Transport of particulate organic matter by bubbles in marine waters 1

Flotation experiments with surface marine waters collected from estuarine, continental shelf, slope, and open ocean waters showed that about half of the originally present particulate organic carbon and nitrogen was adsorbed and transported by bubbles to the surface froth. Recovery values were a function of primary production and other environmental parameters. In only one instance was there evidence of selective removal of particles with C:N ratios differing from those left behind. The estimated open ocean transport of POC by bubbles was five times higher than an earlier estimate due to the unexpected efficiency of the flotation column at low concentrations of open ocean POC. Budget calculations indicated little or no conversion of dissolved to particulate organic carbon. Large macroscopic particles quickly formed in the froth produced by bubbling, an aggregation phenomenon which may be of importance in the transport of large particle POC to deep waters.