Gyrosigma
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Gyrosigma is a genus of diatoms (Bacillariophyta) with around 30 species that occur in fresh and marine water.
features
The representatives are large single cells. They have the pebble shells typical of diatoms from two counters. When viewed from the shell, its shell is sigmoid, ie bent in opposite directions at both ends. They are rectangular in side view. The two plastids per cell are elongated, plate-shaped and lie against the belt ligaments. There are a number of pyrenoids on the inside of the plastids . The nucleus sits in the center of the cell. Both bowls have a raphe in the middle and very fine dots. The cells are capable of creeping movements. It is rare for several cells to be found together in one mucous tube. The cells are between 60 and 180 micrometers long.
Asexual reproduction occurs through the typical dichotomy of diatoms. Sexual reproduction is not known in Gyrosigma .
Occurrence
Gyrosigma occurs primarily in the sea. It is also common in brackish water and in oligo- to eutrophic fresh water.
supporting documents
- Karl-Heinz Linne von Berg, Michael Melkonian u. a .: The Kosmos algae guide. The most important freshwater algae under the microscope. Kosmos, Stuttgart 2004, ISBN 3-440-09719-6 , p. 220.
