WG Ecology of benthic Organisms - Current Projects
Marine Bivalves of Namibia
Duration: 2004 - 2023
This book deals with the Bivalvia of Namibia. Historically, Mollusca of the Namibian coastline have not been systematically studied and when compared to the neighbouring South Africa and Angola, relatively few species are known. The waters of Namibia are one of the deepest gaps of knowledge in World faunistic records. The present book brings together for the first time all previous knowledge from this region with results of extensive recent research. The marine bivalve fauna of Namibia has been illustrated and described using samples mainly colected by German reasearch cruises. The bivalve inventory includes a significant number of recently described species. This book will be particularly useful for hobby biologists, students and marine scientists who study offshore fauna of western Africa and that of Namibia particular.
This handbook is expected to be published by ConchBooks by the end of 2023.
Zettler, M.L., Hoffman, L. 2023: Marine Bivalves of Namibia. Conchbooks, Harxheim (in preparation)
Marine Bivalvia of Germany
Duration: 01.10.2018-31.12.2020
Especially since the beginning of the 1990s, due to the increase of offshore activities associated with wind mill farms, gas pipelines and oil fields and the consequent need for environmental impact assessments, the demand for knowledge of benthic residents, their distribution and ecological needs has increased. There is more than one reason to present a new key book on bivalves for the German parts of the North Sea and Baltic Sea. First, it is an attempt to consider all marine species observed at least once in the whole catchment area. All species are figured and described comprehensively and their distribution is given in a map. Second, due to the rapid increase of non-indigenous species, we included species that seem to be in the process of becoming established as well as those that already are. The reader now has the opportunity to rely on one monograph rather than having to combine several well-known handbooks from neighbouring areas (see above) or to search in several publications dealing with a single species.
The present handbook will be published in the famous series “Die Tierwelt Deutschlands und der angrenzenden Meeresteile”, which did not yet contain the marine bivalves.
Zettler, M.L., Alf, A. 2021: Bivalvia of German marine waters of the North and Baltic Seas. Conchbooks, Harxheim: 329pp [Dahl, F.: Die Tierwelt Deutschlands 85. Teil] https://www.conchbooks.de/?t=53&u=49452
Potential effects of closure for bottom fishing in the marine protected areas (MPAs) of the Baltic Sea - WP3: Makrozoobenthos
Duration: 1.3.2020 – 28.02.2023
MGF-Ostsee is a pilot project of the “Deutsche Allianz Meeresforschung” (DAM), consisting of a consortium of seven research institutes (IOW, University of Rostock, University of Cologne, Thünen Institute, GEOMAR, DZMB, GFZ). It aims to carry out a comprehensive study of benthic communities and sediment functions in habitats affected by mobile bottom trawl fisheries (MGF) in Marine Protected Areas (MPA) of the German EEZ of the Baltic Sea and quantify the potential changes in these areas after MGF has been excluded. By comparison with reference areas outside the MPAs and in combination with experimental studies, an assessment of the influence of MGF on benthic and demersal biocenoses and ecosystem functions in the Baltic Sea shall be established. Combined investigations of sedimentological, micro- and macrobiological and biogeochemical parameters are planned inside and in the reference areas outside of the three MPAs: “Fehmarnbelt”, “Oderbank” and “Westliche Rönnebank”.
Macrozoobenthos has ecological importance in the food web, is one of the main mediators for biogeochemical processes (metabolism) in the sediment, bioturbation activity, resuspension and deposition, it has regulating properties for microorganisms and is often an important component of the bentho-pelagic coupling in coastal waters. In addition to the target species of mobile bottom-contact fishing, macrobenthic organisms are those that are directly and visibly damaged. Tolerance to fishing pressure and dynamics of (re-)colonization after its exclusion are strongly influenced by the taxonomic composition and habitat properties (especially substrate). WP3 aims to detect short and medium-term effects as well as the regeneration times of macrobenthic communities with a special focus on functional aspects, bioturbation and key long-lived species population dynamic (Arctica islandica).
Mapping of habitats (biotopes) and their living communities at the sea floor along the coasts of Mecklenburg-Vorpommern
Benthic communities are an important interface between fluxes of the water column and the sea floor and are sensitive to changes in both compartments. Based on this ecological function and the slow mobility of most benthic species, they play a special role in assessing anthropogenic influences on marine ecosystems. Therefore, the state of benthic communities represents a basis for water quality assessments and is considered in Descriptor 1 ‘biodiversity’, Descriptor 2 ‘non-indigenous species’ and in Descriptor 6 ‘sea-floor integrity’ of the European Marine Strategy Framework Directive (MSFD).
