Lake Peipsi sensu lato consists of limnologically and hydrochemically different parts, Lake Peipsi sensu stricto, Lake Lämmijärv, and Lake Pihkva. The eutrophic L. Peipsi s.s. and the hypertrophic Lake Pihkva were studied. The aim was to find out if the ecological state of these lake parts has improved, stabilized or deteriorated during a ten-year period, 2003–2012. For this purpose, data on loadings, in-lake nutrient concentrations, water transparency, water level, chlorophyll a concentration, as well as phyto- and zooplankton were compared for two five-year sub-periods (2003–2007 and 2008–2012). Comparison demonstrated a decline in the loading of total phosphorus (TP) from rivers on the Estonian and Russian sides as well as in its mean concentration in both lake parts. Both phytoplankton biomass and cyanobacterial biomass decreased in response to the reduced nutrient content in the lake water. The responses of zooplankton were contradictory. Changes in the occurrence of indicator species and declining mean zooplankter weight reflected a continuous eutrophication process while changes in the abundance of rotifers and the genus Daphnia indicated a subtle shift towards recovery. Our results show a modest improvement in the ecological condition of both lake parts.
Agasild, H., Zingel, P., Tõnno, I., Haberman, J., and Nõges, T. 2007. Contribution of different zooplankton groups in grazing on phytoplankton in shallow eutrophic Lake Võrtsjärv (Estonia). Hydrobiologia, 584, 167–177.
https://doi.org/10.1007/s10750-007-0575-z
Arvola, L., Järvinen, M., and Tulonen, T. 2011. Long-term trends and regional differences of phytoplankton in large Finnish lakes. Hydrobiologia, 660, 125–134.
https://doi.org/10.1007/s10750-010-0410-9
Battarbee, R. W., Anderson, N. J., Bennion, H., and Simpson, G. L. 2012. Combining limnological and palaeolimnological data to disentangle the effects of nutrient pollution and climate change on lake ecosystems: problems and potential. Freshwater Biol., 57, 2091–2106.
https://doi.org/10.1111/j.1365-2427.2012.02860.x
Beaulieu, M., Pick, F., and Gregory-Eaves, I. 2013. Nutrients and water temperature are significant predictors of cyanobacterial biomass in a 1147 lakes data set. Limnol. Oceanogr., 58, 1736–1746.
https://doi.org/10.4319/lo.2013.58.5.1736
Bennion, H., Simpson, G. L., and Goldsmith, B. J. 2015. Assessing degradation and recovery pathways in lakes impacted by eutrophication using the sediment record. Front. Ecol. Evol., 3, 1–20.
https://doi.org/10.3389/fevo.2015.00094
Blank, K., Laugaste, R., and Haberman, J. 2010. Temporal and spatial variation in the zooplankton : phytoplankton biomass ratio in a large shallow lake. Estonian J. Ecol., 59, 99–115.
https://doi.org/10.3176/eco.2010.2.02
Buhvestova, O., Kangur, K., Haldna, M., and Möls, T. 2011. Nitrogen and phosphorus in Estonian rivers discharging into Lake Peipsi: estimation of loads and seasonal and spatial distribution of concentrations. Estonian J. Ecol., 60, 18–38.
https://doi.org/10.3176/eco.2011.1.03
Carlson, R. E. 1977. A trophic State Index for lakes. Limnol. Oceanogr., 22, 361–369.
https://doi.org/10.4319/lo.1977.22.2.0361
Carvalho, L., Miller, C., Spears, B. M., Gunn, I. D. M., Bennion, H., Kirika, A., and May, L. 2012. Water quality of Loch Leven: responses to enrichment, restoration and climate change. Hydrobiologia, 681, 35–47.
https://doi.org/10.1007/s10750-011-0923-x
Carvalho, L., Poikane, S., Lyche Solheim, A., Phillips, G., Borics, G., Catalan, J., et al. 2013. Strength and uncertainty of phytoplankton metrics for assessing eutrophication impacts in lakes. Hydrobiologia, 704, 127–140.
https://doi.org/10.1007/s10750-012-1344-1
Dokulil, M. T. and Teubner, K. 2005. Do phytoplankton communities correctly track trophic changes? An assessment using directly measured and palaeolimnological data. Freshwater Biol., 50, 1594–1604
https://doi.org/10.1111/j.1365-2427.2005.01431.x.
Ejsmont-Karabin, J. 2012. The usefulness of zooplankton as lake ecosystem indicators: rotifer trophic index. Pol. J. Ecol., 60, 339–350.
EU. 2000. EU Directive 2000/60/EC establishing a framework for community action in the field of water policy. Official Journal of the European Communities, L327, 1–73.
European Commission. 2009. Common Implementation Strategy for the Water Framework Directive (2000/60/EC), Guidance Document No. 20, Guidance Document on Exemptions to the Environmental objecties. Technical report 2009-027. Office for Official Publications of the European Communities, Luxembourg.
