Abstract:

In situ imagery data were collected from 2016-07-24 to 2016-07-30 onboard the RV Point Sur PS17_02 (PTS03) as part of the CONCORDE summer field sampling campaign. The data includes image segments (regions of interest) for organisms greater than ~1 cm in size or bell diameter. Each individual was classified and merged to the nearest environmental data collected by the In Situ Ichthyoplankton Imaging System, which includes conventional oceanographic sensors (temp, salinity, dissolved oxygen, etc.). The purpose of the data collection was to describe the oceanographic habitats of different large cnidarian medusae and ctenophores during the stratified summer season in the northern Gulf of Mexico.

Suggested Citation:

Treible, Laura M., Luciano M. Chiaverano, and Adam T. Greer. 2022. Fine-scale distributions of large cnidarian medusae and ctenophores (>1 cm) data obtained aboard the R/V Point Sur cruise PS17_02 (PTS03) in the Mississippi Bight from 2016-07-24 to 2016-07-30. Distributed by: GRIIDC, Harte Research Institute, Texas A&M University–Corpus Christi. doi:10.7266/9SR7BD92

Purpose:

Data were collected to describe the abundances and distribution of plankton in relation to differing amounts of river discharge (highest in the west, lowest in the east). These data were evaluated specifically focusing on larger gelatinous organisms that are relatively rare, but about which little is known.

Data Parameters and Units:

Physical files: Central time (HH:MM:SS), julian = julian time (CDT), Time (UTC), timestamp = Unix timestamp (local time), alt = altitude; distance from benthos (m), Temperature (degrees Celsius), Depth (m), fluor = chlorophyll-a fluorescence (raw voltage), fvel = forward velocity (m/s, 0 indicates unreliable reading from ADCP), heading = heading of the ISIIS vehicle (degrees), o2 = oxygen concentration (incorrect- see note), o2volts (volts), par (/m^2), parvolts (volts), pitch= pitch of ISIIS vehicle (degrees), roll = roll of the ISIIS vehicle (degrees), salinity (psu), lat = latitude (decimal degrees), lon = longitude (decimal degrees), vertvel = vertical velocity (mm/sec), altok (binary variable indicates if altitude data are valid, 1-valid, 0-error), transect (DVM only) = transect number (1-3) SigmaInterp files: dist = horizontal tow distance (m), depth = vertical depth (m), sigma OxyInterp files: dist = horizontal tow distance (m), depth = vertical depth (m), oxy = oxygen concentration (mg/L) BioPhys Files: nearjul = nearest julian time (CDT) of physical data to image– the physical data and images are not collected at the same rate (6 Hz for environment, 17 Hz for images), julian = julian time (CDT), ID = taxonomic identification, Junk = image particle type, label = image file name, slice= image number within an image stack of 430 images, xloc = x pixel location within the larger frame, yloc = y pixel location within the larger frame, width = width of bounding box (pixels), height = height of bounding box (pixels), Time (UTC), timestamp = Unix timestamp (local time), alt = altitude; distance from benthos (m), Temperature (degrees Celsius), Depth (m), fluor = chlorophyll-a fluorescence (raw voltage), fvel = forward velocity (m/s, 0 indicates unreliable reading from ADCP), heading = heading of the ISIIS vehicle (degrees), o2 = oxygen concentration (incorrect- see note), o2volts (volts), par (/m^2), parvolts (volts), pitch= pitch of ISIIS vehicle (degrees), roll = roll of the ISIIS vehicle (degrees), salinity (psu), lat = latitude (decimal degrees), lon = longitude (decimal degrees), vertvel = vertical velocity (mm/sec), altok (binary variable indicates if altitude data are valid, 1-valid, 0-error), dist = horizontal tow distance (m), o2delay = corrected oxygen concentration (mg/L) Note: For corrected oxygen ‘o2delay’, we used the formula supplied by the oxygen sensor (Seabird electronics) to convert the oxygen voltage, temperature, salinity, and depth to dissolved oxygen concentration. The oxygen concentration values for ‘o2’ are incorrect for the summer 2016 data due to an error in the software that converts the voltage. Weighted Mean Depth files: label = taxonomic identification, wmd = weighted mean depth (m) Depth Concentration Files: Taxonomic identification, count = individuals counted within depth bin, Depth bin (m), Volume sampled (m^3), Concentration (individuals/m^3)

Methods:

An in situ imaging system was towed along 3 sampling "corridors" in the northern Gulf of Mexico from near surface to ~2m off of the bottom in water depths from 20-40 m, covering approximately 50 km of horizontal distance. Shorter tows (~10 km horizontal distance) were performed in the same area during sequential days and nights, and those are labeled as "diel vertical migration" or DVM.

Individual Files: