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Most canopy-forming macroalgae have disappeared from temperate reefs in southern Japan, one of the ocean warming hotspots, but Sargassum nipponicum is surviving in this region. As this species' annual shoots emerge from holdfasts during summer, both plant components may be highly tolerant to warm and nutrient-poor conditions in this season. The present study examined the effects of temperature and nutrient conditions on holdfast growth, shoot emergence from holdfasts, and shoot growth in S. nipponicum samples collected in Tanegashima Island, southern Japan. The summer temperature in this region (30 °C) allowed holdfast growth and shoot emergence but inhibited shoot growth. Nutrient-poor conditions had limited effects on the first two parameters but suppressed shoot growth. These results suggested that during warm summers and under nutrient-poor conditions in southern Japan, shoots can emerge from S. nipponicum holdfasts but cannot further grow. Additionally, nutrient loading from a nearby river was higher at the only site dominated by S. nipponicum, than at the other sites where this species was absent on Tanegashima Island. This was observed especially between autumn and winter, implying that such a nutrient-rich environment may contribute to shoot growth in S. nipponicum and to the persistence of its population in the area. [ABSTRACT FROM AUTHOR]

Macroalgal canopies, which provide nutrients and habitats for many invertebrates and fishes in coastal waters, are disappearing worldwide. The simultaneous assessment of changes in macroalgae and fish distribution before and after coastal desertification, including deeper coastal waters where beyond macroalgae growth need attention. Therefore, we investigated their spatial distribution in the coastal waters off southwestern Japan in late autumn and winter using the acoustic method combined with visual observation. The number of fish schools was higher in late autumn than in winter, while they had similar acoustic backscattering strength (Sv) and school size, tended to be distributed in shallower waters. The number was lower after the macroalgae disappeared in both seasons, while the average Sv was higher, and the size was larger. They were distributed in similar water depths during the winter season. Fewer fish schools and higher Sv were observed in deeper waters after the macroalgae disappeared. We concluded that more fishes moved to shallower waters in the autumn than in the winter because of higher water temperatures. Macroalgae benefited small juvenile fishes in both shallow and deep coastal waters. Further studies on the distribution of specific species are expected for the assessment and restoration of the macroalgal ecosystem. [ABSTRACT FROM AUTHOR]

Conjugated fatty acids have anticancer effects. Therefore, the establishment of a synthetic method for conjugated fatty acids is important for overcoming cancer. Here, we attempted to synthesize conjugated fatty acids using enzymes extracted from seaweeds containing these fatty acids. Lipids from 12 species of seaweeds from the seas around Japan were analyzed, and Padina arborescens Holmes was found to contain conjugated fatty acids. Then, we synthesized parinaric acid, a conjugated tetraenoic acid, from α-linolenic acid using the enzyme of P. arborescens. This method is expected to have a variety of potential applications for overcoming cancer. [ABSTRACT FROM AUTHOR]

Metabolic diseases, including obesity, diabetes, and fatty liver disease, are dramatically increasing around the world. Seaweed is low in calories and rich in many active ingredients that are necessary for maintaining good health, and is expected to be effective for preventing metabolic diseases. The purpose of this study was to examine the effects of a traditional Japanese edible seaweed Hypnea asiatica (H. asiatica) on obesity, using a mouse model. H. asiatica was dried and powdered, mixed with a high-fat diet, and fed to male C57BL/6J mice for 13 weeks. On the last day of the experiment, blood samples were collected under anesthesia and biochemical parameters such as lipids and adipokines were measured. Liver and adipose tissue were excised, weighed, and oxidant/antioxidant parameters were measured. Some mice were perfused with a fixative solution containing formalin, and tissue specimens were prepared. A glucose tolerance test was used to assess insulin resistance. The inhibition of lipase activity was evaluated in vitro. Thirteen-week supplementation with H. asiatica suppressed body weight gain, body fat accumulation, and blood glucose levels. H. asiatica also improved fatty liver and hypercholesterolemia, and reduced the oxidant and inflammatory parameters of serum and liver. H. asiatica increased fecal triglyceride excretion and polyphenol-rich ethanol extract of H. asiatica inhibited lipase activity in vitro. These results suggest that polysaccharides and polyphenols in H. asiatica may ameliorate obesity and diabetes by inhibiting intestinal fat absorption and reducing oxidative stress and inflammation. H. asiatica may be useful in preventing metabolic diseases such as obesity, diabetes, and fatty liver. [ABSTRACT FROM AUTHOR]

Extensive floating macroalgae have drifted from the East China Sea to Japan's offshore area, and field observation cannot sufficiently grasp their extensive spatial and temporal changes. High-spatial-resolution satellite data, which contain multiple spectral bands, have advanced remote sensing analysis. Several indexes for recognizing vegetation in satellite images, namely, the normalized difference vegetation index (NDVI), normalized difference water index (NDWI), and floating algae index (FAI), are useful for detecting floating macroalgae. Thresholds are defined to separate macroalgae-containing image pixels from other pixels, and adaptive thresholding increases the reliability of image segmentation. This study proposes adaptive thresholding using Sentinel-2 satellite data with a 10 m spatial resolution. We compare the abilities of Otsu's, exclusion, and standard deviation methods to define the floating macroalgae detection thresholds of NDVI, NDWI, and FAI images. This comparison determines the most advantageous method for the automatic detection of floating macroalgae. Finally, the spatial coverage of floating macroalgae and the reproducible combination needed for the automatic detection of floating macroalgae in Kagoshima, Japan, are examined. [ABSTRACT FROM AUTHOR]

SUMMARY: The subtidal brown algal species Sporochnus dotyi Brostoff (Sporochnales, Phaeophyceae), which has been regarded as a Hawaiian endemic, is reported from Kushimoto, Kii Peninsula, Pacific coast of central Honshu, Japan, for the first time outside Hawai'i. The species grew on subtidal rocks ca. 5–20 m deep attached by a small conical holdfast. The erect thalli were 5–30 cm high, terete, robust and alternately branched in 1–2 orders. When mature, pedicellate receptacles developed on the branches, and formed elliptical sori 1 mm long with a pedicel 3–5 mm long. The apical parts of the thalli and the receptacles were terminated with a tuft of simple assimilatory filaments of up to 4 mm long and showed prominent green to yellow underwater iridescence. Reproductive filaments (paraphyses) were densely packed, simple, up to 200 μm long and bore 4–6 mostly unilateral unilocular zoidangia 20–22 μm long and 5–6 m in diameter. In the genetic analyses, the Sporochnus alga from Kushimoto had partial rbcL sequence identical to S. dotyi from Hawai'i. The cox3 phylogeny revealed that this alga formed a fully supported clade with S. dotyi. Therefore, we identified the alga from Kushimoto as S. dotyi. This finding of S. dotyi from Japan, together with the recent reports of the mesophotic macroalgae Ryuguphycus kuaweuweu (=Umbraulva kuaweuweu), Ulva iliohaha and Newhousia imbricata from various localities in the Pacific Ocean including Japan, suggest closer biogeographical connections of subtidal/mesophotic macroalgae in the Pacific than previously recognized. [ABSTRACT FROM AUTHOR]

