Novel conditions for life found in the Baltic Sea

A SEA OF CHANGE: Rapid population growth, accelerated technological development, increased resource consumption. These are just a few of the human activities causing the environment around us to change at unprecedented rates.

Add climate change to the mix and we are seeing a rapid increase in both no-life, “abiotic” conditions and living “biotic” communities that have never before existed in Earth’s history.

Warning signals

So what’s the fuss about? Novel conditions and communities are warning signals for large oncoming changes to ecosystems - changes that could have disastrous consequences for both biodiversity and ecosystem services on which humans rely.

In a new study published in Global Change Biology, centre researchers together with colleagues from the Universities of Hamburg and Montpellier explore the development of such novelty in one of the world’s most stressed marine ecosystems, the Baltic Sea.

Using long‐term monitoring data spanning more than three decades, centre PhD student Yosr Ammar and her colleagues identified highly novel environmental conditions and communities in the Baltic’s confined northern Gulfs and Kattegat.

An ecosystem under stress

The Baltic Sea represents a particularly stressed system due to its enclosed nature, and combined effects of climate change, overexploitation of fish resources, hazardous substances, and eutrophication. It also is one of the marine areas with the highest recorded sea surface temperature increase during the past century.

The authors quantified the rate at which change and novelty emerged in communities from three major trophic levels (1) phytoplankton, (2) zooplankton and (3) fish, as well as in nutrient concentrations and hydrographical conditions across ten basins over 35 years.

They identified novel salinity and temperature conditions as the main drivers of community novelty. These climate‐induced factors, which are projected to change further in the future, are likely, together with other anthropogenic drivers, to increase the biotic novelty in the Baltic Sea.

But as certain marine areas are more susceptible to the rise of novelty than others, more research is needed on the processes that lead to novelty in marine ecosystems, including interactions between species and trophic levels, and the functions of ecosystems under high abiotic novelty.

“Understanding how novelty is generated locally, regionally and globally, its processes in different ecosystem components, and the effects on different trophic levels, will help reduce the risk of missing opportunities for biodiversity conservation, and of unintended management outcomes,” conclude the authors.