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Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea). To test this hypothesis we examined stable nitrogen isotope ratios (delta N-15) of 100-to 135-year-old Saccharina specimens preserved at the Herbarium (Hokkaido University Museum). delta(15) N values of the paleo-Saccharina specimens collected from this region were in the range of 10%, which is significantly higher than the current 3-7% in freshly sampled Saccharina spp. This high delta(15) N indicates that spawning herring (Clupea pallasii) had potentially been a significant source of dissolved inorganic nitrogen (DIN) absorbed by Saccharina, acting as an organism forming a vector for transporting nutrients from eutrophic to oligotrophic coastal ecosystems. Our findings support the hypothesis of so-called "herring-derived nutrients.

Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea). To test this hypothesis we examined stable nitrogen isotope ratios (delta N-15) of 100-to 135-year-old Saccharina specimens preserved at the Herbarium (Hokkaido University Museum). delta(15) N values of the paleo-Saccharina specimens collected from this region were in the range of 10%, which is significantly higher than the current 3-7% in freshly sampled Saccharina spp. This high delta(15) N indicates that spawning herring (Clupea pallasii) had potentially been a significant source of dissolved inorganic nitrogen (DIN) absorbed by Saccharina, acting as an organism forming a vector for transporting nutrients from eutrophic to oligotrophic coastal ecosystems. Our findings support the hypothesis of so-called "herring-derived nutrients.

Historically Saccharina spp. beds occurred along the west coast of Hokkaido, an oligotrophic area, and were commercially exploited. Currently extensive commercial Saccharina spp. beds do not form due to nutrient limitations. Here, we postulate that nutrients assimilated by paleo-Saccharina spp. beds may have been derived from spawning herrings (Clupea pallasii) acting as organisms that formed a vector from their feeding grounds (Okhotsk Sea and Pacific Ocean) to their spawning area (west coast of Hokkaido, Japan Sea). To test this hypothesis we examined stable nitrogen isotope ratios (delta N-15) of 100-to 135-year-old Saccharina specimens preserved at the Herbarium (Hokkaido University Museum). delta(15) N values of the paleo-Saccharina specimens collected from this region were in the range of 10%, which is significantly higher than the current 3-7% in freshly sampled Saccharina spp. This high delta(15) N indicates that spawning herring (Clupea pallasii) had potentially been a significant source of dissolved inorganic nitrogen (DIN) absorbed by Saccharina, acting as an organism forming a vector for transporting nutrients from eutrophic to oligotrophic coastal ecosystems. Our findings support the hypothesis of so-called "herring-derived nutrients.

The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect individual-level variation in S. japonica. The STRUCTURE analysis of the SSR data identified four clusters in the species. Since the geographical distribution of these four different clusters does not correspond exactly to the currently recognized varieties in this species, it will be necessary to re-evaluate the distribution of the varieties of S. japonica.

The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect individual-level variation in S. japonica. The STRUCTURE analysis of the SSR data identified four clusters in the species. Since the geographical distribution of these four different clusters does not correspond exactly to the currently recognized varieties in this species, it will be necessary to re-evaluate the distribution of the varieties of S. japonica.

The genetic diversity of Saccharina japonica inhabiting the Hokkaido coastline and the surrounding area was investigated by AFLP and SSR analyses. A STRUCTURE analysis based on the AFLP data identified two clusters in the species, although a few local populations with genetic structures different from that of the neighboring populations were detected. The two clusters could be identified even within each current variety. In the SSR analysis, genetic variation in nucleotide sequences in all samples was located in four DNA regions (MS10, MS11, MS16, and MS29), and it is thought that these regions can be used as markers to detect individual-level variation in S. japonica. The STRUCTURE analysis of the SSR data identified four clusters in the species. Since the geographical distribution of these four different clusters does not correspond exactly to the currently recognized varieties in this species, it will be necessary to re-evaluate the distribution of the varieties of S. japonica.