Polycarbamate is commonly used as an antifoulant coating on fishing nets in Japan. Although its toxicity to freshwater organisms has been reported, its toxicity to marine organisms is currently unknown. We conducted algal growth inhibition and crustacean immobilization tests to assess the effects of polycarbamate on marine organisms. We also evaluated the acute toxicity of the main components of polycarbamate, namely, dimethyldithiocarbamate and ethylenebisdithiocarbamate, to algae, which are the most sensitive tested organisms to polycarbamate. The toxicities of dimethyldithiocarbamate and ethylenebisdithiocarbamate partially explain that of polycarbamate. To assess the primary risk, we derived the predicted no-effect concentration (PNEC) for polycarbamate in a probabilistic manner using species sensitivity distributions. The 72 h no observed effect concentration (NOEC) of polycarbamate to the alga Skeletonema marinoi–dohrnii complex was 0.45 μg/L. The toxicity of dimethyldithiocarbamate may have contributed up to 72% of the toxicity observed for polycarbamate. The fifth percentile of hazardous concentration (HC5) derived from the acute toxicity values was 0.48 μg/L. Comparison of previously reported environmental polycarbamate concentrations in Hiroshima Bay, Japan, to the PNEC estimated using the minimum NOEC and HC5 suggest that polycarbamate currently poses a high ecological risk. Therefore, reducing the risk by restricting polycarbamate use is necessary. [ABSTRACT FROM AUTHOR]

Brown seaweeds are known as important marine food sources, from which phytosterols have been recognized as functional food components with multiple health-beneficial effects. However, studies on phytosterol extraction and quantitation from edible brown seaweeds are limited. In the present work, extraction methods for seaweed phytosterols were compared and optimized by one-factor-at-one-time method and response surface methodology. Moreover, the quantitation method of total sterols and major sterol components, including fucosterol, saringosterol, and ostreasterol, was established and validated using 1H NMR. Furthermore, the developed extraction and determination methods were applied to investigate three common edible seaweeds from Japan (Hijiki, Wakame, and Kombu). As a result, the finally optimized conditions were ultrasound-assisted extraction with CHCl3-MeOH 2:3 for 15 min followed by saponification with 1.65 mL of 1.85 M KOH for 14.5 h. Based on the developed methods, phytosterols in three seaweeds were compared, and Hijiki showed an abundant total sterol amount (2.601 ± 0.171 mg/g DW), significantly higher than Wakame (1.845 ± 0.137 mg/g DW) and Kombu (1.171 ± 0.243 mg/g DW). Notably, the composition of the sterol components varied in different seaweeds. These findings might help the nutritional investigation and functional food development concerning phytosterols from seaweeds. [ABSTRACT FROM AUTHOR]

Some macroalgae drift on the ocean and are stranded on coasts, and these stranded brown macroalgae are regarded to be degraded by organisms. Alginate is a major component of brown macroalgae. An uncovering of how carbon is cycled through brown macroalgae is needed to deeply understand coastal ecosystems. In this study, to gain insights into metabolism of brown macroalgae and alginate in the organisms, we initially confirmed that supralittoral talitrid amphipods (beach fleas or sandhoppers collected on the Shibagaki coast in Ishikawa Prefecture, Japan) fed on the brown macroalgae. We then isolated bacteria such as Vibrio sp. with alginate-assimilating capability from the gut of the amphipods. Metagenomic analysis of the gut of amphipods housed in several conditions (e.g. macroalgae or paper as feed, non-sterilized or sterilized environment) showed no condition-dependent compositions of bacteria and fungi, but Vibrio sp. were detected at high frequency, in good agreement with the isolation of Vibrio sp. An intervention study using antibiotics showed that amphipods fed on algae or paper at about the same rate in the presence or absence of antibiotics, and that the antibiotics had no effects on the life span. Moreover, intervention with antibiotics completely killed Vibrio sp. and some other bacteria, and had significant effects on the composition of the flora in the gut, with elimination of the variations observed in the guts of amphipods housed without antibiotics. These data suggest that microbes that were killed by antibiotics, including Vibrio sp., in the gut of talitrid amphipods are not essential for assimilation of brown macroalgae. [ABSTRACT FROM AUTHOR]

Climate change is leading to novel species interactions and profoundly altering ecosystems. In marine systems, tropical and subtropical species are increasing in higher latitudes. This has been linked to the deforestation of temperate coastlines, as direct effects of ocean warming combine with increased herbivory from tropical and sub-tropical fishes and lead to the decline of canopy-forming kelp. Here, we tested the hypothesis that this deforestation may be facilitated by greater palatability of temperate kelp and other canopy seaweeds compared to tropical taxa. We used multiple-choice filmed feeding field experiments and chemical analyses to measure the palatability of temperate and tropical seaweeds from Tosa Bay (southeastern Japan) and we used single-species feeding assays to measure changes in consumption of the kelp Ecklonia cava throughout the year. We found no evidence that temperate seaweeds are more palatable to herbivorous fish. In the multiple-choice assays, consumption was concentrated on both tropical and temperate Sargassum species, which are ephemeral and peak in abundance in the spring/early summer. Consumption of the kelp Ecklonia cava peaked during the autumn, when Sargassum species are absent. The highest levels of kelp herbivory coincide with the reproductive season for E. cava and may contribute to the long-term decline of these kelp forests in southern Japan. [ABSTRACT FROM AUTHOR]

Floating macroalgae information is required to manage coastal environments and fishery resources effectively. In situ observations and analyses can result in under-sampling, thereby challenging the comprehension of the floating macroalgae abundance and spatiotemporal alterations. This study reports the spatiotemporal variation of floating macroalgae distribution around Japan from 2018 to 2021 using Global Change Observation Mission-Climate/second-generation Global Imager data. We employed the floating algae index (FAI) scaled from local ocean FAI to minimize the effect of spatial variation in ocean color. Fractional macroalgae coverage in a pixel was determined using a linear unmixing algorithm with lower and upper thresholds. The lower threshold was determined using the cumulative frequency of the scaled FAI, and the upper threshold was modified based on the more precise Sentinel-2 data. The results revealed that monthly macroalgae coverage varies spatially and seasonally, peaking in the spring and summer in the southwestern area. The macroalgae distribution particularly expanded from the East China Sea to west Japan during spring. In 2018–2021, the total biomass of the offshore floating macroalgae was estimated to be 8880–133,790, 8460–141,900, 3910–70,380, and 4620–61,870 tons. The findings of this study validated the empirical knowledge about specific locations and can serve as a reference to analyze temporal and spatial variations in future studies. [ABSTRACT FROM AUTHOR]

