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Roumen Kalchev

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Dr. Roumen Kalchev
Institute of Biodiversity and Ecosystem Research
Bulgarian Academy of Sciences
1000 Sofia, Bulgaria
1, Tsar Osvoboditel Blvd.
Phone: +359-2-988 51 15 (606)
Fax: +359-2-988 28 97

Curriculum vitae

Dr. Roumen Kalchev
Background details
Date and place of birth: November, 20-th, 1951, Koubrat, Bulgaria
Nationality: Bulgaria

Employment and academic vita
2010- present Associate Professor
Institute of Biodiversity and Ecosystem Research, Bulgarian Academy of Sciences
2002 - 2010 Associate Professor
Institute of Zoology, Bulgarian Academy of Sciences
1987 – 2002 Chief Assistant Professor
Institute of Zoology, Bulgarian Academy of Sciences
1984 - 1987 Assistant Professor
Institute of Zoology, Bulgarian Academy of Sciences

1981-1984 Doctorate, at University “Taras Shevchenko” and Institute of Plant Physiology
of Ukrainian Academy of Sciences, Kiev, (former Soviet Union)
Thesis title: Fluorescence characteristics of some algal species and possibilities for their
application for studying primary productivity of freshwaters
Supervisor: Corresponding member of Ukrainian Academy of Sciences, Prof. D.M. Grodzinskii
Laboratory study on algal cultures of Anabena variabilis, Scenedesmus bijugatus,
Phaeodactylum tricornutum. Productivity measurements by released oxygen measured on
gas-chromatographer and fluorescence registrations on a fluorimeter.

1975-1980 Master of Science in Biology University of Rostock (former East Germany)
Diploma Thesis title: Carbohydrates in the alga Scenedesmus quadricauda.
Supervisor: Prof. Dr. E. Wittenburg.
Laboratory study of carbohydrates in the alga Scenedesmus quadricauda and field
carbohydrates investigations in brackish waters.

Teaching experience
2006 – 2011 Supervisor of 1 PhD-student

2001 – 2005, 1987 – 1998 A part-time Assistant Professor
Faculty of Biology, Sofia University, St. Kliment Ohridsky, Sofia
Subject: Methods for assessing primary and secondary productivity in aquatic ecosystems

since 1987 Supervisor of 4 M.Sc. students
Faculty of Biology, Sofia University, St. Kliment Ohridsky, Sofia

National representative of Bulgaria in International Association for Danube Research, (IAD)

Language skills
Bulgarian: native language
English: Very good
Russian: fluent
German: fluent

Other skills
I have very good computer skills and working experience with Microsoft Office as well as in
applying statistical analyses (uni- and multidimensional) with statistical packages Excel, Canoco, Statistica. Clear driver license since 1984.

Participation in selected funded projects

As national project leader
“Impact of Iron Gates reservoirs, hydraulic river structure, tributaries and adjacent wetlands
on ecological interactions, water quality and biodiversity in the low Danube (feasibility
study for a joint research project)”, Joint research project with Institute of Biology of Romanian Academy of Sciences, 2005-2006.

“BioWetMan: A science based approach to understand biodiversity driven functions and
services for improving wetland management” (funded by Austrian Science and
Research Liaison Offices, Contract 4-25-2008, 2008-2009

“Comparison between wetland-Danube River systems of Hungary and Bulgaria related to their biodiversity, functioning, services, management and nature conservation” Joint research project with Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences 2013-2015.

As member of scientific team
“European Mountain Lake Ecosystems: Regionalization, Diagnostics and Socio-Economic
Evaluation, (EMERGE)” (funded by 5th EU Framework Program, 2000-2002)

Determination of reference and inter calibration sites for definite water bodies, selection of appropriate biological criteria for classification of ecological status and analysis implementation after selected criteria according to the Water Framework Directive 2000 of EU (funded by Ministry of Environment and Waters, 2004-2005)

“Southern European Seas: Assessing and Modelling Ecosystem changes (SESAME)” Funded by 6th EU FP, Proposal/Contract no.: 036949-2, 2008-2009.

