Ecology and biogeography of megafauna and macrofauna at the first known deep-sea hydrothermal vents on the ultraslow-spreading Southwest Indian Ridge.

The Southwest Indian Ridge is the longest section of very slow to ultraslow-spreading seafloor in the global mid-ocean ridge system, but the biogeography and ecology of its hydrothermal vent fauna are previously unknown. We collected 21 macro- and megafaunal taxa during the first Remotely Operated Vehicle dives to the Longqi vent field at 37° 47'S 49° 39'E, depth 2800 m. Six species are not yet known from other vents, while six other species are known from the Central Indian Ridge, and morphological and molecular analyses show that two further polychaete species are shared with vents beyond the Indian Ocean. Multivariate analysis of vent fauna across three oceans places Longqi in an Indian Ocean province of vent biogeography. Faunal zonation with increasing distance from vents is dominated by the gastropods Chrysomallon squamiferum and Gigantopelta aegis, mussel Bathymodiolus marisindicus, and Neolepas sp. stalked barnacle. Other taxa occur at lower abundance, in some cases contrasting with abundances at other vent fields, and δ13C and δ15N isotope values of species analysed from Longqi are similar to those of shared or related species elsewhere. This study provides baseline ecological observations prior to mineral exploration activities licensed at Longqi by the United Nations.

Race/ethnicity affects the probability of finding an HLA-A, -B, -C and -DRB1 allele-matched unrelated donor and likelihood of subsequent transplant utilization.

Factors relevant to finding a suitable unrelated donor and barriers to effective transplant utilization are incompletely understood. Among a consecutive series of unrelated searches (n=531), an 8/8 HLA-A, -B, -C and -DRB1-matched unrelated donor was available for 289 (54%) patients, 7/8 for 159 (30%) and no donor for 83 (16%). Patients of Caucasian race (P<0.0001) were more likely to find a donor. Younger age (P=0.01), Caucasian race (P=0.03), lower CIBMTR (Center for International Blood and Marrow Transplantation Research) risk (P=0.005), and 8/8 HLA matching (P=0.005) were associated with higher odds of reaching hematopoietic cell transplantation (HCT). In a univariate analysis of OS, finding a donor was associated with hazard ratio (HR) of 0.85 (95% CI 0.63-1.2), P=0.31. Karnofsky performance status (KPS) accounted for interaction between having a donor and survival. Patients with KPS 90-100 and a donor had significantly reduced hazard for death (HR 0.59, 95% CI 0.38-0.90, P=0.02). These data provide estimates of the probability to find an unrelated donor in the era of high-resolution HLA typing, and identify potentially modifiable barriers to reaching HCT. Further efforts are needed to enhance effective donor identification and transplant utilization, particularly in non-Caucasian ethnic groups.

Implications of dredging induced changes in sediment particle size composition for the structure and function of marine benthic macrofaunal communities.

A meta-analysis approach was used to assess the effect of dredging induced changes in sediment composition, under different conditions of natural physical disturbance, for the structure and function of marine benthic macrofaunal communities. Results showed the sensitivity of macrofaunal communities increased as both the proportion of gravel increased and the level of natural physical disturbance decreased. These findings may be explained by the close association of certain taxa with the gravel fraction, and the influence of natural physical disturbance which, as it increases, tends to restrict the colonisation by these species. We conclude that maintaining the gravel content of surface sediments after dredging and, where practicable, locating extraction sites in areas of higher natural disturbance will minimise the potential for long-term negative impacts on the macrofauna.