To elucidate the effect of macroalgae blooms on dissimilatory nitrate reduction pathways (denitrification, anammox, and DNRA) in sediments of the hypereutrophic Yatsu tidal flat, eastern Japan, sediment denitrification, anammox, and DNRA rates were measured using a 15N tracer technique at two sites affected and unaffected by macroalgae (Ulva) blooms and in incubation experiments with and without Ulva. Anammox was insignificant at both sites and in both experiments. The denitrification rate was consistently higher than the DNRA rate, and its contributions to the total dissimilatory nitrate reduction were 82% and 85% at sites affected and unaffected by Ulva, respectively. In a sediment incubation experiment with Ulva, the contribution of DNRA had increased to approximately 30% on day 7, which is when the sulfide concentration was the highest. Sulfide produced by sulfate reduction during macroalgae blooms inhibited denitrification and did not change the DNRA, and consequently increased the DNRA contribution. On day 21, after reaching the peak sulfide concentration during the late macroalgae collapse, the DNRA contribution decreased to 15%. These results indicated that the DNRA contribution was greater during the macroalgae blooms than at the collapse, although denitrification dominated DNRA regardless of the macroalgal status. Therefore, vigorous macroalgae cover and sulfide production under the macroalgae cover had an important impact on the nitrogen dynamics. [ABSTRACT FROM AUTHOR]

The brown seaweed Sargassum carpophyllum J. Agardh is an unused warm-temperate species in the family Sargassaceae that has been expanding its distribution along the coastal areas of Japan in recent years. In this study, 3 types of phlorotannins were identified from the EtOAc fraction of the 80% MeOH extract of S. carpophyllum. From the spectroscopic (1H NMR, 13C NMR, and HMBC) and ESI/MS data and comparison with those of prior literature, it was demonstrated that the compounds are oligomers of phlorethol, which is one of the subclasses of phlorotannins, that is triphlorethol B (phloroglucinol trimer), tetraphlorethol C (phloroglucinol tetramer), and pentaphlorethol A (phloroglucinol pentamer). Among the phlorethols, tetraphlorethol C and pentaphlorethol A were isolated and identified for the first time from a brown seaweed collected from the East China Sea, including the coastal areas of Japan. The identified phlorethols were tested for their antioxidant properties. In the antioxidant assay using liposomes, the phlorethols showed comparable inhibitory effects to epigallocatechin gallate (tea polyphenol) and α-tocopherol (liposoluble vitamin) on lipid peroxidation by 4 mM 2,2′-azobis(2-methylpropionamidine) dihydrochloride. In addition, it was revealed that pentaphlorethol A has a superoxide anion scavenging activity (50% effective concentration: 21 μM) higher than that (50% effective concentration: 46 μM) of ascorbic acid (hydrosoluble vitamin). [ABSTRACT FROM AUTHOR]

Seaweeds or marine macroalgae are known for producing potentially bioactive substances that exhibit a wide range of nutritional, therapeutic, and nutraceutical properties. These compounds can be applied to treat chronic diseases, such as cancer, cardiovascular disease, osteoporosis, neurodegenerative diseases, and diabetes mellitus. Several studies have shown that consumption of seaweeds in Asian countries, such as Japan and Korea, has been correlated with a lower incidence of chronic diseases. In this study, we conducted a review of published papers on seaweed consumption and chronic diseases. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) method for this study. We identified and screened research articles published between 2000 and 2021. We used PubMed and ScienceDirect databases and identified 107 articles. This systematic review discusses the potential use of bioactive compounds of seaweed to treat chronic diseases and identifies gaps where further research in this field is needed. In this review, the therapeutic and nutraceutical properties of seaweed for the treatment of chronic diseases such as neurodegenerative diseases, obesity, diabetes, cancer, liver disease, cardiovascular disease, osteoporosis, and arthritis were discussed. We concluded that further study on the identification of bioactive compounds of seaweed, and further study at a clinical level, are needed. [ABSTRACT FROM AUTHOR]

The presence and status of harmful algal blooms (HABs) in Japan are reviewed, revealing a decrease in red tides; however, toxic blooms are found to be increasing in western Japan. Environmentally friendly control strategies against HABs are also compared with integrated agricultural pest management. Very high densities (105–108 CFU/g) of algicidal and growth-inhibiting bacteria were found in biofilm on seagrass and seaweed surfaces and in surrounding coastal seawater. The situation in freshwater ecosystems is similar to coastal seas for toxic cyanobacterium, Microcystis aeruginosa, and aquatic plants. These findings offer new insights into the ecology of influential bacteria and harmful algae, suggesting that protection and restoration of native seagrasses and seaweeds in coastal marine environments should be implemented to suppress HABs. Diatom blooms were successfully induced with bottom sediment perturbation to prevent the occurrence of harmful flagellates such as Chattonella spp. and Alexandrium catenella in the Seto Inland Sea; however, this method requires robust and reproducible verification. "Sato-Umi" is a helpful concept for HAB control in the sea and freshwater ecosystems when adequately managed by people (e.g., appropriate bottom perturbation; protection and restoration of seaweeds, seagrasses, and aquatic plants; application of polycultures of fish, seaweeds, etc.). [ABSTRACT FROM AUTHOR]

Blooms of green macroalgae (Ulva spp.) occur frequently in the hypereutrophic Yatsu tidal flat of eastern Japan. In this study, to elucidate the effects of such blooms on nutrients and sulfide dynamics, we measured Ulva nutrients uptakes and stocks, and sulfide release during Ulva blooms decay. NH4+ uptake was greater than NO3– uptake when NH4+ was sufficient, whereas NO3– uptake increased in the absence of NH4+. NH4+ concentration was generally higher than that of NO3– in seawater; thus, Ulva spp. would prefer NH4+ as N substrate. The mean N and P amounts in Ulva blooms were 2,320 kg-N and 116 kg-P, respectively. Sudden, rapid blooms collapse appears to release extremely high amounts of nutrients, especially NH4+. Thus, Ulva blooms affect NH4+ behavior and consequently affect N cycling in the Yatsu tidal flat. High sulfide concentrations were detected under anoxic Ulva mats following peaks in biomass. Incubation experiments revealed that sulfide was derived not only from SO42– in seawater but also from the S contained in Ulva spp. Subsequently, sulfide might be microbiologically oxidized to elemental sulfur thereafter. Moreover, sulfide was not detected without Ulva spp.. Therefore, Ulva blooms also influence S cycling in Yatsu tidal flat. [ABSTRACT FROM AUTHOR]

Pyropia (Porphyra, referred to as 'Gim' in Korea or 'Nori' in Japan), an economically valuable alga, has long been consumed as seafood, especially in north‐east Asian countries. Its well‐established conventional mass cultivation and harvesting methods in coastal areas widen the industrial availability of edible Pyropia sp. However, the unexpected discoloration derived from causative factors during the cultivation process gives rise to serious economic losses in the aquaculture industry. For the industrial use of discoloured laver waste (DLW), recent articles have suggested that DLW biomass could be used as a source of agar polysaccharide, porphyran, γ‐aminobutyric acid and other value‐added bioactive compound productions. Although DLW biomass has economic potential, the lack of integrated information and relevant studies still limits its industrial availability. Therefore, we discussed recent research concerning the functional ingredients, causative factors and potential availability of DLW to provide integrated information. Furthermore, this review suggested the potential industrial application of DLW as a source for other value‐added material production. [ABSTRACT FROM AUTHOR]

