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--- 2017:groups:g8:start [2017/01/11 05:54] – [Questions & Suggestions] martins
+++ 2017:groups:g8:start [2024/01/09 18:45] (current) – external edit 127.0.0.1
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 {{ :2017:groups:g8:arni_midges.jpg?300|Midge swarm in lake Mývatn}}
-The spectacular landscape comes, however, with a feature that may not be so attractive to tourists: massive insect swarms emerging from the lake every summer. In fact, Mývatn is the Icelandic word for lake of midges. The most abundant family of midges inhabiting this lake is the (luckily) non-biting chironomid flies which emerge from algae grazing larvae. To explain how a subarctic lake can sustain such insect densities, Herren and her colleagues (2017) have investigated if chironomid larval populations could have a strong positive effects on algal productivity. These effects would imply that the net interaction between chironomid larvae and its main food source is actually mutualistic and that abundance and/or biomass of both the primary consumer (larvae) and the producer (algae) are expected to increase due to a positive feedback.
+The spectacular landscape comes, however, with a feature that may not be so attractive to tourists: massive insect swarms emerging from the lake every summer (the photo of the swarm is from the [[http://labs.russell.wisc.edu/townsend/2014/06/05/lake-myvatn-iceland/|Townsend lab website]]). In fact, Mývatn is the Icelandic word for lake of midges. The most abundant family of midges inhabiting this lake is the (luckily) non-biting chironomid flies which emerge from algae-grazing larvae. To explain how a subarctic lake can sustain such insect densities, Herren and her colleagues (2017) have investigated if chironomid larval populations could have a strong positive effects on algal productivity. These effects would imply that the net interaction between chironomid larvae and its main food source is actually mutualistic and that abundance and/or biomass of both the primary consumer (larvae) and the producer (algae) are expected to increase due to a positive feedback. They investigate two related mechanisms that could lead to positive effects in this system. First, the silken tubes spun by the larvae for their protection could provide a high-quality substrate for algal growth. Second, larval excretion could provide limiting nutrients to algae.
 ===== Assignment =====
 Develop and analyze a simple mathematical model capturing both negative and positive interactions between chironomids and the algae they consume.
 ===== Questions & Suggestions =====
-  * Do different mechanism of positive interaction lead to different predictions at the level of the population?
+  * Do different mechanisms of positive interaction lead to different predictions at the level of the population?
-  * Chironomid populations fluctuate several orders of magnitude on irregular periods of 4 to 7 years. Can the positive feedback suggested by Herren et al. 2017 help to explain these fluctuations?
+  * Chironomid populations fluctuate by several orders of magnitude on irregular periods of 4 to 7 years. Can the positive feedback suggested by Herren et al. 2017 help to explain these fluctuations?
+  * Suggestion: Taking the discussion section in Herren et al. 2017 as a starting point, debate which are the main factors that impose an upper limit to chironomid population sizes. Are these internal or external factors? How should this be incorporated in a model?
 ===== References =====
-Herren, Cristina M., Kyle C. Webert, Michael D. Drake, M. Jake Vander Zanden, Árni Einarsson, Anthony R. Ives, and Claudio Gratton. 2017. Positive feedback between chironomids and algae creates net mutualism between benthic primary consumers and producers. Ecology. doi:10.1002/ecy.1654.
+Herren, Cristina M., Kyle C. Webert, Michael D. Drake, M. Jake Vander Zanden, Árni Einarsson, Anthony R. Ives, and Claudio Gratton. 2017. Positive feedback between chironomids and algae creates net mutualism between benthic primary consumers and producers. Ecology. doi:10.1002/ecy.1654. [[http://onlinelibrary.wiley.com/doi/10.1002/ecy.1654/abstract|link]]
+===== Results =====
+  * [[http://200.145.112.249/webcast/files/PresentationLake_group%208.pdf|Group presentation]]