144, 2009.

We examined four species of sea pen (Anthoptilum grandiflorum, Halipteris finmarchica, Pennatula aculeata and Pennatula grandis) collected from the Gulf of St. Lawrence and mouth of the Laurentian Channel, eastern Canada. An exponential length-weight relationship was found for all four species, where growth in weight was progressively greater than growth in length with increasing colony size. Halipteris finmarchica, P. grandis and P. aculeata presented the better allometric fits, explaining over 80% of the variance. In addition, a count of growth increments visible in transverse sections in 86 A. grandiflorum and 80 P. aculeata samples was made. Presumed ages ranged between 5 and 28 years for A. grandiflorum and 2 and 21 years for P. aculeata. Radiocarbon assays were inconclusive and could not be used to confirm these ages; further age validation is required. Radial growth of the rod is slow during the first years, increasing at intermediate sizes of the colony and slowing down again for large colonies. Similar results were obtained from the relationship between colony length and number of growth increments where a logistic model was the best fit to the data. On average Spearman's rank correlations showed 11% of shared variance between sea pen length or weight and environmental variables. Bottom temperature and salinity, depth and summer primary production were significantly correlated to sea pen size for most species. ARTICLE HISTORY