Primary production and microbial activity in the euphotic zone of Lake Baikal (Southern Basin) during late winter

Straškrabová, Vêra; Izmestyeva, Lyubov R.; Maksimova, E. A.; Fietz, Susanne; Nedoma, Jiří; Borovec, Jakub; Kobanova, G. I.; Shchetinina, E. V.; Пислегина, Е. В.

doi:10.1016/j.gloplacha.2004.11.006

Cited by 54 publications

(29 citation statements)

References 19 publications

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“…For this system, shorter duration of the ice cover could even curtail or prevent the diatom bloom (Moore et al 2009). An early spring increase in phytoplankton biomass under the ice in Lake Baikal also led to increased bacterial abundance, biomass, and production, such that heterotrophic bacteria processed roughly 20-40% of the daily primary production in the top 20 m (Straškrabova et al 2005). A third example is from shallow and eutrophic Lake Balaton, where an under-ice bloom of picoeukaryotes was significantly coupled to decreasing water temperature (Vö rö s et al 2009).…”

Section: Bacterial-phytoplankton Couplingmentioning

confidence: 99%

The under‐ice microbiome of seasonally frozen lakes

Bertilsson

Burgin

Carey

et al. 2013

Limnology & Oceanography

170

207

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Compared to the well-studied open water of the ''growing'' season, under-ice conditions in lakes are characterized by low and rather constant temperature, slow water movements, limited light availability, and reduced exchange with the surrounding landscape. These conditions interact with ice-cover duration to shape microbial processes in temperate lakes and ultimately influence the phenology of community and ecosystem processes. We review the current knowledge on microorganisms in seasonally frozen lakes. Specifically, we highlight how under-ice conditions alter lake physics and the ways that this can affect the distribution and metabolism of auto-and heterotrophic microorganisms. We identify functional traits that we hypothesize are important for understanding under-ice dynamics and discuss how these traits influence species interactions. As ice coverage duration has already been seen to reduce as air temperatures have warmed, the dynamics of the underice microbiome are important for understanding and predicting the dynamics and functioning of seasonally frozen lakes in the near future.The quality of freshwater, which is tightly tied to many essential ecosystem services, is influenced in large part by the activities of microbial communities. In inland waters, as in other ecosystems, microorganisms are at the hub of most biogeochemical processes and largely control ecosystem functioning via their metabolic activities. However, attempts to describe the taxonomy and ecology of the freshwater microbiome mainly involve samples collected during the icefree season and, hence, largely neglect microbial communities and their activities during the ice-covered period. Knowledge about the year-round ecological and biogeochemical traits of typical freshwater microorganisms is required to understand when and where certain microorganisms will appear and how they will influence other organisms or biogeochemical processes and, hence, water quality. Together, this information will improve our ability to predict and model freshwater ecosystem and biogeochemical dynamics and to determine their role in the landscapes in the face of environmental change.A large number of lakes, particularly those situated at high altitude and the numerous high-latitude lakes in the temperate and boreal climate zones, are seasonally covered by ice for more than 40% of the year (Walsh et al. 1998). Despite this, surprisingly little is known about the ecology, diversity, and metabolism of microorganisms that reside under the ice cover in such lakes (Salonen et al. 2009). The traditional view is that ecosystems subjected to low temperatures are ''on hold'' and that cellular adaptations for survival at low temperatures control the composition of the winter microbial community, which awaits environmental conditions more conducive for growth. This traditional concept fails to recognize that the winter season affects the ecology and metabolic features of freshwater microorganisms, as well as their involvement in food webs and global biogeochemical c...

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Section: Bacterial-phytoplankton Couplingmentioning

confidence: 99%

The under‐ice microbiome of seasonally frozen lakes

Bertilsson

Burgin

Carey

et al. 2013

Limnology & Oceanography

170

207

View full text Add to dashboard Cite

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“…et Zwetkow (Pomazkina et al, 2010) и хризофитовой Dinobryon cylindricum (Votintsev et al, 1975). Подо льдом биомасса фитопланктона в фотическом слое воды может достигать 1 г/м 3 (Popovskaya, 1977), что приводит к увеличению общей концентрации органических веществ (Votintsev et al, 1975) и повышению численности гетеротрофных бактерий (Straškrábová et al, 2005). Бактерии играют важную роль в круговороте веществ в водных экосистемах, они потребляют растворенное органическое вещество, синтезируемое продуцентами, и передают энергию на следующие трофические уровни (Azam et al, 1983;Azam and Malfatti, 2007).…”

