Microbial Mats from the Sippewissett Saltmarsh

Microbial Diversity Course 1997, MBL, Woods Hole

ann

Microbial Mats

Take a knife and cut into the firm sand in a salt marsh. This is what you may find: Colored bands in the sand. In the upper 2 to 5 mm you'll find a green and a pink layer. The green layer contains diatoms and cyanobacteria. The color of the pink layer stems from carotinoids, the major pigments of phototrophic purple sulfur bacteria. Just a little bit deeper you'll find a black layer - iron sulfide, precipitated from iron ions with sulfide formed by anoxic sulfate reducing bacteria. These bacteria decompose the organic matter formed in the top layers, and thus recycle the biomass. Underneath the colored bands the sand turns grey due to a chemical formation of pyrite. Below that you'll find more layers - left-overs from passed years. The hole in the sand has a size of about 5 cm (2 inch).

Some of the bacteria of the so called "Farbstreifen-Sandwatt" are presented here on this page. The samples were taken at the Great Sippewissett Saltmarsh at Woods Hole, MA, USA.

You are welcome to download the images. Just push "shift" and click with the mouse at the pictures you like. Annotations are included. If you want to see them first, click on ann.

If you intend to publish the images please observe the copyright (names of the persons taking the pictures added in the annotations):
© 1997, Microbial Diversity

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Last modified: 16-Dez-97

Green layer		Back to top Pink layer Black layer Grey layer
		Filamentous cyanobacteria from the top (green) layer of a microbial mat in the Great Sippewisset Saltmarsh. Left: phase contrast, right: The same view after illumination with green light. The red autoflourescence demonstrates the presence of phycobiliproteins ann

ann	ann	Some more filamentous cyanobacteria from the green layer of a microbial mat from the Great Sippewissett Saltmarsh. Left: phase contrast micrograph, right: autofluorescence of the same view after illumination with green light.. Lenght of the borderline: approx. 0.4 mm left picture: © 1997 MBL

A short fragment of the cyanobacterium Spirulina spec. (center) and a diatom. Left: phase contrast. Right: Autofluorescence of the same view after illumination with green light. The weak fluorescence of the diatom due to its chlorophyll a cannot be seen. Diameter of the microbes: approx: 3 µm	ann	ann

ann	ann	Lyngbya spec, a sheeted cyanobacteriam found in the Great Sippewissett Saltmarsh. Two cells are leaving the sheet. Left: phase contrast micrograph. right: autofluorescence after illumination with green light. Size of the picture: 100X100 µm

Pink layer		Back to top Green layer Black layer Grey layer
	The major microbes of the pink layer are phototrophic purple sulfur bacteria. The egg shaped organisms are diatoms. Phase contrast. 75x75 µm ann

		Purple sulfur bacteria and a diatom from the pink layer of a microbial mat from the Great Sippewissett Saltmarsh. The bright spots in the cells are sulfur granules. DIC micrograph. 75x75 µm ann

	A typical bright field micrograph of microbes of the pink layer of microbial mats. The layer contains various purple sulfur bacteria (mostly in packets), some diatoms (center), and some single cells. Size of the picture: 150x150 µm ann

	Close-up of a group of purple sulfur bacteria (Thiopedia spec) clustered around a cell of a diatom. Phase contrast Size of the picture: about 75X75 µm ann

A large empty shell of a diatom and several bacterial cells. The bright spots in the bacteria are sulfur granules. Size of the picture: about 75X75 µm ann

Black layer		Back to top Green layer Pink layer Grey layer
		Microorganisms of the black, iron sulfide rich layer of the microbial mat from Great Sippewissett Saltmarsh, clustered around the remainings of an insect's eye (?). The spiral shaped organism (top left) is a Spirochaete. Phase contrast micrograph ann

	The curved cells resemble typical sulfate reducing bacteria (Desulfovibrio spec). Phase contrast, 75X75 µm ann

		Spirochaetes are easyly recognized by their irregular spiral shape. Living cells crawl between the sand particles; they show a typical twisting behaviour. Phase contrast. 400x400 µm ann

Grey layer		Back to top Green layer Pink layer Black layer
	Less bacteria are found in the grey layer than in the black bands. Here are some spirochaetes along with two empty shells of diatoms. The bright spot in the center was not identified. Phase contrast micrograph. 150X150 µm ann

		Shells of diatoms consist of silicate. Therefore, they are long lasting. Their fine structure is often used to classify the diatoms. Here are a few examples. Phase contrast micrograph. ann

	Sometimes bacteria in the grey layer (and elsewhere) live together in associations. Phase contrast micrograph ann

Annotations:

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Size

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pixels

Annotations

matte.jpg

261K

741x488

Cross section through a microbial mat from the Great Sippewissett Saltmarsh, Falmouth, MA. A hole of about 5 cm (cross section) was cut into the sand. The color of the green and the pink layer stems from bacterial pigments. The black color is due to iron sulfide, the grey color is in part pyrite.

