Lovén Centre

Achievements for each project

Trond Amundsen:

We successfully achieved our main goal of testing how a change in habitat structure (as would be caused by eurotrophication) affects female mate sampling patterns and male mating success in two-spotted gobies, with decent sample sizes (n=16 tank replicates for each treatment). We also succeeded in performing personality tests of all males involved (several hundred), which can be linked with their behaviour and success. As results are yet to be analyzed, it remains to be seen what the experiments will tell.

We aimed to test the structural consequences of eutrophication (a more structured habitat) on our model fish. Initially, we planned to do this establishing “eutrophic” and “non-eutrophic” experimental conditions by means of natural algae. This proved difficult, both logistically and in terms of establishing treatments that were sufficiently homogenous across trials. We therefore decided to simulate natural structuring by means of artificial (pvc) dividing structures that are more amenable experimentally. This should be relevant for understanding the structuring effect of eutrophication. Future work may be extended to include a combination of artificial and natural habitat manipulation.

Dahllöf

To methods were developed based on image analysis of the structure of the meiofauna communities and their activity during a medium-term experiment. The final assessment of the methods is still ongoing.

Furthermore, samples that can be used for future molecular methods were collected.

Apart from that the sea was frozen in February; no real difficulties were identified, apart from normal mishaps. I was very well received at the Lovén centre and can only hope to be able to get back at some point in time.

Dutz

In Tjärnö, we aimed to test if the response observed for A. lusitanicum is generally representative for the feeding response of copepods to Alexandrium and if different copepod species behave similarly.  Three different strains of Alexandrium minutum were set up in the laboratory and feeding and egg production experiments were conducted in addition to the determination of algal toxicity and lytic activity (as a measure of allelopathic activity).  Most interesting, the strains we used had very distinctive toxic and allelopathic profile, with one strain displaying both toxicity and allelopathic activity and the other two strains having either toxicity or allelopathy. This allowed differentiating between the causative agents that control the grazing response of copepods. Indeed, results show that the strain producing saxitoxin was fed at high rates while the non-toxic strain having allelopathic activity has a reduced grazing loss.  This is a very novel result of high significance for further research: until know it is general consensus that algal toxicity and co-evolutionary experience by copepods control grazing, but our results suggest that the hitherto unknown allelopathic compounds are the causative compound. In contrast to this success our attempt to study the effect of culture age and the response different copepod species failed. Unfortunately, early exponential cultures failed to grow. The zooplankton catches from the field, from which experimental specimen were isolated, were dominated by gelatinous plankton. Therefore, we were able to isolate only Acartia clausi while from other species we haven’t found enough individuals.

Rosenqvist

The aim of this project is to experimentally evaluate different metrics of mating systems and sexual selection in the sex role reversed pipefish Syngnathus typhle. And especially to investigate the effect of sex ratios, density, and spatial patterns on the genetic mating system. We used experimental breeding populations with different sex ratios and densities to investigate how these factors influenced the number of mates in both sexes. We have started to reconstruct the mating system using microsatellites to reveal the parents of all offspring. This work will provide knowledge important to the field of sexual selection, especially since density is understudied in this field. Preliminary results indicate that both the sex ratio and density influences the number of mates per individual. It is especially interesting to note that density seems to decrease the variation in the number of mating per individual, something that would indicate that dense populations may experience weaker sexual selection than more sparse populations. In the close future the complete mating system of several replicates of these experimental populations will have been reconstructed, this will provide us with unique data that can be used to evaluate different ways to measure mating systems and sexual selection

This results will be important for evaluate the impact of environmental changes.

K. Norling

Sediments were successfully collected, sieved and is stabilizing until start of experiment in July-August 2010. The planned experiment activities during the second ASSEMBLE period was not funded due to several reasons, but some of the planned experimental activities will be performed in cooperation with a local research group during late summer and autumn 2010 using private facilities for accommodation and Norwegian funding for consumables and experimental equipment.

Martinez

During my stay at the Kristineberg Marine station I used the anti-S2 antibody raised in the Thorndyke’s laboratory many years ago. It reacts with a neuropeptide of the SALFamide family, in echinoderms. I wanted to test whether this antibody would cross-react with other peptides in different taxa, in particular ophiuroids (an echinoderm group) and acoel flatworms (basal bilaterians).

Given the time constraints I was only able to use acoel flatworm embryos and some cnidarians (under culture at KMF). Surprisingly I found that this antibody was able to recognize several cells, spread in the epidermis of the acoel. Some structures could be detected also in the cnidarians but these were difficult to recognize (we need to improve fixation methods for cnidarians).

A detailed analysis of the pattern suggested that the positive cells might be sensory cells, localized preferentially in the anterior part of the animal. These cells could be easily distinguished with the help of the confocal microscope.

I brought the antibody to my laboratory in Barcelona where we are trying again to repeat the staining, under different fixation conditions. We hope that the pattern will reveal some sub domain of the nervous system, an organ not well characterized in the Acoela. Moreover, we should extend the use of the antibody to the embryos of some echinoderm classes, as suggested in the original proposal. Conservation of patterns may give us some insights on the conservation of neural structures or circuits over evolutionary time.