Glenk, K., Lago, M., and Moran, D. 2011. Public preferences for water quality improvements: implications for the implementation of the EC Water Framework Directive in Scotland. Water Policy, 13, 645–662.
https://doi.org/10.2166/wp.2011.060
Gunn, I. D. M., O’Hare, M. T., and Maitland, P. S. 2012. Long-term trends in Loch Leven invertebrate communities. Hydrobiologia, 681, 59–72.
https://doi.org/10.1007/s10750-011-0926-7
Haberman, J. 2001. Zooplankton. In Lake Peipsi. Flora and Fauna (Pihu, E. and Haberman, J., eds), pp. 50–68. Sulemees Publishers, Tartu.
Haberman, J. and Haldna, M. 2014. Indices of zooplankton community as valuable tools in assessing the trophic state and water quality of eutrophic lakes: long term study of lake Võrtsjärv. J. Limnol., 73, 1–23.
https://doi.org/10.4081/jlimnol.2014.828
Haberman, J., Haldna, M., Laugaste, R., and Blank, K. 2010. Recent changes in large and shallow Lake Peipsi (Estonia/Russia): causes and consequences. Pol. J. Ecol., 58, 645–662.
Ibneeva, N. I. 1983. Exploitation of food resources by planktophagous fishes in Lake Peipsi-Pihkva. Sbornik nauchnykh trudov GosNIORKh, 209, 44–50 (in Russian).
Jaani, A. 2001. Hydrological regime and water balance. In Lake Peipsi: Meteorology, Hydrology, Hydrochemistry (Nõges, T., ed.), pp. 38–72. Sulemees Publishers, Tartu.
Jeppesen, E., Jensen, J.-P., and Søndergaard, M. 2002. Response of phytoplankton, zooplankton, and fish to re-oligotrophication: an 11 year study of 23 Danish lakes. Aquat. Ecosyst. Health Manage., 5, 31–43.
https://doi.org/10.1080/14634980260199945
Jeppesen, E., Søndergaard, M., Jensen, J.-P., Havens, K. E., Anneville, O., Carvalho, L., et al. 2005. Lake responses to reduced nutrient loading – an analysis of contemporary long-term data from 35 case studies. Freshwater Biol., 50, 1747–1771.
https://doi.org/10.1111/j.1365-2427.2005.01415.x
Jeppesen, E., Meerhoff, M., Holmgren, K., González- Bergonzoni, I., Teixeira-de Mello, F., Declerck, S. A. J., et al. 2010. Impacts of climate warming on lake fish community structure and potential effects on ecosystem function. Hydrobiologia, 646, 73–90.
https://doi.org/10.1007/s10750-010-0171-5
Johnson, R. K. and Angeler, D. G. 2010. Tracing recovery under changing climate: response of phytoplankton and invertebrate assemblages to decreased acidification. J. N. Am. Benthol. Soc., 29, 1472–1490.
https://doi.org/10.1899/09-171.1
Kangur, M., Kangur, K., Laugaste, R., Punning, J.-M., and Möls, T. 2007. Combining limnological and palaeolimnological approaches in assessing degradation of Lake Pskov. Hydrobiologia, 584, 121–132.
https://doi.org/10.1007/s10750-007-0597-6
Kangur, A., Kangur, P., Pihu, E., Vaino, V., Tambets, M., Krause, T., and Kangur, K. 2008. Kalad ja kalapüük. In Peipsi (Haberman, J., Timm, T., and Raukas, A., eds), pp. 317–340. Eesti Loodusfoto, Tartu (in Estonian).
Kangur, K., Kangur, P., Ginter, K., Orru, K., Haldna, M., Möls, T., and Kangur, A. 2013. Long-term effects of extreme weather events and eutrophication on the fish community of shallow Lake Peipsi (Estonia/Russia). J. Limnol., 72, 376−387.
https://doi.org/10.4081/jlimnol.2013.e30
Laugaste, R., Nõges, T., Nõges, P., Jastremskij, V. V., Milius, A., and Ott, I. 2001. Algae. In Lake Peipsi: Flora and Fauna (Pihu, E. and Haberman, J., eds), pp. 31–49. Sulemees Publishers, Tartu.
Laugaste, R., Panksep, K., and Haldna, M. 2013. Dominant cyanobacterial genera in Lake Peipsi (Estonia/Russia): effect of weather and nutrients in summer months. Estonian J. Ecol., 62, 229–243.
https://doi.org/10.3176/eco.2013.4.01
Lindpere, A., Starast, H., Milius, A., and Saan, T. 1990. Peipsi-Pihkva järve vee omaduste muutumine maist septembrini. In Peipsi järve seisund (Timm, T., ed.), pp. 10–11. Eesti Teaduste Akadeemia, Zooloogia ja Botaanika Instituut, Tartu (in Estonian).
Loigu, E. and Leisk, Ü. 1996. Water quality of rivers in the drainage basin of Lake Peipsi. Hydrobiologia, 338, 25–35.
https://doi.org/10.1007/BF00031708
Loigu, E., Leisk, Ü., Iital, A., and Pachel, K. 2008. Peipsi järve valgla reostuskoormus ja jõgede kvaliteet. In Peipsi (Haberman, J., Timm, T., and Raukas, A., eds), pp. 179–199. Eesti Loodusfoto, Tartu (in Estonian).
