Spatiotemporal Distribution of Harmful Algal Flora in the Tropical Estuarine Complex of Goa, India

Suraksha M Pednekar,S G Prabhu Matondkar,Vijaya Kerkar

doi:10.1100/2012/596276

Suraksha M Pednekar, S G Prabhu Matondkar + Show 1 more

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https://doi.org/10.1100/2012/596276

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Abstract

Mandovi and Zuari estuarine complex is monsoon-influenced estuaries located along the central west coast of India. During the past few years, there has been an increase in nutrient loading specially during monsoonal runoff which is responsible for the growth of harmful algal flora. To understand occurrence and distribution of harmful algal blooms species, daily/alternate day samplings were carried out in Mandovi and Zuari estuaries during 2007-2008 and 2008-2009 periods, respectively, comprising of monsoon (June–November) and nonmonsoon (December–May). In Mandovi, total 54 HAB species with 49 in monsoon and 36 during nonmonsoon period were reported. In Zuari, total 46 HAB species with 38 in monsoon and 41 were reported during nonmonsoon period. Bray-Curtis cluster analysis based on log-transformed phytoplankton density detected seven well-defined groups revealing spatiotemporal variability. The density of the dominant harmful algal species was significantly positively correlated with nutrients, but negatively correlated with salinity. The results of the study indicate that monsoon plays an important role in occurrence and distribution of harmful algal species having direct correlation with salinity variations and nutrient loading.

Highlights

Harmful algal blooms occur when the algal cells in the marine or fresh water grow out of proportion causing economic loss and severe impacts on marine life and human health [1]
In the case of Mandovi, sampling station (St.1) was ∼2 km upstream from the mouth of the estuary, and in Zuari, the site (St.2) was ∼13 km upstream from the mouth of the estuary (Figure 1). These sites were chosen for two major reasons: first, because of its accessibility from the National Institute of Oceanography (NIO), vessel CRV Sagar Shakti which was to be anchored at the point during the entire southwest monsoon season, and second, on account of the large salinity range (0 to 37 psu) that this locations experienced [16]
It can be concluded that monsoon acts as a major player in the spatiotemporal distribution of large number of harmful algal species

Summary

Introduction

Harmful algal blooms occur when the algal cells in the marine or fresh water grow out of proportion causing economic loss and severe impacts on marine life and human health [1]. Some are potentially toxic even at low concentrations (few cells per litre) and produce toxic effects affecting the marine life whose intern affects the human health. In India, “red-tide” events were caused by Noctiluca miliaris along southern Kerala coast [4,5,6], and severe fish mortality was observed. Paralytic shellfish poisoning outbreak was observed in Mangalore along the west coast where the causative organism was not known [7, 8], and the stench of Cochlodinium polykrikoides was observed along the southern Malabar Coast by [9]. Many cysts of toxic dinoflagellate species have been reported in the sediments along the south west of India during the southwest monsoon period [10, 11]

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