Multivariate Analysis of Short Term Spatial and Temporal Variations in Plankton Communities and Marine Snow in the Offshore Gulf of Mexico as Estimated by the Video Plankton Recorder and MOCNESS

Resolving the small-scale distributions of planktonic communities in relation to environmental parameters is critical for understanding the mechanisms driving vertical and horizontal patchiness in plankton communities over small temporal scales. In situ imaging technologies, such as the Digital Autonomous Video Plankton Recorder (DAVPR) coupled with stratified net systems (MOCNESS), can resolve plankton distributions on small spatial and temporal scales. There is little or no data of this type from the offshore waters in the Gulf of Mexico. The event of the Deepwater Horizon oil spill put a significant emphasis on the need for data characterizing the community composition and vertical distribution patterns of plankton and particles in these waters. Using the non-destructive Video Plankton Recorder (VPR), marine plankton, and coincident environmental data were collected from the northern Gulf of Mexico’s offshore waters during the spring of 2011. Comparative measurements to the VPR data were made with samples collected by a 1m² MOCNESS (Multiple Opening and Closing Net, and Environmental Sensing System). Multivariate statistical methods were used to explore differences in plankton communities at different stations and depth in relation to environmental parameters. Short-term variations in the plankton communities largely occurred in the upper 210m of the water column while the deep 210-410m samples exhibited low species variances at all stations over a three day period of observation with the exception of one near-to-shore station. Environmental data collected at all stations described a stable well stratified system with pronounced subsurface chlorophyll-a peak centered above the pycnocline.