Section: Introductionunclassified

Cultivated bacteria from the sub-ice algae-bacterial communities of Lake Baikal

Bashenkhaeva¹,

Zakharova²

2017

abs

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A collection of pure cultures isolated from the sub-ice algae-bacterial communities inhabiting the lower ice surface of Lake Baikal was obtained. The differences in morphology of the cultured bacteria and their enzymatic activities were revealed by the methods of classical microbiology. The taxonomic affiliation of several cultures was determined by the 16S rRNA gene sequencing. They belong to the genera Pseudomonas putida, P. psychrophila, Methylobacterium extorquens, Rhodococcus aerolatus, Brevundimonas aurantiaca, B. vesicularis, Sphingomonas subarctica, Roseomonas frigidaqua, and Janthinobacterium lividum. These taxa are adapted to low-temperature environments. Key words: Lake Baikal; sub-ice communities; microalgae; bacteria; enzymatic activity; 16S rRNA sequencing

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“…Data from other times of the year are scarce, and it is commonly believed that APP are of little importance in winter (Vörös et al 1991). Recent observations have shown that in some lakes, APP are most abundant in winter, under the ice-cover (Mózes & Vörös 2004, Stra$krábová et al 2005. From winter to early spring, APP communities are mainly composed of eukaryotic picoalgae and some phycocyanin-rich picocyanobacteria (Mózes et al 2006, Ivanikova et al 2007.…”

Section: Introductionmentioning

confidence: 99%

Grazing of heterotrophic nanoflagellates on the eukaryotic picoautotroph Choricystis sp.

Brek-Laitinen¹,

Ojala

2011

Aquat. Microb. Ecol.

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Autotrophic picoplankton (APP, < 2 µm), composed of both prokaryotes and eukaryotes, play an important role in the production and transformation of organic carbon in freshwaters. Eukaryotic APP are commonly found in winter and spring, and heterotrophic nanoflagellates (HNF) are regarded as significant consumers of APP. Here, we analysed the grazing impact and the growth ability of the HNF culture derived from a boreal clearwater lake on the picoalga Choricystis sp. For comparison, we used HNF monocultures of Rhynchomonas sp. and Bodo saltans flagellates with distinct feeding behaviours. In the grazing experiments, all HNF cultures ingested picoalgae and reached feeding rates between 0.08 and 0.81 cells HNF -1 h -1. We observed large species-specific differences in grazing rate (0.97 to 1.96 d ) in the growth experiments. Surprisingly, we found an increase in picoalgal growth in the presence of a grazing HNF population. Although HNF appear to be active herbivores capable of significantly reducing APP stock, flagellates were unable to control the picoalgal population. Overall, this study demonstrates an unexpected role of HNF in microbial food webs by imposing a positive feedback on picoalgal growth through grazing.KEY WORDS: Heterotrophic nanoflagellates · Picoeukaryotes · Grazing · Choricystis sp. · Rhynchomonas sp. · Bodo saltans Resale or republication not permitted without written consent of the publisherAquat Microb Ecol 62: [49][50][51][52][53][54][55][56][57][58][59] 2011 plankton (Christaki et al. 2001), thereby forming the major pathway of picoalgal carbon transport to higher trophic levels (Stockner 1988). Knowledge about grazing on eukaryotic APP is limited, and the majority of studies have concentrated on prokaryotic Synechococcus and Prochlorococcus (Worden et al. 2004). To the best of our knowledge, only 2 studies to date (Parslow et al. 1986, Christaki et al. 2005 have reported species-specific grazing of nanoflagellates on eukaryotic picoalgae, both in marine environments, while no parallel data on the grazing of freshwater HNF on Choricystis exist.Grazing studies have mainly been based on such approaches as size fractionation, dilution, use of specific inhibitors or disappearance of prey analogues (Caron et al. 1991, Liu et al. 1995, Worden & Binder 2003. However, these methods rely on communities and do not consider the different feeding modes of HNF. Investigation of prey items in the food vacuole of a single flagellate at a high resolution enables calculations of ingestion and clearance rates . Additionally, chlorophyll-containing autofluorescing cells of APP can easily be seen in food vacuoles of HNF without using fluorescing dyes (Dolan & 2imek 1998).Here we quantified the grazing impact of HNF on eukaryotic APP and also examined the potential of HNF to control APP at low temperatures. Our simple 2-step experimental set-up consisted of 1 defined prey item, i.e. a rod-shaped unicellular Choricystis sp., and 3 different types of HNF as grazers, i.e. Bodo saltans Ehrenberg, Rhyncho...

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Primary production and microbial activity in the euphotic zone of Lake Baikal (Southern Basin) during late winter

Cited by 54 publications

References 19 publications

The under‐ice microbiome of seasonally frozen lakes

The under‐ice microbiome of seasonally frozen lakes

Cultivated bacteria from the sub-ice algae-bacterial communities of Lake Baikal

Grazing of heterotrophic nanoflagellates on the eukaryotic picoautotroph Choricystis sp.

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