Calcite production by the calcifying green alga Phacotus lenticularis

Submitted: 20 July 2017
Accepted: 16 December 2017
Published: 4 January 2018
Abstract Views: 2593
PDF: 496
HTML: 20
Publisher's note
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.

Authors

The importance of carbonate precipitation by phytoplankton in fresh water lakes has not been sufficiently considered in global carbon cycles and climate change scenarios. The objective of this study was to determine the influence of the calcifying bivalved phytoflagellate Phacotus lenticularis (Ehrenberg) Deising 1866 on the total calcite precipitation in five European hard-water lakes. For this purpose, an accurate mass determination of single Phacotus lenticularis shells was required. We developed a novel methodological approach to precisely determine the volume and mass of the calcified shells. Focused ion beam (FIB) techniques were employed to investigate internal structural features. Thin layer cross-sections of the shell profiles were reproduced and perforation as well as the crystalline structure of the calcite plates were monitored. 3D-shell models were computed by 360° rotation of the shell cross-sections using a CAD 3D imaging software to calculate precise volumes and estimate realistic masses. In contrast to previous estimates, we determined a 2.8-fold higher shell mass of 0.86 ng CaCO3 (standard deviation SD = 0.18) for the highly massive shells at a mean volume per individual of 334.1 µm³ (SD = 70). An initial shell porosity of less than 5% was derived from thin layer cross-section images, resulting in a presumed mean shell density of 0.0026 ng µm−3. The shell diameter was significantly influenced by the lake’s origin. The shells from each lake displayed substantial variations in diameter and shape. The pores in the shells showed two variations. Wider pore canals penetrated the whole shell wall, whereas small, elongated pores were located along the interspaces between calcite crystals with tabular habit. The approximate average dimensions of these calcite plates were 1.0 × 1.6 × 0.2 µm. The mean lateral wall thickness at the rim and centre of the shell were 1.98 µm (SD = 0.42) and 0.79 µm (SD = 0.17), respectively. The average carbonate precipitation by Phacotus lenticularis in relation to the total epilimnetic suspended calcite precipitation was 6.0% in the oligotrophic lake Großer Ostersee (Bavaria, Germany). During the growing season, Phacotus lenticularis contributed up to 21% of the particulate calcium carbonate in the epilimnion. These findings suggest that Phacotus lenticularis should be considered in the assessment of hard-water lake carbon cycling.

Dimensions

Altmetric

PlumX Metrics

Downloads

Download data is not yet available.

Citations

Supporting Agencies

Bavarian State Ministry of the Environment, Swiss Federal Laboratories for Materials Science and Technology, Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Sebastian Lenz, Technical University of Munich
Department of Life Sciences Weihenstephan, Aquatic Systems Biology Unit, Limnological Research Station Iffeldorf, Doctoral student
Uta Gruenert, University of Tübingen
Institute of Evolution and Ecology, Plant Evolutionary Ecology, Postdoc
Juergen Geist, Technical University of Munich
Department of Life Sciences Weihenstephan, Aquatic Systems Biology Unit, Limnological Research Station Iffeldorf, Professor (Chair owner)
Michael Stiefel, EMPA, Swiss Federal Laboratories for Materials Science and Technology
Specialist in electron and ion microscopy (SEM,TEM,FIB)
Maren Lentz, IGB, Leibniz-Institute of Freshwater Ecology and Inland Fisheries
Detp. of Experimental Limnology, laboratory manager
Uta Raeder, Technical University of Munich
Department of Life Sciences Weihenstephan, Aquatic Systems Biology Unit, Limnological Research Station Iffeldorf, Co-Director and superviser

How to Cite

Lenz, Sebastian, Uta Gruenert, Juergen Geist, Michael Stiefel, Maren Lentz, and Uta Raeder. 2018. “Calcite Production by the Calcifying Green Alga Phacotus Lenticularis”. Journal of Limnology 77 (2). https://doi.org/10.4081/jlimnol.2018.1692.

List of Cited By :

Crossref logo