Research

The deep Southern Ocean hosts a highly diverse animal fauna, including many sponge species still unknown to science.  As part of our Antarctic research projects, we are working on their documentation and publication. The sponge family Cladorhizidae (carnivore sponges) is widely distributed in the deep oceans, and they are found to be the deepest sponge occcurrences World-wide. However, in the cold environment of the Antarctic continental shelf these sponges thrive in shallower depths of a few hundred meters, and here we also find many species new to science.

Species of the family Latrunculiidae, particularly Latrunculia, are known as promising producers of bioactive compounds, efficient against cancer and other diseases. Such chemical agents are now increasingly discovered within Antarctic sponges. However, the diagnosis and definitions of Southern Polar Latrunculia  species are largely inconsistent and unresolved, therefore this family is in urgent need of taxonomic revision. This is currently in progress by means of morphological comparisons combined with molecular research.

Sponge communities on the Antarctic continental shelf currently represent the most extensive sponge grounds inthe World. These ecosystems harbour sponges from all four classes but the Demospongiae and Hexactinellida are byfar the most spectacular, abundant and diverse members of the Southern Ocean benthos. Two hexactinellid generaendemic to the Southern Ocean, Rossella spp. and Anoxycalyx (Scolymastra) joubini, which locally dominate andaccount for a large portion of the benthic biomass, are of special importance due to their ecological function as bio-constructors. They structure the sea floor, harbor vast invertebrate communities and act as pioneers in the settlement of former ice-shelves after their disintegration due to melting and breaking up of large ice areas, e. g. at theAntarctic Peninsula.  However, the species identification within the Antarctic Rosselliidae is severely hampered by the outdated taxonomy, the species definitions being contradictory and vague, probably due to an ongoing speciation process of these Hexactinellida. We are working on an integrated systematic taxonomy useful also for monitoring of the Antarctic to better understand the ecological implications of Global warming in the Southern Ocean.

The Clarion-Clipperton Fracture Zone (CCFZ) in the equatorial northeastern Pacific is the world’s largest potential deep-sea mining area for polymetallic nodules, also known as manganese nodules.  The total area comprises approximately 5.2 million km². In this region the glass sponges (Porifera, Hexactinellida) belong to the main taxa of benthic animals , and many of the discovered species are new to science. Based on new collections, taxonomic data and underwater video surveying we analyze the ecological  implications which can be expected from the planned deep-sea mining in this region.

The Kurile-Kamchatka Basin with ist maximal depth  of  9700 m  is one of the Earth`s  deepest marine biotopes  and harbours numerous abyssal and bathyal animals which are so far are almost unknown. These organisms were observed and collected within the German-Russian KuramBio II Expedition (Kuril Kamchatka Biodiversity Studies II with RV Sonne). They are partly published but many taxa are still under study.  Currently, we investigate a highly diverse Porifera fauna from this expedition. Among the deepest findings of sponges World-wide are Demospongiae of the family Cladorhizidae (carnivore sponges). We also find many new species of glass sponges in this fauna.

Porifera (sponges) probably represent the oldest stem of animals still living on Earth. Their  fossil record can be traced back to Late Precambrian, and  their evolutionary history is probably much longer.

The Anji Biota of Zhejiang Province, South China, is an exceptionally preserved, sponge-dominated fauna from the latest Ordovician. It contains more than 100 sponge species, mainly glass sponges new to science, which probably thrived in a deep-water environment. Many of these sponges show striking similarities to extant sponge orders and families and allow important conclusions about the early evolution of these animals.

The late Ediacaran deep-water marine shale deposits of the Kushk Series in Central Iran host a diverse assemblage of fossils, including terminal-Ediacaran index fossils that confirm a latest Ediacaran age (Nama-Assemblage ~545-539 Ma) for these deposits. The detected new sponge fossils confirm their presence in late Ediacaran and just before the Cambrian Explosion as the earliest animals in Earth history.