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Patterns of microbial food webs in Mediterranean shallow lakes with contrasting nutrient levels and predation pressures

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Arda Özen at Çankırı Karatekin Üniversitesi,Çankırı
Arda Özen
  • Çankırı Karatekin Üniversitesi,Çankırı
Ülkü nihan tavşanoğlu
Ülkü nihan tavşanoğlu
Ayse Idil Cakiroglu at Koc University
Ayse Idil Cakiroglu
Eti Ester Levi at Aarhus University
Eti Ester Levi
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Abstract and Figures

To elucidate the specific and combined effects of bottom-up and top-down control on the microbial community in warm lakes, we sampled microbial community along with physical–chemical and biological variables and performed in situ food web experiments, in 14 Turkish shallow lakes with contrasting nutrient levels and predation pressures. Our field results revealed that differences in microbial communities correlated with differences in zooplankton community structure, temperature (increasing nutrient concentrations, change in zooplankton composition), nutrient concentrations (increasing bacteria and heterotrophic nanoflagellate abundances with increasing nitrogen concentrations and temperature) and macrophyte coverage (ciliates as potential consumers of bacteria and HNF was strongest in macrophyte-dominated lakes). Our in situ experimental study revealed that the zooplankton not only affect the biomass and composition of microbial communities but also alter the microbial structure and trophic relationships. Our results therefore indicate that both bottom-up factors and top-down effects were important for the efficiency of the carbon transfer from bacteria to higher trophic levels in the study lakes. Due to an anticipated increase in eutrophication, temperature and alteration of the classical food web with climate warming, major changes in the microbial community of lakes are, therefore, expected in a warmer future in semi-arid Mediterranean climatic regions.
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PRIMARY RESEARCH PAPER
Patterns of microbial food webs in Mediterranean shallow
lakes with contrasting nutrient levels and predation
pressures
Arda O
¨zen .U
¨lku
¨Nihan Tavs¸anog
˘lu .Ays¸e I
˙dil C¸akırog
˘lu .Eti Ester Levi .
Erik Jeppesen .Meryem Bekliog
˘lu
Received: 12 January 2017 / Revised: 6 June 2017 / Accepted: 31 July 2017 / Published online: 8 August 2017
ÓSpringer International Publishing AG 2017
Abstract To elucidate the specific and combined
effects of bottom-up and top-down control on the
microbial community in warm lakes, we sampled
microbial community along with physical–chemical
and biological variables and performed in situ food
web experiments, in 14 Turkish shallow lakes with
contrasting nutrient levels and predation pressures.
Our field results revealed that differences in microbial
communities correlated with differences in zooplank-
ton community structure, temperature (increasing
nutrient concentrations, change in zooplankton com-
position), nutrient concentrations (increasing bacteria
and heterotrophic nanoflagellate abundances with
increasing nitrogen concentrations and temperature)
and macrophyte coverage (ciliates as potential
consumers of bacteria and HNF was strongest in
macrophyte-dominated lakes). Our in situ experimen-
tal study revealed that the zooplankton not only affect
the biomass and composition of microbial communi-
ties but also alter the microbial structure and trophic
relationships. Our results therefore indicate that both
bottom-up factors and top-down effects were impor-
tant for the efficiency of the carbon transfer from
bacteria to higher trophic levels in the study lakes. Due
to an anticipated increase in eutrophication, temper-
ature and alteration of the classical food web with
climate warming, major changes in the microbial
community of lakes are, therefore, expected in a
warmer future in semi-arid Mediterranean climatic
regions.
Handling editor: Mariana Meerhoff
A. O
¨zen (&)
Department of Forest Engineering, Cankiri Karatekin
University, 18200 C¸ ankırı, Turkey
e-mail: ardaozen@gmail.com
A. O
¨zen
Department of Biology, Faculty of Science, Atatu
¨rk
University, 25400 Erzurum, Turkey
A. O
¨zen U
¨. N. Tavs¸ anog
˘lu A. I
˙.C¸akırog
˘lu
E. E. Levi M. Bekliog
˘lu (&)
Limnology Laboratory, Department of Biological
Sciences, Middle East Technical University, U
¨niversiteler
Mahallesi, Dumlupınar Bulvarı, 06800 C¸ ankaya, Ankara,
Turkey
e-mail: meryem@metu.edu.tr
E. Jeppesen
Department of Bioscience and Arctic Research Centre
(ARC), Aarhus University, Vejlsøvej 25, 8600 Silkeborg,
Denmark
E. Jeppesen
Sino-Danish Centre for Education and Research (SDC),
Beijing, China
M. Bekliog
˘lu
Kemal Kurdas¸ Ecological Research and Training Centre,
Lake Eymir, Middle East Technical University, Oran
Mahallesi, 06400, C¸ ankaya, Ankara, Turkey
123
Hydrobiologia (2018) 806:13–27
https://doi.org/10.1007/s10750-017-3329-6
Content courtesy of Springer Nature, terms of use apply. Rights reserved.
... It should be point out that we observed considerable variability in HNF and ciliates abundances among lakes; therefore, it would be necessary to analyze a greater number of lakes to reduce this variability; and also incorporate mixotrophic communities, to evaluate the relative weight of each group and obtain clearer evidence about the effect of the fish introduction on the different trophic levels of the microbial food web in the lakes of this region. Besides, it should also be highlighted that the effects of trophic cascades can be attenuated at the bacterial level due to the already mentioned complexity of the interactions inside microbial food web (Pace & Funke, 1991;Özen et al., 2018). Summed to this, the distance between fish and bacterial trophic levels might contribute to explain the lack of statistically significant effect of fish in the variation partitioning analysis, despite the significant effect observed in the pRDA and the envfit analyses. ...
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Freshwater Microbiology: Biodiversity and Dynamic Interactions of Microorganisms in the Aquatic Environment
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This unique textbook takes a broad look at the rapidly expanding field of freshwater microbiology. Concentrating on the interactions between viruses, bacteria, algae, fungi and micro-invertebrates, the book gives a wide biological appeal. Alongside conventional aspects such as phytoplankton characterisation, seasonal changes and nutrient cycles, the title focuses on the dynamic and applied aspects that are not covered within the current textbooks in the field. Complete coverage of all fresh water biota from viruses to invertebrates. Unique focus on microbial interactions including coverage of biofilms, important communities on all exposed rivers and lakes. New information on molecular and microscopical techniques including a study of gene exchange between bacteria in the freshwater environment. Unique emphasis on the applied aspects of freshwater microbiology with particular emphasis on biodegradation and the causes and remediation of eutrophication and algal blooms.
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Microbial trophodynamics in temperate lakes
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Role of Submerged Macrophytes for the Microbial Community and Dynamics of Dissolved Organic Carbon in Aquatic Ecosystems
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Examination of the multifaced functions of submerged macrophytes in shallow lakes has once again placed emphasis on the habitat characteristics of the vegetation for fish and motile invertebrate communities. The habitat support functions of the macrophytic community are critical to these animals for refuge and related cryptic behavioral functions. We argue here, however, that much more fundamental structuring of microbial metabolism and biogeochemical cycling of the ecosystem result from the development of submerged macrophytic communities. These metabolic functions not only control biogeochemical cycling within these lake ecosystems but are essential to the success of diverse integrated higher trophic levels.
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