On 15 June, the WSTP was lowered to an approximate depth of 3931.8 meters below sea level (mbsl), or 8 m above seafloor, for a 38-min station before drilling operations began in Hole 1274A (Fig. F66A). A temperature time series of ocean bottom water and a water sample were obtained for microbiology studies (see "Microbiology"). The temperature time series shows a gradual increase for ~6.8 min before the water-sampling valve opened, followed by a 2-min period with no sampling of temperature data, one stationary temperature reading, another 2-min interval with no temperature readings while the water-sampling valve was closing, and a 9-min period before the tool began its ascent to the rig floor (Fig. F66B).
The ocean bottom water temperature increased from 3.16° to 3.23°C, or a rate of ~0.0002°C/s over a time interval of 6.8 min before the water-sampling valve was opened (Fig. F66B). These temperatures are consistently higher than the range of 2.91°–3.04°C recorded in Hole 1268A. For comparison, Shinkai Dive 6500 Dive 416 traversed this area in 1998 and measured water temperatures of 2.53°C at 3930 mbsl (descending) and 2.52°C at 3927 mbsl (ascending). On the seafloor at 3981 mbsl near Site 1274, the water temperature was measured at 2.515° ± 0.002°C over a period of 13 min during sampling (P. Kelemen, pers. comm., 2003).
A temperature anomaly was recorded after the water-sampling valve closed prior to the tool's ascent. This event is similar to the one recorded above Hole 1268A but is larger in magnitude. The nature of the temperature profile after the water-sampling valve closed and the proximity to the time of tool retrieval profile raises questions about whether this event is an artifact created by electronics of the tool itself or related to warmer fluids emanating from the seafloor.