Cyanobacteria & Algae

Cyanobacteria & Algae

Cyanobacteria

~3,500 mya cyanobacteria evolved

Stromatolites• Stromatolites are produced when colonies of

cyanobacteria bind calcium–rich sediments.

Stromatolites

• Cyanobacteria have an abundant fossil record, evidence that cyanobacteria was prevalent throughout this time period

Stromatolites

Early Earth’s Atmosphere

Cyanobacteria

• Earth’s early atmosphere practically devoid of free Oxygen.

• Cyanobacteria first photosynthetic organism to evolve (~3,500 mya) on earth

• Cyanobacteria played the decisive role in elevating the level of oxygen in the atmosphere of early Earth, staging it for the arrival of life as we know it on this planet!

HOORAY FOR CYANOBACTERIA!

Cyanobacteria

• Earth’s early atmosphere practically devoid of free Oxygen.

• Cyanobacteria first photosynthetic organism to evolve (~3,500 mya) on earth

• Cyanobacteria played the decisive role in elevating the level of oxygen in the atmosphere of early Earth, staging it for the arrival of life as we know it on this planet!

HOORAY FOR CYANOBACTERIA!

~3,500 mya cyanobacteria evolved

FIRST POLLUTION CRISIS!

Oscillatoria

• Filamentous Cyanobacteria• The cells are usually joined only by their walls or mucilaginous sheaths.• Each cell leads an independent life.

Nostoc

filamentous cyanobacteria in a ball!

Freshwater habitats

Many Cyanobacteria fix nitrogen

• Plants (and other organisms) need nitrogen for survival.

• Nitrogen gas, in the atmosphere, is not in form plants can take up.

• Many cyanobacteria can convert the nitrogen gas to ammonium, a useable form of nitrogen! (“Nitrogen fixation”)

Anabaena• Rice can often be grown continuously on the same

land without the addition of fertilizers because of the presence of nitrogen-fixing cyanobacteria, such as Anabaena, in the rice paddies.

AlgaePhycology: the study of algae

Phylum Dinophyta: the Dinoflagellates

• Closely related to some protozoa (“animal-like protists).

• 2000-4000 species known

• Found in marine and freshwater habitats (most are marine)

Phylum Dinophyta: the Dinoflagellates• Most are unicellular

biflagellates• Flagella beat in two

grooves, causing whirling-forward motion

• Greek word dinos: ‘whirling’

• Latin flagellum: diminutive term for whip

Theca: stiff cellulose plates “coat of armor”

(Gonyaulax polyedra)

Not all Dinoflagellates have theca

Bioluminescent marine dinoflagellate (Noctiluca scintillans)

Dinoflagellate nutrition

• Only about half of all dinoflagellate species are photosynthetic.

• Non-photosynthetic dinoflagellates (and some photosynthetic dinoflags) obtain nutrition either by ingesting solid food particles or by absorbing dissolved organic compounds.

Dinoflagellate nutrition• 20% produce highly toxic compounds• Pfiesteria piscicida produce a toxic substance

that paralyzes the fishes’ respiratory systems, and then feeds on the fish.

Symbiosis with Dinoflagellates• Symbiotic relationship

with sponges, jellyfish, sea anemones, corals, octopuses and squids, snails, etc…)

• In coral polyps, the dinoflagellates produce glycerol, which is used for coral respiration

• The coral produces amino acids for the dinoflagellates

Bioluminescent Dinoflagellates• When disturbed (by a

wave, or other physical aggitation), some dinoflagellates produce bioluminescent compounds

• Thought to serve as protection against predators by startling them.

Phylum Euglenophyta (Euglenoids)• 900 known species• Habitat: mostly

freshwater, some marine

• About 1/3 of the genera in the phylum are photosynthetic.

• Euglenoides are flagellated and unicellular (except for one colonial genus)

Phylum Bacillariophyta (Diatoms)• Over 100,000 living species• Habitat: Marine &

Freshwater• Unicellular of colonial, lack

flagella• Important components of

the phytoplankton, a primary source of food for marine and freshwater aquatic animals.

• Provide carbohydrates, fatty acids, and vitamins to animals

Phylum Bacillariophyta (Diatoms)• Unique structure of

two-part cell walls, that overlap each other like a petri dish.

• Each part is called a frustule and is made of silica.

• Species distinguished by frustule ornamentation.

• Diatomaceous earth (DE): fine, crumbly, yet abrasive substance made from silica frustules of diatoms that have accumulated in ocean sediments over millions of years.

• Used as silver polish, filtering material, natural insecticide, used in cosmetics, used to rid intestinal worms and parasites from animals and humans, used as an insulating material.

Phylum Bacillariophyta (Diatoms)

Phylum Chrysophyta (Chrysophytes)• About 1000 species• Habitat: Mainly freshwater, few

marine• Unicellular or colonial, flagella• Many have characteristic gold color

(Greek chrysos, “gold,” and phyton, “plant”)

• i.e. Dinobryon, a colony of single cells living in tubes. Each cell can consume 36 bacteria/hour.

• Major consumer of bacteria in cooler North American lakes

Phylum Phaeophyta (Brown Algae)• About 1500 species, most

multicellular• Almost entirely marine• Dominate rocky shores in

cool climates• Range in size to

microscopic (Ectocarpus) to as much as 195 feet and 650 lbs (kelp)!

• Greek: phaeo, “dark-colored”

Kelps and Rockweed

Holdfast

Laminaria sp.

Fucus sp.

Fucus sp.

Phylum Phaeophyta (Brown Algae)• Algin: mucilaginous material used

economically as a stabilizer and emulsifier for some foods and for paint, and as coating for paper

• In the cell, algin provides flexibility and toughness to allow the algae to withstand stress from waves

• Also helps prevent drying when the algae are exposed during low tides.

Phylum Rhodophyta (Red Aglae)• 4000-6000

species, mostly multicelluar

• Habitat: Mainly marine, about 100 freshwater

• Many tropical species, many found in coral reefs

• Carageenan: gelatinous extracts from red algae (i.e. Chondrus crispus)

• Used as food additives for hundreds of years.• Used in Products such as ice cream, pudding,

condensed milk, toothpaste, shampoo, soy milk, artificial Alien saliva.

Phylum Rhodophyta (Red Aglae)

Phylum Chlorophyta (Green Algae)

• 17,000 species (multicellular and unicellular)• Habitat: Marine and Freshwater, some

terrestrial (in the soil, in snow, on tree trunks…), some living symbiotically with other organisms.

Closest relatives to plants

• Class Charophyceae within the phylum Chlorophyta (green algae) includes members that most closely resemble true plants.

• Bryophytes (mosses, etc.) probably derived from an extinct member of Charophyceae Class.

• The Order Charales possess traits found otherwise only in true plants (i.e. mosses and vascular plants).

Chara (class Charophyceae)• Chara aka “stonewort” (Class

Charophyceae) grows in shallow waters of temperate lakes.

• Very closely related to true plants as evidenced by DNA analysis and several other characteristics

• Branched growth• Retention of egg• Sperm morphology• Numerous chloroplasts per cell

Moss sperm

Chara sperm

We Love Algae