仙台湾の南端部に位置する相馬市にある浦は，南北に細長い海跡湖で太平洋と浦の水域を分けるように細長い砂州が延びている．この浦では，2011年3月11日の東日本大震災時に，砂州上で生じた津波の砕波および越流により，大規模な地形変化および海岸保全施設の被害が生じた．加えて，海中生態系の生息条件として重要な底質環境も浦全域で変化した可能性があった．さらに，浦の大規模な水深（海底地形）変化は，将来的に浦内の流況を変化させ，結果として津波前と異なる水質環境や生物生産環境を引き起こす可能性もあるので，浦で底質と水域地形の現地調査を行い，津波前の状況と比較することにした．

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　浦においては周辺よりも流入する宇多川の上流域において空間線量率が高いことから，放射性セシウムの浦内への初期沈着だけではなく，さらなる流入と蓄積も懸念されている．本研究では浦における放射性セシウムの蓄積様を明らかとすることを目的として，浦内各所からコア採取した底質の放射性セシウム濃度測定および性状分析を行なった．放射性セシウムが同程度に高濃度であっても底質性状は異なり，結果として放射性セシウムの蓄積量も異なった．含泥率の高い南西部では，放射性セシウムが高濃度であっても蓄積量は西部よりも少ないことが明らかとなった．浦全域の底質20cmまでの総蓄積量は220GBq程度と見積もられ，その80％以上が15cm以浅に蓄積していることが明らかとなった．

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　浦への淡水流入量の推定および浦口周辺の水圏環境についてモニタリングを行った．水収支式によって，淡水流入量を推定した結果，陸域からの流出量(11,839.1万ｍ³/yr)に対して，河川流量が93.1%(11,069.1万m³/yr)，地下水量が6.9 %(824.6万m³/yr)と推定された．地下水量824.6万m³/yrは0.26m³/sであり，浦流域の小河川である梅川の推定流量0.19m³/sと同レベルの値であった．浦口周辺の地形は，汽水湖の典型的な地形であるFlood Tidal Shoal（浅瀬）と水深の深い水路で特徴づけられ，下げ潮時の観測では表層・底層共に流速分布はほぼ同程度であることが分かった．また，潮汐と潮流は基本的に同位相に近く，観測地点においては流速が最大で約1.0m/sであった．2013年9月6日から11月7日にかけての浦口のChl.a濃度は0.1～9.9μg/ℓの範囲で，平均値は3.6μg/ℓであった．

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浦において，サキグロタマツメタの分布や駆除実態を調査した。その結果，本種が他の水域からのアサリ移植種苗に混入していることを確認した。分布の初記録は 2002 年 5 月にみられ，その後 2004 年にかけて浦全域へ拡大した。2004 年から 2010 年にかけてサキグロタマツメタの分布密度は大きく低下しておらず，アサリ食害軽減のためには駆除努力を強化する必要があると考えられた。

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　2011年3月11日に発生した東日本沿岸域での津波により，砂浜や砂丘の消失，砂丘背後での溝状洗堀地形の形成，あるいは，海岸保全構造物背後での溝状浸食地形の形成が生じた．このような砂丘および海岸保全構造物背後の浸食形態に関する知見は少ない．また，巨大津波による砂丘侵食の数値モデルや解析モデル作成のためには，実際の浸食機構を観察する必要がある．さらに，第I砂丘は後背地保護の最終防御ラインとなることも多いので，どのように補強すべきか検討するための基礎データを収集する必要がある．そこで，第I砂丘および海岸保全構造物背後周辺の砂面がどのような形態，かつ，どのような規模で浸食したのか明らかにするために，本研究では，洗堀地形(溝状地形)に着目して調査を行う．

