Effect of monsoonal perturbations on the occurrence of phytoplankton blooms in a tropical bay

Patil, Jagadish S. ; Anil, Arga Chandrashekar (2015) Effect of monsoonal perturbations on the occurrence of phytoplankton blooms in a tropical bay Marine Ecology Progress Series, 530 . pp. 77-92. ISSN 0171-8630

Full text not available from this repository.

Official URL: http://www.int-res.com/abstracts/meps/v530/p77-92/

Related URL: http://dx.doi.org/10.3354/meps11289


In this study, the influence of intraseasonal variations in rainfall and the resultant freshwater flux (monsoon perturbations) on phytoplankton bloom dynamics were evaluated by quantifying live phytoplankton at a fixed station (Dona Paula Bay, west coast of India) every day during the 2008 southwest monsoon season (June-September). Pre-processing of the sample for live phytoplankton analysis using FlowCAM through fluorescence-based quantification of phytoplankton size fractions is described for the first time. Six diatom blooms of autochthonous origin were encountered during the observations, coinciding with nutrient enrichment and a lull in river runoff. The blooms observed at the beginning (1st bloom) and the end of the season (6th bloom) were dominated by nano- and picophytoplankton, and the intervening blooms by microphytoplankton. All blooms coincided with flood tide or high tide under optimal salinity (>15) and light (depth of light penetration: >50 cm; solar radiation: 30-70 mW cm-2) conditions following heavy rainfall and nutrient flux. Termination of blooms coincided with nitrate exhaustion. Dinoflagellate (2nd dominant group) abundance was positively associated with depth of light penetration >100 cm and low nutrient concentrations. Bloom duration of 1-6 d was recorded, indicating that such events are widespread and can significantly influence the system’s metabolic balance. The average net photic zone production of the season was positive (0.11 ± 0.67 g O2 m-2 d-1), and a quarter of the monsoon season was net autotrophic. Although bloom production was underutilized (up to 63%), much of the system’s carbon requirement (up to 70%) was met by allochthonous supply.

Item Type:Article
Source:Copyright of this article belongs to Inter-Research.
Keywords:Tropical Bay; Flowcam; Phytoplankton; Diatoms; Dinoflagellates; Blooms; Monsoon
ID Code:99289
Deposited On:26 Feb 2016 11:41
Last Modified:26 Feb 2016 11:41

Repository Staff Only: item control page