Video Plankton Recorder Survey
Carin Ashjian, Woods Hole Oceanographic Institution
Redfield 2-44, MS#33
Woods Hole, MA 02543
The southern Japan/East Sea (JES) was surveyed from the R/V Roger Revelle using the Video Plankton Recorder (VPR) (Davis et al., 1992) mounted on a v-fin during June 24-July 14, 1999. The cruise track covered over 5000 km, extending from the Tsushima Strait in the south to just north of Tsugaru Strait between Hokkaido and Honshu, Japan, and covered several distinct hydrographic regions including the Ulleung Basin, the Yamato Basin, and the subpolar front.
The cruise track was punctuated by stations at which CTDs and optical casts were conducted; the Video Plankton Recorder was towed between all CTD stations along the transects. The VPR was towyoed between near surface and 80 m at ~9 knots, yielding an inter-profile distance of ~4 km. The VPR collected images of plankton from high (imaged volume = 3 ml; field of view = 8 x 7 mm; pixel size = 0.02 x 0.03 mm) and low (imaged volume = 29.6 ml; field of view = 23.5 x 21 mm, pixel size = 0.05 x 0.08 mm) magnification cameras as well as coincident hydrographic (temperature, conductivity) and environmental (light transmission, fluorescence, ambient light) data which were relayed to the ship via a fiber optic cable and merged with supporting data (latitude, longitude, time, and bottom depth). Plankton images were identified to major taxa using an image analysis and recognition system (Tang et al., 1998); this system yields type specific plankton abundances with coincident depth and environmental information. Only abundant plankton types were identified.
The plankton types identified for the high magnification camera were unidentified calanoid copepods, Oithona, diatom chains, copepod nauplii, sarcodines, acantharians, larvaceans, unidentified phytoplankton, an unidentified yet visually distinctive protozoan, and an unidentified tear drop shaped particle. The categories identified in the low magnification camera were Calanus spp. (including Neocalanus spp.; herein Calanus) unidentified copepods, marine snow, and all others.
Data are presented here as abundances (#/L) of each taxa or particle in ~ 5 second time intervals. The files contain 12 columns of time, geographic location, environmental, and along-track data plus 10 columns of taxa/particle abundance for the high magnification camera and 4 columns of taxa/particle abundance for the low magnification camera. Data are presented here as abundances (#/L) of each taxa or particle in ~ 5 second time intervals. Yearday (column 1) is calculated with January 1 being day zero. Along-track distance (km; column 12) is calculated from the geographic positions of the observations, in temporal order. Bottom depth (m; column 11) was from the shipboard Knudsen Echo Sounder; these data are very noisy. Position (latitude, longitude) logged from the ship's P-Code GPS. All other variables (pressure, temperature, salinity, density, fluorescence, light transmission, and PAR) were measured or calculated using sensors on the Video Plankton Recorder.
Davis, C.S., Gallager, S.M., Solow, A.R. 1992a. Microaggregations of oceanic plankton observed by towed video microscopy. Science 257, 230 232.
Davis, C.S., Gallager, S.M., Berman, M.S., Haury, L.R., Strickler, J.R., 1992b. The Video Plankton Recorder (VPR): Design and initial results. Archiv für Hydrobiologie Beiheft, Ergebnisse der Limnologie, 36, 67-81.
Tang, X., Steward, W.K., Vincent, L., Huang, H., Marra, M., Gallager, S.M., Davis, C.S. 1998. Automatic plankton image recognition. Artificial Intelligence Review 12, 1-23.