Library > Name > Blue-green algae

Particle surface as a rich environment

This view shows the rolling locomotion of Synula between particles. The surface of each particle is covered with bacteria and algae. These biofilms offer a rich environment to protozoa and other small organisms.


Commentary by Prof. Yuji Tsukii, Hosei University
A plate-like figure appearing right side of the video is a colony of blue-green algae, Merismopedia.

http://protist.i.hosei.ac.jp/PDB/Im.....

The particle surfaces are covered with a lot of bacteria and humic substances, but it may not be a developed biofilm in the strict sense.

Sampling Date : 03 July 2009

Sampling Site : Hirose River B  Google Map

Diatoms and algae playmates?

One by one numerous diatoms approach a long chain of algae that is moving in a leisurely arc. Sometimes the diatoms snuggle against and push or poke the algae, but the algae chain continues its journey as if it doesnt care.


Commentary by Prof. Yuji Tsukii, Hosei University
This blue-green alga belongs to genus Oscillatoria.

http://protist.i.hosei.ac.jp/PDB/Im.....

Many species are included in genus Oschillatoria, and their identification is tricky.

But judging from the unique shape of this organism, it might be Oschillatoria jovis.

http://protist.i.hosei.ac.jp/PDB/Im.....

The cell-size of O.jovis is reported to be 3.4~4.2μm in width, and if the width of this organism is similar, the organism is likely to be O.jovis.

The diatoms passing by Oschillatoria might be a species of genus Navicula, but this is difficult to determine because there are so many small diatoms with a similar appearance.

http://protist.i.hosei.ac.jp/PDB/Im.....

Diatoms are usually difficult to identify without observing their shell pattern using a scanning electron microscope or a high-resolution optical microscope. To do this, it is necessary to remove cell material from the shell through a chemical process.

Sampling Date : 08 August 2009

Sampling Site : Hirose River A  Google Map

A colony of green algae

A colony composed of about twenty green algae cells remains still. Its occasional movements may be caused by the flow of water, or the colony may be actively moving.


Commentary by Prof. Yuji Tsukii, Hosei University
From the cell size and color, this organism is not green algae but blue-green algae.

The organism most likely belongs to genus Microcystis, but as there are many species in this genus, it is difficult to decide the species of this organism.

http://protist.i.hosei.ac.jp/PDB/Im.....

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map

Journey of blue-green algae

Twelve cells are connected like a chain. They slowly begin their journey to another place despite the lack of any specialized moving apparatus. Where are they going and why?


Commentary by Prof. Yuji Tsukii, Hosei University
This organism is definitely a blue-green alga belonging to the genus Oscillatoria.

Its classification into species is difficult because the genus Oscillatoria includes so many species. Using the Illustrated Book of Japanese Fresh-Water Algae (1977), there are two species that are most likely to match the one in this video. Both of them are made up of long chains of cells characterized by narrow “waists” where two cells connect, and round tips at both ends of the chain. The blue-green cells of one species, Oscillatoria iwanoffiana, are 5~9μ in width and have a pseudo-vacuole within each cell.

http://protist.i.hosei.ac.jp/PDB/Im.....

The cells of another species, Oscillatoria jovis, are 3.4~4.2μ in width and seem to be homogeneous.

http://protist.i.hosei.ac.jp/PDB/Im.....

If the width of the trichome (chain of cells) and its inside view (whether cytoplasm is homogeneous or includes a pseudo-vacuole) are clearly observed, we may classify these organisms according to the above reference book. However, we cannot dismiss the possibility that new species have been identified since its publication is in 1977.

Sampling Date : 09 August 2009

Sampling Site : Hirose River B  Google Map

A still-life view of algae and diatoms

This is a tranquil scene featuring various kinds of diatoms and green algae, none of which is moving.


Commentary by Prof. Yuji Tsukii, Hosei University
The organism in this video is not green algae but a diatom.

Synedra

http://protist.i.hosei.ac.jp/PDB/Im.....

Tabellaria

http://protist.i.hosei.ac.jp/PDB/Im.....

Fragilaria

http://protist.i.hosei.ac.jp/PDB/Im.....

The two long green organisms in the central part of the figure are Oscillatoria

http://protist.i.hosei.ac.jp/PDB/Im.....

A small Scenedesmus can be seen between Synedra and Oscillatoria.

Sampling Date : 18 October 2009

Sampling Site : Hirose River A  Google Map

Diatoms seem to play with green algae

A long colony of light-green algal cells proceeds in a straight line. Numerous diatoms accompany the algae on its journey, playfully interacting with it, even attaching themselves and riding it like a conveyor belt. Some diatoms are also connected with each other in chains. Diatoms seem to benefit from these connections to move around from place to place.


Commentary by Prof. Yuji Tsukii, Hosei University
The title of this video is incorrect.

This organism is not green algae but a blue-green algae named Oscillatoria.

http://protist.i.hosei.ac.jp/PDB/Im.....

Since its cell size is not so large as that of O. princeps or O. limosa, the organism is probably one of the following smaller species:

O. irrigua, O. simplicissima or O. agardhii

http://protist.i.hosei.ac.jp/PDB/Im.....

http://protist.i.hosei.ac.jp/PDB/Im.....

http://protist.i.hosei.ac.jp/PDB/Im.....

Sampling Date : 18 October 2009

Sampling Site : Hirose River A  Google Map