Plattform Platform	Reise-Nr. Cruise-No.	Zeitraum Period	Projekt Project	Arbeitsgebiet Working area
Sonne	SO250	17.08.2016 - 26.09.2016		NW Pacific (Limit 180?)

Fahrtleiter Chief Scientist	Institut Institute	Auslaufhafen Port of departure	Einlaufhafen Port of return	Stationskarte Station map	Schiffsroute Trackchart
Brandt Angelika	UNI HAMBURG	Hakodate	Yokohama

Ziel der Reise / Objectives of Cruise:

The German-Russian expedition KuramBio II (Kurile-Kamchatka Biodiversity Studies II) with RV Sonne has been performed between 16.8.–26.9.2016 in the Kurile-Kamchatka Trench (KKT) region (SO-250). This expedition follows the Russian-German SoJaBio (Sea of Japan Biodiversity Studies) expedition to the Sea of Japan in 2010, the German-Russian KuramBio expedition to the KKT area in 2012, and the Russian German SokhoBio (Sea of Okhotzk Biodiversity Studies) expedition in 2015. The goals of these expeditions were to study the biodiversity and biogeography as well as trophic characteristics of the benthic organisms in these different northwest Pacific deep-sea environments. Specific hypotheses tested were: Hypothesis 1: The hadal of the Kuril-KamchatkaTrench is characterized by a high number of species (not lower than in the abyssal plain near the KKT). The Kuril basin of the Sea of Okhotsk is characterized by a higher number of species than the deep Sea of Japan because it is less bathymetrically isolated, but lower species richness than the abyssal Northwest Pacific and the KKT (KuramBio II). H1 will be tested using systematic and zoogeographic comparisons. Hypothesis 2: The number of endemic species will increase with increasing the depth in the KKT. The hadal depths of the KKT will isolate species of the Sea of Okhotsk from species of the abyssal northwest Pacific. H2 will be tested using both morphological as well as molecular genetic analyses of frequent families. For example, within the Isopoda species of the Munnopsidae can swim, species of the Macrostylidae cannot swim. One would expect a higher genetic divergence within species or populations occurring on both sides of the KKT within the Munnopsidae than within the Macrostylidae. Hypothesis 3: The hadal depths of the Kuril-Kamchatka Trench are isolated species of the Sea of Okhotsk from species of the abyssal Northwest Pacific. The number of endemic species will increase with increasing hadal depth in the KKT. H3 will be tested using systematics and zoogeographic analyses. We have deployed a CTD, multi-beam echo sounder, multinet, multiple corer, box corer, epibenthic sledge, and Agassiz trawl at eleven working areas between 5100 and 9583 m depth in order to document the topography of the seafloor and to collect organisms of all size classes from protists to megafauna. During the first investigations on board of the RV Sonne (KuramBio I), we documented a rich fauna at two stations deeper than 5000 m in the Kuril-Kamchatka Trench in all groups of organisms, from protists to meio-, macro-, and megafauna. During this expedition we sampled a much higher number of species than were previously known and increased the knowledge of deep-sea species from depths between 5000-6000 m from 300 known species to >1781 species. The fauna of the open NW Pacific differs to the fauna of Sea of Japan and also to the fauna of the Sea of Okhotsk. We therefore have to assume that the Kuril-Kamchatka Trench indeed isolates the fauna of the Kuril Basin of the Sea of Okhotsk from the NW Pacific. Nevertheless, there appear to be species which can cross the Krusenstern and Bussol Straits and reach the abyssal depth of the NW Pacific Ocean. Whether the percentage of endemic species in the Kuril-Kamchatka Trench increases with increasing depth can only be answered after more detailed analyses and identification of the species in the home laboratories. The German-Russian expedition KuramBio II (Kurile-Kamchatka Biodiversity Studies II) with RV Sonne has been performed between 16.8.–26.9.2016 in the Kurile-Kamchatka Trench (KKT) region (SO-250). This expedition follows the Russian-German SoJaBio (Sea of Japan Biodiversity Studies) expedition to the Sea of Japan in 2010, the German-Russian KuramBio expedition to the KKT area in 2012, and the Russian German SokhoBio (Sea of Okhotzk Biodiversity Studies) expedition in 2015. The goals of these expeditions were to study the biodive

Messungen / Measurements