Assessment and management of invasion of Dreissena sp. mussels in Bulgarian water basins (funded by Bulgarian National Scientific Fund, ДО 02-259/08, 2009 – 2012)

Biological diversity of aquatic ecosystems in wetlands of flood plane of the Lower Danube
regarding optimizing ecosystem functions under global climate change (funded by
Bulgarian National Scientific Fund,ДО 02-352/08, 2009-2012).

Research interests

I have been investigating plankton primary production, chlorophyll, phytoplankton abundance, nutrients, nutrient limitations, organic load, solar radiation above and under water (spectral light extinction coefficient) in stagnant inland freshwaters, in the Danube River and Black Sea. Based on such data conclusions have been drawn about trophic status and classification of various kinds of stagnant and flowing freshwater and marine ecosystems. In that aspect I was partly involved in the reference site estimation for Bulgarian reservoirs in connection with the implementation of EU Water Framework Directive.
The list of investigated freshwater ecosystems includes about 10 alpine lakes of Rila mountain, 5-6 lowland lakes, 3 sand-pit lakes, 12 man-made lakes (reservoirs), fishponds of the Institute for Aquaculture and Fishery in Plovdiv and the Bulgarian stretch of the Danube River.
My interest and experience cover also the whole lake metabolism, trophic relations in the pelagial of lakes, reservoirs and fishponds, i.e. relationships between solar energy, nutrients, bacterio- phyto- and zooplankton. The water quality gradients in reservoirs and their connection to nutrients and phytoplankton abundance were also treated. Main aspects of restoration of Danube wetlands (several temporary and permanent riverine wetlands and the Srebarna lake inclusive) and other lake ecosystems (Shabla lake) were also considered. The trophic relations in the pelagial of the last lake and their significance for ecological status improvement (i.e. by catchment influences and biomanipulations) were studied. The effect of fertilizer of organic origin on plankton primary production, bacterioplankton and nutrients infishponds were investigated. The influence of joint rearing of ducks and fishes on important productivity and water quality characteristics of fish ponds were analyzed.
Most of water chemistry characteristics, especially the nutrients and its limitation (nitrogen to phosphorus ratio) of phytoplankton growth as well as the seasonal and long-term variations of both nutrients and phytoplankton were investigated in reservoirs, lakes and in the Danube river in close connection with the ecosystem trophic status (degree of eutrophication) and water quality gradients.
Another research topic is devoted to the relationship between chlorophyll-a and biovolume of phytoplankton. The influence of algal size and taxonomic composition of phytoplankton on this relationship was profoundly studied.
Recently I am actively studying the effect of zebra mussel on physicochemical variables, chlorophyll, phyto and bacterioplankton in infested freshwater reservoirs in Bulgara.


List of selected publications

Kalchev R. K., M. B. Beshkova, I. Sl. Botev H. V. Kalcheva, L. A. Kenderov, D. St. Kozuharov, T. A.Trichkova. (in press) Relation of transparency, dissolved oxygen and pH to Dreissena spp. occurrence in Bulgarian standing waters. – Acta zoologica bulgarica, 2014,

Kalchev R.K., M.B.Beshkova, I.S.Botev, H.V.Kalcheva, D.St. Kozhuharov, T.A. Trichkova (2013) Effect of Dreissena polymorpha (Molusca, Dreissenidae) on physicochemical characteristics of Zhrebchevo Reservoir (Central Bulgaria.). – Proceedings of Bulgarian Academy of Sciences, 66(11): 1571-1578.