The constitution of Laurencia snackeyi (Weber-van Bosse) Masuda (Ryukyu-sozo in Japanese) from three locations, Minna Island, Sesoko Island and Kayo Coast in Okinawa Prefecture, Japan, is reported. This species produced snyderane-type sesquiterpenes, palisadin A (1), palisadin B (2) and aplysistatin (3) as characteristic metabolites. The species name of "Laurencia luzonensis Masuda", which has previously been reported in several papers, should be revised to L. snackeyi. [ABSTRACT FROM AUTHOR]

Natural seaweed beds, which play an important role for coastal ecosystems and marine fisheries, have been changing drastically in Japan. Interventions, such as decreasing the over-grazing by sea urchins, are being undertaken to maintain natural seaweed beds. Japan has at least 15 seaweed genera of economic importance utilized either directly as human food, as ingredients in food, or as raw materials for extraction of chemical compounds for various applications. Most species are produced through various cultivation methods that usually start in a land-based facility and are completed when seaweeds are transferred for open-sea cultivation. Cultivation, as well as harvesting, from natural populations, has sustained the Japanese seaweed industry for many years, but recently a downfall in seaweed production has been experienced in some areas for certain species due to warming oceans. Efforts to improve production have led to the development of forced cultivation techniques to reduce the cultivation period for Saccharina japonica while hybridization of different morphological forms of Undaria pinnatifida has resulted in the production of so-called "southern" and "northern types" that have desirable shapes for harvesting and processing. The future of the seaweed industry in Japan is geared towards producing high-grade products from seaweeds grown in land-based tanks using deep-ocean water. [ABSTRACT FROM AUTHOR]

SUMMARY Trade‐offs are considered key to understanding mechanisms supporting the coexistence of multiple plant species. Thus, understanding the mechanisms underlying trade‐offs is expected to contribute to conservation and management of macroalgal beds composed of diverse macroalgae of rocky shore ecosystems. To test the occurrence of trade‐offs between productivity and thallus toughness as well as pair‐wise thallus trait relationships that are expected to indirectly relate to any trade‐offs, traits and relationships for 13 species of macroalgae from the central area along the Japan Sea coast of Honshu, Japan were examined. In each species we examined for photosynthetic capacity per unit biomass (as Amass) and nitrogen (i.e., photosynthetic nitrogen‐use efficiency, PNUE), nitrogen content (as Nmass), thallus mass per unit thallus area (as TMA) and force required to penetrate the thallus (as Fp, a common index of leaf toughness in land plants by punch test). A significant negative correlation indicating a trade‐off between productivity and thallus toughness was found between Amass or PNUE and Fp. Pair‐wise relationships that were expected to indirectly relate to the trade‐off were as follows. Amass was positively correlated with Nmass. Thalli with high Nmass extensively utilizing nitrogen in the photosynthetic parts, and consequently exhibiting elevated metabolic rates. Moreover, thalli with high Nmass tended to be associated with low TMA, and Nmass decreased with increasing TMA. A significant negative correlation was observed between TMA and Amass or PNUE because of the linkage of high Amass or PNUE with high Nmass and high Nmass associated with low TMA, while a significant positive correlation was observed between TMA and Fp. The two correlations indicate a physiological and structural trade‐off, which underlies the interdependency of thallus traits. Results of multivariate analyses also indicated that the thallus traits interdependently vary across a single axis based on the trade‐off. [ABSTRACT FROM AUTHOR]

Photosynthetic marine macrophytes such as seaweeds have been proposed to provide habitat refugia for marine calcifiers against ocean acidification (OA) by increasing the local pH. However, the effectiveness of seaweed as a potential habitat refugia for marine calcifiers such as corals remains to be investigated. This study focused on the seaweed Nemacystus decipiens , which are widely farmed in the shallow reef lagoon of Okinawa coral reefs, Japan, and aimed to evaluate their response to high p CO 2 and whether they can mitigate the effect of high p CO 2 on the coral Montipora digitata. Corals were cultured with and without seaweed under control (300–400 μatm) or high p CO 2 conditions (OA, 900–1000 μatm) for 2 weeks. Results showed that all photo-physiological parameters examined in the seaweed N. decipiens were not affected by high p CO 2 , suggesting that OA will not positively affect their productivity. The calcification rate of the coral M. digitata was found to decrease under OA and the effect was further exaggerated by the presence of seaweed. The present study suggests that farming seaweeds will not act as a potential habitat refugia for adjacent corals under future OA, but instead can exaggerate the negative effect of OA on coral calcification. • OA did not affect the physiological responses of seaweed Nemacystus decipiens. • OA significantly decreased the calcification of coral Montipora digitata , and this was worsened by the presence of seaweed. • Seaweed may not always provide habitat refugia for corals. [ABSTRACT FROM AUTHOR]

Abstract: Wakame (Undaria pinnatifida) aquaculture is one of the major fishery industries on the Sanriku Coast of Japan. Low concentrations of nutrients in the autumn, when the germinated wakame sporophytes are installed at aquaculture facilities, induce defective growth, resulting in withering. To determine the characteristics of the nutrient variations in this region, we conducted hydrographic measurements off the coast of Iwate Prefecture. The measured results showed that in the autumn, vertical mixing pumped nutrients from the deeper layers to the mixed layer, where nutrients had been depleted during the summer. Based on these results, we developed a one‐dimensional model incorporating vertical mixing by atmospheric cooling to project the vertical distribution of the nutrient concentrations. By conducting ensemble calculations, we created a probability projection calendar for the nutrient supply up to 50 days ahead. This information was provided to wakame farmers before they installed the germinated sporophytes. The projected probability calculated from the initial conditions on 11 October 2016 was 0% until 25 October and gradually increased to 85% on 30 November. The nitrate concentration detected by an ultraviolet nitrate sensor moored at a wakame farm revealed that the nutrient concentrations reached a critical threshold on 18 November. The projected probability on that date was 75%; therefore, the projection was successful. The observed temporal evolution of the temperature, salinity, and nutrient concentrations was well reproduced by our model. The information obtained using this model is expected to reduce the risk of wakame withering and improve the efficiency of wakame production. [ABSTRACT FROM AUTHOR]

ABSTRACT Miura, H.; Ito, Y., and Suenaga, Y., 2018. Construction of Climate Change-Adapted Seaweed Beds on the Japanese Coast. In: Shim, J.-S.; Chun, I., and Lim, H.S. (eds.), Proceedings from the International Coastal Symposium (ICS) 2018 (Busan, Republic of Korea). Journal of Coastal Research, Special Issue No. 85, pp. 391–395. Coconut Creek (Florida), ISSN 0749-0208. Japanese coastal seaweed beds are experiencing a long-term decline in area coverage in a phenomenon called isoyake, which has massively impacted the fisheries industry. Therefore, research has been performed on seaweed bed restoration. Consequent measures have been implemented along with the promulgation of relevant technology. Meanwhile, increasing seawater temperatures and other environmental changes associated with climate change, which is one of the causes of isoyake, are spreading globally and have become increasingly severe in recent years. With respect to methods of coping with the effects of climate change, the Intergovernmental Panel on Climate Change's Fifth Assessment Report (2014) calls for “adaptation” to effects that have already occurred and unavoidable medium- and long-term effects. In this context, this paper discusses the present state of and future forecasts for seaweed beds on the Japanese coast, and it then considers the future trends of climate change-adapted seaweed bed construction. [ABSTRACT FROM AUTHOR]

