Aranda Cruise

We are at the moment on a research cruise on the Baltic Sea: http://cflux16.blogspot.com/

Phytoplankton community change alter biogeochemical cycles

Long term data sets suggest that ongoing environmental changes alter the species composition at the bottom of the foodweb. In this recent paper (Biogeosciences, 11, 7275–7289, 2014), we present data indicating that this change in phytoplankton community modifies carbon pathways and stoichiometry of coastal material fluxes. This might have implications for the grazing community (e.g. food quality) and for biogeochemical cycles in the Baltic Sea:

http://www.biogeosciences.net/11/7275/2014/bg-11-7275-2014.pdf

We have just returned after a week on Aranda, sampling in the Gulf of Finland, Archipelago Sea and Baltic Proper. Nitrate have been depleted but there phosphate left for the blue green algae in most of the Gulf of Finland

In Chile

We are a group working in Chile for three weeks:

http://humboldt2014.blogspot.com/

It is soon time for some doing some experiments again. This is from Tvärminne, spring 2012.

 Getting water from the ice edge

Setting up water with different manipulation of phytoplankton community composition

The spring bloom in the Baltic Sea, as in most temperate aquatic systems, is by far the most important phase of the annual succession in terms of primary production as typically 40 to 60% of the annual carbon fixation takes place during a few weeks. Two phytoplankton groups are predominant during spring in the Gulf of Finland: diatoms and dinoflagellates. The relative abundances of these algal groups may have a large effect on remineralization of the organic matter. Diatoms settle quickly to the sea floor whereas dinoflagellates either lyse before reaching the sediment, releasing the organic material to the water. Alternatively, they produce resting cysts that do not easily decompose in the sediment. The dominance by either phytoplankton group may thus have direct effect on both the summertime nutrient pools of the water column, and the input of organic matter to the bottom sediments, to contrasting directions.

In parts of the Baltic Sea, dinoflagellates are getting more abundant at the expense of diatoms during spring bloom. What effect this change in phytoplankton community composition will have on biogeochemical fluxes is currently not known, and this is the key issue that I am working with at the moment. The goal is to better understand how the phytotplankton community composition may affect the pathways of organic material in the system.

The start of a project

Scientists are, for various reasons, primarily focused on communicating with each other, although most of the funding for the research conducted comes from the tax payers. Popularizing science can be difficult, in particular conveying all the uncertainties that are prominent in most fields of science. In my opinion it is, however, a task worthwhile doing, both as a service to the public discourse, and in these times of financial crisis, perhaps also a necessity to explain why public research funding is important.

I recently started a 5-year, publicly funded project titled: Changing phytoplankton community composition and its effect on biogeochemical fluxes in the Baltic Sea. This blog is an attempt of public outreach, and I will try to follow up on the tasks done and what the results might imply. I will also try to write about more general topics covering Baltic Sea science.