Spring bloom of Alexandrium tamarense in Chinhae Bay, Korea

Abstract

Chinhae Bay, one of the most eutrophic coastal embayments in Korea, is known for recurring red-tide blooms. To understand bloom development of the toxic dinoflagellate Alexandrium tamarense, weekly sampling was carried out from March to May of 1996 and 1997 in 2 regions, reflecting different flow regimes: one region (2 sites) was more susceptible to the influence of freshwater discharge than the other (2 sites). Nutrient concentrations remained high at nearly all depths throughout the study periods, suggesting that A. tamarense was not nutrient-limited for growth. A. tamarense cell density comprised < 5% of the total phytoplankton cell density at all times, in accordance with previous claims that this motile phytoplankton is unlikely to out-compete other spring bloom phytoplankton in high nutrient-level environments. The blooms occurred in a relatively wide temperature window (11 to 18°C SST), but in a narrow range of salinity (31 to 33 psu), and were associated with a stratified water column. Prolonged high temperature or reduced water column stability were ascribable for the demise of the blooms. In cases when blooms disappeared, even under favorable environmental conditions, life-cycle transition via sexual reproduction may have been responsible for their demise. Physical dilution processes, such as advection and dispersion, appeared to determine the magnitude of blooms, as supported by the occurrence of larger blooms and higher in situ growth rates in locations less subjected to the direct influence of river runoff or tidal currents. KEY WORDS: Alexandrium tamarense · Bloom dynamics · Chinhae Bay Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 33: [271][272][273][274][275][276][277][278] 2003 ogy, toxicity, cysts, and physiology of A. tamarense have been made (Lee 1990, Kim et al. 1993, Lee et al. 2000, Kim et al. 2002.Little is known, however, of the factors affecting the initiation, development, and decline of Alexandrium tamarense in Chinhae Bay. We present spring population dynamics of A. tamarense in Chinhae Bay in 1996 and 1997, in an attempt to elucidate the relationship of A. tamarense dynamics to environmental variables (e.g. water temperature, salinity, water column stratification, and inorganic nutrients). MATERIALS AND METHODSSampling of waters and analysis. The 4 sampling sites in Chinhae Bay, Korea, were selected to represent 2 flow regimes (see also below), with 2 of the sites being affected by a greater influence of river discharge (Stn M1 in 1996 and Stn M2 in 1997) than the other 2 sites (Stn C1 in 1996 and Stn C2 in 1997) (Fig. 1). Within the M sites, Stn M2 was more directly influenced by river runoff and the discharge from an adjacent sewage treatment facility, located west of Stn M2, than Stn M1. Within the C sites, Stn C1 was more directly affected by tidal currents than Stn C2. The results from the 4 sampling sites, therefore, were treated quasi-independently.Weekly sampling was conducted at Stns M1 (13 m depth) and C1 (1...

Change in Paralytic Shellfish Toxins in the Mussel Mytilus galloprovincialis Depending on Dynamics of Harmful Alexandrium catenella (Group I) in the Geoje Coast (South Korea) during Bloom Season

“…In the present study, A. catenella cells appeared when the temperature was 10–19 °C, indicating that this temperature range was suitable for A. catenella growth. Our field results are similar to previous reports over the past two decades by Lee et al [ 15 ] and Kim et al [ 16 ], suggesting that seasonal blooms of A. catenella mainly occur during spring in Korean coastal waters. In particular, high A. catenella cell concentrations were present when the nutrient concentrations were relatively high during March and April, as noted below.…”

“…From 16 May, the outbreak gradually decreased toward June, with increasing water temperature. Thus, the annual trend in PST outbreaks caused by A. catenella was similar to that reported by Lee et al [ 15 ] and Kim et al [ 16 ]. In 2018, the PST outbreak was detected on 5 March, and a shellfish collection ban was imposed (i.e., approximately one month earlier than in 2017).…”

Variation and Profile of Paralytic Shellfish Poisoning Toxins in Jinhae Bay, Korea

“…Therefore, mussels could be useful as a bioindica- area surrounded by populated cities and is one of the most eutrophic coastal bays in Korea. The bay is known for recurring red-tide blooms, including Alexandrium tamarense bloom (Lee et al, 2003). PSP toxins are detected annually in bivalves in Jinhae Bay during the spring season (Chang et al, 1989;Park et al, 2000;Shon et al, 2009;Mok et al, 2012).…”

RECOGNIZING DINOFLAGELLATE SPECIES USING ITS rDNA SEQUENCES1

“…A complex interplay between mutation, gene conversion, unequal crossover events, and sexual reproduction increases genetic divergence between the ITS regions of different species while maintaining a lower than expected within-species variation (Gerbi 1986, Silva and Faust 1995, Giacobbe and Yang 1999, Probert et al 2002, Lee et al 2003, Nagai et al 2003, Shankle et al 2004). This implies that if gene conversion is operating effectively, intraspecific ITS region genetic distances would be consistently lower than interspecific distances.…”