MEPS 346:75-88 (2007)  -  DOI:

Tropical phytoplankton community development in mesocosms inoculated with different life stages

Karolina Härnström1,*, Anna Godhe1, V. Saravanan2, Indrani Karunasagar2, Iddya Karunasagar2, Ann-Sofi Rehnstam-Holm3

1Department of Marine Ecology, Marine Botany, Göteborg University, PO Box 461, 405 30 Göteborg, Sweden
2Department of Fishery Microbiology, College of Fisheries, Karnataka Veterinary Animal and Fisheries Sciences University, PO Box 527, Mangalore 575 002, India
3Institution of Mathematics and Natural Sciences, Kristianstad University, 291 88 Kristianstad, Sweden

ABSTRACT: Many diatom species have the ability to form benthic resting stages, but the importance of these stages as a supply for planktonic blooms is uncertain. A mesocosm study was carried out in December 2005 to January 2006 in Mangalore, India. Mesocosms were inoculated with various combinations of benthic and/or planktonic cells, sampled from the coastal SE Arabian Sea, and the development of the planktonic community was followed. Diatoms dominated the phytoplankton community in all mesocosms, irrespective of inoculum. The most significant differences among inoculum types were altered species composition, and the timings of the maximum cell abundances, which lagged behind in the sediment mesocosms. Populations of Thalassiosira were initiated by both plankton and benthic propagules. Taxa known from temperate coastal areas to seed bloom by benthic propagules, such as Chaetoceros and Skeletonema, were predominantly seeded by planktonic cells in this experiment; this implies differential seeding strategy within the same species at different latitudes. The species assemblage encountered in the plankton and sediment was similar, which indicates that the benthic resting stages seed an autochthonous phytoplankton flora in the area. High species diversity in all inoculated mesocosms was maintained throughout the experimental period, although the actual number of species was fewer at the end. The hydrographic conditions and timing of formation, survival, and germination of diatom resting stages in SE Arabian Sea are discussed.

KEY WORDS: Benthic resting stages · Mesocosm · Arabian Sea · Phytoplankton · Community development

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Cite this article as: Härnström K, Godhe A, Saravanan V, Karunasagar I, Karunasagar I, Rehnstam-Holm A (2007) Tropical phytoplankton community development in mesocosms inoculated with different life stages. Mar Ecol Prog Ser 346:75-88.

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