[LTER-sbc_all] Fwd: EEMB Seminar Monday April 3 @ 4pm -- Grace Wilkinson, Iowa State University

[Kyle Emery]

Hi All,

The first EEMB seminar of the Spring Quarter will be Grace Wilkinson of
Iowa State University on Monday April 3rd at 4pm. Grace researches early
warning indicators of ecosystem state change, carbon biogeochemistry and lake
food webs using stable isotopes and Bayesian mixing models.

http://iowalimnology.weebly.com/

Please sign up to meet with Grace on this schedule
<https://docs.google.com/spreadsheets/d/1paOBP-Z6aN_C5v1D0-rKW9QQVmU8eVBAIkVZea88uWk/edit?usp=sharing>
 .

Interested faculty please sign up or contact me about dinner with Grace on
Monday.
The grad student lunch will be on the 2nd floor balcony of MSI from *12:30
- 1:30pm* now so that it does not conflict with the EEMB SciComm workshop.
Please sign up at the link above.

Please let me know if you have any questions or would like a meeting time
that is not listed on her schedule.

Thanks,

Kyle


Grace Wilkinson
Iowa State Univeristy
Monday April 3, 2017

*Title*
Ecosystem Alarms: Searching for early warnings of large changes in lakes

*Abstract*: Ecosystem regime shifts are abrupt changes from one dynamical
state to another, such as the shift from a clear-water state to an algal
bloom state in lakes. These transitions are hard to forecast but theory
suggests early warning indicators can predict impending regime shifts which
may allow for management intervention to prevent or mitigate an unwanted
change. The efficacy of early warning indicators has been demonstrated in
modeling and laboratory experiments, but rarely in the field where
environmental drivers are numerous and interacting. It is unclear if early
warning indicators are observable or timely enough to allow for
intervention under these conditions. We performed six whole-lake
experimental nutrient additions to test the utility of early warning
indicators for predicting the regime shift from a clear-water state to a
cyanobacterial-dominated state. The lakes were monitored for increases in
resilience indicators including rises in standard deviation and
autocorrelation of algal pigments and dissolved oxygen saturation. A
statistical method, quickest detection, determined when resilience
indicators in manipulated lakes deviated substantially from those in a
reference ecosystem. Blooms occurred in five of the six lake-years.
Although there was substantial variability in bloom size and timing, at
least one indicator foreshadowed the peak chlorophyll a concentration in
all but one instance. The number of early warning signals increased with
the magnitude of the subsequent bloom. Early warnings occurred 1-61 days
prior to a bloom which in some instances may allow managers to notify the
public or intervene to prevent blooms. The resilience indicators correctly
identified changes in resilience over time within a lake and also correctly
ranked differences in resilience among lakes. Our findings suggest that
resilience indicators can be used to classify ecosystems on a landscape and
across time with respect to proximity to a critical threshold.


------------------------------------------------------------------
Kyle Emery
Interdepartmental Graduate Program in Marine Science
University of California, Santa Barbara
phone: 609-760-5993 <(609)%20760-5993>
email: kyle.emery at lifesci.ucsb.edu
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