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Bacterivory by co-occurring red-tide algae, heterotrophic nanoflagellates, and ciliates

2006; Inter-Research; Volume: 322; Linguagem: Inglês

10.3354/meps322085

1616-1599

KA Seong, Hae Jin Jeong, Sung-Ho Kim, G T Kim, Kang Jh,

Marine and coastal plant biology

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 322:85-97 (2006) - doi:10.3354/meps322085 Bacterivory by co-occurring red-tide algae, heterotrophic nanoflagellates, and ciliates Kyeong Ah Seong1, Hae Jin Jeong1,*, Shin Kim2, Gwang Hoon Kim3, Jung Hoon Kang4 1School of Earth and Environmental Sciences, College of Natural Sciences, Seoul National University, Seoul 151-747, Republic of Korea 2MarineBio Co., Kunsan National University, Kunsan 573-701, Republic of Korea 3Department of Biology, College of Natural Sciences, Kongju National University, Kongju 314-701, Republic of Korea 4Southern Coastal Environment Research Division, South Sea Institute, KORDI, Changmokmyun, Koje 656-830, Republic of Korea *Corresponding author. Email: hjjeong@snu.ac.kr ABSTRACT: We investigated feeding of natural populations of red-tide algae, heterotrophic nanoflagellates (HNFs), and ciliates (<30 µm in cell length) on natural populations of marine bacteria (mostly heterotrophic bacteria) in diverse Korean waters (Masan Bay, Jinhae Bay, Shiwha Bay, Keum River estuary, and the open coastal waters off Yeosu) during red tides in 2004 to 2005. To explore the functional responses of the dominant red-tide algae to bacteria, we also measured the ingestion rates of the dinoflagellates Cochlodinium polykrikoides, Heterocapsa rotundata, H. triquetra, and Prorocentrum minimum as well as the raphidophytes Chattonella ovata and Heterosigma akashiwo as a function of bacterial concentration in the laboratory. During red tides, ingestion rates of the red-tide algae C. polykrikoides, H. rotundata, H. triquetra, H. akashiwo, P. minimum, and P. triestinum on natural populations of bacteria in Korean waters (1.2 to 20.6 cells alga–1 h–1) were comparable to those of co-occurring HNFs (0.7 to 39.4 cells HNF–1 h–1), but much lower than those of co-occurring ciliates (15 to 713 cells ciliate–1 h–1). However, the combined grazing coefficients attributable to the dominant algal predators on natural populations of bacteria during red tides (0.04 to 1.71 d–1) were usually higher than those attributable to co-occurring HNFs (0.01 to 0.20 d–1) or ciliates (0.00 to 0.72 d–1). With increasing mean prey concentration, the ingestion rates of C. polykrikoides, H. rotundata, H. triquetra, P. minimum, C. ovata, and H. akashiwo on bacteria rapidly increased at prey concentrations of ca. 5 to 10 × 106 cells ml–1, and slowly increased or became saturated at higher prey concentrations. The maximum ingestion and clearance rates of C. polykrikoides, H. rotundata, H. triquetra, P. minimum, C. ovata, and H. akashiwo on bacteria (6 to 25 cells alga–1 h–1 and 1.0 to 4.5 nl alga–1 h–1) were comparable to those so far reported in the literature of HNFs on bacteria. The results of the present study suggest that, potentially, red-tide algae can have a considerable grazing impact on populations of bacteria during red tides and are sometimes the most effective protistan predators of marine bacteria. KEY WORDS: Bacteria · Graze · Harmful algal bloom · Ingestion · Marine · Protist · Red tide Full text in pdf format PreviousNextExport citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 322. Online publication date: September 20, 2006 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2006 Inter-Research.