Marine Chronobiology

A fundamental feature of ocean life is that it is exposed to strong environmental rhythms. Lunar and solar influences create regular cycles of various period lengths and their interference frequencies. Scientific work revealed that organisms often use endogenous oscillators to be “in tune” with the ocean’s rhythms. But whereas the “right” timing is crucial to intra- and interspecies interactions, and hence food webs and ecosystem balance, the biological rules of these marine oscillators have remained poorly understood. Besides the lack of understanding of extant marine timing mechanisms, it is even less clear how they have responded to drastic environmental changes in past. However, it will be important to know key adaptive mechanisms to anticipate how these systems can react in the future. The group focusses on three different aspects of marine timing: 

- the role of the moon in biological timing
- rhythms, clocks and light in pelagic habitats
- rhythms, clocks and light in the deep sea
 

The sun and moon provide time information for human cultures and biological systems in their natural environment
The sun and moon provide time information for human cultures and biological systems in their natural environment (Graphic: Claudia Amort, under CC-BY license)


Besides these main foci, the group engages in several collaborations that investigate the extent and mechanisms by which endogenous clocks and rhythms impact on animal physiology and behaviors. 

Last but not least, it becomes increasingly clear that endogenous oscillators and environmental rhythms also impact on developmental processes of marine animals, in particular stem cells. Thus, we also collaborate on aspects, such as the impact of monthly timing on animal nervous system plasticity and marine microbes on regeneration abilities in sponges.

Projects

 

Scientific Approach

We focus on selected species that we study in detail in the lab, as well as under field conditions. These species are selected based on:

– accessibility and unique biology. This is especially the case for the bristle worm Platynereis dumerilii, which possesses a very well documented lunar cycle that is driven by an inner monthly oscillator. Other species which also exhibit this phenomenon are at present more difficult to culture and also not (yet) available for in depth functional genetic dissection. With all its available molecular tools and resources, we aim to make Platynereis as useful for circalunar biology as Drosophila has been for circadian biology.

– ecological relevance with little understood chronobiology. This is especially the case for the copepod species Calanus finmarchicus and the mussle Bathymodiolus azoricus. Both are critical key species in their respective ecosystems and it is clear that biological rhythms are relevant for their physiology and behavior. However, how the molecular and cellular mechanisms underlying these rhythms, as well as the limits of their plasticity are not understood. We are establishing the respective species and/or tissue cultures for detailed molecular and cellular analyses that we subsequently put in context with the results from the field.

Implementation
Our analyses range from field sampling, behavioral and physiological analyses to -omics studies across time and test of biochemical protein interaction and transcriptional activity.

Head

Prof Dr Kristin Tessmar-Raible
Prof Dr Kristin Tessmar-Raible (Photo: Peter Rigaud)

Prof Dr Kristin Tessmar-Raible

Researches at the AWI as well as at  University of Vienna and the University of Oldenburg


Team:

Dr Sören Häfker
Dr Sören Häfker (Photo: Tanja Glawatty)

Dr Sören Häfker
Project Leader:
“Light, rhythms & clocks in pelagic habitats”

Peggy Wellner, Technical Assistant
Peggy Wellner, Technical Assistant (Photo: Alfred-Wegener-Institut)

Peggy Wellner
Technical Assistant

Dr Audrey Mat
Dr Audrey Mat (Photo: Dr. Audrey Mat)

Dr Audrey Mat
Project Leader “Rhythms, clocks and 
light in the deep sea”

Dr Roger Revilla
Dr Roger Revilla (Photo: R. Revilla)

Dr. Roger Revilla
Project Leader "Microbial influences on 
developmental regenerative timing in sponges"