Diatoms of the microphytobenthic community in a tropical intertidal sand flat influenced by monsoons: spatial and temporal variations |
| |
Authors: | Smita Mitbavkar Arga Chandrashekar Anil |
| |
Institution: | (1) National Institute of Oceanography, 403 004 Dona Paula, Goa, India |
| |
Abstract: | Seasonal variations in the microphytobenthic diatom community were investigated in an intertidal sand flat of a tropical marine
environment influenced by monsoons. Cores of sediments were collected along the beach gradient: low tide, mid tide and high
tide zone up to a depth of 15 cm.. Diatom abundance was lowest during the monsoons and highest during the post-monsoons and
the early pre-monsoon season throughout the intertidal transect. Diatom diversity was highest at the mid tide, followed by
the high and low tide zones. Diatoms were viable up to a depth of 15 cm throughout the intertidal transect. The diatom community
included the pennates, the permanent residents of this area, centric genera, which lead an attached mode of life and also
some planktonic genera, brought in from ambient waters. Among the pennates, Navicula and Amphora were the dominant genera whereas in the case of centrics, Thalassiosira dominated the community throughout the intertidal transect down to a 15 cm depth. . Grain size fractions, which served as
predictors of some diatom genera changed with tidal zones. The effect of winds on the resuspension of the pennate diatoms
was evident only at the low tide zone down to a depth of 5 cm . Chlorophyll a concentration proved to be a good predictor of both pennate and centric diatom abundance at the low tide zone down to a depth
of 10 cm and at the mid tide zone down to a depth of 5 cm.. However, even though chlorophyll a concentrations failed to reveal any positive correlation with the diatom abundance at both the deeper sediment layers and
the high tide zone, the fact that viable cells were present at these areas reveal that the diatoms adopt survival strategies,
contributing significantly to the carbon budgets of such unstable habitats. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|