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Though from early days the divisions of HAMADORI, NAKADORI, and AIZU in Fukusima prefecture have been recognized, there are same other regions which are to be distinguished each other from the landscapical point of view. The author has classified these regions into live groups: the group of Hamadori-lowland, Abukuma-plateau, Nakadori-lowland, Central divide, and Aizu. (Fig. 5)
(A) Belt of Hamadari-lowland. It is the littoral belt which is made of desected coastal terraces and delta plains, and has warm winter and cool summer. Therefore evergreen tree, Oak and pasauia oak, distributes there mixing among the deciduous trees, Rice culture prevails over the region. In spite of wonderful growth of rice-plant in early summer, the output of rice per acre is not more than that in Aizu-basin, since the summer temperature is not high, A₁ Region of Soma-shineha. There were many lagoons, but now except Matsukawa-ura, these lagoons have been drained artificially. It is among the main regions of rice and cocoon production. A₂ Region of Naraha is most narrow part which has many tablelands and hills, but without low plains. A₃ Region of Iwaki-lowland is the most wide and populous portion with coal mines, and industrial and fishing towns; Taira-city, Onahama, Ena and Yotsukura. (B) Belt of Abukuma-plateau. Mountain grazing has been performed in a rigion which is below 10% of the ratio of arableland to total area. Some fields of barley, wheat, tobaco, and mulbery Tree distributes on the slope and top of low hills. The pattern of distribution of rice paddies are dendritions. B1. Region of Abukuma-sanchu is most mountainous and sparsely populated region in the belt. And it has many mountain pastures. Main products are horses and charcoal. The Region of B2 is almost non-resident, since the relief is very great, because of desection of rivers crossing the escarpment which laced A1 and A2. The region of B3 is a transition zone between B1 and B7. B₄ legion of southeastern Ahukurna-plateau is an analogous part of B1, but has lower summit level, main products is horse, charcoal, tobaco, A rum-root, and timber of cryptmeria. B₅. Valley of Kuji is an old path way between the Valley of Abukuma and the Kanto, B₆. Tobaco region of Abukuma plateau. Because of the production of tobacoes of Matsukawaleaf speces, it is famous region. planting rice-plant, raising sild worm and havesting barley and wheat from late spring to early summer, havesing tobaco in late summer, and rice in Autumn are busy work in this region. There are numerous money crops. Horses are raised in stall almost all season. The core of tobaco region (B6a) lies in the central part of the plateau. B₇. Sericultural region of Kenpoku-plateau, In B belt it is the most important region of sericultnres in Spring, Summer, and early Autumn. Though the region had produced raw silk and silk stuff by house industries, according to the developement of manufactures, the production of those items has concentrated in a few towns: Kawamata, Iino and Nihonmatsu (B7.a) is the southern part of B7. and has wide piedmont lowland (200-400m) Settlements and fields distributes not only over the slopes but even to the tops of hills there, (C) Belt of Nak dori-lowland. It is a series of intermountains basins along the River Abukuma, and has a dense population and high ratio of arableland to total area, C₁. Fukushima basin is one of the most populous region in the prefecture. Commercial tree cultures of apple, pear, peach, and cherry are generally confined in this basin, some of them are monoculture. Market gardens spreadding over the northeastern part of Fukushima city supplies various vegetables to that city and to the Hokkaido destricts, etc. The most intensive agricultures in this Prefecture are seen on the basin floor.

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　2021年2月13日に

沖で発生したスラブ内地震（マグニチュード7.3）は，法面や住宅に大きな被害をもたらした．本稿では，強震動データ（防災科学技術研究所）と先行研究のデータに基づき，本地震の発生メカニズムと法面崩壊の要因について調査・検討した．その結果，本地震はスラブ内の地震活動によるものと推定され，表面最大加速度はプレート間地震や内陸地震に比べて大きな値を示したことが明らかとなった．さらに，浦大橋付近で発生した道路法面の崩壊跡から岩石サンプル採取し，岩石サンプルから珪藻や緑藻等の微生物が観察され，これらの微生物が法面崩壊の一要因となっている可能性が明らかとなった．

