著者

大塚 攻 平野 勝士 宮川 千裕 近藤 裕介 菅谷 恵美 中井 敏博 高田 健太郎 福島 英登 大場 裕一 三本木 至宏 浅川 学 西川 淳

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.66, no.2, pp.86-100, 2019-08-25 (Released:2019-09-03)

参考文献数

94

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In marine ecosystems, bacterial interactions with zooplankters are highly complex, and much attention has recently been given to these interactions. Bacteria not only play the role of food and symbionts for zooplankters, but also function as decomposers for their carcasses, exuviae and feces. Free-living bacteria are involved as major producers in microbial loops, and form the diet of nanoplanktonic flagellates, ciliates, appendicularians and thaliaceans. Epibiotic and enteric bacteria use zooplankters as refuges to avoid predation and/or as food sources. However, aggregations of epibiotic bacteria or biofilms may function as “a second skin,” sensu Wahl et al. (2012), to modulate hosts metabolism and behaviors. Because they contain rich nutrients, low pH and low oxygen, copepod guts provide a unique environment for bacteria in which anaerobes can survive. Bacterial communities on copepods vary seasonally and among species, depending on the physiology of the host. The conveyor-belt hypothesis implies that bacteria vertically, and presumably horizontally, hitchhike in different water masses in accordance with the migrations of zooplankters. Bioluminescent bacteria are likely used as biomarkers of detrital foods for some planktonic copepods belonging to the Bradfordian families and as obligate symbionts for bioluminescent ichthyoplankters. Tetrodotoxin-producing bacteria are associated with chaetognaths that may use toxins to capture prey animals. Colonial cyanobacteria provide substrata for miraciid harpacticoid copepods. Hyrdomedusae play a role as vectors of pathogenic bacteria, causing lesions in farmed fish. Modern genetic analysis is a powerful tool that will be the first step in revealing the physiological and functional interactions between bacteria and zooplankton.

著者

櫻井 久惠 佐野 雅美 高橋 邦夫 真壁 竜介 小達 恒夫

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.67, no.1, pp.19-23, 2020-02-25 (Released:2020-02-28)

参考文献数

9

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Using plankton sampled from the Southern Ocean and archived at the National Institute of Polar Research (NIPR, Tokyo), we prepared resin-embedded plankton specimens as a marine education material. This form of preservation allows one to observe the specimens’ appearance in multiple aspects with the naked eye. In addition, resin-embedded specimens are solid, robust and lightweight, and so can be easily transported and handled. Moreover, such specimens can be used for observations of fine structure, which has various advantages as a learning material for graduate students and young scientists. As of October 2019, we produced 210 individual pieces, comprising 52 species of marine plankton in 12 major groups. The specimens have so far been used at various locations and events, such as the “Open House” and the “Polar Science Museum” of the NIPR, for display at the GRAntarctic booth of the JpGU, at junior high school classes, and in science cafes. Plankton are important organisms for understanding marine ecosystems, yet social awareness of this assemblage of organisms is often poor. Therefore, we intend to improve and increase our production of resin-embedded marine plankton specimens. Resin-embedded specimens are now registered in the ‘Database of Animal Specimens from Polar Regions’ of the NIPR. We expect that this type of preserved material will make a valuable contribution to marine education, at the primary- to graduate-school levels as well as for the general public.

著者

内田 直行 木村 俊介 中園 金吾 片桐 律子 荒 功一 広海 十朗

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.58, no.2, pp.146-156, 2011-08-26

参考文献数

45

被引用文献数

1

著者

成田 光好 羽生 和弘 関口 秀夫

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.49, no.2, pp.127-135, 2002-08-25

