Life in the Main Channel: Long-Term Hydrologic Control of Microbial Mat Abundance in McMurdo Dry Valley Streams, Antarctica
- First Online:
Given alterations in global hydrologic regime, we examine the role of hydrology in regulating stream microbial mat abundance in the McMurdo Dry Valleys, Antarctica. Here, perennial mats persist as a desiccated crust until revived by summer streamflow, which varies inter-annually, and has increased since the 1990s. We predicted high flows to scour mats, and intra-seasonal drying to slow growth. Responses were hypothesized to differ based on mat location within streams, along with geomorphology, which may promote (high coverage) or discourage (low coverage) accrual. We compared hydrologic trends with the biomass of green and orange mats, which grow in the channel, and black mats growing at stream margins for 16 diverse stream transects over two decades. We found mat biomass collectively decreased during first decade coinciding with low flows, and increased following elevated discharges. Green mat biomass showed the greatest correlations with hydrology and was stimulated by discharge in high coverage transects, but negatively correlated in low coverage due to habitat scour. In contrast, orange mat biomass was negatively related to flow in high coverage transects, but positively correlated in low coverage because of side-channel expansion. Black mats were weakly correlated with all hydrologic variables regardless of coverage. Lastly, model selection indicated the best combination of predictive hydrologic variables for biomass differed between mat types, but also high and low coverage transects. These results demonstrate the importance of geomorphology and species composition to modeling primary production, and will be useful in predicting ecological responses of benthic habitats to altered hydrologic regimes.
Keywordsalgae cyanobacteria climate change resilience ecology polar region
- Alger AS, McKnight DM, Spaulding SA, Tate CM, Shupe GH, Welch KA, Edwards R, Andrews ED, House HR. 1997. Ecological processes in a cold desert ecosystem: the abundance and species distribution of algal mats in glacial meltwater streams in Taylor Valley. Institute of Arctic and Alpine Research Occasional Paper: Antarctica. 51Google Scholar
- Barrett JE, Virginia RA, Wall DH, Doran PT, Fountain AG, Welch KA, Lyons WB. 2008. Persistent effects of a discrete warming event on a polar desert ecosystem. Global Change Biol 14:1–13.Google Scholar
- Burnham KP, Anderson DR. 2002. Model Selection and Multimodel Inference: A Practical Information-Theoretic Approach. New York: Springer New York.Google Scholar
- Conovitz PA, McKnight DM, MacDonald LH, Fountain AG, House HR. 1998. Hydrologic processes influencing streamflow variation in Fryxell Basin, Antarctica. In: Priscu JC, Ed. Ecosystem dynamics in a polar desert: the McMurdo Dry Valleys, Antarctica, Vol. 72. Washington, DC: American Geophysical Union. Google Scholar
- Cullis JD, Gillis CA, Bothwell ML, Kilroy C, Packman A, Hassan M. 2012. A conceptual model for the blooming behavior and persistence of the benthic mat-forming diatom Didymosphenia geminata in oligotrophic streams. J Geophys Res Biogeosci (2005–2012) 117:G2.Google Scholar
- Fuller FL, Doyle S, Levy L, Owens J, Shope E, Vo L, Wolyniak E, Small MJ, Doyle MW. 2011. Impact of regulated releases on periphyton and macroinvertebrate communities: the dynamic relationship between hydrology and geomorphology in frequently flooded rivers. River Res Appl 27:630–45.CrossRefGoogle Scholar
- Harrell Jr FE, Dupont C. 2014. Hmisc: Harrell miscellaneous. R package version 3.14-5. http://cran.r-project.org/web/packages/Hmisc/index.html. Accessed 26 Oct 2014.
- Hawes I, Howard-Williams C. 1998. Primary production processes in streams of the McMurdo Dry Valleys, Antarctica. In: Priscu JC, Ed. Ecosystem dynamics in a polar desert: the McMurdo Dry Valleys, Antarctica. Washington, DC: American Geophysical Union, Antarctic Research Series. Google Scholar
- House HR, McKnight DM, von Guerard P. 1995. The influence of stream channel characteristics on stream flow and annual water budgets for lakes in Taylor Valley. Antarct J Unit States 30:284–7.Google Scholar
- Jaros CL. 2003. Temperature-elevation effect on glacial meltwater generation in dry valley streams, Antarctica. MSc thesis, University of ColoradoGoogle Scholar
- Lorenzen, C, Jeffrey, S. 1980. Determination of chlorophyll in seawater. UNESCO Tech Paper Mar Sci 35:1–20.Google Scholar
- McKnight DM, Alger AS, Tate CM, Shupe G, Spaulding S. 1998. Longitudinal patterns in algal abundance and species distribution in meltwater streams in Taylor Valley, Southern Victoria Land, Antarctica. In: Priscu JC, Ed. Ecosystem dynamics in a polar desert: the McMurdo Dry Valleys, Antarctica. Washington, DC: American Geophysical Union, Antarctic Research Series. Google Scholar
- Niyogi DK, Tate CM, McKnight DM, Duff JH, Alger AS. 1997. Species composition and primary production of algal communities in Dry Valley streams in Antarctica: Examination of the functional role of biodiversity. In: Hawes I, Ed. Lyons WB, Howard Williams C. Ecosystem processes in Antarctic ice-free landscapes. Rotterdam: Balkema. Google Scholar
- R Core Team. 2014. R: a language and environment for statistical computing. Vienna: R Foundation for Statistical Computing. http://www.R-project.org/. Accessed 26 Oct 2014.
- Royall RM. 1997. Statistical evidence: a likelihood paradigm. New York: Chapman and Hall.Google Scholar
- Spaulding S, Elwell L. 2007. Increase in nuisance blooms and geographic expansion of the freshwater diatom Didymosphenia geminata. Open-File Report 2007-1425. U.S. Geological Survey.Google Scholar
- Steinman A, Lamberti GA, Leavitt PR. 1996. Biomass and pigments of benthic algae. In: Hauer FR, Lamberti GA, Eds. Methods in stream ecology. 2nd edn. California: Academic Press, San Diego. Google Scholar
- Stevenson RJ. 1996. The stimulation and drag of current. In: Stevenson RJ, Bothwell ML, Lowe RL, Eds. Algal ecology: freshwater benthic ecosystems. California: Academic Press, San Diego. Google Scholar
- Strickland JDH, Parsons TR. 1972. A practical handbook of seawater analysis. Bulletin 167. 2nd edn. Ottawa: Fisheries Research Board of Canada.Google Scholar
- Wood S. 2014. mgcv: Mixed GAM Computation Vehicle with GCV/AIC/REML smoothness estimation. R package version 1.8-3. http://cran.r-project.org/web/packages/mgcv/index.html. Accessed 26 Oct 2014.