Description
Summary:This is the CTD data set from RV Tangaroa cruise tan0803, 26th March to 26th April 2008, along the Macquarie Ridge. This was the recovery cruise for the Macquarie Ridge mooring array. The primary aims of the oceanographic program were: 1. recovery of a New Zealand/Australia collaborative mooring array spanning two gaps in the Macquarie Ridge north of Macquarie Island, and 2. occupation of a CTD transect running south from New Zealand to 60o S along the Macquarie Ridge. Eight of the nine moorings were successfully recovered. The mooring at site number 3 (NIWA gear) was unrecoverable, with acoustic release communication indicating only the bottom portion of the mooring remaining and lying flat on the ocean floor. Complete details of the mooring work are included in a separate mooring recovery report. Mooring instruments were downloaded on the ship, with a very high percentage of successful data recording. Ship maneouvering and deck operations all went well throughout the recoveries. Shiptime at the mooring locations was well spent, with daylight hours dedicated to mooring recovery, and night time used for nearby CTD, swath mapping, coring and sea mount activities, and for unspooling of mooring line. The additional container space created on the top deck portside (above the trawldeck) proved extremely valuable for stowage of mooring gear. 58 CTD's were completed during the cruise, including 54 along the main transect, and 4 at coring locations (part of the geology program). Main transect CTD's included 2 across the northern mooring group, and 3 across the southern mooring group. Most casts were to within 25 metres of the bottom. Instrument problems resulted in incomplete casts at the following locations: CTD 9, CTD 11 and CTD 27. CTD 46 was skipped due to bad weather, while further instrument problems prevented a cast at the southernmost site (CTD 50). Niskin bottles were sampled at each station for dissolved oxygen and salinity, with a subset of stations selected for 18O sampling. Some stations were additionally sampled for DIC, alkalinity, 13C, silicate, and U/Th, as part of the geology program. Note that dissolved oxygen data have been removed from this data set, as oxygen bottle samples were never analysed.