Phytoplankton Changes During Eutrophication and P and N Metabolism

Herodek, Sándor

doi:10.1007/978-3-642-82707-5_8

Cited by 32 publications

(24 citation statements)

References 9 publications

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“…Lake Balaton suffered rapid eutrophication due to the nutrient load of Zala River during the 1970s (HERODEK, 1986). Two Kis-Balaton reservoirs were constructed (the upper one in 1985 and the lower one in 1993) for the water quality management of the lake.…”

Section: Study Sitementioning

confidence: 99%

A Study of the Decomposition of Reed (Phragmites australis ) as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes

Balogh

Présing

Vörös

et al. 2006

International Review of Hydrobiology

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A Study of the Decomposition of Reed (Phragmites australis)as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes key words: litter breakdown, DOC, water colour, humic acids fulvic acids AbstractThe decomposition of leaf and steam litter of reed (P. australis) was measured both in the field and in the laboratory. The breakdown rates, the total carbon and the stable carbon isotope dynamics of reed litter were determined. The stable carbon isotope ratios of isolated humic substances (fulvic and humic acids) were also analysed. The δ 13 C value in reed remains increased from -26‰ to -24‰ for stems and from -27‰ to -26‰ for leaves. The dissolved fulvic and humic acids isolated from the experimental bottles (mean δ 13 C was -27.6‰) and the reservoir water were depleted in 13 C (mean δ 13 C was -28.6‰) relative to the reed remains. The results show that reed litter is an important source of coloured aquatic humic substances. IntroductionThe shallow lower Kis-Balaton reservoir is located in a former peat-marshy area in the catchment area of the Zala River in Hungary. It was constructed for the water quality management of Lake Balaton. It was flooded in 1993 following the flooding of the upper reservoir in 1985. Large amounts of humic substances have been exported from this area into the western basin of the lake (V. -BALOGH and VÖRÖS, 2001).According to the dominant view that supported the creation of the reservoir, the peatmarshy soil -as the main source of humic sunstances -would be exhausted in a few years. We, on the other hand, have the opinion -shared by some others -that the release of humic substances from the reservoir would remain unchanged, as humic substances can be derived not only from soil/sediment (i.e. formerly degraded plants) but also from freshly degraded plants, even more so as 80% of the reservoir's surface is covered in emergent macrophytes, mainly reed (Phragmites australis). This study tests that hypothesis.Aquatic macrophytes release large amounts of dissolved organic matter during their decomposition, some of which have humic characteristics (WETZEL, 1990). Humic substances from aquatic macrophytes may provide a significant source of fresh and degradable humic matter in some lakes (WETZEL, 1992).The decomposition process of Phragmites australis (CAV.) TRIN. ex. STEUD. has been studied with different objectives by several authors (POLUNIN, 1982;KUFEL and KUFEL, 1988;TANAKA, 1991; VAN DER VALK et al., 1991;WRUBLESKI et al., 1997; DENWARD and Internat. Rev. Hydrobiol. 91 2006 1 15-28

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Section: Study Sitementioning

confidence: 99%

A Study of the Decomposition of Reed (Phragmites australis ) as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes

Balogh

Présing

Vörös

et al. 2006

International Review of Hydrobiology

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“…Lake Balaton is a large (surface area 596 km 2 ), shallow (mean depth 3.2 m) lake, that became eutrophichypertrophic because of increased nutrient loads in the 1970s (Herodek, 1986). The most dramatic change occurred in the western basin (surface area 38 km 2 ) in the shallowest (mean depth 2.5 m) and smallest basin of the lake.…”

Section: Introductionmentioning

confidence: 99%

Nitrogen uptake and the importance of internal nitrogen loading in Lake Balaton

et al. 2001

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SUMMARY1. The importance of various forms of nitrogen to the nitrogen supply of phytoplankton has been investigated in the mesotrophic eastern and eutrophic western basin of Lake Balaton. 2. Uptake rates of ammonium, urea, nitrate and carbon were measured simultaneously. The uptake rates were determined using 15 N and 14 C methodologies, and N 2 -fixation was measured using the acetylene-reduction method. The light dependence of uptake was described with an exponential saturation equation and used to calculate surface-related (areal) daily uptake. 3. The contribution of ammonium, urea and nitrate to the daily nitrogen supply of phytoplankton varied between 11 and 80%, 17 and 73% and 1 and 15%, respectively. N 2 -fixation was negligible in the eastern basin and varied between 5 and 30% in the western region of the lake. The annual external nitrogen load was only 10% of that utilized by algae. 4. The predominant process supplying nitrogen to the phytoplankton in the lake is the rapid recycling of ammonium and urea in the water column. The importance of the internal nutrient loading is emphasized.

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“…The lake was subject to rapid eutrophication during the 1970s and since 1973 heterocystic cyanobacterial bloom (Aphanizomenon flos-aquae and Anabaena spiroides) have appeared regularly, first in the western basin and later in the entire lake. Since 1977, peak values of phytoplankton biomass have exceeded 40 mg fresh weight L -1 (HERODEK, 1986).…”

Section: Study Sitementioning

confidence: 99%

“…The water is frequently turbid because of sediment resuspension and calcite precipitation. The organic matter content of the sediment is <4% of dry weight (HERODEK, 1986). Crustacean plankton is dominated primarily by copepods.…”

Section: Study Sitementioning

confidence: 99%

The Role of Fish Communities in Water Quality Management of a Large Shallow Lake

Tátrai

Paulovits

Mátyás³

et al. 2003

International Review of Hydrobiology

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Management measures of Lake Balaton such as wetland reconstruction at the main inflow to the lake along with the "unplanned" commercial fishery led to great changes in the density and biomass of fish populations. There was no significant difference in CPUE data between the two, eastern and western, basins. Biomass of total fish stock in Lake Balaton has decreased substantially, 2-3 times between 1991-1999, and ranges between 120-194 kg ha -1. Bottom-up effects are more important than the topdown effects due to the impact of internal nutrient load. Changes in the biomass and thus the activity of omnivorous fish in the lake lowered the intensity of various indirect effects and feedback mechanisms causing changes in the nutrient metabolism of the lake. Intensified fishery effort in Lake Balaton did not result in an increased stock of piscivores. The ratio of piscivores and omnivores remained at 5% during the whole study period. Despite this low piscivores to omnivores ratio, the water quality has improved in all basins.

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Phytoplankton Changes During Eutrophication and P and N Metabolism

Cited by 32 publications

References 9 publications

A Study of the Decomposition of Reed (Phragmites australis ) as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes

A Study of the Decomposition of Reed (Phragmites australis ) as a Possible Source of Aquatic Humic Substances by Measuring the Natural Abundance of Stable Carbon Isotopes

Nitrogen uptake and the importance of internal nitrogen loading in Lake Balaton

The Role of Fish Communities in Water Quality Management of a Large Shallow Lake

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