How did the research turn out? What were the findings? Researchers themselves report briefly on the research they have undertaken with funding support from the Formas Research Council.
Editor: Margaretha Nordahl
Incidence of algal mats in shallow bays: The significance of biochemical processes in sediment
Leif Pihl (project leader)
Summary of results with list of publications from Kristineberg Marine Research Station, 450 34 Fiskebäckskil.
Email: leif.pihl@marecol.gu.se
The increasing supply of nutrients in the marine environment is today a common phenomenon all over the world. Nutrients entering our coastal waters give rise to increased production of phytoplankton and benthic algae, and this often results in structural and functional changes in ecosystems. One evident effect of the supply of nutrients is large scale spread of algae along the Swedish coast over the past 20 years.
Fast growing fine-filamentous green algae have taken over and now dominate the upper coastal zone. They have a large surface in relation to their volume and can effectively utilise the increased amount of nutrients and outcompete the more slow-growing annual algae. In bays they form mats which can cover the bottom sediment. This dramatic spread has changed the living conditions for the animals which live in or above the sediment. They affect, for example, the ability of the animals to move, hide and avoid predators, or to find food. Algal production also has an influence on nutrient cycling in the ecosystem. Owing to their effective uptake of nutrients, algae can store large quantities of carbon, nitrogen and phosphorus. When the algae die and fall to the bottom, they enrich the sediment with organic matter. During subsequent decomposition on the bottom, nutrients are again liberated and become available for new production in the system. In this way, the increased supply of nutrients can transform shallow sedimentous bottoms into self generating systems.
Macroalgae can be outcompeted by microalgae and cyanobacteria and/or be exposed to grazing by fauna, which can prevent the formation of algal mats. The marine bristleworm is an important grazer which can influence the growth, and reduce the quantity, of algae. A good supply of nutrients can however reduce the grazing pressure from fauna and simulate the growth of algae.
The taxonomy and phylogeny of polychaetes
Fredrik Pleijel (project leader)
Summary of results with list of publications from Tjärnö Marine Bilogy Laboratory.
Email: fredrik.pleijel@marecol.gu.se
The project focuses on analyses of relationships and systematic revisions of polychaetes (marine bristle worms). This group of animals dominates sea bottoms and is present as fossil in strata from the Cambrian together with the first multicellular animals. In spite of this, we have poor insight today into their relationships (phylogeny) and basal taxonomy. For marine biologists working on bottom samples, this is the one single group which is most time consuming to identify.
The project has enhanced knowledge of the relationships and biology of the group based on combinations of molecular and morphological data. A number of new species are described and highlight the difference between “morphological” and “molecular” species concepts and the occurrence of species that cannot be distinguished on the basis of their external characteristics. This is important since at present we make gross errors in estimating the actual number of species. The project has also produced an identification guide which enables the public and other biologists to identify organisms.
Responsible for this page: Kerstin Franklin