The brown algal genus Acinetospora is characterised by sparsely branched uniseriate filaments, scattered meristematic zones, short laterals ("crampons") and scattered reproductive organs. The morphology and life history of the generitype A. crinita have been studied repeatedly, and accounts of the species' highly varied reproductive patterns were assumed to be due to the presence of multiple taxa that were reported under this name. Herein, we attempt to contribute to the taxonomy of the genus by conducting morphological and culture studies on 33 Acinetospora samples collected from Japan. We recognised two Acinetospora species and propose to name them A. filamentosa comb. nov. and A. asiatica sp. nov. These two species are distinguished from A. crinita by the absence of monosporangia and plurilocular acinetosporangia/megasporangia. Acinetospora filamentosa and A. asiatica have similar vegetative morphologies but possess different reproductive patterns. The former forms unilocular sporangia on erect filaments and both unilocular sporangia and plurilocular zoidangia on prostrate filaments, while the latter forms plurilocular zoidangia only on both erect and prostrate filaments. Molecular analyses based on rbcL and cox1 genes supported independence of these species.

The brown algal genus Acinetospora is characterised by sparsely branched uniseriate filaments, scattered meristematic zones, short laterals ("crampons") and scattered reproductive organs. The morphology and life history of the generitype A. crinita have been studied repeatedly, and accounts of the species' highly varied reproductive patterns were assumed to be due to the presence of multiple taxa that were reported under this name. Herein, we attempt to contribute to the taxonomy of the genus by conducting morphological and culture studies on 33 Acinetospora samples collected from Japan. We recognised two Acinetospora species and propose to name them A. filamentosa comb. nov. and A. asiatica sp. nov. These two species are distinguished from A. crinita by the absence of monosporangia and plurilocular acinetosporangia/megasporangia. Acinetospora filamentosa and A. asiatica have similar vegetative morphologies but possess different reproductive patterns. The former forms unilocular sporangia on erect filaments and both unilocular sporangia and plurilocular zoidangia on prostrate filaments, while the latter forms plurilocular zoidangia only on both erect and prostrate filaments. Molecular analyses based on rbcL and cox1 genes supported independence of these species.

Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurencia sp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated.

Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurencia sp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated.

Proceedings of 4th JSPS-VAST Joint Seminar on 'Coastal Marine Science', Hai Phong, Viet Nam, 26-28 October 2009, Oceanography

The production of labeled brominated metabolites with radioactive 82Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [82Br], thin-layer chromatography (TLC), and TLC-autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP12NTA including Na82Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific 82Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [82Br] in combination with the TLC-ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia.

The production of labeled brominated metabolites with radioactive 82Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [82Br], thin-layer chromatography (TLC), and TLC-autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP12NTA including Na82Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific 82Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [82Br] in combination with the TLC-ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia.

The production of labeled brominated metabolites with radioactive 82Br in Laurencia species was investigated as part of a study of the biosynthesis of halogenated metabolites from species belonging to the red algal genus Laurencia (Rhodomelaceae, Ceramiales). Radiobromide [82Br], thin-layer chromatography (TLC), and TLC-autoradioluminography (ARLG) were used. When cultured in artificial seawater medium (ASP12NTA including Na82Br) under 16:8 h light:dark (LD) illumination cycles for 24 h, each of the strains of Laurencia, Laurencia japonensis Abe et Masuda, Laurencia nipponica Yamada (laurencin-producing race and laureatin-producing race), and Laurencia okamurae Yamada, produced species- (or race-) specific 82Br-containing metabolites. In the case of the laurencin-producing race of L. nipponica, laurencin and deacetyllaurencin were found to be produced in approximately 1:1 ratio, though laurencin is the major metabolite in the wild sample. Furthermore, when cultured in the dark, the production rates of brominated metabolites in Laurencia spp. were found to be diminished. The present study strongly indicates that the use of radiobromine [82Br] in combination with the TLC-ARLG method is an effective approach for investigating the biosynthesis of brominated metabolites in Laurencia.

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In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofucin (3). The structures of these compounds were determined from their spectroscopic data (IR, 1H NMR, 13C NMR, 2D NMR, and MS). Pannosanol and pannosane are novel halometabolites with an unusual rearranged chamigrane framework. Antibacterial activities of these metabolites against marine bacteria are also described.