The work of the section Benthic Biogeography concentrates on organisms living on the marine bottom or directly above the sediment. Taxonically the main focus is marine isopods, especially the typical deep-sea taxa from the abyssal plains from recent expeditions.
We are planning and supporting expeditions with german research vessels and coordinate the sorting of the samples from the epibenthic sled. In our responsibility are samples from the expeditons von DIVA-2 und 3, ANDEEP, SYSTCO, MANGAN und IceAGE1 und 2.
We aim to fix samples from the epibenthic sled for genetic studies using precooled 96% ethanol and establishing a permanent cooling of the samples even during sorting. In our barcoding project we are dealing with sequences of peracarid crustaceans like isopods, amphipods and tanaids from recent expeditions.
The international project IceAGE project (Icelandic marine Animals: Genetics and Ecology) aims to observe and explain patterns of the marine benthic biodiversity around Iceland and adjacent marine regions.
EBS
The sampling area is characterised by several local peculiarities like submarine ridges (geographical barriers) and influence of different water masses of different origin. This allows the analysis of factors influencing the distribution and migration of species as well as investigation of the background of biogeographic zonation. Enhanced focus lies on the ridge structure between Iceland and the Faroer Islands in the climatic sensitive region around Iceland. The IceAGE project combines scientific questions of modern taxonomy like pyhlogeography (population genetics and DNA barcoding) with ecological modeling of species distribution.
Taxonomy, Systematics and biogeography of selected isopod taxa (Crustacea)
Asellote Isopoda (Crustacea) are one of the most important and abundant macrofaunal groups in the deep sea. A high number of undescribed species (more than 80% of collected species are new) and low numbers of specimens per species is typical for abyssal plains. Species descriptions are a very important task to name the diversity of species found in the deep and to gain the basis for phylogentic analyses.
At the DZMB in Hamburg currently new species of the families Macrostylidae Hansen, 1916 and Desmosomatidae Sars, 1897 are in description.
Following project is running until 2008 (grant of the German Science Foundation, DFG):
The existing system of the deep-sea family Desmosomatidae Sars, 1897(Crustacea: Isopoda) is brought up to date in a phylogenetic analysis based on morphological data. The morphological study yields the taxonomic background for molecular analyses of deep-sea Desmosomatidae. Using molecular methods seems to be necessary to access a better understanding of the relationships in Desmosomatidae. The aim of the present project is to compare results of a molecular analysis with the phylogenetic ideas obtained out of the morphological analysis of the family Desmosomatidae. Yet, the molecular work depends on fresh material for DNA extraction.
This could be gained during the ANDEEP (ANtarctic benthic DEEP-sea biodiversity, colonization history and recent community patterns) cruises with RV Polarstern and DIVA-2 (DIVersity of the Atlantic benthos) with RV Meteor in 2005. Sequences of new species of Desmosomatidae could be gained for three genes (18 S, 16 S and CO I). Additionally, the material can be used for comparative studies (population genetics) between deep-sea basins for selected taxa.
CeDAMar studies the diversity of abyssal fauna, a challenging task for several reasons, The most obvious being the very high number of undescribed species combined with generally low abundances. This is typical for abyssal plains, and although it makes working with abyssal fauna so exciting, it is also extremely time consuming, and global biodiversity comparisons are a difficult task.
New methodologyUsing genetic rather than morphological methods is one of the innovative ways to address this problem. The use of barcoding has been considered for species determination in recent years. However, in the case of the deep sea the difficulty is to obtain non degraded DNA samples. In CeDAMar we had to overcome this impediment by optimizing sampling gears and protocols. Our project is attempting DNA barcoding in deep-sea isopods for the first time using the mitochondrial gene COI. Recently, the use of COI sequences for species discrimination of Crustacea has been shown to be successful. Additionally, we want to test other mitochondrial genes for their applicability in species differenciation.
Aims and ApplicationsThe main aims are to link morphological descriptions with barcodes and to establish a storage of DNA together with voucher specimens. Barcoding and other alternative forms of molecular systematics need to be used alongside traditional taxonomic methods. We want to use the CeDAMar facilities like the exchange program to engage interest in the analysis of barcode data generated by taxonomists working with CeDAMar material, and also to develop and disseminate the most effective analytical procedures and display tools for barcode data gained from deep-sea Isopoda.
In future, it is also planned to extract the DNA of copepods in our new DNA-laboratory at the DZMB Wilhelmshaven.
Cooperation with Jörundur Svavarsson (Reykjavik, Iceland)
The distribution of species in the deep world oceans remains still poorly understood, partly due to the fact that many species have only been observed at a few locations and major zoogeographical barriers in the deep-world oceans are still poorly defined.
The northernmost part of the North Atlantic Ocean differs from most other parts of the North Atlantic in having a relatively shallow ridge, the Greenland-Iceland-Faeroe Ridge, extending across the Atlantic, separating the Nordic Seas (Greenland, Iceland and Norwegian Seas and the Arctic Ocean) from the North Atlantic proper. The area is further characterized by several water masses with temperatures ranging from <0°C to approximately 12°C. The effects of the ridge on the distribution of benthic invertebrates may be substantial, both due to the physical presence of the ridge and due to the strong thermal gradient in the area.
Asellote isopods are among the most diverse of deep-sea invertebrates. The BIOICE project (Benthic Invertebrates of Icelandic waters) was designed to investigate the faunal composition around Iceland. This project presents the first and one of the most extensive studies investigating the faunal composition and distribution of Invertebrates around Iceland on both sides of the Greenland-Iceland-Faroe Ridge.
