Life in the Slow Lane: Growth and Longevity of Cold‐seep Vestimentiferans

Section: Pressure Experimentsmentioning

confidence: 99%

mentioning

confidence: 99%

Preliminary data on carbon production of deep-sea vent tubeworms

Ravaux¹,

Gaill²,

Delachambre³

et al. 1999

“…While the range of temperatures for shallow-living polychaetes and vent paralvinellids overlap, the low temperatures at cold seeps are much lower (in the range from 2 to 5°C). These observed overall low enzyme activities of cold seep polychaetes dwelling in a spatially and temporally very stable habitat suggest that cold seeps favor slow growth and, thus, low metabolic activity, as observed for other hydrocarbon seep polychaetes (Fisher et al 1997). …”

mentioning

confidence: 89%

Pathways, activities and thermal stability of anaerobic and aerobic enzymes in thermophilic vent paralvinellid worms

Lee¹

2009

Animals living at deep sea hydrothermal vents experience high values of both temperature and hypoxia/sulfide. In these harsh environments polychaetes represent an important proportion of the biomass and diversity. To determine the mechanisms facilitating survival, we investigated the activities and thermal stability of 6 enzymes functioning under anaerobic and aerobic conditions, as well as glycogen levels, in 2 paralvinellid species from hydrothermal vents. In addition, the enzyme activities of several polychaetes from hydrocarbon cold seeps, which encounter low oxygen and high sulfide, but not elevated temperature, were investigated for comparative purposes. 'Anaerobic' (lactate dehydrogenase, opine dehydrogenases) and 'aerobic' enzyme (citrate synthase) activities of hydrothermal vent paralvinellids were similar to those of shallow water polychaetes, and significantly higher than those in cold seep species. Surprisingly, we detected different metabolic pathways in various body parts of hot vent species. The branchiae were identified to be the body part in which aerobic metabolism likely dominates, whereas the body wall is the major focal point of anaerobic glycolysis. Enzyme activity levels remained nearly constant in paralvinellids maintained for up to 120 h in high-pressure chambers. Thermal stability observations of in vitro enzyme activities showed stability after exposure to elevated temperatures: up to 60°C for lactate dehydrogenase and up to 50°C for opine dehydrogenases, the latter correlating with the preferred temperatures of living paralvinellids. Heat shock experiments with live specimens revealed lethal temperatures of 45°C for Paralvinella palmiformis and 63°C for P. sulfincola. Heat shock treatments also reduced enzyme activity. Glycogen levels in vent species were lower than in shallow water species, suggesting that paralvinellids can obtain carbon through feeding under anoxic conditions. KEY WORDS: Hydrothermal vent · Paralvinellids · Temperature · Hypoxia · Glycogen · Cold seep · Dehydrogenase · Citrate synthase Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 382: [99][100][101][102][103][104][105][106][107][108][109][110][111][112] 2009 formis co-occurs at vent sites with P. sulfincola, but colonizes different niches with lower temperatures (5 to 14°C; Sarrazin et al. 1999) and less hydrogen sulfide with about 20 to 65 µmol l -1. P. palmiformis specimens also avoided temperatures > 35°C in in vivo experiments (Girguis & Lee 2006), and died at temperatures > 40°C (Lee 2003).Environmental biochemical adaptations in these species are less well characterized than those in the thermophilic alvinellid Alvinella pompejana, which inhabits the high temperature niche at East Pacific Rise vents (e.g. Cary et al. 1998, Chevaldonné et al. 2000.Biochemical evidence indicates that high temperature alvinellids have macromolecules that are thermally stable at temperatures up to 50°C. These findings are consistent with a likely ability to tolerate ...

“…26 mM, Sahling et al 2002) (Table 7). However, individual whale falls are small in areal extent and short-lived (lasting for decades vs. 100 to 1000 yr) for some cold seeps (Fisher et al 1997, Hornafius et al 1999, Schuller et al 2004 (Table 7). The skeletons of whale falls, with apparently low and heterogeneous SR rates associated with hard substrates, might be more similar to hydrothermal vent systems, where sulfide concentrations in the surrounding water reach relatively low levels (< 0.1 to 1 mM) -due to rapid dilution -and are often patchy (Johnson et al 1986, Luther et al 2001 (Table 7).…”

Section: Comparison With Other Sulfur-based Habitatsmentioning

confidence: 99%

Biogeochemistry of a deep-sea whale fall: sulfate reduction, sulfide efflux and methanogenesis

Treude¹,

Smith²,

Wenzhöfer³

et al. 2009

131

169

Present address: Bundesanstalt für Geowissenschaften und Rohstoffe, Stilleweg 2, 30655 Hannover, GermanyABSTRACT: Deep-sea whale falls create sulfidic habitats supporting chemoautotrophic communities, but microbial processes underlying the formation of such habitats remain poorly evaluated. Microbial degradation processes (sulfate reduction, methanogenesis) and biogeochemical gradients were studied in a whale-fall habitat created by a 30 t whale carcass deployed at 1675 m depth for 6 to 7 yr on the California margin. A variety of measurements were conducted including photomosaicking, microsensor measurements, radiotracer incubations and geochemical analyses. Sediments were studied at different distances (0 to 9 m) from the whale fall. Highest microbial activities and steepest vertical geochemical gradients were found within 0.5 m of the whale fall, revealing ex situ sulfate reduction and in vitro methanogenesis rates of up to 717 and 99 mmol m -2 d -1, respectively. In sediments containing whale biomass, methanogenesis was equivalent to 20 to 30% of sulfate reduction. During in vitro sediment studies, sulfide and methane were produced within days to weeks after addition of whale biomass, indicating that chemosynthesis is promoted at early stages of the whale fall. Total sulfide production from sediments within 0.5 m of the whale fall was 2.1 ± 3 and 1.5 ± 2.1 mol d -1 in Years 6 and 7, respectively, of which ~200 mmol d -1 were available as free sulfide. Sulfate reduction in bones was much lower, accounting for a total availability of ~10 mmol sulfide d Skeleton of a whale on the deep-sea floor, covered by chemoautotrophic bacterial mats, anemones, and bone-eating worms Osedax spp., 6 yr after arrival at the seafloor.