At the 2024rd Research Meeting of the Japanese Society of Diatomology, held at the Shiga Prefectural Lake Biwa Museum (Kusatsu City, Shiga Prefecture) from November 10th to November 19th, 10, our university's research student, Yoshinaga Morira, and graduate student, Yamanaka Takuto, were both awarded the Best Presentation Award.

【Winner】
Shinra Yoshinaga (Research Student, Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology)
Takuto Yamanaka (2nd year master's course, Tokyo University of Marine Science and Technology, Graduate School of Marine Science and Technology)

[Title and content of award-winning research]
Shinra Yoshinaga
Title: Umbilical cordifolia Gomphonemopsis Lineage and classification / poster
It is a genus of marine benthic diatoms.GomphonemopsisWe carried out molecular phylogenetic analysis and morphological observation of the species. Four previously described species and three undescribed species were found in the coastal areas of Japan.rbcL andpsbAnalysis of the base sequence of C. divided the genus into two clades with different lineages. Comparison between the clades based on the results of morphological observations revealed differences in the following three main structures: (2) the number of spore patterns along the shell edge, (3) the position of the open end of the symphyseal segment, and (1) the presence or absence of a row of spore patterns at the foot pole end of the second segment. The clade that does not include the type species isPhaeodactylumHowever, since no morphological characteristics were found to support the relationship between the two, it was suggested that it may be a new genus.

Yoshinaga-san

Takusho Yamanaka　
Title: Relationship between attached diatoms and water retention of substrate in intertidal zone / oral
We investigated the vertical distribution of diatoms at Nojima Park in Yokohama, Kanagawa Prefecture, and conducted a comparison of their desiccation resistance in a laboratory experiment. It was found that diatoms that are relatively vulnerable to desiccation and are distributed mainly in the middle and lower parts are dominant on Ulva in the upper intertidal zone. It is believed that the high water retention properties of Ulva enable these diatoms to grow in the upper part. Furthermore, the experiment confirmed that gradually lowering the humidity during drying allows the diatoms to acclimate to the dry conditions and improves their survival rate. It is believed that similar acclimation occurs in nature as the water retention properties of the substrate suppress rapid drying, allowing diatoms to survive even after prolonged drying.

Yamanaka

From left: Yamanaka-san, Yoshinaga-san

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The Japanese Society of Diatomology