Low stream diatom biodiversity potentially decreasing stream oxygen production in remote islands

Benthic diatoms are the most important and biodiverse primary producers in streams and comprise the basis for the food webs, fueling animals such as insects and stream fishes including trout.

“It is known that highly biodiverse diatom communities are very efficient in producing oxygen” says Professor Janne Soininen from University of Helsinki.

“Islands have long been considered natural laboratories as they comprise a unique environment for living organisms and contribute strongly to global biodiversity, usually being biodiversity hotspots” says Ramiro Martín-Devasa, postdoctoral researcher at the Aquatic Community Ecology group  https://blogs.helsinki.fi/jhsoinin/  at the University of Helsinki. He is the first author of a recent research article about diatom biodiversity on islands, published in the journal Global Ecology and Biogeography.

They found that if island is very distant, diatom biodiversity is lower than on islands nearby the continents. Lower biodiversity may decrease the oxygen production of diatoms.

Islands have been an exciting study system for investigating plant and animal diversity since the early days of biodiversity studies. Their isolation from other land masses makes it difficult for species with a poor dispersal ability to colonize them, but, on the other hand, allows evolutive processes to take place leading to many endemic species on islands.

The new article highlights that island diatom biodiversity is affected by dispersal and evolutionary processes and environmental factors and varies with island location on Earth, island age and how far island is from continents. Such factors are thus potentially important also for oxygen production by diatoms in freshwater ecosystems.

The study is related to the Research Council of Finland funded project: 

BIOISLAND – Biodiversity loss in freshwaters under changing environment – lessons from island diatoms. Duration 2022-2026. The aim of the project is to examine freshwater diatom functional and taxonomical biodiversity patterns and drivers on islands and continents. We use both observational global and regional diatom data sets and conduct field experiments at smaller spatial scales. These results will increase our understanding of how ecosystem fragmentation affects biodiversity in freshwaters.