Fish assemblages associated with three types of artificial reefs: density of assemblages and possible impacts on adjacent fish abundance

We evaluated the effectiveness of wooden artificial reefs (ARs) as fish habitat. Three types of ARs, made of cedar logs, broadleaf tree logs, and PVC pipes, respectively, were deployed in triplicate at 8-m depth off Maizuru, Kyoto Prefecture, Sea of Japan, in May 2004. Fish assemblages associated with each of the nine ARs were observed by using SCUBA twice a month for four years. Fish assemblages in the adjacent habitat were also monitored for two years before and four years after reef deployment. In the surveyed areas (ca. 10 m2) associated with each of the cedar, broadleaf, and PVC ARs, the average number of fish species was 4.14, 3.49, and 3.00, and the average number of individuals was 40.7, 27.9, and 20.3, respectively. The estimated biomass was also more greater when associated with the cedar ARs than with other ARs. Visual censuses of the habitat adjacent to the ARs revealed that the number of fish species and the density of individuals were not affected by the deployment of the ARs. Our results support the superiority of cedar as an AR material and indicate that deployment of wooden ARs causes no reduction of fish abundance in adjacent natural reefs

Dynamin 2 Cooperates with Amphiphysin 1 in Phagocytosis in Sertoli Cells

Testicular Sertoli cells highly express dynamin 2 and amphiphysin 1. Here we demonstrate that dynamin 2 is implicated in phosphatidylserine (PS)-dependent phagocytosis in Sertoli cells. Immunofluorescence and dual-live imaging revealed that dynamin 2 and amphiphysin 1 accumulate simultaneously at ruffles. These proteins are specifically bound in vitro. Over-expression of dominant negative dynamin 2 (K44A) inhibits liposome-uptake and leads to the mis-localization of amphiphysin 1. Thus, the cooperative function of dynamin 2 and amphiphysin 1 in PS-dependent phagocytosis is strongly suggested.</p

Grazing and food size selection of zooplankton community in Lake Biwa during BITEX \u2793

金沢大学教育学部理科教育Community grazing rate of zooplankton larger than 98 μm in body size were examined at the north and south basins of Lake Biwa in late summer, 1993. The lake seston labeled with 14C was divided into different size fraction (20 μm, however, the largest size fraction contributed 57% of the ingested carbon, suggesting that the food source of zooplankton is not necessarily restricted to the small sestonic particles, even if feeding efficiency was low for large sestonic particles. Based on grazing rate, 6 to 10% of total seston was estimated to be removed by the zooplankton community within a day

Summer distribution and short-term variation of the bottom turbid layer in Suo-sound in the Western Seto Inland Sea, Japan

2009年の6月29日-7月2日と8月22-23日に，周防灘において水温，塩分，クロロフィルα（以下chl. α），濁度の鉛直分布を調べた。6-7月にはchl. αの亜表層極大と海底高濁度層がほぼ調査海域全体に形成されていた。8月にはchl. α の亜表層極大は弱くなり，6-7月と較べて海底高濁度層の発達が顕著で，chl. α濃度の増加も見られた。6-7月と8月の両観測期間は，それぞれ小潮と大潮の時期に相当していたことから，潮汐周期が海底高濁度層の発達に影響を及ぼしている可能性が示唆された。また，両観測期間中に，灘西部の2観測点（水深10mの浅海域と30mの沖合域）において1-3時間毎の連続観測を行って日周変動を調べた。海底高濁度層は水温・塩分（および密度）の急激な変化時に最大値を示し，濁度層の分布パターン・厚さは潮汐周期と底層の水温･塩分･密度分布によく対応していた。さらに，塩分－chl. α，塩分－濁度，chl. α－濁度の関係から，粒状懸濁物を陸（河川）起源，海底高濁度層，亜表層クロロフィル極大，異水塊に由来するものに分別することができた。During June 28 to July 2 and August 22 to 23 in 2009, we investigated the distributiosn and diurnal variations of temperature, salinity, chlorophyll a (chl.α) and turbidity in Suo-sound, Seto Inland Sea. In June to July observation, the subsurface chl.α maximum layer (SCM) and the bottom turbid layer (BTL) were found throughout the Suo-sound. In August, the SCM almost diminished but the BTL significantly developed compared to June to July observations and chl.α also showed a noticeable increase in the bottom layer. June to July and August observations corresponded with a neap and spring tides, suggesting a close relation between the development of the BTL and the tidal cycle. The turbidity values of BTL showed a maximum when temperature and salinity changed rapidly, and the distribution pattern of the BTL well-corresponded to those of temperature and salinity, particularly in spring tide in August. Particulate matter was classified into four groups such as terrigeous matter, BTL, SCM, and different water mass according to salinity-chl.α, salinity-turbidity, and chl.α-turbidity relationships