Interannual variations in abundance and distribution of Chattonella cysts, and the relationship to population dynamics of vegetative cells in the Yatsushiro Sea, Japan.

The fish-killing raphidophytes Chattonella spp. have a resting cyst stage. To investigate the abundance and distribution of Chattonella cysts and determine their relationship to the population dynamics of vegetative cells, we conducted field observations from 2002 to 2017 in the Yatsushiro Sea, a semi-enclosed embayment in Japan, and analyzed the data including environmental conditions.

Variability of factors driving spatial and temporal dispersion in river plume and Chattonella antiqua bloom in the Yatsushiro Sea, Japan.

The dynamics of river plume in relation to harmful blooms of the raphidophycean flagellate, Chattonella antiqua in summer 2008-2010 in the Yatsushiro Sea, Japan were studied using a hydrodynamic model and monitoring data. In the southern area, the bloom formed in the waters stratified by a halocline caused by the southward expansion of riverine water from the Kuma River after the bloom initially forming in the northern area. The timing of the southward riverine water advection can be explained by the balance between the wind stress term and the pressure gradient term calculated from the horizontal density difference between the northern and southern areas.

[Shellfish monitoring system for paralytic shellfish toxins using enzyme-linked immunosorbent assay].

We investigated the applicability of enzyme-linked immunosorbent assay (PSP-ELISA) using a monoclonal antibody against paralytic shellfish toxins (PST) for screening oysters collected at several coastal areas in Kumamoto prefecture, Japan. Oysters collected between 2007 and 2010 were analyzed by PSP-ELISA. As an alternative calibrant, a naturally contaminated oyster extract was used to quantify toxins in the oyster samples.

Multiple plastids collected by the dinoflagellate Dinophysis mitra through kleptoplastidy.

Kleptoplastidy is the retention of plastids obtained from ingested algal prey, which may remain temporarily functional and be used for photosynthesis by the predator. We showed that the marine dinoflagellate Dinophysis mitra has great kleptoplastid diversity. We obtained 308 plastid rbcL sequences by gene cloning from 14 D.

High-level congruence of Myrionecta rubra prey and Dinophysis species plastid identities as revealed by genetic analyses of isolates from Japanese coastal waters.

We analyzed cryptophyte nucleomorph 18S rRNA gene sequences retained in natural Myrionecta rubra cells and plastid 16S rRNA gene and psbA sequences retained in natural cells of several Dinophysis species collected from Japanese coastal waters. A total of 715 nucleomorph sequences obtained from 134 M. rubra cells and 564 plastid 16S rRNA gene and 355 psbA sequences from 71 Dinophysis cells were determined.