Historical delta(15) N records of Saccharina specimens from oligotrophic waters of Japan Sea (Hokkaido)

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

Path Loss Prediction Model for a Sloped Area in Microcell Based on Scale Model and Real Environment Measurements

The forests in Japan occupy 70% of the country, and there are many mountains and hills in Japan. As cities and residential areas have expanded the living space for people has spread to such hilly or sloped areas. Mobile communication systems are already a vital infrastructure to daily life, so covering these sloped areas is important in terms of service provisioning. It is necessary to predict propagation losses over the sloped areas for radio link design.The 1st IEEE Asia Pacific Conference on Wireless and Mobile 2014 (APWiMob 2014), Aug. 28-30, 2014, Grand Inna Kuta Hotel, Bali, Indonesi

Maps of <i>δ</i>¹⁵N in the tissue of <i>Saccharina</i> collected from coastal areas around Hokkaido, Japan during the periods from 1881 to 1920 and 1971 to 2014.

<p>The <i>δ</i>¹⁵N ranges are classified by color differences.</p

Historic photographs from the west coast of the Japan Sea off Hokkaido, Japan.

<p>(a) A large number of spawning herring that became stranded on the shore (in Yoichi, 1919), reprinted from Mitsuru Hayashi under a CC BY license, with permission from Mitsuru Hayashi, original copyright 1919. (b) Phenomenon of milky-white turbidity of the sea surface due to herring spawning, called “<i>kuki</i>”, in coastal areas (in Otaru, 2011) reprinted from Takanori Kuribayashi under a CC BY license, with permission from Takanori Kuribayashi, original copyright 2011. (c) Seaweed bed covered with herring eggs (off Haboro, 2004), reprinted from Shoichi Akaike under a CC BY license, with permission from Shoichi Akaike, original copyright 2004. (d) Processing herring for use in “<i>migaki-nishin</i>,” a dried and sliced herring food (in Suttsu, 1911 or 1914), reprinted from <i>Suttsu gojyuwa</i> under a CC BY license, with permission from Tatsuya Yamamoto, original copyright 2014.</p

<i>δ</i>¹⁵N changes (1881–2014) in <i>Saccharina</i> specimens collected from coastal areas around Hokkaido, Japan.

<p>(a) The west coast of the Japan Sea off Hokkaido. (b) The coast of the Pacific Ocean off Hokkaido. (c) The coast of the Okhotsk Sea off Hokkaido. <i>Saccharina japonica</i> var. <i>ochotensis</i> designated with a black circle; <i>Saccharina japonica</i> var. <i>religiosa</i> designated with a gray circle; <i>Saccharina japonica</i> designated with a green solid circle; <i>Saccharina sculpera</i> designated with a pink circle; <i>Saccharina yendoana</i> designated with a green open circle; <i>Saccharina angustata</i> designated with a blue circle; <i>Saccharina coriacea</i> designated with a orange circle; <i>Saccharina longissima</i> designated with a red circle; <i>Saccharina japonica</i> var. <i>diabolica</i> designated with a purple circle. (d) Other species of seaweeds collected from the west coast of the Japan Sea off Hokkaido. The Herbarium in the Hokkaido University Museum is registered officially as SAP with the Index Herbariorum. SAP houses almost all marine benthic algal type specimens described by Japanese researchers. It is one of the marine benthic algal herbariums in the world (<a href="http://sap.museum.hokudai.ac.jp/index.html" target="_blank">http://sap.museum.hokudai.ac.jp/index.html</a>).</p