Although many fish species are known to feed on jellyfish, only a few quantitative studies on this subject have been conducted in the field or laboratory. We combined field observations and feeding experiments to quantitatively evaluate the potential feeding capability of the black scraper Thamnaconus modestus on giant jellyfish Nemopilema nomurai in a jellyfish-abundant area. Underwater observations revealed that shoals of T. modestus fed voraciously on jellyfish when the jellyfish were close to the fish's seaweed habitat. Gut contents of field-collected T. modestus almost exclusively consisted of jellyfish. In tank trials, feeding activity of black scraper was high when light intensity was between about 1.1 lx and 50 × 10 lx. The estimated feeding speed of T. modestus on the jellyfish in the Sea of Japan when the jellyfish bloom occurred was 10.0 ± 2.0 times fish body weight per day. The results support the prediction that T. modestus and probably other coastal medusivorous fishes have a substantial capability to eliminate jellyfish blooms. Considering that they are highly dependent on seaweed bed, protection of such habitats for these medusivores may be the most cost-efficient control method for jellyfish blooms. [ABSTRACT FROM AUTHOR]

Wakame seaweed is an important aquatic resource in Iwate Prefecture. However, a suctorian Ephelota gigantea sometimes causes great damage to wakame culture. Since little is known about the biological characteristics of E. gigantea, its detailed morphology and temporal change of biological characteristics during the 2010 culture season were investigated. Scanning electron microscope observations showed that E. gigantea had different striation patterns on the stalk; there was a swell made of cement by which the stalk was attached to wakame firmly; and the buds had cilia arranged in concentric circles about a ring in the center of the ventral side. A suctorian parasite was found to infect E. gigantea, and the infection seemed to have decreased drastically the attached density of E. gigantea on wakame. Cell size of parasite-infected E. gigantea individuals was larger than that of uninfected individuals, probably because larger E. gigantea has larger surface area for attachment of the parasite. Cyst formation or conjugating individuals were not observed. [ABSTRACT FROM AUTHOR]

Brown seaweed, Sargassum thunbergii is thought to be effective for As, Cu and Zn sensor. Green seaweed, Ulvales, red seaweed, Caulacanthus ustulatus and Ahnfeltiopsis flabelliformis are thought to be effective for just Cu sensor. High Zn concentration and large volume of Zn drainage water from the closed Kanayama mine flowed into sea and drainage water and groundwater containing Cu, Zn and As contacted with muck along the coast also flowed into sea in the closed Shizuki mine. Cu, Zn and As concentrations for many kinds of seaweed sampled at the two mines and no contamination places, the Kii and Izu Peninsula, were measured. Cu Zn and As concentrations for Sargassum thunbergii are 1000, several 100 and several 100 ppm at the Shizuki mine and 10, several 1000 and 100 ppm at the Kanayama mine, and 10, several 10 and 100 ppm at the no contamination places. [ABSTRACT FROM AUTHOR]

Abstract: Given the growing importance of the aquaculture sector in contributing to global seafood production, there needs to be a concerted effort to develop commercially relevant and ecologically sustainable feeds for the cultivation of commercially important species. Limitations on the availability and use of fish meal through EU directives (EC Regulation 999/2001 & EC Regulation 183/2005) are focussing research efforts to find alternative sources of protein for aquaculture feeds. Marine algae, although low in protein, are widely being considered as a potential alternative to fish meal as not only do they have the potential to impart additional health benefits when ingested but they can also be cultured under enrichment conditions to enhance their nutritional profile as a feed additive. For abalone (a marine gastropod mollusc), several studies have highlighted the benefits of a diet of fresh mixed species seaweed for cultivation. However, the performance of a mixed species marine algae meal, consisting of Laminaria digitata meal, Palmaria palmata meal and Ulva lactuca meal, in a formulated diet for abalone has not apparently been investigated. In this study, the performance of five novel, isonitrogenous, konjac glucomannan–xanthan gum (KX) bound feeds for the abalone Haliotis discus hannai were evaluated in a 12-week experimental growth trial. Comparisons were made between a basal diet formulation (Diet A), a basal diet+lipids+choline chloride (Diet B) and diets containing mixed seaweed meal (Diet C) or fish meal (Diet D) or mixed seaweed meal+fish meal (Diet E). Freshly harvested L. digitata was included as a natural feed type and experimental control. Dry matter leaching was assessed and no significant differences in the dry matter loss over 3 and 4days were observed between the experimental KX feeds, although L. digitata was a significantly more seawater stable feed type. Daily food consumption (DFC) of Diet C and Diet E was significantly lower than that of fresh L. digitata and the DFC of Diet D was significantly higher than that of L. digitata. Diet E had significantly higher food conversion efficiency than L. digitata, Diet A, Diet B and Diet D. There was no difference in the protein efficiency ratio (PER) between the formulated diets but the PER of Diet D was significantly different to L. digitata. L. digitata had significantly higher linear growth rates than Diet B, and significant differences in the specific growth rates were observed between Diet A and Diet D only. No significant differences in body weight to shell length ratios and percentage survival between treatments were observed. This study highlights the potential for a mixed species seaweed meal as a fish meal replacement in formulated feeds for abalone. [Copyright &y& Elsevier]

A new heterotrophic sand-dwelling dinoflagellate, Ankistrodinium armigerum K. Watanabe, Miyoshi, Kubo, Murray et Horiguchi sp. nov., is described from Ishikari Beach, Hokkaido, Japan and Port Botany, NSW, Australia. The dinoflagellate is laterally compressed, possessing a short triangular epicone and a large sac-like hypocone. It possesses a right-handed cingulum and a deeply-incised sulcus. The sulcus descends towards the posterior of the cell where it becomes much deeper and wider, resulting in a bilobed ventral side to the hypocone, with a greater excavation of the left lobe than the right. In addition, the right lobe of the hypocone is shorter than the left lobe, which allows a partial view of the left sulcal wall when the cell is viewed from its right side. The sulcus ascends in the epicone to form an apical groove. The apical groove is linear but terminates in an ellipsoid fashion and its extremity approaches, but does not form a closed loop with the apical end of the linear portion. The dinoflagellate possesses two distinct size classes of trichocysts. The large trichocysts are located in the posterior part of the cell, while small trichocysts are distributed throughout the cell. The dinoflagellate shares morphological characteristics with the heterotrophic sand-dwelling dinoflagellate, Ankistrodinium semilunatum, the type species of the genus. These include a laterally compressed cell, a right-handed cingulum, a deeply-incised sulcus and the same basic structure to the apical groove. Molecular phylogenetic analyses based on small and large subunits of rDNA showed that in both trees, A. semilunatum and A. armigerum formed a robust clade, suggesting that these two species are closely related. Because no organism with the characteristics of this species exists and because this species is closely related to A. semilunatum, we concluded that this species should be described as a second species of the genus Ankistrodinium. [ABSTRACT FROM AUTHOR]

