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1

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The consequences of a drastic fish stock reduction in the large and shallow Lake Wolderwijd, The Netherlands. Can we understand what happened? (1994)

Meijer, M. L. ; Nes, E. H. ; Lammens, E. H. R. R. ; [et al.]

Springer

Hydrobiologia 275-276 (1994), S. 31-42

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ISSN: 1573-5117

Keywords: fish-stock reduction ; Daphnia grazing ; Neomysis

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract In 1990 an experiment started in the large and shallow lake Wolderwijd (2700 ha, mean depth 1.5 m) to improve the water quality. About 75% of the fish stock was removed (425 000 kg fish). The fish was mainly composed of bream and roach. In May 600000 young pikes (3–4 cm) were introduced. In May 1991 the water became very clear (Secchi depth 1.8 m) during a spring bloom of large Daphnia. Then the grazing by zooplankton was eight times higher than the primary production of algae and the total suspended matter concentration became very low. Compared to the situation before the fish reduction, the grazing had increased only slightly, while the primary production had decreased significantly in early spring. The fish stock reduction might have contributed to the reduction in primary production by a reduced internal nutrient load. The clear water period lasted six weeks. Daphnia disappeared in July due to food limitation, the algal biomass increased and the Secchi depth became 50 cm. Daphnia did not recover during summer, due to predation that was not caused by 0 + fish but by the mysid shrimp Neomysis integer. Neomysis could develop abundantly, because of the reduced biomass of the predator perch. The production of young fish had been low because of the cold spring weather. The cold weather was probably also responsible for the slow increase in density of macrophytes. After 1991, perch probably can control Neomysis. Due to lack of spawning places and shelter for 0 + pike, pike was probably not able to control the production of 0 + fish. In a lake of this scale, it will not be easy to get more than 50% coverage of macrophytes, which seems necessary to keep the algal biomass low by nutrient competition. Therefore, we expect also in the future a decrease in transparency in the summer. Locally, especially near Characeae, the water might stay clear.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00026697

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2

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Impact of cyprinids on zooplankton and algae in ten drainable ponds (1990)

Meijer, M L. ; Lammens, E. H. R. R. ; Raat, A. J. P. ; [et al.]

Springer

Hydrobiologia 191 (1990), S. 275-284

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ISSN: 1573-5117

Keywords: biomanipulation ; cyprinids ; zooplankton ; algae ; drainable ponds

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract To study the impact of cyprinids on algae, zooplankton and physical and chemical water quality, ten drainable ponds of 0.1 ha (depth 1.3 m) were each divided into two equal parts. One half of each pond was stocked with 0 + cyprinids (bream, carp and roach of 10–15 mm), the other was free of fish. The average biomass of the 0 + fish at draining of the ponds was 466 kg ha−1, to which carp contributed about 80%. The fish and non-fish compartments showed significant differences. In the non-fish compartments the density of Daphnia hyalina was 10–30 ind. l−1 and that of Daphnia magna 2–4 ind. l-−1, whereas in the fish compartments densities were c. 1 ind. l−1. Cyclopoid copepods and Bosmina longirostris, however, showed higher densities in the fish compartments. The composition of algae in the two compartments differed only slightly, but the densities were lower in the non-fish compartments. The significant difference in turbidity was probably caused by resuspension of sediment by carp. No significant difference in nutrient concentration between the compartments was found.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00026063

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3

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Available phosphorus in lake sediments in The Netherlands (1982)

Klapwijk, S. P. ; Kroon, J. M. W. ; Meijer, M -L.

Springer

Hydrobiologia 91-92 (1982), S. 491-500

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ISSN: 1573-5117

Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made with Scenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00000047

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4

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Available phosphorus in lake sediments in The Netherlands (1982)

Klapwijk, S. P. ; Kroon, J. M. W. ; Meijer, M -L.

