NZAPLUME III, TAN 04-10

Voyage objectives: (1) Collect EM300 bathymetric data and discrete water samples above Richie Ridge and analyse for CH4, (2) Deploy 3 current meter moorings outside Brothers volcano (Chico, 34 49.6'S, 179 5.8'E, 2240 m; Groucho, 34 54.9'S, 179 6.1'E, 2270 m; Harpo, 34 52.8'S, 179 0.4'E, 2000 m) for Brothers ‘flux’ experiment, (3) Deploy 4 hydrophone moorings inside Brothers caldera (sites to be determined) for retrieval during 2005 Ocean Exploration expedition, (4) Collect EM300 bathymetric data of submarine volcanoes (and transects in between) from Macauley Island to south of volcano #19 of the 2003 TELVE expedition, inside Tongan territorial waters, a transect of ~325 n.m. (~560 km). (5) Collect continuous hydrographic and optical data using conductivity-temperature-depth (CTD) and nephelometer sensors as part of the GNS profiling system, (6) Collect continuous chemical (pH, Eh, CH4) data from sensors installed on the GNS profiling system, (7) Using a rosette of PVC sampling bottles, sample discrete seawater samples for various dissolved metals (e.g., Fe, Mn), gases (e.g., 3He/4He, CH4, H2S) and particulate (e.g., by filtration) hydrothermal species, and to sample microbes in the plumes, (8) Conduct a series of vertical-cast and tow-yo, water column surveys over the summits of ~12 volcanic edifices (volcanoes?) mapped by single line bathymetry during the TELVE cruise. Additional tow-yo surveys may be done over any one site if plumes are detected during the initial surveys, (9) Conduct a series of vertical-cast, water column surveys between the volcanoes, as background casts for helium and particulates, probably on the return leg of the voyage, (10) Do a ‘time series’ survey of plumes with tow yo’s over the two main vents sites associated with Brothers volcano to compare and contrast with 1999 NZAPLUME I and 2002 NZAPLUME II results, as part of flux experiment, (11) Collect continuous and discrete seawater samples from shallow depths to analyse for dissolved trace gases CH4, N2O and CO related to surface layer biology, (12) Perform dredging operations on the most active hydrothermal site(s), to recover mineralized samples, rocks, and vent-related animals, and (13) Drop off and pick up 2 weeks later, Raoul Island party who will do mapping and sampling related to geothermal activity recent volcanological events.