A systematic oceanographic monitoring program was initiated in September 1989 at twenty-five monitoring stations in the Passamaquoddy Bay area and approaches by Dr. Shawn Robinson based out of the St. Andrews Biological Station (SABS). Stations were established in a uniform grid pattern of two arcminutes latitude and longitude over the study area in order to develop a database on the spatial patterns of water properties. Monthly measurements of the water column for the temperatures and salinity at all stations was completed using a Seacat SBE 19 internally recording CTD from Sea-bird Electronics Inc. The CTD was programmed to record conductivity, temperature, and depth at a frequency of 2 hz, corresponding to 2 measurements per meter of water depth.

CTD casts were recorded for each of the 25 stations in the study area monthly using the R/V Pandalus, and later the CCGS Viola M. Davidson based out of SABS. The CTD was configured such that the sensors were oriented towards the benthos and the CTD was then attached to a hydraulic winch on the deck of the ship by a stainless steel cable one meter above a weight, and lowered 1 m below the water's surface in order for the CTD to equilibrate for one minute. The CTD was then lowered at 1 m/s to the benthos using a metered block on the winch to determine when the CTD had reached the maximum depth at that station. Once the weight had touched the bottom, the CTD was retrieved from the water, turned off, and placed in a bucket of fresh seawater in order to minimize equilibration time at the next station.

Initially, the CTD measured salinity via water forced through the salinity cell with the drop rate of 1 m/s, but in August 1992, a pump was mounted on the CTD in order to provide a more consistent flow of water across the salinity cell. Surface temperatures were measured from bucket samples collected upon arriving at each station using a hand-held mercury thermometer at each station, and Secchi disk measurements were recorded.

All data were downloaded from the CTD upon return to SABS using a DFO computer and the proprietary Sea-Soft software. Downcast data from each profile was retained, binned into 1 m intervals, and processed to remove data spikes, density inversions, and anomalies due to inadequate instrument equilibration. Processed data was then stored in the DFO's Oracle database (PTRAN) under the IMTA_SABS schema in the INVHYD and INVINF tables. Station numbers and locations are recorded in the CTD_STATIONS table in the IMTA_SABS schema.

Cite this data: Robinson, S. Data of: Passamaquoddy Bay monthly Conductivity Temperature and Depth (CTD) sampling (1989 - 2018). Published: October 2019. Coastal Ecosystems Science Division, Fisheries and Oceans Canada, St. Andrews, NB. https://open.canada.ca/data/en/dataset/12184962-7879-4214-aef0-b31162f04a27