Last Wednesday, we had the pleasure to listen to our 2nd year Aquatic Ecology students as they presented their theses, experiments and prospective outlines. Maurice, Lina, Lingni, and Nelson all had thought provoking research to share on a variety of concentrations within the aquatic ecology field.
Maurice took us through the wonderful world of microalgae and his investigation into the effects of various harvesting techniques on algal biomass quality. His two-fold hypotheses were (1) Chemical flocculation and flocculation induced by high pH will increasemicroalgae products (Lipids, Proteins, and Carbohydrates) and (2) Tangential Flow Filtration will decrease the biomass products. By employing the different harvesting methods on microalgae both from the autumn bloom (biomass from the lab) and the eventual spring bloom, Maurice will also be able to compare seasons. In case flocculation increases microalgae products, further tests will be done since this can be due to more products accumulation which results from the environmental stress or to the softened cell wall that makes the products’ extraction more easier. More tests will be also done to verify the hypothesis that if tangential flow filtration reduced the products because of the cell damage.
Lina began her presentation by reminding us quite effectively of last year’s doomsday– August 13th – the day we began to live on borrowed time, when we are officially using more resources than the world can give us! She went on to explain that the possibilities to use microalgae are large and far-reaching, giving us things like biofuel and renewable resources.
Microalgal lipids – a source for biofuel – is of particular interest for society, and Lina has concentrated her research on lipid accumulation in microalgae. The aim in her research is to test light, temperature & nutrient effects on lipid accumulation in lab experiments and to study seasonal patterns of lipids in the natural community at LMO/constructed communities.
Using lipid staining and lipid extraction (in larger communities), Lina tested her hypothesis that increasing light and temperature will increase lipid accumulation, as well that nitrogen limitation will increase lipid accumulation. While her preliminary results did not show a significant increase in lipids for increased light and temperature, she indicated that as those samples were taken in October, the concentrations were already high. Lina is still working on the protocol in preparation for the spring bloom, so there is more to learn!
Lingni introduced us to her project on bacterioplankton dynamics stimulated by the phytoplankton bloom, entitled “What Can We Find After the Spring Bloom?” She outlined her two null hypotheses, that (1) DOM provides the food for bacteria growth so that bacteria abundance will increase, and (2) the higher temperature of sea water stimulates the growth of bacteria. Measurements taken will be chlorophyll concentration, temperature, salinity and pH value.
She’s now going into the meatiest part of the experiment, and will process samples following the spring bloom. More to come!
Nelson rounded out the presentations with his presentation on the Northern pike (Esox lucius). The aim of his project is to develop methods to estimate fish age and growth rates in Northern pike using sagittae otoliths so as (a) to get timeline or time access of sagittae otoliths used for chemical analysis, and (b) To use methods developed to determine growth rates differences among sub populations in Kalmar and Öland. Though the methods tested were not effective, he will use his preliminary results to alter his methods, varying exposure times, application techniques, microscope and light source variation.
Great job to all of our aquatic ecology students, we look forward to the final presentations this spring!