Ascending and descending particle flux from hydrothermal plumes at Endeavour Segment,Juan de Fuca Ridge |
| |
| Institution: | 1. Department of Oceanography, University of Hawaii, 1000 Pope Road, Honolulu, Hawaii 96822, USA;2. Skidaway Institute of Oceanography, 10 Ocean Science Circle, Savannah, Georgia 31411, USA;3. Department of Fisheries and Oceans, Institute of Ocean Sciences, 9860 West Saanich Road, Sidney, BC, Canada V8L 4B2;4. Pacific Marine Environmental Laboratory, National Oceanographic and Atmospheric Administration, 7600 Sand Point Road NE, Seattle, WA 98115, USA;1. Departamento de Ecoloxía e Bioloxía Animal, Universidade de Vigo, 36310 Vigo, Spain;2. Instituto de Oceanografía y Cambio Global (IOCAG), Universidad de Las Palmas de Gran Canaria, 35017 Las Palmas de Gran Canaria, Spain;3. Applied Ocean Physics and Engineering Department, Woods Hole Oceanographic Institution, Woods Hole, MA 02543-1541, USA;1. Woods Hole Oceanographic Institution, 266 Woods Hole Rd., Woods Hole, MA 02543, USA;2. Joint Institution for the Study of the Atmosphere and Ocean—PMEL, University of Washington, Seattle, WA 98115, USA;1. Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton, UK;2. Ocean BioGeosciences, National Oceanography Centre, Southampton, European Way, Southampton, UK;3. Henry M. Jackson Foundation for the Advancement of Military Medicine (HJF), 6720A Rockledge Drive, Bethesda, MD, 2081, United States |
| |
| Abstract: | Bio-acoustic surveys and associated zooplankton net tows have documented anomalously high concentrations of zooplankton within a 100 m layer above the hydrothermal plumes at Endeavour Segment, Juan de Fuca Ridge. These and other data suggest that congregating epi-plume zooplankton are exploiting a food substrate associated with the hydrothermal plume. Ascending, organic-rich particles could provide a connection. Consequently, two paired sequentially sampling ascending and descending particle flux traps and a current meter were deployed on each of three moorings from July 1994 to May 1995. Mooring sites included an on-axis site (OAS; 47°57.0′N, 129°05.7′W) near the main Endeavour vent field, a “down-current” site 3 km west of the main vent field (WS), and a third background station 43 km northeast of the vent field (ES). Significant ascending and descending particle fluxes were measured at all sites and depths. Lipid analyses indicated that ascending POC was derived from mid-depth and deep zooplankton whereas descending POC also contained a component of photosynthetically derived products from the sea surface. Highest ascending POC fluxes were found at the hydrothermal plume-swept sites (OAS and WS). The limited data available, however, precludes an unequivocal conclusion that hydrothermal processes contribute to the ascending flux of organic carbon at each site. Highest ascending to descending POC flux ratios were also found at WS. Observed trends in POC, PMn/PTi, and PFe/PTi clearly support a hydrothermal component to the descending flux at the plume-swept WS site (no descending data was recovered at OAS) but not at the background ES site. Alternative explanations for ascending particle data are discussed. First-order calculations for the organic carbon input (5–22 mg C m?2 d?1) required to sustain observed epi-plume zooplankton anomalies at Endeavour are comparable both to measured total POC flux to epi-plume depths (2–5 mg C m?2 d?1: combined hydrothermal and surface derived organic carbon) and to estimates of the total potential in situ organic carbon production (2–9 mg C m?2 d?1) from microbial oxidation of hydrothermal plume H2, CH4 and NH4+. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
