Digging into lake microbiomes

Two new papers have just been published from our RELATED project.  The work shows how future changes in forest cover around lakes will influence the contributions of inland waters to global carbon cycles.

The first paper published in ISME finds that the positive effects of microbial diversity on CO2 production depends on present and past environmental gradients.  Using a space-for-time substitution for forest greening, the study also finds that a doubling in the tree cover around lakes can increase CO2 production by five-times.  More broadly, the work highlights how widely reported biodiversity-ecosystem functioning relationships need to be contextualised with other ecosystem properties.

A second paper published in Global Change Biology sheds light on the mechanisms underpinning the decomposition of terrestrial organic matter in lake sediments.  Using the RELATED experimental platform, the study finds that identical organic matter additions to sediments have contrasting outcomes for carbon cycling depending on lake-specific characteristics.  In lakes with clear waters, future increases in terrestrial organic matter inputs can stimulate CO2 production because of photo-oxidation.  By contrast, bacteria in darker waters may possess functional genes for degrading organic matter, thereby priming their productivity.  I’m particularly proud of the teamwork on this one, which involved almost the entire group!


A closed loop of ideas

This week, I was lucky enough to go to Lausanne, a small Swiss city on Lac Léman, to attend the MELiSSA Workshop. What is MELiSSA? As an ecologist, it is unlikely that you are acquainted with this European Space Agency (ESA) project, which stands for Micro-Ecological Life Support System Alternative. It was created in 1989 (read more on how it began here) and brings together European and Canadian partners from 13 different countries in an attempt to fulfill human needs in outer space via the development of life in closed systems. The main ideas include: recycling waste and carbon dioxide aboard spacecraft by using bacteria; and producing food, water, and oxygen in a regenerative way to keep costs low. Put in their words, it aims “at a total conversion of the organic wastes and CO2 to oxygen, water and food”.


Terrestrial lake eco-loop. Copyright: ESA.


Continue reading

Tree genomics meets biogeography

This slideshow requires JavaScript.

We recently returned from a trip to the impressive Umeå Plant Science Centre, where we learnt more about tree genomics.  UPSC is home to a lot of the cutting-edge work sequencing the genome of the European aspen (Populus tremula), though other species as well, such as Norway spruce (Picea abies).  Although work with P. tremula, particularly genome assembly, has been slowed by the much higher levels of sequence variation than in other tree species, it is producing a number of really novel findings, strengthened by large-scale latitudinal studies.

For example, a recent common garden experiment with genotypes from across Sweden found that foliar herbivores reflected the genetic structure of plant defense genes, with fewer herbivores on trees from the local region than those that originated further away.  During our trip, Benedicte Albrectsen kindly took us to see one of these more recent experiments, where different genotypes were being exposed to simulated nitrogen deposition to test how foliar metabolites associated with plant defenses might change in the future.  There was quite a clear N effect as you can see above!

We’re now hoping to start putting together some attempts at merging some of this growing genomic data with biogeography.  This isn’t a new idea by any means,  but we’re hoping to bring some fresh eyes to the questions.  As always, any thoughts are welcomed below!