Hadjinikolova L., A. Ivanova, D. Terziyski, R. Kalchev, 2013. Relationships between fish density, forage quantity applied and chemical variables in free water column and sediment of fishponds J. Int. Sc. P.: Agriculture & Food, v. 1, p. 1, рр. 135-144. ISSN 1314–8591 (link)

Kalchev R.,V. P. Vasilev, V. Tzavkova, M. Beshkova (2012) Water transparency, chlorophyll-a and plankton primary production in the course of Srebarna Lake recovery. In:Uzunov Y et al. eds: Ecosystems of the Biosphere Reserve “Srebarna Lake” 2012, Prof. Marin Drinov Academic Publishing House, Sofia, p.57-68.

Beshkova M., R. Kalchev, V. P. Vasilev (2012) Taxonomical and functional structure, species diversity and abundance of the phytoplankton assemblages of the Srebarna Lake in relation to changes of ecological conditions. In:Uzunov Y et al. eds: Ecosystems of the Biosphere Reserve “Srebarna Lake” 2012, Prof. Marin Drinov Academic Publishing House, Sofia, p.39-55.

Kalchev R., M. Beshkova, H. Kalcheva, S. Kazakov, V. Nikolov, M. Pavlova, L. Pehlivanov, V. Tzavkova, 2012 Morphological, topographical and physicochemical characteristics of Bulgarian Danube River wetlands. 39th IAD Conference Living Danube, 21-24 August 2012, Szentendre, Hungary, Limnological reports 39, p.71-79.

Kalchev R., V. Beshkov, T. Bogdanovic, A. Coman, M.Edinger, T. Hein, B. Ivanov, D. Krasic, M. Mihaljevic, V. Nokolov, L. Pehlivanov, S. Puzovic, C. Sandu, N. Stojnic, M.Vasilev and A. Vujic. 2010 Vertebrate species distribution in selected wetlands of the Danube River basin. - Transylvanian Review of Systematical and Ecological Research 10, The Wetlands Diversity p.153-170.

Kalchev R., Beshkova M., L. Pehlivanov 2010 First records on effect of renewed flooding of three wetlands from Belene Island (Lower Danube, Bulgarian stretch) 38th IAD Conference | Large River Basins: Danube meets Elbe. Challenges – Strategies – Solutions Dresden, 22-25 June 2010

Terziyski, D., R. Kalchev, L. Hadjinikolova,K. Dochin and A. Ivanova. 2010, Variability of chemical characteristics and their relations to environmental and biological variables in two variants of ponds stocking with fish larvae. Bulg. J. Agric Sci. 16 (No 3) 342-350.

Terziyski, D., R. Kalchev, K. Dochin I. Piskov, H. Kalcheva and L. Pehlivanov 2010 Variability of biological characteristics and their relations to environmental variables in fish ponds stocked with carp fish larvae in two different proportions Bulg. J. Agric Sci. 16 (No 3) 333-341.

Kalcheva H., D. Terziyski, R. Kalchev 2010 Control of zooplankton and nutrients on bacterioplankton in fish ponds with carp larvae Bulg. J. Agric Sci. 16 (No 3) 284-297.

Terziyski D. I., Kalchev R. K., Vasileva P. L., Piskov I. A., Iliev I. Z., 2009 Fish abundance differences and relations to plankton primary production in two variants of pond stocking with common carp ( L.), grass carp (Val.) and bighead carp ( Rich.) larvae. AACL Bioflux 2(3):251-260.

Kalchev R., Ionica D., Beshkova M., Botev I., Sandu C 2008 Long-term and seasonal changes of nutrients, seston and phytoplankton concentrations in the Lower Danube (Bulgarian-Romanian stretch) Fundamental and Applied Limnology/Arch. Hydrobiol. Suppl. 166, No 1-2, p.25-43.

Beshkova M B., H. V. Kalcheva, R. K. Kalchev. 2008 Phytoplankton and bacterioplankton in three reservoirs (North-East Bulgaria) recommended as a potential Reference Sites According to the Water Framework Directive of EU Acta zool. bulg. ,2, p. 155-164.

