Test Design Lighthouse


GAME - Marine Researchers study globally

GAME is an international student training and research programme intended to further international experience and cooperation among young scientists. During their project term, participants address a marine-ecological problem in simultaneous experiments at coastal sites distributed widely over the whole globe, most importantly including the southern hemisphere. After finishing practical work, the experiments are evaluated collaboratively in Kiel.

 

GAME currently cooperates with 31 marine science institutes on five continents. GAME was invented by Prof. Dr. Martin Wahl (IFM-GEOMAR) in 2002.

 

he fact that organisms differ in their general ability to cope with fluctuating environmental conditions is a cornerstone of theoretical concepts that seek to explain the large-scale distribution of species. These inter-specific differences are most often ascribed to the adaptation of organisms to regionally prevailing abiotic and biotic regimes over evolutionary time scales. This concept predicts that organisms that originate from habitats in which, e.g., energy availability is constant, should be generally less tolerant towards fluctuating environmental conditions than species stemming from regions subjected to temporal variability.

 

However, though the adaptionist viewpoint is widespread among ecologists, its significance has rarely been tested experimentally. In the upcoming GAME project we therefore intend to test whether organisms from habitats with a constant energy supply, such as tropical shallow subtidal systems, are generally worse in coping with fluctuations in energy abundance than species from less predictable habitats. This would be temperate regions where energy acquisition in primary but also in many secondary producers is subjected to annual fluctuations in solar radiation intensity.

 

Multi-site comparisons between various regions worldwide should enable us to test the hypothesis that the ability to cope with unpredictable energy supply is a function of latitude. For this, marine invertebrates or macroalgae should be reared under laboratory conditions for time spans that allow the reliable assessment of fitness components such as growth or mortality. At each of the sites, one or more species should be kept a) under predictable food/light/nutrient regimes, i.e. resource availability is constant throughout the experiment, and b) under stochastic regimes, i.e. food/light/nutrients are provided in pulses at irregular time intervals. However, the total amount of energy provided during the course of the experiment should be the same for both groups. Finally, the performance of the test organisms under the two scenarios will be compared. The resulting ratio (e.g. growth under variable food supply/growth under constant food supply) will provide us a species- and site-specific measure for tolerance towards unpredictable conditions and can be compared between sites/species. Furthermore, it can be correlated with latitude.

 

For this type of experiments, the most promising test organisms are either macroalgae or animals in which energy acquisition is subjected to annual fluctuations in the abundance of food items and which cannot migrate to avoid periods of suboptimal conditions. This will restrict us to benthic filter/tentacle feeders such as bivalves, ascidians and barnacles.