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(1) On 9th May, 1952, there was a destructive frostdarnage in Fukushi-ma prefecture. A few parts in this prefecture suffered additional frostdama-ges vocally on 17th, 22nd, and 26th, May. (2) 3.n the Fukushima Basin mulberries, pears and peaches only sufferd the first frostdamage of the year. The distribution of several grades on in mulberrydamage is mapped in Fig. 1. The distribution of “Super high” and “high” grades is found in two belts; one is in the flood-plain of River Abukuma situated on the north-eastern lovvest part of the basin, and the other on the gentle slope of the young compound fans in the south-western part of the basin. The pattern of this distribution relates closely to that of the minimum temperature, since the time of mulberries germination. is almost similar th rdughout the basin floor. The form er is so. low in its height that cold air settles early in the morning, and the latter is a stagnant part of the cold air, caused by windbreaks maide of dense cryptimerias and bamboos, and by other reasons. (3) The distribution of frotdamage in Fukushiia prefecture.
In the Abukma valley, and on the Abukuina plateau, or Nakadori, there is almost always a tendency of suffering severer frostdaznage than in Aizum and Hamadori. Although the minimuin. temperature is lowest in the south-wastern part of the prefecture there is no frostdamage of mulberries untill early in May. Since Aizu is a mountainous, snowy province, mulberry buds are later than in the other pprovinces, and there is also few frostda-mage in April and early in May. In Hamadori or the littoral province it is as warm as in the Fukushima Basin, but the littoral has longer frostless period owing to oceanic influences. In spring, 1952, and 1941, etc, the middle Abukuma valley and. the plateau suffered severe damages, while there Little or no daiiiage in the gorge and its outlet on the south-easten manin of the Fukushima Basin. since the Surimagi and Okawa Valley also have gorges at the lower parts, and bear some resemblanees to the middle hukilnza Valley, severe frostd.ainage sometimes occurred in the upper part but a little or no frostdauiage occurred in the gorge and its outlet. (a) In the gorge the canyon wall is so steep that the Katabatic wind hlows as soon as tre air cools down. By the drainage of the speedy air, the cool air mingles with the warmer air of the upper. layer. (b) cold airsaagniates on, the Wide, gentle slope of the upper valley, and through a narrow steep floor of the gorge, it is drained off as fast as a rapid stream in the canyon. it mingles With. warm. air, and they blow down towards a gorge outlet. That is one of the reasons why frostdamage is not so severe in the gore and its outlet. (4) On the flood-plain of the Abukuma-River in the Fuku sima Basin, the frostdamage occured in 33 years out of 52 years from 1889 to 1941. Among these 33 years, very great damages were made in 9 years. In spite of the frequent damages one of the most integrated sericuture region of Japan, located on the flood-plain in north-eastern Ft kusinia Basin did not move towards a frostless region on. the slope of its surrounding mountain. Where the latest frost occurs in June or at the latter part of May, silkworms of summer or autumn are mainly reared. (5) The method of protection front frostdainage is has made no progress in this region. The difficulties of prevention increased rather than before the war owing to the dispersion of mulberry fields, resultedf rom the expansion. of fields for food production during the wartime, and to other various reasons. Whereas such sensitive crops, as pears and some sort of vegetables came to be raised. in the re ion where the damage e was repeated in almost every season, thus resulting in suffering severer damage. (6) With a few e ceptions. the people are not adequately utilizing the frmtle s belts of a temperate zone on the slope of surrounding mountains and of isolated hills.

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1.イシガレイ浮遊期仔魚の浦への移入過程を検討するため, 1986年1月23日から2月17日にかけて, 浦湾口において稚魚ネットの水平曳による採集調査を行った。
2.イシガレイ浮遊期仔魚の出現に関する採集層による違いは認められず, その出現量は, 1月27日に最高値を記録した後, 減少傾向を示した。
3.24時間にわたる連続観測の結果, イシガレイ浮遊期仔魚の出現のピークは, 漲潮流が穏やかになる満潮の潮止まりに認められ, その時間帯は, いずれも昼間に当たっていた。
4.出現したイシガレイ仔魚は全長3～7mmのものが大部分であり, 逆に着底期に近い全長7～11mmの仔魚の出現は認められなかった。このことから, 浦周辺海域においては, 孵化後間もない遊泳力に貧弱な個体が着底期以前に既に接岸しており, 潮流によって湾口部付近を受動的に移動していたものと考えられた。
5.出現したイシガレイ仔魚の摂餌率は, 組織学的検討の結果80%以上であると推測されたにも関わらず, 主要な餌料と考えられるコペポーダノープリウスの出現密度は10個体/l前後と低く, 今後他の餌料プランクトンの存在, 仔魚の摂餌行動等についても検討する必要があると考えられた。

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This is the first comprehensive report on Japanese Gyrosigma spp. with special reference to their taxonomy and distribution. They are very conspicuous in permanent slides because usually they have large valves with characteristic shapes. However they have not been well studied probably because of their paucity in most samples. In total 30 taxa were identified from samples collected from various localities throughout Japan. The following five taxa are newly reported from Japan: G. acuminatum var. curta, G. acuminatum var. lacustre, G. plagiostomum, G. simile, and G. spencerii var. curvula.

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