参考文献数

17

被引用文献数

1

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伊勢湾は本州中央部の太平洋岸に位置し、その平均深度は19.5m、湾中央の最深部は約35m、面積は約1738㎡であり、少なくとも70m以上の水深をもつ伊良湖水道を通して外海沿岸域と海水交換をおこなう半閉鎖的な湾である。その海底地形からも明らかなように、湾中央の最深部から愛知県側にかけての海底勾配はどちらかといえば急峻であり、三重県側にかけては緩やかな勾配の海底が続いている。伊勢湾奥部には本邦有数の河川である木曽三川から大量の淡水が流入し、一方、湾口部の伊良湖水道を通して高水温・高塩分の黒潮系沿岸水が湾内に進入しているので、そこでは典型的なエスチュアリー循環流(密度流)が卓越している。伊勢湾や東京湾や大阪湾と同規模の内湾であり湾奥部に大河川が流入していることでもこれらの湾は共通している。伊勢湾の北部域から湾中央域にかけての海底にはシルトー粘土の底土が、湾口域には砂質底が湾南部域の三重県沖には粗砂ー砂礫または礫の底土が広がっている。近年、伊勢湾の北岸及び西岸に位置する都市からの汚水廃棄のために、伊勢湾の富栄養化は著しく、しばしば赤潮の発生が報告されている。伊勢湾の底層の溶存酸素量は季節的に著しく変動することが知られており、とくに夏季においては湾中央域から三重県側の西部域を中心に貧酸素域が発達し、秋季から冬季には海表面の冷却と季節風による鉛直混合の強化によって湾全域の底層において溶存酸素量の回復が見られる。

著者

沢田 好史 坂本 亘

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.39, no.2, pp.p87-96, 1993-02

被引用文献数

1

著者

西岡 智哉 池脇 義弘 秋山 諭 山本 圭吾 田中 咲絵 宮原 一隆 原田 和弘 山下 泰司 濱﨑 正明 長谷川 尋士 本田 恵二

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.65, no.2, pp.36-43, 2018-08-25 (Released:2018-10-26)

参考文献数

19

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A widespread bloom of the harmful raphidophyte Chattonella ovata Y. Hara & Chihara occurred for the first time in the east Seto Inland Sea in the summer of 2016. From July 11 to 17, cell densities in Hiuchi-Nada and Bisan-Seto reached 10 cells mL-1. From July 19 to 24, the highly dense distribution area expanded to Harima-Nada, and cell densities reached their peak (max. 222 cells mL-1) in all areas affected from July 25 to 31. In Harima-Nada, the species decreased rapidly, whereas the level at Hiuchi-Nada and Bisan-Seto was maintained until August. From July 11 to 18, a westerly wind had prevailed in the Takamatsu area facing Bisan-Seto while the wind was weak during other periods. That caused eastward wind-induced passage flow, and expansion of the cell distribution from Bisan-Seto to Harima-Nada. In addition, the sunlight hours were long (average 8.6 h) and the water temperature was high (approximately 25 to 29˚C).Furthermore, salinity remained at around optimum for C. ovata (approximately 28 to 31) in the east Seto Inland Sea while the species bloomed. This indicates that these environmental conditions were suitable for growth of this species, which is adapted to strong irradiance, high water temperature and high salinity. In Bisan-Seto and Hiuchi-Nada, Chattonella marina and Chattonella antiqua appeared at high cell densities in mid-July when the distribution of C. ovata expanded. However, in Harima-Nada, C. marina and C. antiqua maintained low cell densities consistently. In Harima-Nada, DIN (dissolved inorganic nitrogen) and DIP (dissolved inorganic phosphorus) remained at 0.51–1.17 µM and 0.08–0.25 µM, respectively, from July 4 to August 15. The minimum cell quotas of nitrogen for C. ovata are lower than for C. antiqua. We presumed this gave a competitive advantage to C. ovata for growth. In Harima-Nada, cell density of diatoms decreased temporarily in late-July, but the density remained above 100 cells mL-1 after August. However, in Hiuchi-Nada and Bisan-Seto, cell densities of diatoms were kept below 100 cells mL-1 through the observation period. We inferred that a low concentration of nutrients, less westerly wind, and a high density of diatoms were factors that led to the regulation of the low level of C. ovata after August in Harima-Nada. We considered that the low diatom density was one of the causes of the C. ovata bloom being prolonged in Hiuchi-Nada and Bisan-Seto.

著者

喜多村 稔

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.50, no.2, pp.103-109, 2003-08-25

著者

品田 章良 伴 修平 池田 勉 津田 敦 齊藤 宏明

出版者

日本プランクトン学会

雑誌

日本プランクトン学会報 (ISSN:03878961)

巻号頁・発行日

vol.47, no.2, pp.119-124, 2000-08-25

参考文献数

26

被引用文献数

3