Reproduced from a 35 mm color slide. Picture taken with a 100 mm Macro lense.

spagh_st_bg.jpg

178K

1076x520

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial Mat, green layer.

Filamentous cyanobacteria.

Left picture: phase contrast micrograph.

Right picture: same view after illumination with green light, autofluorescence showing the presence of phycobiliproteins and chlorophyll a.

Size of the individual pictures: about 75X75 µm

knit_bg.jpg

71K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial mat, green layer. String of cyanobacteria.

Phase contrast micrograph,

Autoflourescence of the same view is shown in file knitf.jpg

Size of the picture: 400X400 µm

knitf_bg.jpg

52K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA,

microbial mat, green layer. String of phototrophic cyanobacteria.

Autofluorescence after illumination with green light showing the phycobiliproteins and Chlorophyll a of the cyanobacteria

Same view as knit.jpg

Size of the picture: about 400X400µm

spirul_bg.jpg

32K

508x480

Great Sippewissett Saltmarsh, microbial mat, green layer. Short fragment of Spirulina (cyanobacterium) and a diatom. Phase contrast micrograph. An autofluorescence picture of the same view is stored under spirulfl.jpg.

Diameter of the cell: about 3 µm

spirulfl_bg.jpg

53K

508x480

Great Sippewissett Saltmarsh, microbial mat, green layer. Autoflourescens picture of spirul.jpg showing phycobiliprotein and Chlorophyll a in Spirolina after illumination with green light.

salzm2a_bg.jpg

125K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial Mat, green layer.

Lyngbya spec, a sheeted cyanobacterium. Two cells are leaving the shell.

Phase contrast micrograph, size of the picture: about 100X100 µm

Autofluorescence of the same view is shown in file salzm2bf.jpg

salzm2bf_bg.jpg

33K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial Mat, green layer.

Lyngbya spec, a sheeted cyanobacterium. Two cells are leaving the shell.

Phase contrast micrograph, size of the picture: about 100X100 µm

Autofluorescence after illumination with green light, indicating the presence of phycobiliprotein and chlorophyll . Same view as file salzm2a.jpg

berry2_bg.jpg

82K

508x480

Great Sippewissett Saltmarsh, microbial mat, pink layer. Consortia of purple sulfur bacteria plus a few diatoms (egg shaped organisms).

Size of the picture: about 75x75 µm

Phase contrast micrograph.

stuffdic_bg.jpg

91K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial mat, pink layer

Plates of Thiopedia (phototrophic purple sulfur bacteria) and other sulfide oxidizing bacteria.

DIC micrograph. Size of the picture: about 75X75 µm

stuff_bg.jpg

135K

508x480

Great Sippewisset Saltmarsh, Falmouth, MA

Microbial mat, pink layer. Various typical sulfid oxidizing bacteria. Internal sulfur granules are seen as bright spots.

phase contrast micrograph. Size of the picture: about 150X150 µm

thio_bg.jpg

87K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial mat, pink layer.

Thiopedia spec. (plates of phototrophic purple sulfur bacteria) around empty shells of diatoms

phase contrast micrograph.

Size of the picture: about 75X75 µm

paket_bg.jpg

70K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA

Microbial mat, grey layer.

Packages of cells, some containing bright sulfur granules (purple sulfur bacteria, Thiopedia ?)

Two empty shells of diatoms.

Size of the picture: about 75X75 µm

Microbial Diversity 1997 (copyright) Elke Jaspers and Rolf Schauder

fac_col_bg.jpg

87K

508x480

Great Sippewissett Salt Marsh, Falmouth MA.

Microbial Mat, Black Layer.

Various bacteria clustered around what seems to be the remains of an insect's eye.

Spirochaete (spiral shaped organism) in the top left corner.

Phase contrast micrograph.

Size of the picture: about 200X200 µm

green-3_bg.jpg

73K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial Mat, black layer.

Motile bacteria that resemble typical cells of sulfate-reducing bacteria (Desulfovibrio spec).

Phase contrast micrograph,

Size of the picture about 75X75 µm.

spiro1_bg.jpg

84K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial Mat, black layer.

Spiral shaped Spirochaetes.

Phase contrast micrograph.

Size of the picture: about 400X400 µm

spiril1_bg.jpg

65K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA

Microbial Mat, grey layer.

The spiral shaped bacteria are Spirochaetes. The oval shaped structures are empty shells of diatoms.

Phase contrast micrograph.

Size of the picture: about 150X150 µm

diatom3_bg.jpg

78K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA.

Microbial mat, grey layer.

Empty shells of diatoms

Phase contrast micrograph.

kugel_bg.jpg

89K

508x480

Great Sippewissett Saltmarsh, Falmouth, MA

Microbial mat, grey layer.

Phase contrast micrograph.

Size of the picture: about 100X100 µm