The ATLAS project is funded by the „Landesamt für Umwelt, Naturschutz und Geologie Mecklenburg-Vorpommern (LUNG M-V)“ and the European Maritime and Fisheries Fund (EMFF). In the framework of the project habitat mapping in the coastal water of Mecklenburg-Pomerania is conducted to create a basis for assessment. In general, Specially Protected Habitats by law (Section 30 of the Federal Nature Conservation Act) and Broad Habitat Types (BHT) are distinguished. This leads to higher resolution mapping within protected areas and lower resolution mapping in broad habitats. Within the ATLAS project three focus areas were defined in the coastal waters of Mecklenburg-Western Pomerania, being located in the Bay of Wismar, Darss Sill and Plantagenetgrund.
For the mapping of the sea floor, acoustic data has to be collected first by using side scan sonar and multibeam echosounder in yet uncharted areas. Macrobenthic communities are sampled by Van Veen grab in sandy to gravel sediments and scratch samples are taken by divers on hard bottom substrate. Secondly, in large areas dominated by homogeneous soft substrates, the existing database of macrobenthic communities is complemented by additional sampling stations. Low resolution biotope maps will be delineated using predictive modelling. The recorded data will be used to apply and develop state of the art habitat classification models based on acoustic as well as macrobenthic data over a large-scale area in the Baltic Sea.
EVAR-WP7 (Adaptation of macrozoobenthic species to fluctuating oxygen concentrations and their effect on benthic fluxe)
- Duration: 01.01.2019 - 31.12.2022
- Workpackage-PI: Dr. Michael L. Zettler
- Funded by: Bundesministerium für Bildung und Forschung (BMBF)
The coe areas of oxygen minimum zones (OMZs) have been subject to studies concerning ecological consequences of permanent low oxygen. The boundaries of OMZs, however, have not been considered as intensely despite their importance with regard to climate change and expansion of OMZs. Several studies concluded that organisms that are able to simultaneously cope with potentially long-lasting hypoxic periods and intense oxygen input e.g. by upwelling events, can build up high densities and biomass if food supply is abundant. Given the high variety of adaption mechanisms to these conditions, successful organisms in and along OMZs likely rely not only on one mechanism, but rather combine several strategies such as, for example, morphological and behavioural traits. In general, the boundaries of the Benguela Upwelling System have been poorly investigated in terms of species inventory, but during preliminary investigations we have observed that certain species occur with highest biomass directly at the edges of the OMZ. Therefore, we now aim to address the question:
By which mechanisms and up to which extent can abundant macrobenthic species survive fluctuations in oxygen availability and how does their activity affect benthic fluxes?
To clarify this, we will initially investigate the distribution of macrobenthic organisms along the transect with changing availability of oxygen in the bottom water. In addition, we will assess the abundance of macrobenthic species in the in situ and ex situ experiments planned to quantify benthic fluxes. This will reveal how the composition and activity of benthic macro organisms affect the fluxes between the sediment and water column. Furthermore, we will conduct targeted incubation experiments with selected, highly abundant species to determine how long they can survive without oxygen and their activity under fluctuations of oxygen availability on different time and concentration scales. This will contribute important boundary conditions for implementation of bioturbation in the benthic modelling work.
Several new species for science could be observed and described during the last years (2009 to 2023).A tabular overview of the species and where they were published can be found HERE.
It is part of a successive series of projects funded by the German Federal Agency for Nature Conservation (BfN) with the goal to establish a sound scientific basis for the implication of relevant European Marine Directives with regard to benthic habitats. Within the project, we will continue our investigations on the spatial-temporal variability of the benthic communities in offhsore areas with a focus on special habitats such as boulder fields and exposed coarse substrates. Our work includes the mapping of benthic habitats on different spatial scales as well as the establishment of new monitoring programmes. We also will apply our findings on common assessment indicators and suggest alternative indicators if required. The analysis will be done in close cooperation with national and regional expert groups and consequently will be integrated into the national and regional discussion on the implementation of European Marine Strategy Framework Directive and the Habitats Directive.