The "blue carbon" concept and the role of blue carbon stored in shallow coastal ecosystems in mitigating climate change have attracted attention worldwide. In addition to typical blue carbon ecosystems, such as mangroves, tidal marshes, and seagrass meadows, macroalgal beds and macroalgae farming are also gaining recognition as potential blue carbon sinks. Effective policies and methodologies are important for the conservation and expansion of blue carbon sinks, as well as the consequent reduction of atmospheric carbon dioxide (CO 2). One of the most effective methods is carbon offset credit schemes. However, to date, almost all credit schemes have been implemented for mangroves and saltmarshes. None has been implemented for seagrass meadows, macroalgal beds, and macroalgae farming, although their CO 2 uptake potentials are large. Here, we review three blue carbon offset credit projects for seagrass meadows, macroalgal beds, and macroalgae farming implemented in Japan. We show the blue carbon offset crediting projects of (1) Yokohama City, the first in the world; (2) Fukuoka City, the second such project in Japan; and (3) the first Japanese national governmental demonstration project. Furthermore, we highlight their characteristics by comparing them with the other blue carbon offset projects. Finally, we discuss the need to accelerate blue carbon offset credit projects and related initiatives in the future. [ABSTRACT FROM AUTHOR]

The elderly are known to have an inadequate immune response to influenza vaccine. Mekabu fucoidan (MF), a sulfated polysaccharide extracted from seaweed, was previously shown to have an immunomodulatory effect. We therefore investigated antibody production after influenza vaccination in elderly Japanese men and women with and without oral MF intake. A randomized, placebo-controlled, double-blind study was conducted with 70 volunteers >60 y of age. They were randomly assigned to 1 of 2 groups, consuming either MF (300 mg/d) or placebo for 4 wk, and then given a trivalent seasonal influenza vaccine. Serum was sampled at 5 and 20 wk after vaccination to measure the hemagglutination inhibition titer and natural killer cell activity. The MF group had higher antibody titers against all 3 strains contained in the seasonal influenza virus vaccine than the placebo group. Titers against the B/Brisbane/60/2008 (B) strain increased substantially more in the MF group than in the placebo group over the product consumption period. The immune response against B antigen met the European Union Licensure criteria regarding the geometric mean titer ratio in the MF group (2.4), but not in the placebo group (1.7). In the MF group, natural killer cell activity tended to increase from baseline 9 wk after MF intake (P = 0.08). However, in the placebo group no substantial increase was noted at 9 wk, and the activity decreased substantially from 9 to 24 wk. In the immunocompromised elderly, MF intake increased antibody production after vaccination, possibly preventing influenza epidemics. [ABSTRACT FROM AUTHOR]

We evaluated the acute toxicity of the antifouling biocide Sea-Nine 211 to the algae Chaetoceros calcitrans, Dunaliella tertiolecta, Tetraselmis tetrathele, and Skeletonema costatum, the crustacea Tigriopus japonicus and Portunus trituberculatus, and the polychaete Perinereis nuntia. The algae, and especially the diatoms C. calcitrans and S. costatum, were sensitive to Sea-Nine 211 toxicity, with the average acute toxicity values being 0.32, 3.9, 1.6, 0.22, 1.6, 12, and 27 μg/l for C. calcitrans, D. tertiolecta, T. tetrathele, S. costatum, T. japonicus, P. trituberculatus, and P. nuntia, respectively. A sediment toxicity test for Sea-Nine 211 using the polychaete P. nuntia revealed demonstrated that the 14-day median lethal concentration was 110 μg/kg dry-wt sediment and that growth was the most sensitive indicator. The chronic toxicity values of Sea-Nine 211 for the diatoms C. calcitrans and S. costatum were within the range of reported Sea-Nine 211 concentrations in seawater in coastal Japan, and the toxicity values for P. nuntia were within the reported concentrations in sediment. Based on these results, Sea-Nine 211 may have toxic effects on some sensitive species residing in the coastal areas of Japan, but the ecological risk posed by Sea-Nine 211 would appear to be confined to a limited area of Japanese coastal waters. [ABSTRACT FROM AUTHOR]

Blooms of toxic dinoflagellates of the genus Ostreopsis, which is known as a producer of palytoxin (PTX) analogs, may pose a threat to human health in tropical, subtropical, and temperate regions around the world. In the present study, we established a suitable culture method for Ostreopsis spp. isolated from Japanese coastal waters and characterized their growth potential using the method to discuss their bloom dynamics. Each clonal strain of Ostreopsis cf. ovata, Ostreopsis sp. 1, Ostreopsis sp. 5, and Ostreopsis sp. 6 was incubated in 25 × 150 mm test tubes with a flat bottom containing various kinds of medium. Since Ostreopsis spp. strains grew well in IMK and/or f/2 media, we selected these media for cultivation of all the Ostreopsis spp. isolates. Growth rates of O. cf. ovata (0.834 divisions/day), Ostreopsis sp. 1 (0.619 divisions/day), and Ostreopsis sp. 6 (1.04 divisions/day) that produce PTX analogs significantly differed ( p < 0.05) respectively and are clearly higher than those of other reported epiphytic dinoflagellate Gambierdiscus toxicus, Prorocentrum lima, and Coolia monotis cultures, which suggest that these species have ecological advantages to predominate through the algal succession in Japanese coastal waters, resulting in a potential risk to human health in this region. [ABSTRACT FROM AUTHOR]

Occurrence of α-N-acetylgalactosaminidases among 177 strains of marine bacteria of the phylum Bacteroidetes, epiphytes of marine algae growing on the littoral of the Seas of Okhotsk and Japan, was studied. About 36% of the isolates studied contained α-N-acetylgalactosaminidase. All of the bacteria of the genus Arenibacter (species A. latericius, A. certesii, and A. palladensis), irrespective of the source of isolation, synthesized this enzyme. The greatest number of α-N-acetylgalactosaminidase producers was found among the isolates from the algae Neosiphonia japonica, Acrosiphonia sonderi, and Ulva fenestrata sampled in the Cove of Trinity, Posyet Bay, the Sea of Japan. These were mainly bacteria of the genera Zobellia (50%) and Maribacter (58%). Among the epibionts studied, the bacteria Arenibacter latericius KMM 3523, an epiphyte of the brown alga Chorda filum from the Sea of Okhotsk, and Cellulophaga sp. KMM 6488, an epiphyte of the green alga Acrosiphonia sonderi from the Sea of Japan, were marked as the most promising sources of the enzyme. The results of this study showed that aerobic nonpathogenic marine Bacteroidetes, algal associants not requiring special cultivation conditions, are the promising, economical, and ecologically pure sources of unique and biotechnologically significant α-N-acetylgalactosaminidases. [ABSTRACT FROM AUTHOR]

