Bacterial growth efficiency: do consumer and resource diversity influence the fate of carbon in aquatic ecosystems?

Transcription

1 Bacterial growth efficiency: do consumer and resource diversity influence the fate of carbon in aquatic ecosystems? Muscarella M.E. & Lennon J.T. Department of Biology, Indiana University, USA Join the conversation tag our talk about me

2 Acknowledgements

3 BGE in Aquatic Ecosystems del Giorgio & Cole., 1998 (Annu. Rev. Ecol. Syst)

4 What differs across these habitats? Microbial Communities Alex et al., 2011 (PNAS)

5 What differs across these habitats? Microbial Communities Resources N C P Alex et al., 2011 (PNAS)

6 What differs across these habitats? Microbial Communities Resources (Chemo Diversity) Alex et al., 2011 (PNAS) FT IRC Mass Spec Lechtenfeld et al., 2011 (Nat Comm.)

7 Do Resources Alter BGE? Changes in phosphorus resources alter BGE Growth efficiency increases for all samples Changes in organic matter concentrations alter BGE Muscarella et al., 2014 (AME) Lennon et al., 2013 (PLOS ONE) Growth efficiency decreases with DOC

8 However, Communities Change If we experimentally change resources, we alter microbial diversity!

9 How do we move forward? del Giorgio & Cole., 1998 (Annu. Rev. Ecol. Syst)

10 Traits Based Approaches What are the patterns in BGE and other physiological traits across the microbial tree of life? How do these traits differ with based on resource identity?

11 The HMWF Culture Collection In this talk: 3 Alphaproteobacteria 3 Betaproteobacteria 17 Gammaproteobacteria 3 Xanthomonadales 5 Aeromondales 9 Pseudomodales

12 Resources & Physiological Traits Glucose Succinate Protocatechuate

13 Experimental Outline 1. Measure resource specific physiology on each resource a) Bacterial Respiration b) Bacterial Production c) Bacterial Growth Efficiency 2. Test for phylogenetic signal for each trait 3. Partition variance in BGE between species taxonomy and resource identity

14 Consumer Traits: Random Example Phylogenetic Signal Blomberg s K K = 1: Brownian Motion K < 1: Overdispersed K > 1: Clustered Example Data: K = <0.001 P = 0.034

15 Example Predictions Taxonomy Dominates Resource Identity Dominates

16 Bacterial Respiration

17 Bacterial Respiration: No Signal Glucose Succinate Protocatechuate K <0.001 < P NS NS NS Phylogenetic Signal Blomberg s K K = 1: Brownian Motion K < 1: Overdispersed K > 1: Clustered

18 Bacterial Production

19 Bacterial Production: No Signal Glucose Succinate Protocatechuate K <0.001 <0.001 <0.001 P NS NS NS Phylogenetic Signal Blomberg s K K = 1: Brownian Motion K < 1: Overdispersed K > 1: Clustered

20 Bacterial Growth Efficiency

21 BGE: No Signal Glucose Succinate Protocatechuate K < P NS NS NS Phylogenetic Signal Blomberg s K K = 1: Brownian Motion K < 1: Overdispersed K > 1: Clustered

22 So what is going on? It appears that certain taxa are more efficient regardless of resource However, some groups have taxa with drastically different efficiencies In general, efficiency seems to decline with resource complexity

23 Taxonomy vs. Resource Model R 2 AIC BGE ~ Taxonomy (Subphylum) BGE ~ Taxonomy (Class) BGE ~ Resource BGE ~ Taxonomy + Resource

24 Taxonomy vs. Resource Model R 2 AIC BGE ~ Taxonomy (Subphylum) BGE ~ Taxonomy (Class) BGE ~ Resource BGE ~ Taxonomy + Resource

25 The Next Steps Lots of unexplained variation! 1. Measuring strain specific parameters such as protein content and leucine corrections 2. Measuring basal metabolic rate 3. Measuring BGE across resource concentrations 4. Measuring BGE in other phyla of bacteria

26 Take Home Messages There is large variation in respiration, production, and efficiency across the microbial tree of life Though we have yet to detect a phylogenetic signal, there appears to be patterns that warrant further exploration Taking both taxonomy and resource identity into account, we can explain a portion of the variation in growth efficiency

27 Bacterial growth efficiency: do consumer and resource diversity influence the fate of carbon in aquatic ecosystems? Muscarella M.E. & Lennon J.T. Department of Biology, Indiana University, USA Join the conversation tag our talk about me