Mao, F. and Richards, K. 2012. Irreversible river water quality and the concept of the reference condition. Area, 44, 423–431.
https://doi.org/10.1111/j.1475-4762.2012.01124.x
May, L., Spears, B. M., Dudley, B. J., and Gunn, I. D. M. 2014. The response of the rotifer community in Loch Leven, UK, to changes associated with a 60% reduction in phosphorus inputs from the catchment. Int. Rev. Hydrobiol., 99, 65–71.
https://doi.org/10.1002/iroh.201301705
Ministry of the Environment. 2009a. Procedure for the Establishment of Bodies of Surface Water and a List of the Bodies of Surface Water the State of Which is to be Established, Classes of the States and the Values of Quality Indicators Corresponding to These State Classes, and the Procedure for the Establishment of the Classes of State. Riigi Teataja, 2009, 64, 941.
Ministry of the Environment. 2009b. Order from 28.07.2009, No. 44. www.riigiteataja.ee/akt/13210253 (accessed 2016-11-11).
Nõges, T., Nõges, P., and Laugaste, R. 2003. Water level as the mediator between climate change and phytoplankton composition in a large shallow temperate lake. Hydrobiologia, 506–509, 257–263.
https://doi.org/10.1023/B:HYDR.0000008540.06592.48
Nõges, T., Tuvikene, L., and Nõges, P. 2010. Contemporary trends of temperature, nutrient loading and water quality in large lakes Peipsi and Võrtsjärv, Estonia. Aquat. Ecosyst. Health Manage., 13, 143−153.
https://doi.org/10.1080/14634981003788987
Paerl, H. W. and Huisman, J. 2008. Blooms like it hot. Science, 320, 57–58.
https://doi.org/10.1126/science.1155398
Piasecki, W. G. and Wolska, M. 2007. Pelagic zooplankton as an indicator of lake Pełcz (Westpomerania, Poland) trophic state. Limnol. Rev., 7, 213–218.
Piirimäe, K., Loigu, E., Pachel, K., and Iital, A. 2015. Virtual mapping of reference conditions of pollutant load in water bodies: phosphorus in the Lake Peipsi basin. Boreal Environ. Res., 20(3), 391–402.
Räike, A., Pietiläinen, O. P., Rekolainen, S., Kauppila, P., Pitkänen, H., Niemi, J., et al. 2003. Trends of phosphorus, nitrogen, and chlorophyll a concentrations in Finnish rivers and lakes in 1975–2000. Sci. Total Environ., 310, 47–59.
https://doi.org/10.1016/S0048-9697(02)00622-8
Riccardi, N. and Rossetti, G. 2007. Eudiaptomus gracilis in Italy: how, where and why? J. Limnol., 66, 64–69.
https://doi.org/10.4081/jlimnol.2007.64
Sas, H. 1989. Lake Restoration by Reduction of Nutrient Loading. Expectation, Experiences, Extrapolation. Acad. Ver. Richardz Gmbh., Germany.
Søndergaard, M., Bjerring, R., and Jeppesen, E. 2013. Persistent internal phosphorus loading during summer in shallow eutrophic lakes. Hydrobiologia, 710, 95–107.
https://doi.org/10.1007/s10750-012-1091-3
Starast, H., Milius, A., Möls, T., and Lindpere, A. 2001. Hydrochemistry of Lake Peipsi. In Lake Peipsi: Meteorology, Hydrology, Hydrochemistry (Nõges, T., ed.), pp. 97–131. Sulemees Publishers, Tartu.
Tammeorg, O., Niemistö, J., Möls, T., Laugaste, R., Panksep, K., and Kangur, K. 2013. Wind-induced sediment resuspension as a potential factor sustaining eutrophication in large and shallow Lake Peipsi. Aquat. Sci., 75, 559–570.
https://doi.org/10.1007/s00027-013-0300-0
Tammeorg, O., Möls, T., and Kangur, K. 2014. Weather conditions influencing phosphorus concentration in the growing period in the large shallow Lake Peipsi (Estonia/Russia). J. Limnol., 73, 11–19.
https://doi.org/10.4081/jlimnol.2014.768
Verschuren, D., Johnson, T. C., Kling, H. J., et al. 2002. History and timing of human impact on Lake Victoria, East Africa. R. Soc., 269, 289–294.
https://doi.org/10.1098/rspb.2001.1850
Vollenweider, R. A. and Kerekes, J. 1982. Eutrophication of Waters – Monitoring, Assessment and Control. Synthesis Report. OECD, Paris.
Yan, N. D., Leung, B., Keller, W., Arnott, S. E., Gunn, J. M., and Raddum, G. G. 2003. Developing conceptual frameworks for the recovery of aquatic biota from acidification. Ambio, 32, 165–169.https://doi.org/10.1579/0044-7447-32.3.165
