V. Sathepathak et al., THRAUSTOCHYTRID AND FUNGAL COMPONENT OF MARINE DETRITUS .1. FIELD STUDIES ON DECOMPOSITION OF THE BROWN ALGA SARGASSUM-CINEREUM J AG, Indian journal of marine sciences, 22(3), 1993, pp. 159-167
Thraustochytrid protists and fungi were isolated and enumerated in cul
ture from detritus of the brown alga Sargassum cinereum. Both groups o
ccurred epi and endobiontically in the detritus. The thraustochytrid L
abyrinthuloides minuta occurred in healthy as well as decomposing alga
l tissues, whereas Ulkenia visurgensis was found only in the latter. U
p to 2.9 X 10(7) of the two thraustochytrids, 5.2 X 10(4) of fungi and
5.5 X 10(11) of bacteria (per g dry wt. detritus) were found, using i
mmunofluorescence, culture techniques and direct counts respectively.
Populations of all 3 groups (thraustochytrids, fungi and bacteria were
lowest in healthy algae containing higher amounts of phenolics than i
n detritus. Concentrations of total carbohydrates (TCH), total phenols
, proteins, alginate and mannitol, as well as C/N ratios declined as d
ecomposition progressed, concomitant with an increase in microbial bio
mass. Both thraustochytrids and bacteria attained peak biomass values
in 21 d detritus. Maximum observed biomass of thraustochytrids corresp
onded to 0.07 % C and that of bacteria to 1.1 % C of detrital dry weig
ht. The constant association of thraustochytrids with the brown algal
detritus and their endobiontic habitat suggest a definite role for the
se protists in detrital dynamics.