[Aqualist] Special GES Seminar Friday May 3rd - Dr Marie Perga

[Michael-Shawn Fletcher]

Hi Everyone,

 

I'd like to draw your attention to a special University of Melbourne
Geography and Environmental Studies seminar by Dr Marie Perga from the
French National Institute for Agronomical Research THIS FRIDAY: 2 pm, Friday
May 3rd.

 

Marie uses traditional and novel palaeolimnological techniques to study the
response of lake systems (ecology, food webs, nutrient flux) to
environmental change, with a particular focus on recent climate change and
resource exploitation.

 

 

Dr Marie Perga

French National Institute for Agronomical Research

Disentangling the impacts of climate and local human perturbations on lake
ecological trajectories: responses from recent sediment archives

2:00 pm, Friday May 3rd 

Theatre 2, 221 Bouverie St Carlton

 

ABSTRACT:

Studies covering long-term climatic variability have shown that lake systems
can respond to climatic change divergently depending on lake location and
morphology. Our knowledge, then, of how climate influences lake ecology is
hampered by the complexity of the pathways under which climate can act on
these ecosystems. On top of that, local anthropogenic pressures exert strong
structuring effects on lakes or their watersheds. Our assumption in this
work is that the impact of climate change on lake ecological and geochemical
processes will depend on the intensity of locally derived anthropogenic and
climatic pressures.

 

We use a set of three peri-alpine lakes in Geneva that exhibit similar
morphologies and that have experienced the same climatic variability. These
lakes have been subjected to similar local forcing over the last century
(changes in nutrient inputs and fisheries management practices), but with
varying intensities. To achieve a holistic and ecosystem-wide view on how
these three lakes changed over the last century, we implemented a novel
paleolimnological approach that includes: molecular methods for microbial
diversity; stable isotope analysis for food web structure; and geochemical
indicators of anoxia. We then created a hierarchy of ecological drivers
observed over time. For instance, detected changes in the pelagic food web
structure or C fluxes at the air/water interface resulted from the
interactions between local and global forcing in all cases. However, using
adequate models, we could show that climatic impacts on food webs are
modulated by the intensity of local stressors, especially eutrophication.
Bottom processes though (food web or deep anoxia) are much more influenced
by climatic variability rather than local influences.

 

 

See attached abstract and bio.

Full program and updates:
http://www.land-environment.unimelb.edu.au/news-and-events/seminars/ 

 

Cheers,

Michael.

 

Dr Michael-Shawn Fletcher

Department of Resource Management and Geography

221 Bouverie Street

The University of Melbourne

Parkville, 3010

Victoria, Australia

 

Phone:          +61 3 90353048

Email:             msfl at unimelb.edu.au

Webpage:    http://michaelsresearch.wordpress.com/

                         http://www.msf-photograph.com/