Phacotus lenticularis (Chlorophyta) population dynamics in both nature and culture

Schlegel, Ines; Koschel, Rainer; Krienitz, Lothar

doi:10.1080/03680770.1998.11901324

Cited by 4 publications

(5 citation statements)

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“…This was considered as indicator for carbonate dissolution of Phacotus shells already in the water column (5), which was surprising since the conditions in the epilimnion of a hard-water lake, with a Ca 2+ ionic concentration of 37.6 mg L −1 , pH >8.6 (SD = 0.5) and temperature of 20.9°C (SD = 2.7°C) as described by Lenz et al (2018), did not indicate carbonate undersaturated conditions. These parameters are within acceptable ranges indicated for the occurrence of Phacotus in lakes (Gruenert et al, 2016;Schlegel et al, 2000;Schlegel, 2001). A Phacotus mass occurrence was even documented at IGS in 2006(Bavarian Environment Agency, 2016, which suggests suitable water conditions for Pha- cotus in this lake.…”

Section: Discussionsupporting

confidence: 61%

“…Koschel and Raidt (1988) studied the morphology of Phacotus shells, while Giering et al (1990) and Krienitz (1996, 1997) terns. Schlegel et al (2000) described four morphotypes of Phacotus shells, which are suggested to reflect organismic calcification control. The abundance of Phacotus and its contribution to suspended autochthonous calcite content in hard-water lakes of northern Germany have been studied (Krienitz et al, 1993).…”

Section: Introductionmentioning

confidence: 99%

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Representative monitoring of the calcifying alga Phacotus lenticularis (Chlamydophyceae) in lentic ecosystems

2020

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The biogenic carbonate precipitation by the freshwater alga Phacotus lenticularis may play a role in long-term carbon (C) fixation that has not yet been quantified. This is partly due to the absence of a standardised methodology to representatively sample and assess the cell density and sedimentation of P. lenticularis in lakes. The objective of the present study was to define an adequate sampling methodology taking into account the spatiotemporal variation of P. lenticularis as well as the sedimentation and dissolution of calcite shells. Simultaneous measurements in three different lake sub-basins of Lake Grosser Ostersee, Germany, showed that the spatial cell density of P. lenticularis was similar in each sub-basin. At all sites, the vertical P. lenticularis cell density maxima corresponded with the slowly downshifting thermocline from depths of 2 to 6 m. During the entire growth period, composite samples from 0 to 7 m included 89% of the total P. lenticularis population. Lake bathymetry, as well as external factors like wind exposure, did not appear to affect the abundance of these calcifying algae. Sediment traps at a depth below the thermocline (at 7 m) and 1 m above the lake bottom recorded sedimentation rates of P. lenticularis shell halves (sh) between 1.1×106 and 1.1×108 sh m−2 d−1, while mean cell concentrations in the water column were between 1.1×108 and 1.7×109 shells per m². Sinking velocity ranged between 3 and 4 m d−1. Sediment from traps installed at a depth of 7 m did not reflect mean shell concentrations in the water column above. Dissolution of carbonates reduced the number of shells in sediment traps at the lake bottom and during the storage of samples. A laboratory experiment showed that even distilled water used for dilution during microscopic analysis led to dissolution of P. lenticularis shells. In conclusion, combined sampling of P. lenticularis from open water and sediment traps close to the lake bottom delivers a most representative assessment of biogenic carbonate precipitation. Due to dissolution effects, high temporal resolution along with appropriate sample preservation are crucial, whereas spatial representativeness was already achieved with low number of sampling sites per lake.

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Section: Discussionsupporting

confidence: 61%

Section: Introductionmentioning

confidence: 99%

Representative monitoring of the calcifying alga Phacotus lenticularis (Chlamydophyceae) in lentic ecosystems

2020

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“…Since planktonic blooms of Phacotus lenticularis are restricted to the summer months in field observations (Schlegel et al . 2000) and their shells are made up of calcite, blooms are probably also related to wind conditions during the summer time. Windier summer seasons with higher turbidity should allow the relatively heavy shells to stay longer in the epilimnion than less windy summer seasons.…”

Section: Results and Interpretationmentioning

confidence: 99%

“…Planktonic blooms of Phacotus lenticularis are restricted to the summer months in field observations in northern Germany (Schlegel et al . 2000). Additionally, the occurrence of hypidiomorphic calcite precipitation layers (spring, summer) was documented.…”

Section: Methodsmentioning

confidence: 99%

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Limnological response to the Laacher See eruption (LSE) in an annually laminated Allerød sediment sequence from the Nahe palaeolake, northern Germany

Dreibrodt

Krüger

Weber

et al. 2020

Boreas

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This paper presents evidence for a limnological response to the Laacher See eruption (LSE) as detected in lake sediments from Nahe, northern Germany. The sediment section of the Allerød period dating to between 13 422 and 12 708 cal. a BP is preserved in annual laminations. Within this section, the LSE was identified as a cryptotephra layer (12 944±44 cal. a BP). Microfacies analysis, continuous high‐resolution geochemical measurements and pollen analyses enabled a high‐resolution reconstruction of environmental change. The older part of the Allerød (c. 13 422 to 12 943 cal. a BP) was characterized by relatively stable sedimentation conditions. Evidence for windier conditions dating to c. 13 160 to 13 080 cal. a BP probably reflects the Gerzensee oscillation. Pronounced changes of the lake sedimentation followed the LSE. Four unusually thick varves with increased amounts of allochthonous material indicate serious disturbance of the local environment immediately after the LSE, related to increased storminess and/or the occurrence of high intensity rainfall events. A pronounced reduction of biogenic silica accumulation for c. 60 years after the LSE could reflect a period of acidification. Indications of a simultaneous lake level increase until c. 60 years after the LSE are in line with the supposed reduced evapotranspiration associated with cooler conditions. About 120 years after the LSE, increased oxygen access at the lake bottom, allochthonous input and Cl fluxes point to an onset of increasingly stronger westerly winds, probably as a long‐term response to the LSE. This supports the idea of a southward shift of the mid‐latitude westerlies wind system within the interval between the LSE and the beginning of the Younger Dryas. The pace of the southwards shift of this wind system decreased from 10 km a−1 in the initial phase (40–120 years after LSE) to 6 km a−1 in the later phase (120–200 years after LSE).

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Assessing phytoplankton structure and spatio-temporal dynamics in a freshwater ecosystem using a powerful multiway statistical analysis

Rolland¹,

Bertrand²,

Maumy³

et al. 2009

Water Research

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Phacotus lenticularis (Chlorophyta) population dynamics in both nature and culture

Cited by 4 publications

References 4 publications

Representative monitoring of the calcifying alga <em>Phacotus lenticularis</em> (Chlamydophyceae) in lentic ecosystems

Representative monitoring of the calcifying alga <em>Phacotus lenticularis</em> (Chlamydophyceae) in lentic ecosystems

Limnological response to the Laacher See eruption (LSE) in an annually laminated Allerød sediment sequence from the Nahe palaeolake, northern Germany

Assessing phytoplankton structure and spatio-temporal dynamics in a freshwater ecosystem using a powerful multiway statistical analysis

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