Beshkova M.B, Kalchev R.K.,.Vasilev V, Tsvetkova R.L. 2008 Temporal and spatial changes of the phytoplankton abundance and structure in the Biosphere Reserve Srebarna (Northeastern Bulgaria) in relation to some environmental variables - Acta zool.bulg. 2, 165-174.

Terziyski D. G. Grozev, R. Kalchev, A. Stoeva 2007 Effect of organic fertilizer on plankton primary productivity in fish ponds. Aquacult Int 15:181-190.

Lyubenova M., R.Kalchev Ecotoxicology, a small practicum, 1st edition, AN-DI publisher, Sofia, 2007, ISBN 978-954-91730-6-2, 312p. (in Bulgarian)

Beshkova M., Kalchev R., Botev I. 2007. Review on the studies of Bulgarian reservoirs with emphasis upon the phytoplankton and related physical and chemical factors. Journal Balkan Ecology 10(1), 13-28.

Kalchev R. & Botev I.2005. Phosphorus and Nitrogen Limitation of Phytoplankton. Related to their Gradients (Retention) in Reservoirs. Journal Balkan Ecology, 8 (1), 61-66.

Kalchev R., M. Beshkova, A. Kurejshevich, D. Saiz 2004 Influences of division predominance and algal size on the relationship between chlorophyll-a and biovolume of phytoplankton. J. Balkan Ecology, Vol.7(1), 59-65.

Kalchev R., Botev I., Hristozova M., Naidenow W., Raikova-Petrova G., Stoyneva M., Temniskova-Topalova D. & Trichkova T. 2004. Ecological relations and temporal changes in the pelagial of the high mountain lakes in the Rila Mountains (Bulgaria). Journal of Limnology, 63 (1): 90-100.

Kalchev R.K., M.Beshkova, D.Saiz.2003. Algal Size Influence on Relationship between Chlorophyll-a and Biovolume of Phytoplankton. J. of Balkan Ecology, 6(4): 403-408.

Kalchev R.K., L.Z.Pehlivanov, M.B.Beshkova. 2002. Trophic relations in two lakes from the Bulgarian Black Sea coast and possibilities for their restoration. Water Science and Technology, 46(8): 1-8.

Kalchev R.K., I.S.Botev.1999. Long-term eutrophication development in five coastal lakes of the bulgarian Black Sea region. - Water Science and Technology, 39 (8): 1-7.

Kalchev R.K., Kurejschevich, A.V. 1997. Beziehungen der Strömung zu den Pigmenten und Primarproduktion des Planktons in der Unteren Donau (Bulgarien und Ukraine). Limnologische Berichte Donau 1997, Band I, Wien, p.175-178.

Kalchev R.K., Kurejschevich A.V., Sais D. 1996. Photosynthetische Pigmente und Biomasse des Phytoplanktons in der Bulgarischen Donaustrecke - Verteilung und Zusammenhange. - 31. Konferenz der IAD, Baja - Ungarn 1996. Limnologische Berichte Donau 1996, Band I, Wissenschaftliche Referate, 137-142.

Kalchev R.K., M.B.Beshkova, C.S.Boumbarova, R.L.Tsvetkova. 1996. Some allometric and non-allometric relationships between chlorophyll-a and abundance variables of phytoplankton.- Hydrobiologia, 341:235-245

Kourteva M.K., R.K. Kalchev 1984. Study of atmospheric industrial pollution influence on growth and development of tree plants by means of variance analysis. Ukrainian Journal of Botany 50(6) p. 74-76.(in Ukrainian)

Kalchev R.K., S.M. Kochoubei, D.M. Grodzinskii 1983. Relationship between in vivo chlorophyll-a fluorescence and productivity of algae Anabena variabilis. Journal of hydrobiology 19(6): 36-39.(in Russian)


Aquatic Ecosystems
Biodiversity and Processes in Freshwater Ecosystems
Research group
Lentic Ecosystems


Member for
8 years 24 weeks