Metadata for Tagging of Pacific Predators (TOPP) elephant seal temperature profile data.

Data were collected by Daniel Costa at UC Santa Cruz in Santa Cruz, California, USA.
costa@biology.ucsc.edu

If using these data for a publication or other analysis, please reference the TOPP project using the following format:

Costa, D.P. (2011) Northern elephant seal temperature cast data, Tagging of Pacific Predators.

A publication containing the details of data collection and processing is in progress.

Each file represents data from a single instrument on one adult female elephant seal.
Temperature and depth data were obtained from data logging tags manufactured by Wildlife Computers (MK9 or MK10).
Temperature and depth values are uncorrected, raw instrument readings.

Position data were obtained from a combination of GPS loggers and ARGOS PTT transmitters manufactured by Wildlife computers (SPOT4, SPOT5, or MK10) or the Sea Mammal Research Unit (SMRU SRDL)).
Position data were irregular in time and contained substantial spatial error.  So, we estimated a position for each station by smoothing the data using the CRAWL package in R-Cran and then applied a linear interpolation for each station.

File header information:
ID,STATION,MATLABDATE,YEAR,MONTH,DAY,HOUR,MINUTE,SECOND,LAT,LON,DEPTH,TEMP

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Relevant peer-reviewed journal articles:

Simmons, S. E., Y. Tremblay, and D. P. Costa (2009), Pinnipeds as ocean temperature samplers: Calibrations, validations and data quality, Limnol. Oceanogr. Methods, 7, 648–656.

Padman, L., D. P. Costa, S. T. Bolmer, M. E. Goebel, L. A. Huckstadt, A. Jenkins, B. I. McDonald, and D. R. Shoosmith (2010), Seals map bathymetry of the Antarctic continental shelf, Geophys. Res. Lett., 37, L21601, doi:10.1029/2010GL044921.

Costa, D. P., P. W. Robinson, J. P. Y. Arnould, A.-L. Harrison, S. E. Simmons, J. L. Hassrick, A. J. Hoskins, S. P. Kirkman, H. Oosthuizen, S. Villegas-Amtmann, and D. E. Crocker (2010b), Accuracy of ARGOS locations of pinnipeds at-sea estimated using Fastloc GPS, PLoS ONE, 5(1):e8677, doi:10.1371/journal.pone.0008677.

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Abstract from Simmons et al (2009)

Recently marine organisms have emerged as ocean-sensing platforms, generating data useful to biologists and oceanographers. However, sensor calibrations, performance over time, and effects of behavior and sampling frequency on data quality have not been adequately examined. We performed temperature calibration trials on 36
Wildlife Computers Mk9 time-depth recorders (stated accuracy 0.1°C ± 0.05°C) versus Rosemount Model 162CE standard platinum resistance thermometer (0.001°C, ± 0.0001°C). Sixty-four percent of trials were within ± 0.1°C. Subtracting 0.05°C from all calibrations brought this to 83%. Six instruments calibrated before and after deployment on free-ranging pinnipeds, showed no significant drift in temperature measurements. Mk9 performance was tested against a Seabird© CTD (SBE-19). Root mean square (rms) difference between CTD and Mk9 temperature was 0.15°C (max. 0.45°C, min. 0.10°C). Applying a 1-s time-lag improved the data fit. To assess animal effects on thermal data, Mk9s were deployed on juvenile elephant seals released between CTD casts. Overall rms were within ± 0.1°C. Subsampling of Mk9 data revealed a sampling frequency of 10 s was sufficient to accurately resolve thermal features, e.g., thermocline depth, for these CTD experiments. We present four equations to assess temperature data quality from diving marine animals around the globe carrying different thermistors.