U. Passow et P. Wassmann, ON THE TROPHIC FATE OF PHAEOCYSTIS-POUCHETII (HARIOT) .4. THE FORMATION OF MARINE SNOW BY P-POUCHETI, Marine ecology. Progress series, 104(1-2), 1994, pp. 153-161
The formation of aggregates by Phaeocystis was investigated in coastal
waters of northern Norway and in laboratory experiments. No evidence
was found to support the hypothesis formulated by Wassmann et al. [(19
90); Mar, Ecol. Prog. Ser. 66: 183-195] that Phaeocystis blooms are te
rminated by the formation of Phaeocystis aggregates from senescent col
onies. Although Phaeocystis was observed to form aggregates in some in
stances, senescent colonies did not appear to have a higher sticking e
fficiency than growing ones. At senescence Phaeocystis colonies appear
ed to disintegrate. Further laboratory studies revealed that dissolved
carbohydrates derived from the colonial matrix of Phaeocystis formed
mucous particles which attached to siliceous fibers and glued them tog
ether. Detrital mucous flocs also formed from a natural particle assem
blage and dissolved carbohydrates accumulated during the Phaeocystis b
loom when rotated. We develop the hypothesis that cells and colonies o
f Phaeocystis may not contribute significantly to vertical flux, but t
hat the sedimentation of mucous flocs presents a secondary pathway by
which carbon assimilated during Phaeocystis blooms may sink to greater
depth.