A certified reference material, NMIJ CRM 7405-a, for the determination of trace elements and As(V) in algae was developed from the edible marine hijiki ( Hizikia fusiforme) and certified by the National Metrology Institute of Japan (NMIJ), the National Institute of Advanced Industrial Science and Technology (AIST). Hijiki was collected from the Pacific coast in the Kanto area of Japan, and was washed, dried, powdered, and homogenized. The hijiki powder was placed in 400 bottles (ca. 20 g each). The concentrations of 18 trace elements and As(V) were determined by two to four independent analytical techniques, including (ID)ICP-(HR)MS, ICP-OES, GFAAS, and HPLC-ICP-MS using calibration solutions prepared from the elemental standard solution of Japan calibration service system (JCSS) and the NMIJ CRM As(V) solution, and whose concentrations are certified and SI traceable. The uncertainties of all the measurements and preparation procedures were evaluated. The values of 18 trace elements and As(V) in the CRM were certified with uncertainty ( k = 2). [ABSTRACT FROM AUTHOR]

To reduce the volume of seaweed wastes and extract polysaccharides, seaweed-degrading bacteria were isolated from drifting macroalgae harvested along the coast of Toyama Bay, Japan. Sixty-four bacterial isolates were capable of degrading 'Wakame' ( Undaria pinnatifida) thallus fragments into single cell detritus (SCD) particles. Amongst these, strain 6532A was the most active degrader of thallus fragments, and was capable of degrading thallus fragments to SCD particles within a day. Although the sequence similarity of the 16S rRNA gene of strain 6532A was 100% similar to that of Microbulbifer elongatus JAMB-A7, several distinct differences were observed between strains, including motility, morphology, and utilization of d-arabinose and gelatin. Consequently, strain 6532A was classified as a new Microbulbifer strain, and was designated Microbulbifer sp. 6532A. Strain 6532A was capable of degrading both alginate and cellulose in the culture medium, zymogram analysis of which revealed the presence of multiple alginate lyases and cellulases. To the best of our knowledge, this is the first study to directly demonstrate the existence of these enzymes in Microbulbifer species. Shotgun cloning and sequencing of the alginate lyase gene in 6532A revealed a 1,074-bp open reading frame, which was designated algMsp. The reading frame encoded a PL family seven enzyme composed of 358 amino acids (38,181 Da). With a similarity of 74.2%, the deduced amino acid sequence was most similar to a Saccharophagus enzyme ( alg 7C). These findings suggest that algMsp in strain 6532A is a novel alginate lyase gene. [ABSTRACT FROM AUTHOR]

Seasonal relationships among stranded wrack quantity, seaweed fly abundances, and parasitism at the pupal stage were studied along three sandy beaches in central Japan. The seasonal occurrence patterns of puparia of seaweed flies Coelopa frigida and Fucellia spp. generally corresponded to seaweed deposition, which peaked in May-July and October-December. Parasitoids use fly puparia in these seasons. However, the occurrence of seaweed flies and their parasitoids varied among the three sandy beaches and did not correspond to the wrack amounts. These findings suggest that populations of seaweed flies and their parasitoids are seasonally, but not spatially, regulated by bottom-up processes. The parasitoid assemblage of fly puparia was composed of two Aleochara (Coleoptera: Staphylinidae), two Trichopria (Hymenoptera: Diapriidae), and five pteromalid species (Hymenoptera), but the rate of parasitism was less than 20% and might have had little effect on fly populations. [ABSTRACT FROM AUTHOR]

Abstract: This study aimed to elucidate the relationship between the chemical composition and the growth of a marine alga, Sargassum horneri (Turner) C. Agardh (abbreviated as S. horneri) harvested from the Chikuzen Sea, Fukuoka, Japan, as well as the changes in the chemical composition during pre-heating of harvested S. horneri. Both its length and weight reached maximum levels late in March. The mean chemical composition of S. horneri from December 2004 to May 2005 was 87.7% moisture, 1.0% protein, 0.1% lipid, 3.4% ash and 5.7% total dietary fiber. The ash contents of the male plants were higher in February but lower in March and April than those of the female plants. The lipid contents of the males were higher in March than those of the female plants. The protein content reached its maximum in February. The total dietary fiber content began to increase in February and reached its maximum at the end of March. The total dietary fiber content increased after full growth and maturity. S. horneri is a potential source of dietary fiber and minerals as a food ingredient. [Copyright &y& Elsevier]

The article presents a study focusing on assessment of Japanese iodine intake based on seaweed consumption in Japan. As stated, seaweed consumption frequency differs from person to person in Japan which results in a constantly fluctuating iodine intake. The study shows that seaweed is served in approximately 21 percent of Japanese meals with 20-38 percent of the Japanese male and female population aged 40-79 years. It concludes that iodine intake from seaweed in Japan is linked to health benefits not seen in cultures with dissimilar diets.

Polyopes lancifolius (Harvey) S. Kawaguchi & H.W. Wang has been recorded for the first time in Europe, during the summer of 2008. A small population was discovered in the Gulf of Morbihan (northeast Atlantic, France). This is the first observation of P. lancifolius outside its native range. Vegetative and reproductive morphological features are compared with previous descriptions. rbcL sequences show no divergence from Japanese populations. Imports of Pacific oysters Crassostrea gigas (Thunberg 1793) are likely to be responsible for its accidental introduction into the Gulf of Morbihan, either directly from northwest Pacific regions or indirectly (secondary dispersal) by transfers from another European oyster farming site. The history of previous algal introductions from Japan suggests that if it becomes successfully established at Morbihan, the species is likely to spread to other European coastal areas. [ABSTRACT FROM AUTHOR]

Abstract: We measured the environmental radioactivity and isotope ratio, 87Sr/86Sr ratio, 234U/238U, δ13C, and 228Ra/226Ra activity ratio, of adhesion that adhered to a wooden tubing vessel obtained from the Matsusaki site, one of the salt-production sites where Moshio is manufactured, in Aichi Prefecture, Japan. The environmental radioactivity and isotope ratio verified that the adhesion originated from the seaweed and/or sea grass. [Copyright &y& Elsevier]

Seaweed and soy foods are consumed daily in Japan, where breast cancer rates for postmenopausal women are significantly lower than in the West. Likely mechanisms include differences in diet, especially soy consumption, and estrogen metabolism. Fifteen healthy postmenopausal women participated in this double-blind trial of seaweed supplementation with soy challenge. Participants were randomized to 7 wk of either 5 g/d seaweed (Alaria) or placebo (maltodextrin). During wk 7, participants also consumed a daily soy protein isolate (2 mg isoflavones/kg body weight). After a 3-wk washout period, participants were crossed over to the alternate supplement schedule. There was an inverse correlation between seaweed dose (mg/kg body weight) and serum estradiol (E2) (seaweed-placebo = y = 0.28 × dose - 42.8; r:= 0.70; P= 0.003), which was linear across the range of weights. Soy supplementation increased urinary daidzein, glycilein, genistein, and O-desmethylangolensin (P= 0.0001) and decreased matairesinol and enterolactone (P < 0.05). Soy and seaweed plus soy (SeaSoy) increased urinary excretion of 2-hydroxyestrogen (2-OHE) (P= 0.0001) and the ratio of 2-OHE:16α-hydroxyestrone (16αOHE1) (P= 0.01). For the 5 equol excretors, soy increased urinary equol excretion (P= 0.0001); the combination of SeaSoy further increased equol excretion by 58% (P= 0.0001). Equol producers also had a 315% increase in 2:16 ratio (P= 0.001) with SeaSoy. Seaweed favorably alters estrogen and phytoestrogen metabolism and these changes likely include modulation of colonic bacteria. [ABSTRACT FROM AUTHOR]

