Climate change and freshwater biodiversity
Professor Erik Jeppesen delivers second Rick Battarbee Lecture
On 30th May Professor Erik Jeppesen, from the University of Aarhus, Denmark, gave the 2nd Rick Battarbee Lecture on ‘Trophic dynamics and biodiversity in freshwaters: a climate change perspective’
The lecture drew on examples from The Arctic to the Sub-tropics, and on decades of research , with several large EU grants and over 150 co-authors, into lakes in Greenland, Denmark, Turkey, China, Uruguay and England’s’ Lake Windermere. Erik swept enthusiastically through many graphs to summarise, first, threats to ecosystems and lakes from climate change and, second, the increase of nutrients from growing agricultural activity. He then explored how prospective changes in rainfall and temperature will affect freshwater biodiversity, food web structure and the way lakes operate.
Climate change is already affecting lakes through water temperature increases and the loss of cold-adapted fish species. It was suggested that important species such as the Arctic Charr, which is declining in Windermere, should be seen as the ‘Polar Bears’ of such lakes. One of the main themes, however, was how stresses already arising from nutrient enrichment (eutrophication) were being reinforced by warming and precipitation changes.
We need therefore to understand food web interactions, especially the importance of fish, in maintaining a healthy algal population. Not all fish are equal, however - carp are the ‘bad guys’, since they do not encourage algae, instead stirring up sediment, increasing turbidity and releasing stored nutrients.
Finally Erik linked lake ecology to palaeolimnology and to Rick Battarbee’s work, sharing some very affectionate memories, as expressed in his acknowledgement in the recent special issue of the Journal of Palaeolimnology dedicated to Rick:
The authors wish to express sincere THANKS to Rick Battarbee for really great leadership in the various projects in which we have been involved. Thanks for wise scientific guidance, English gentleman leadership (saying very interesting when you perhaps mean something else) good humour and fine smoked island whiskies, but (excellent) bad fish and chips. You will always have a very central place in our hearts.
Jonathan Holmes presented Rick with a bound copy of this special issue and all adjourned, appropriately, for a fish supper.
For the Special Issue of the Journal of Palaeolimnology, see: http://link.springer.com/journal/10933/49/3/page/1