The National Science Foundation's (NSF) Tokyo Office periodically receives and disseminates reports on research developments in Japan that are related to the Foundation's mission. NSF-sponsored researchers currently working in Japan prepare many of these reports. These reports present information for use by NSF program managers and policy makers; they are not statements of NSF policy. .

Special Scientific Report #98-28 (October 17, 1998)

Mr. Matthew Julius, a Ph.D. candidate in the Center for Great Lakes and Aquatic Sciences of the University of Michigan, Ann Arbor, Michigan, prepared the following report. Mr. Julius was a participant in the 1998 Monbusho Summer Program sponsored by NSF and the Ministry of Education, Science, Sports and Culture (Monbusho). Professor Shigeki Mayama of the Department of Biology at Tokyo Gaugei University, Tokyo, Japan hosted Mr. Julius. Mr. Julius can be reached via email at: mjulius@umich.edu

My research focuses on a group of freshwater centric diatoms (microscopic algae) with an evolutionary origin near the Miocene/Pliocene boundary and a Pacific Rim biogeographic distribution. The extension of this research in Japan was to obtain samples of freshwater diatoms, both living and fossil, for morphological comparison through time with species from the western United States. A second goal was to initiate a phylogentic study with fossil marine diatoms similar to the freshwater species in an attempt to discover the ancestral lineage of the freshwater group. Both of these research objectives were only possible in Japan. The National Science Museum houses the most comprehensive diatom collection for the eastern Pacific Rim; and the curator the collection, Dr. Y. Tanimura, is an expert on fossil and extant marine diatoms.

A typical routine included performing research activities at the National Science Museum with Dr. Y. Tanimura, from roughly 0900 to 1800hrs. While at the museum both light and scanning electron microscope work was performed with original and museum collections of living and fossil diatoms. Development of a morphological character matrix and cladistic analysis for a group of Miocene marine diatoms, genus Thakassiosira, were also performed at the museum. Evenings were spent in Tokyo Gakugei's diatom laboratory (Dr. S. Mayama's lab). At Gakugei, the progress of my research was discussed and essential literature surveys were performed.

Other activities varying from this routine included:

1. A visit to Dr. T. Nagumo at the Nippon Dental Instiute for a tour of the facilities and a demonstration of the Hitachi high resolution scanning electron microscope housed there.

2. A 2 day collecting trip to Nagano and Gunma Prefecture where Lakes Nojiriko and Onuma were sampled along with fossil diatomite deposits around Mt. Ataki.

3. A 1 day collecting trip to the Mount Fuji area where Lakes Ashinoko, Kawaguchico, Motosu, and Yamanaka were sampled.

4. A 4 day collecting trip to Kyushu island with Dr. K. Kashima of Kyushu University. Fossil diatomite collections were performed in Kumamoto, Miyazaki, and Oita prefectures. Approximately 60 samples were obtained ranging in age from 0.3 to 3.5 million years.

5. A short day trip to Myoko Kogen in Nigata prefecture to participate in an informal diatom seminar held by the Mayama lab.

In all over 100 samples of original and museum collections were obtained with collections representing living and fossil diatoms from all three of the major Japanese islands. Two new species have been identified from some of these samples, an extant Cyclotella species and a fossil Stephanodiscus species. Progress has begun on writing formal taxonomic descriptions of these species for future publication. A detail phylogeny for the group of marine Thalassiosira was also completed. A collaborative manuscript detailing the group from its Miocene origins to the present is in draft form and should be submitted for publication by late fall or early winter.

Information in this manuscript will also be used for a chapter in my dissertation concerning the origin of the genera Cyclostephanos, Cyclotella, and Stephanodiscus. Additionally, the samples obtained in Japan will be used in my doctoral research, providing important information on temporal and morphological diversity for Asian species in the above genera. This will directly supplement species information gathered from materials obtained through the California Academy of Sciences, which detail taxonomic diversity in the western United States. This research should eventually demonstrate a distinctive evolutionary relationship among a majority of the Pacific Rim species, distinct from other species in the family occurring outside of the Pacific Rim.

This was simply one of the best experiences in my career. My Japanese colleagues have helped to advance my research projects considerably. Not only have they shared ideas and information with specific benefit to my current projects, but our work together has broadened the scope of my general research interests. These new friends have become a resource for me, and it is inevitable that we will exchange information and ideas for discussion with one another during the rest of our careers.