Abstract: To evaluate the relative importance of possible food sources, including riverine particulate organic matter, reeds, benthic microalgae, seaweeds, cultured laver (Porphyra) and coastal phytoplankton, for commercial bivalves and co-occurring benthic animals, 73 macrofaunal species were collected from intertidal and subtidal soft bottoms in the inner part of Ariake Sound, Kyushu, southern Japan, and their isotopic compositions were analyzed. The results revealed that (1) both intertidal and subtidal food webs were constituted of 3 trophic levels, (2) suspension-feeding bivalves utilize a mixture of benthic microalgae and coastal phytoplankton, and omnivores and carnivores incorporate benthic microalgae and phytoplankton through their intermediate prey, and (3) 3 bivalves (Scapharca kagoshimensis, Modiolus metcalfei and Atrina lischkeana) inhabiting both intertidal and subtidal bottoms showed similar seasonal fluctuations, suggesting no difference in the diet composition among the species and between the 2 habitats. We conclude that a large biomass of benthic microalgae which was approximately equal to that of phytoplankton and the strong tidal currents that would resuspend benthic microalgae and transport them to subtidal bottom areas account for the benthic microalgal and phytoplankton based trophic structure in the inner part of Ariake Sound. [Copyright &y& Elsevier]

The genetic structure and phylogeography of the brown seaweed Sargassum horneri/filicinum complex in Japan were studied based on the mitochondrial cox3 haplotype. The cox3 haplotypes found were divided into three clades in a statistical parsimony network, among which there were large numbers of steps. Contrary to the reported large amount of drifting S. horneri along the Japanese coast, the three clades were dividedly distributed on the Japanese coast: the northern Pacific, the central Pacific, and western Japan. The western Japan S. horneri had haplotypes that were phylogenetically closer to those of S. filicinum than to the northern and central Pacific S. horneri populations. The S. filicinum populations were included within the western Japan clade and grouped together with the S. horneri samples from western Japan. Taken together with the unstable morphological diagnosis, this result suggests that S. filicinum should be reduced into a synonymy of S. horneri. The TMRCA analysis suggested that the divergence time of each clade may go back to the last interglacial period and a skyline plot suggested that the last glacial maximum had only a small effect on the population size of S. horneri. The geographic subdivision of the three groups, in spite of a large amount of drifting mats, suggests a limited contribution of drifting mats to gene flow on a large geographic scale. On a small geographic scale, a small number of haplotypes were shared between S. horneri-type and S. filicinum-type populations. This result suggests that populations of these two types are partially, though not completely, isolated from each other, possibly by selfing in S. filicinum-type populations or by a difference in peak reproduction. [ABSTRACT FROM AUTHOR]

Nitrogen budgets and predominant benthic organisms were examined at a matured artificial tidal flat of Osaka Nanko bird sanctuary and an artificial young tidal flat of Hannan Second District, Osaka Bay, Japan. At the Osaka Nanko bird sanctuary, indexes of the quality of the bottom sediment increased over the time course and no abiotic area was observed in the macrobenthic fauna. Dissolved inorganic nitrogen imported into the tidal flat changed its form and was exported in the form of dissolved organic nitrogen. As a result, total nitrogen was trapped at the tidal flat at an average rate of 138mgNm−2 day−1. At the young tidal flat of Hannan Second District net exchange of nitrogen varied markedly among 2000, 2001, 2002 and 2003. In September 2000 when only 5 months had passed after construction, the tidal flat functioned as a site of source for nitrogen. However, it changed as a sink for nitrogen in 2001–2002 in relation to the growth of seaweeds (Ulva spp. and Gracilaria vermiculophylla) and clams (Tapes philippinarum). In 2003 nitrogen was again released from the artificial tidal flat due to the decrease of biomass of the dominant organisms. Comparing the nitrogen budget between the two sites on a per unit time and area basis, net exchanges of nitrogen by tidal exchange were apparently low and relatively constant at the tidal flat of Osaka Nanko bird sanctuary. This suggests that the aged artificial tidal flat of Osaka Nanko bird sanctuary has a stable ecosystem compared to the young artificial tidal flat of Hannan Second District. [Copyright &y& Elsevier]

Vibrio vulnificus is a ubiquitous toxigenic bacterium found in a coastal environment but little is known about its occurrence and seasonality among seaweeds, which are widely consumed as seafood in Japan. Therefore, we have observed the bacterium's abundance in seawater and seaweed samples from three areas of the Kii Channel, Japan, during June 2003 to May 2004. A total of 192 samples were collected: 24 from each source in summer, autumn, winter and spring. The samples were selectively cultivated following the most probable number (MPN) technique. Vibrio vulnificus population ranged from 0 to 103 MPN 100 mL−1 seawater or 10 g seaweeds; higher counts were observed during summer. The optimum temperature, salinity and pH for the bacterium were 20–24 °C, 24–28 p.p.t. and 7.95–8.15, respectively. However, seaweeds always contained higher V. vulnificus than seawater. Among 280 V. vulnificus strains, detected by species-specific colony hybridization and PCR, 78, 74, 11 and 16 were from seaweeds and 46, 42, 2 and 11 were from seawater during summer, autumn, winter and spring, respectively. Ribotyping of 160 selected strains revealed a higher genotypic diversity (18 patterns) among strains from seaweeds than from seawater (10 patterns). Seaweeds can thus act as a potential habitat for V. vulnificus and are more unsafe for consumption during summer. [ABSTRACT FROM AUTHOR]

Objectives:To evaluate the dietary fiber (DF) intake pattern among the Japanese general population.Design:We performed a dietary survey among the general population in northern Japan to evaluate the intake patterns. DF intake was calculated by substituting the DF content of each food in the Dietary Fiber Table for the intake of each food from this dietary survey.Subjects:Five hundred and seventy-seven subjects participated in the study, 198 men and 379 women.Results:In subjects with higher DF intakes the origins of the DF that were from all food groups, but with the notable exception of rice. The contribution of the seaweed group was of particular interest. From multiple regression analysis, as for food group, seaweeds showed the highest positive correlation with DF intake in both genders, followed by vegetables, pulses, fruits. On the other hand, rice showed the negative correlation with DF intake in both genders. As for life factor, body mass index showed the negative correlation with DF intake in women.Conclusion:Seaweed, a typical Japanese food, was most related to the increase in DF intake for the Japanese general population, whereas rice, the Japanese staple, had a small influence on decreased DF intake.European Journal of Clinical Nutrition (2007) 61, 99–103. doi:10.1038/sj.ejcn.1602505; published online 2 August 2006 [ABSTRACT FROM AUTHOR]