Unexpected biotic resilience on the Japanese seafloor caused by the 2011 Tohoku-Oki tsunami

Takashi Toyofuku (1) , Pauline Duros (1) , Christophe Fontanier (2, 3) , Briony Mamo (1) , Sabrina Bichon (3) , Roselyne Buscail (4) , Gérard Chabaud (3) , Bruno Deflandre (3) , Sarah Goubet (3) , Antoine Grémare (3) , Christophe Menniti (4) , Minami Fujii (5) , Kiichiro Kawamura (5) , Karoliina Annika Koho (6, 7) , Atsushi Noda (8) , Yuichi Namegaya (8) , Kazumasa Oguri (1) , Olivier Radakovitch (9) , Masafumi Murayama (10) , Lennart Jan De Nooijer (11) , Atushi Kurasawa (1) , Nina Ohkawara (1) , Takashi Okutani (1) , Arito Sakaguchi (1, 5) , Frans Jorissen (12) , Gert-Jan Reichart (6, 11) , Hiroshi Kitazato (1)

1 JAMSTEC - Japan Agency for Marine-Earth Science and Technology
2 LPG - Laboratoire de Planétologie et Géodynamique [UMR 6112]
3 EPOC - Environnements et Paléoenvironnements OCéaniques
4 CEFREM - Centre de Formation et de Recherche sur les Environnements Méditérranéens
5 Yamaguchi University [Yamaguchi]
6 Department of Earth Sciences [Utrecht]
7 Faculty of Biological and Environmental Sciences [Helsinki]
8 Geological Survey of Japan
9 CEREGE - Centre européen de recherche et d'enseignement des géosciences de l'environnement
10 Center for Advanced Marine Core Research
11 NIOZ - Royal Netherlands Institute for Sea Research
12 BIAF - Bio-Indicateurs Actuels et Fossiles

On March 11th, 2011 the Mw 9.0 2011 Tohoku-Oki earthquake resulted in a tsunami which caused major devastation in coastal areas. Along the Japanese NE coast, tsunami waves reached maximum run-ups of 40 m, and travelled kilometers inland. Whereas devastation was clearly visible on land, underwater impact is much more difficult to assess. Here, we report unexpected results obtained during a research cruise targeting the seafloor off Shimokita (NE Japan), shortly (five months) after the disaster. The geography of the studied area is characterized by smooth coastline and a gradually descending shelf slope. Although high-energy tsunami waves caused major sediment reworking in shallow-water environments, investigated shelf ecosystems were characterized by surprisingly high benthic diversity and showed no evidence of mass mortality. Conversely, just beyond the shelf break, the benthic ecosystem was dominated by a low-diversity, opportunistic fauna indicating ongoing colonization of massive sand-bed deposits.

Keywords: Biodiversity; Palaeoceanography

Domains: Ecology, environment

Takashi Toyofuku, Pauline Duros, Christophe Fontanier, Briony Mamo, Sabrina Bichon, et al.. Unexpected biotic resilience on the Japanese seafloor caused by the 2011 Tohoku-Oki tsunami. Scientific Reports, 2014, 4, pp.7517. ⟨10.1038/srep07517⟩. ⟨hal-01287834⟩