Springer

Hydrobiologia 91-92 (1982), S. 491-500

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ISSN: 1573-5117

Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made withScenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF02391963

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5

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Long-term responses to fish-stock reduction in small shallow lakes: interpretation of five-year results of four biomanipulation cases in The Netherlands and Denmark (1994)

Meijer, M L. ; Jeppesen, E. ; Donk, E. ; [et al.]

Springer

Hydrobiologia 275-276 (1994), S. 457-466

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ISSN: 1573-5117

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The effects of fish stock reduction have been studies in 3 Dutch lakes (Lake Zwemlust, Lake Bleiswijkse Zoom and Lake Noorddiep) and 1 Danish lake (Lake Væng) during 4–5 years. A general response id described. The fish stock reduction led in general to a low fish stock, low chlorophyii-a, high transparency and high abunuance of macrophytes. Large Daphnia became abundant, but their density decreased, due to food limitation and predation by fish. The total nitrogen concentration became low due to N-uptake by macrophytes and enhanced denitrification. In Lake Bleiswijkse Zoom the water transparency deteriorated and the clear water state was not stable. The fish stock increased and the production of young fish in summer was high. lear water occurred only in spring. Large daphnids were absent in summer and the macrophytes decreased. In Lake Zwemlust, Lake Væng and Lake Noorddiep the water remained clear during the first five years. In summer of the sixth year (1992) transparency decreased in Lake Zwemlust (with high P-concentration of 1.0 mg P l-1). Also in Lake Væng (with a low nutrient concentration of 0.15 mg P.⋆-1) a short term turbid stage (1.5 month) occurred in summer 1992 after a sudden collapse of the macrophytes. Deterioration of the water quality seems to start in summer and seems related to a collapse in macrophytes. At a low planktivorous fishstock (e.g. Lake Væng)thhe duration of the turbid state is shorter. than in presence of a high planktivorous fish biomass (e.g. Lake Zwemlust, and later years of Lake Bleiswijkse Zoom).

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00026734

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6

Electronic Resource

Available phosphorus in lake sediments in The Netherlands (1982)

Klapwijk, S. P. ; Kroon, J. M. W. ; Meijer, M -L.

Springer

Hydrobiologia 91-92 (1982), S. 491-500

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ISSN: 1573-5117

Keywords: phosphate ; sediment ; bioassay ; algae ; phosphate fractionation ; NTA extraction

Source: Springer Online Journal Archives 1860-2000

Topics: Biology

Notes: Abstract The amount of phosphorus available to algae in the sediments of four lakes in the western part of the Netherlands has been assessed by means of chemical extraction and bioassay techniques. In addition to direct chemical sediment analyses, extractions were carried out with an NTA column method and a stepwise NH4 Cl-NaOH-HCI shaking method, the latter supposedly separating the weakly bound, the Fe- and Al-bound and the Ca-bound phosphates in the sediments. Bioassays, with sediment as the sole source of P, were made withScenedesmus quadricauda in modified Skulberg's 28 medium to determine the amount of phosphates available to algae. The average total P concentration of the sediments varied from 0.8 to 3.6 mg P g−1 dry wt and correlated well with the net external P loading of the lakes. Uptake of P by algae in the bioassays varied from 0.4 to 36% — while NTA extracted 36–69% of the total P. The ratio NH4Cl extracted/ NaOH extracted/ HCI extracted phosphates is different from lake to lake, although in all lakes the highest extractions (27–62% of total P) are found in the NaOH fraction. However, in the peaty sediments of these lakes, the NaOH step extracted not only the Fe- and Al-bound phosphates but, also, large amounts of humus compounds. Hence, this fraction also contains non-available organic P. The results are related to soil type and chemical characteristics of the sediments, and compared with data from other authors. A positive correlation was found between phosphate available to algae and NTA- and NaOH-extractable P, but the correlation with total phosphorus was higher. Moreover, algal-extractable P proved to be positively correlated with total iron and clay content and negatively with the amount of organic matter. It is concluded that the sediments in the investigated lakes show great variability and that the chemical extraction techniques cannot replace the bioassays to assess the amount of phosphorus available to algae.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00940137

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