Population dynamics of the harmful diatom Eucampia zodiacus Ehrenberg causing bleachings of Porphyra thalli in aquaculture in Harima-Nada, the Seto Inland Sea, Japan

Nishikawa, Tetsuya; Hori, Yutaka; Tanida, Keisuke; Imai, Ichiro

doi:10.1016/j.hal.2007.04.005

Cited by 70 publications

(34 citation statements)

References 19 publications

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“…This minimum value is in close accordance with field observations in the Harima-Nada (Nishikawa et al 2007(Nishikawa et al , 2013. In diatoms, cell size usually decreases with the number of cell divisions, as a result of the mechanism of frustule formation, according to the MacDonald-Pfizer Rule (e.g.…”

supporting

confidence: 88%

“…In the present culture experiment, the range of the mean restored size (22.7-34.0 µm) attained after reaching the minimum size was smaller than that of the maximum size (around 80 µm) observed in field samples from Harima-Nada (Nishikawa et al 2007(Nishikawa et al , 2013. Cell size restored to over 80 µm was observed only once, in the H31-C strain, when the cell size decreased to around 50 µm.…”

contrasting

confidence: 67%

“…Previous studies have investigated its population dynamics to elucidate the ecology of Eucampia zodiacus (Nishikawa et al 2007(Nishikawa et al , 2013, and mean cell densities of the E. zodiacus population in autumn had a significant negative correlation with the integrated number of days during the period from restoration of cell size to the peak of the bloom . Using the correlation, proposed that the time of bleaching occurrence could be predicted by monitoring the cell size restoration and mean cell density of E. zodiacus in autumn.…”

mentioning

confidence: 99%

“…In E. zodiacus, restoration of cell size has been reported to occur once in each autumn, with great seasonal regularity, just after reaching their minimum viable size, and that the restored-size cells gradually decrease in size to reach a minimum again about one year later in the Harima-Nada (Nishikawa et al 2007(Nishikawa et al , 2013. The present results suggest that the maximum cell size of E. zodiacus can reach the minimum viable size within one year if the mean growth rate is over ca.…”

mentioning

confidence: 99%

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Cell size reduction and restoration of the diatom <i>Eucampia zodiacus</i> in culture

Nishikawa

2017

Plankton Benthos Res

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Abstract:We investigated the cell size reduction and size restoration of Eucampia zodiacus, an organism causing bleaching of aquacultured nori seaweed (Pyropia yezonensis), in laboratory culture observations. Mean cell size (apical length) of four E. zodiacus strains, which at the beginning of the experiment ranged between 59.2-73.4 µm, decreased to approximately 10 µm after 265-315 days with increasing number of cell divisions. The mean reduction rates in cell size ranged from 0.04 to 0.28 µm division -1 at 5 µm intervals of cell size. The rates were almost stable at cell sizes between 35 and 60 µm, and then declined with decreasing cell size. When the mean cell sizes reached <15 µm, they restored cell size. However, the restored-size cells ranged from 22.7-34.0 µm and were smaller than the maximum size (ca. 80 µm) observed in field samples from the Harima-Nada, eastern part of the Seto Inland Sea, Japan. Cell size restored to over 80 µm was observed only once, in the H31-C strain, when the mean cell size decreased to around 50 µm. The process of size restoration that was observed only once in the H31-C strain, was clearly different from the other size restoration mechanisms, suggesting that E. zodiacus has two different processes by which cell size is restored: sexual reproduction via auxospore formation and vegetative cell enlargement.

