The Marine Microbial World
Marine Microbes and Primary Producers
Prokaryotes
Bacteria
Archae
Unicellular Algae
Diatoms
Dinoflagellates
Protozoans
Formaniferans
Radiolarians
Ciliates
Fungi
Multicellular Algae
Red-Rhodophyta
Green-Chlorophyta
Brown-Phaeophyta
Flowering Plants
True Plants
Seagrass
Salt Tolerant
Mangroves
Salt marsh grass
Chap 5 Outline
Prokaryotes = “before nucleus”
2 Domains, 2 Kingdoms:
Bacteria and Archaea (more closely related to Eukaryotes)
Simplest and oldest life forms
Cell wall, cell membranes
No membrane bound organelles
DNA not in a nucleus
Great metabolic diversity
Prokaryotes: Life Processes
Various ways to obtain energy
Autotrophs –
“Self feeders”
Use light or chemicals to create own energy
Photosynthesis (light) or Chemosynthesis (chemicals)
Light, Hydrogen Sulfide, Ammonium, Nitrate, Iron, etc.
Heterotrophs –
Cannot make their own food/energy
Must eat/ingest to get their food/energy
Prokaryotes: Life Processes
Various ways to break down and release this energy =Respiration
Aerobic
Organic matter broken down using oxygen to release energy
10/13/14
Anaerobic
Organic matter broken down in the absence of oxygen
Bacteria
Most abundant form of life on earth!
Ensure the recycling of nutrients in detritis (VERY important!)
Live in open water and sea floor, everywhere
Accumulate on the ocean floor
Large masses=marine snow
Bacteria reproduction
Bacteria reproduces by a process called binary fission.
Binary Fission is where the bacterial cell divides into 2 cells that look the same as the original cell.
Can reproduce every 20 minutes.
Significance of Bacteria
Ecosystem Significance
Break down organic material into nutrients for other organisms to use
Cause diseases in marine animals
Phytoplankton blooms
Human Impact
Disease in humans
Food spoilage
Respiratory issues, rash.
Toxins stored in shellfish, then humans eat it.
Other Significance of Bacteria
Symbiotic Bacteria = associates with other organisms closely.
Parasites-harmful
Beneficial, Live in a host organism
Examples of Beneficial
Wood-Digesting Bacteria in wood eating organisms
Bioluminescence: attract mates, lure prey, communicate
Examples of Parasitic
Some toxic
Ex: Cyanobacteria
Photosynthetic
Most abundant photosynthetic org. in ocean
Prob. 1st on planet
Accumulated oxygen for Earth’s early atmosphere
Many pigments to help capture light
Chlorophyll-green
Phycocyanin-blue
Phycoerythrin-red
Cyanobacteria & Red Tide
Unpredictable, unsure of cause.
Massive blooms of phytoplankton
Some toxic
By cyanobacteria, dinoflagelletes, diatoms
Harms marine life:
-cuts fish gills, deplete oxygen levels, some poisonous
Harms humans
-toxic fumes cause sore throats, respiratory issues, eating marine life that stores these toxinsharmful/deadly
Archaea
Ancient organisms – fossils found that date back 3.8 billion years
Extremophiles – Found in extreme environments like hydrothermal vents and salt flats (two very extreme
environments)
Variety of metabolic types
Widely distributed in the marine community
They can tolerate wide ranges in temperature, salinity and even desiccation (drying out)
Unicellular Algae (Alga, sing.)
Eukaryotes-Protists (some animal-like/some plant-like)
Membrane bound organelles = “little organs”
Have a nucleus containing DNA
Unicellular
Cell Wall
silicon in diatoms; cellulose in dinoflagellates
Most photosynthetic
Often animal-like
Flagella
Some heterotrophic
Diatoms
Photosynthetic
Around half of the 12,000 known species are marine
Yellow-brown from photosynthetic pigments
Shell of silica
Most important primary producer on Earth
Oxygen. And Bottom of the food chain
Mostly solitary and unicellular, but some colonial
Used as filtration aid
mild abrasive in products including toothpaste
mechanical insecticide
absorbent for liquids
cat litter
Dinoflagellates
Most 1,200 species live in marine environment
Mostly photosynthetic, some can ingest particles
Each species has unique shape reinforced by plates of cellulose
Two flagella in grooves on body for motion
Some are bioluminescent, produce light
Zooxanthellae
The corals and algae have a mutualistic relationship.
The coral provides the algae with a protected environment and compounds they need for photosynthesis.
The algae produce oxygen and help the coral to remove wastes.
Most importantly, zooxanthellae supply the coral with glucose, product of photosynthesis.
The coral uses these products to make proteins, fats, and carbohydrates, and produce calcium carbonate
Dinoflagellates Symbiodinium sp.
live in a symbiotic relationship with corals, sea anemones and other organisms (many of these host
organisms have little or no growth without their symbiotic partner)
translocate products of photosynthesis to the host and in turn receive inorganic nutrients
Red tide
Karenia brevis
-Many microbes are beneficial, but others, can pose problems.
-This toxic dinoflagellate is linked to dangerous “red tide” outbreaks in the Gulf of Mexico.
Dinophysis: species like these are associated with diarrhetic shellfish poisoning.
Thalassionema
Hundreds of diatoms can fit on the head of a pin, but these tiny organisms exist in countless numbers—
enough to change seawater color during periodic population “blooms.”
Protozoans= “first animals”
Animal-like
Single cell
Heterotrophs, ingest food (Some photosynthetic)
Found everywhere in oceans
3 main types:
Foramaniferans, Radiolarians, Ciliates
Protozoa: Foraminiferans
Foraminiferans (forams)
Exclusively found in marine community
Found on sandy or rocky bottoms
Shells of calcium carbonate
Pseudopods (false feet) extend through pores in the shell where they are used to capture minute
food particles such as phytoplankton
Skeletons form sediment
Foraminifera skeletons can be important contributors of calcareous material on coral reefs or sandy beaches
Ex: Pink sand in Bermuda
Protozoa: Radiolarians
Planktonic, mostly microscopic
Shell of silica (glass)
Like forams, they use pseudopods that extend through pores in the shell where they are used to
capture minute food particles such as phytoplankton
Protozoa: Ciliates
Cilia present for locomotion
Hair-like projections
Most live as solitary cells
Some build shells made of organic debris
May live on hard substrate
Some are planktonic
Fungi
Eukaryotic
Mostly multicellular
Heterotrophic
Mostly decomposers
Most of the 1500 species of marine fungi are microscopic
On mangroves, seagrass, sponges, shellfish, fish parasites.
Fungi, lichen
Like bacteria, many fungus break down dead organic matter into detritus
Some fungus live in symbiosis with green algae, or cyanobacteria, these are known as lichens.
Marine lichens often live in wave-splashed areas of rocky shorelines and other hard substrate