Looking for zooplankton in Dalby

An overview of Dalby quarry.

In NanoLab we perform mechanistic studies where we quantify the behaviour of zooplankton when exposed to different threats, such as ultraviolet radiation (UVR) and predation. Zooplankton have both behavioural and morphological adaptation to cope with threats, and one strategy is to perform diel vertical migrations, swimming down to deeper waters during the day and then swim upwards again during the night when the threat of UVR and/or predation is absent. A second strategy to handle the UVR threat is to induce photoprotective pigmentation, which protects the organism, much like us humans who also increase our melanin pigmentation during periods of high UVR, giving us suntan. How these strategies are employed can differ between genera and for example Daphnia rely more on the diel vertical migration and less on the photoprotective pigmentation, whereas copepods induce high levels of photoprotective pigmentation, making it safer for them to stay higher up in the water column.

Concentrated zooplankton sample containingmany
highly pigmented copepods.

For about one year now we have had an on-going field study in Dalby quarry where the aim has been to quantify the temporal and spatial variation in pigmentation of zooplankton. We perform monthly samplings during day (high UVR) and night (low UVR) along a depth gradient. The distribution of zooplankton is quantified along the depth gradient and pigment samples are collected at the various depths along the gradient, providing both morphological (pigments) and behavioural responses by the animals. 

Water sampler used for collecting zooplankton along the depth gradient.

 With two more samplings to go before we have performed a whole year study, we are soon finishing the field part of this study and will start to analyse the data in relation to UVR levels and pigmentation. We then aim to study the patterns found in the quarry in NanoLab, where we can induce various levels of pigmentation by rearing zooplankton in environments with higher and lower levels of UVR. Labelling the zooplankton with nanoparticles will then allow us to obtain detailed information on the UVR response at the individual level. Hence, by applying nanotechnology we are now able to perform similar studies on small, mm-sized animals as can be done on larger animals tracked with radar, data loggers and satellites! 

Light and UVR measurements. Measuring the levels of photosynthetic active radiation (PAR, 400-700 nm) and UVR A (UV-A 315-400 nm).

Dalby quarry.

/Mikael and the Nano Biology Lab group