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supporting

confidence: 88%

contrasting

confidence: 67%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Cell size reduction and restoration of the diatom <i>Eucampia zodiacus</i> in culture

Nishikawa

2017

Plankton Benthos Res

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“…4) E. zodiacus f. zodiacus has no resting stage in life cycle, or resting period is much shorter than that of other diatom species possessing resting stage (Nishikawa et al 2007). E. zodiacus f. zodiacus has radial ribs and large central area in ocellus characteristics.…”

Section: Eucampia Zodiacus F Cylindrocornis Syvertsen Inmentioning

confidence: 99%

Morphological study of the genus Eucampia (Bacillariophyceae) in Korean coastal waters

Lee¹,

Lee²

2012

ALGAE

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Regardless of continuous researches, recent researches on the genus Eucampia (Bacillariophyceae) have focused mainly on E. zodiacus f. zodiacus In the present study, species of the genus Eucampia have been studied based on their morphological characteristics. Eucampia species were collected at 24 sites from July 2008 to June 2011 in Korean coastal waters. Species were mainly identified based on the shape of valve, ocellus, and aperture, along with the length and shape of the bipolar elevations. As a result, five Eucampia species were identified: Eucampia cornuta, E. groenlandica, E. zodiacus f. zodiacus, E. zodiacus f. cylindrocornis, and E. zodiacus var. cornigera. E. cornuta and E. groenlandica have long pervalvar axis length, but the others display short or moderate length. Ocellus shape of E. cornuta, E. groenlandica and E. zodiacus f. cylindrocornis are linear ribs, whereas E. zodiacus f. zodiacus and E. zodiacus var. cornigera have radial ribs with central area. E. cornuta and E. zodiacus f. cylindrocornis have long and narrow cylindrical elevations. E. groenlandica and E. zodiacus f. zodiacus have short and broad elevations with blunt tips. E. zodiacus var. cornigera has long and broad conical elevations. In terms of aperture shape, E. cornuta has large elliptical form, E. groenlandica has almost circular to rounded rectangular form, E. zodiacus f. zodiacus has narrow and elliptical rounded rectangular to a narrow lanceolate form, E. zodiacus f. cylindrocornis has almost rectangular form, and E. zodiacus var. cornigera has rounded rhombic form. On the basis of elevations in broad girdle view, 5 Eucampia taxa could be divided into 3 types: 'narrow H type', E. cornuta and E. groenlandica; 'regular H type', E. zodiacus f. cylindrocornis and E. zodiacus var. cornigera (partial); 'wide H type', E. zodiacus f. zodiacus (almost).

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Discolored Red Seaweed Pyropia yezoensis with Low Commercial Value Is a Novel Resource for Production of Agar Polysaccharides

Sasuga

Yamanashi²,

Nakayama³

et al. 2018

Mar Biotechnol

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The red seaweed Pyropia yezoensis has been demonstrated to be a novel resource for the production of high-quality agar. P. yezoensis is grown for the food industry in large-scale Japanese mariculture operations. However, discolored P. yezoensis is mostly discarded as an industrial waste, although it has some kind of utility values. Here, we evaluated the utility of discolored P. yezoensis as a resource for agar production. The quality of agar from the discolored seaweed was comparable to that from normal seaweed. In addition, as a distinguishing characteristic, agar yield was higher from discolored seaweeds than from normal types. Moreover, we successfully used agar from discolored P. yezoensis for bacterial plate media and DNA electrophoresis gels without agarose purification. Thus, our results demonstrate that discolored P. yezoensis is suitable for agar production and use in life science research. Diverting discolored P. yezoensis from disposal to agar production provides a solution to the current industrial waste problem in mariculture, as well as a secure source of agar for research purposes.

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Population dynamics of the harmful diatom Eucampia zodiacus Ehrenberg causing bleachings of Porphyra thalli in aquaculture in Harima-Nada, the Seto Inland Sea, Japan

Cited by 70 publications

References 19 publications

Cell size reduction and restoration of the diatom <i>Eucampia zodiacus</i> in culture

Cell size reduction and restoration of the diatom <i>Eucampia zodiacus</i> in culture

Morphological study of the genus Eucampia (Bacillariophyceae) in Korean coastal waters

Discolored Red Seaweed Pyropia yezoensis with Low Commercial Value Is a Novel Resource for Production of Agar Polysaccharides

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