Exopolymeric substances (EPS) mechanisms in aggregation & dispersion of oil: Fragmentation of Skeletonema grethae-775 snow – Disaggregation dynamics

Results from a laboratory experiment on the fragmentation potential of marine snow (MS) and marine oil snow (MOS) formed in roller tanks filled with Skeltonema grethae and Macondo oil [1mL per L] to form MOS, and filtered seawater to form MS. Single aggregates were placed into a tank with an oscillating grid that generates turbulence; fragmentation behavior of aggregates was observed and noted in lab book (aggregates fragmented yes (y) or no (n)). Aggregates were sized using a digital microscope (at 75x magnification); the aggregate area was measured using ImageJ software. After aggregates were removed, the tank water was subsampled and fixed with formalin (2% v/v) and stored at 4 degrees for later analysis of particle concentrations using a Coulter counter (CC). Individual samples were run 3 times on the CC (i.e., analytical replicates: A, B, C). Particle concentration was measured between 4 size ranges: 5-10 um, 10-20 um, 20-50 um, 50-100 um.