サロマコ カラ タンリ シタ ケイソウ 7カブ ノ ケイタイ ト ゾウショク トクセイ

単一藻株として安定した増殖を示しているサロマ湖からの単離株(7株)の形態と低温培養下での増殖に関する特性を調べた.単離株はChaetoceros属2株,Navicula属2株,Nitzschia属3株であった.それぞれの株で得られた増殖速度は株ごとにわずかに差があり,誘導期・対数増殖期間の長さにも株ごとの違いが認められた.40日間におよぶ実験期間内において,いずれの株にも急激な死滅が生じたような変動は認められず,見た目上増殖停止した後,少なくとも10日間は,クロロフィル蛍光強度が最大値付近を保っていた.また低温培養にも関わらず,対数増殖期の増殖速度が0.27-0.47 d^という高い増殖能を示した.We observed morphological and growth properties of diatoms isolated from Saroma Ko lagoon, and cultured them under a low-temperature condition (1.7°C ). Seven strains which belonged to three genera, Chaetoceros (2 strains), Navicula (2 strains), and Nitzschia (3 strains) were used for the present study. Each strain showed slightly different growth rate, lag and logarithmic growth phase lengths; however, they never showed any signs of occurrence of the senescent phase in 40 days of experiments. After the logarithmic growth phase, chlorophyll fluorescence of all cultures kept nearly the maximum level (stationary phase), at least for 10 days. Logarithmic growth rates under 1.7°C temperature ranged from 0.27 to 0.47 d^, suggesting psychrophilic growth ability of all isolated strains

ウミタカマル ニヨル ナンタイヨウ ノ タイキチュウ リュウカジメチル ノウド ソクテイ

2009年1月から2月の南半球の夏期間に,東京海洋大学の研究練習船「海鷹丸」にプロトン移動反応質量分析計を搭載して,南大洋の大気中の硫化ジメチル濃度の連続観測を実施した.海鷹丸は昭和基地沖とケープダンレー沖の氷縁域を含む南大洋を航行し,研究観測を実施した.この海域での大気中の硫化ジメチル濃度の連続観測は初めてである.海水中の硫化ジメチル濃度の観測も行われ,そのデータとの対比が可能となった.大気中の連続観測から,昭和基地沖およびケープダンレー沖の氷縁域では,2ppbを越える高い濃度の硫化ジメチルが観測された.Observations of atmospheric dimethyl sulfide were performed in the Southern Ocean during a cruise from Cape Town to Fremantle on the research vessel Umitakamaru" of the Tokyo University of Marine Science and Technology during the austral summer from January to February 2009. The main observation area was south of 60°S in the Southern Ocean, which includes the margin of Antarctic sea ice. The results represent the first continuous measurements of atmospheric dimethyl sulfide in the area. We also undertook point measurements of dimethyl sulfide in the ocean. High concentrations of dimethyl sulfide (>2ppb) were recorded in the atmosphere at the margin of sea ice off Syowa and off Cape Darnley

ウミタカマル ヲ モチイタ ナンキョク ケンキュウ ワークショップ 2008 ホウコク

「海鷹丸を用いた南極研究ワークショップ2008」を東京海洋大学品川キャンパスにおいて2008年8月8日に開催した.参加者は36名であった.2002/03年,2004/05年,2005/06年,2007/08年シーズンに行われた東京海洋大学「海鷹丸」の南極海研究航海(それぞれ,UM0203,UM0405,UM0506,UM0708航海)で得られた結果が報告された後,得られたデータやサンプルの管理及び成果取りまとめについて議論した.A workshop "Southern Ocean Study by RT/V (research and training vessel) Umitaka-Maru, 2008" was held on 8th August 2008 at the Shinagawa Campus of the Tokyo University of Marine Science and Technology (TUMSAT), with 36 participants. Results obtained during RT/V Umitaka-Maru (TUMSAT) cruises in austral summer of 2002/03 (UM0203), 2004/05 (UM0405), 2005/06 (UM0506), and 2007/08 (UM0708) and the current status of data were reported. Data management and synthesis of scientific results were discussed

The morphological and growth properties of seven diatom strains isolated from Saroma Ko lagoon, Hokkaido, Japan

We observed morphological and growth properties of diatoms isolated from Saroma Ko lagoon, and cultured them under a low-temperature condition (1.7°C ). Seven strains which belonged to three genera, Chaetoceros (2 strains), Navicula (2 strains), and Nitzschia (3 strains) were used for the present study. Each strain showed slightly different growth rate, lag and logarithmic growth phase lengths; however, they never showed any signs of occurrence of the senescent phase in 40 days of experiments. After the logarithmic growth phase, chlorophyll fluorescence of all cultures kept nearly the maximum level (stationary phase), at least for 10 days. Logarithmic growth rates under 1.7°C temperature ranged from 0.27 to 0.47 d^, suggesting psychrophilic growth ability of all isolated strains

DMSP and DMS in coastal fast ice and under-ice water of Lützow-Holm Bay, eastern Antarctica

The combined concentration of total dimethylsulfoniopropionate and dimethylsulfide (DMSP+DMS) were measured in Antarctic fast ice on the coast of Lützow-Holm Bay, eastern Antarctica. High bulk-ice DMSP+DMS and chlorophyll a concentrations were found at the bottom of the sea ice, and these concentrations were higher than those in the under-ice water. The bulk-ice DMSP+DMS and chlorophyll a concentrations were highly correlated (r2=0.68, P<0.001), suggesting that the high bulk-ice DMSP+DMS concentrations were caused mainly by the presence of algae assemblages in the ice. The calculated brine DMSP+DMS concentrations were as high as 1100 nM in the bottom ice layer, and the vertical profile patterns of brine DMSP+DMS concentrations were almost the same as for the bulk ice, mainly because of the small amount of variability in the vertical brine volume fraction. DMSP+DMS and chlorophyll a concentrations in the under-ice water increased, whereas the salinity of the under-ice water decreased, during the sampling period. These results reflect the supply of freshwater containing high levels of DMSP+DMS to the water just under the ice as the ice melted. These results suggest that sea-ice melting could be important to sulfur cycling in coastal ice-covered regions of the polar oceans