Department of Hydrochemistry and Ecosystem Modelling (HEM)

The Department of Hydrochemistry and Ecosystem Modelling (HEM) of the Institute of Hydrobiology of the Biology Centre CAS studies biogeochemical cycles and processes that control composition and quality of surface waters. This interdisciplinary research is focused on the structure, functions, problems and management of aquatic environments like reservoirs, natural lakes and their catchments.

The staff also provide lecturing of aquatic and environment sciences at the University of South Bohemia and are engaged in advisory services on water quality and aquatic ecosystem functioning for water policy and water management.

The main subjects of studies include:

  • recovery of mountain lakes and their catchments after atmospheric acidification;
  • eutrophication of water ecosystems as a result of external and internal nutrient loading;
  • reconstruction and modelling of historical trends in biogeochemical cycling of the macronutrients in aquatic ecosystems;
  • photochemical processes involved in the transport of macro- and micronutrients via dissolved organic matter from soils to aquatic systems;
  • the role of sediments and organic matter in the internal cycling of nutrients in lakes;
  • the environmental characteristics which can best explain the patterns of nutrient flux to waters in complex catchments.

Current research projects

Phosphorus dynamics in unmanaged terrestrial ecosystems: Links with nitrogen and carbon cycling.

Project No.: 17-15229S

Applicant: Jiří Kopáček

Financial support: Czech Science Foundation

Duration: 2017 - 2019

Unmanaged central European ecosystems (the Bohemian Forest and Tatra Mountains) have been exhibiting world’s largest recovery from atmospheric acidification. Resulting changes in biogeochemical processes and P, N and C cycles in soils are further affected by rapid changes in climate and vegetation, resulting in undesired losses of these nutrients from terrestrial to aquatic ecosystems. The extent and rate of nutrient losses and water pollution differ between catchments, reflecting soil and bedrock composition and vegetation health. On the basis of our long-term research in these areas, we propose a set of integrated laboratory and field studies on effects of changing precipitation chemistry, climate, and vegetation on (1) soil microbial community at sites differing in P sources and availability, (2) P cycle in soils and its links with C and N cycles, especially effects of P availability on N-saturation of catchments and the role of organic C in P leaching, (3) weathering rate and P liberation from bedrock and soils, and (4) pollution of receiving waters with this key nutrient.

The efffect of natural dieback of mountain spruce forest on microclimate

Project No.: P504/12/1218

Applicant: Jiří Kopáček

Financial support: Czech Science Foundation

Duration: 2012 - 2016

Windthrows and climatic factors have promoted bark beetle (Ips typographus) development and a large-scale dieback of Norway spruce in the unmanaged parts of the Bohemian Forest (central Europe). In 2004-2007, the defoliation killed >90% of forest in the Plesne Lake catchment. Windthrows occurred also in catchments of Certovo and Laka lakes. All these areas have been subjects of our intensive long-term ecological research (water, climate, soil, and forest) since 1984-2002. Available pre-disturbance data, current research, and new proposed studies provide a worldwide unique opportunity for a complex ecological research on the effects of natural forest dieback on the individual ecosystem parts. We propose (1) mass budget study on changes in element fluxes and pools on a whole-catchment scale (forest, soil, waters); (2) evaluation of effects on microclimate, hydrology, and soil and aquatic chemistry and biodiversity; and (3) projection of the net effects to other mountain areas, for different forestry practices, and along the anticipated trends in climate and atmospheric pollution.

Sediments of water bodies - identification, quantification, characterisation, sanitation - new approaches

Project No.: TA04021342

Applicant: Jakub Borovec

Financial support: Technology Agency of the Czech Republic

Duration: 2015 - 2017

Do long-term zooplankton data in the Slapy reservoir reflect land use and/or climate changes in the past 50 years?

Project No.: 15-04034S

Applicant: Jaroslav Vrba, Přírodovědecká fakulta, Jihočeská Univerzita v Českých Budějovicích

Co-principal Investigator: Josef Hejzlar

Financial support: Czech Science Foundation

Duration: 2015 - 2017

The project aims on so far unexplored legacy of the Czech reservoir limnology, such as unprocessed zooplankton samples and long-term data sets on stratification, chemistry and plankton of the Slapy reservoir, and will increase the understanding of important environmental drivers that influence freshwater ecosystems. Thorough analyses of the reservoir data sets will improve general understanding of the driving forces in plankton ecology, mainly the impacts of climate variability, hydrologic condition and temperature stratification, reservoir  hydrodynamics, and nutrient loading on structure and plankton community succession. The detailed processing of zooplankton samples gathered during 60 years will allow to describe possible changes in species composition, phenology, biomass and size structure of copepods and cladocerans, and to determine the species-specific responses to both human-driven and climate-driven changes within the Vltava River basin since building the reservoir cascade. The project outputs will be relevant for other similar reservoirs in the temperate zone.

The effect of solar light on key members of freshwater Betaproteobacteria

Project No.: 15-09721S

Applicant: Petr Porcal

Financial support: Czech Science Foundation

Duration: 2015 - 2017

Planktonic bacteria are key players in biogeochemical processes, e.g. responsible for the transformation of dissolved organic matter (DOM) that represents crucial processes for the entire ecosystems. One of the key components of freshwater bacterioplankton is represented by Betaproteobacteria. Only two of its taxa have been identified as key players – genus Limnohabitans and species Polynucleobacter. Both taxa have been described as abundant parts of bacterioplankton, responding fast to changing environmental conditions. It is now accepted that photoproducts, generated by exposure of DOM to sunlight, are affecting growth of bacteria. In this proposal, we intend to widen our rapidly growing knowledge on two bacterial groups of interest. We will employ our world-wide unique culture collections of the target bacteria together with our specific expertise on DOM characterization by combining irradiation and incubation experiments.

Functional diversity of soil microorganisms in spruce swamp forest and its effect on soil DOM

Project No.: 13-17398S

Applicant: Tomáš Picek, Přírodovědecká fakulta, Jihočeská Univerzita v Českých Budějovicích

Co-principal Investigator: Jakub Borovec

Financial support: Czech Science Foundation

Duration: 2013 - 2016

Disentangling the effects of changing environmental chemistry and climate on biogeochemistry and biodiversity of natural alpine soils and waters

Project No.: 14-09231S

Applicant: Jiří Kopáček

Financial support: Czech Science Foundation

Duration: 2014 - 2016

CONTACT

Biology Centre CAS
Institute of Hydrobiology
Na Sádkách 702/7
370 05 České Budějovice

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