SeaweedsMarineMacroAlgae Flashcards
Seaweeds are ancestors of what? How old are they? What Kingdom are they?
- Ancestors of Land Plants
- Green Algae is 700-800mya
- Kingdom Plantae (and Protista)
Historically, what were seaweeds referred to?
Marine Plants
How many species of seaweed have been identified, and where are they most prominent?
- over 7000 species
- Temperate waters
Physical form of most seaweeds
- Benthic, attach to rock (one exception)
- Diverse physical forms
- Some have gas bladders for flotation and keep posture erect
- Hydroskeletons
Colloid polysaccharides provide what for seaweeds?
- flexible hydroskeleton
How much do seaweeds contribute to ocean primary productivity?
2-10%
How do seaweeds absorb nutrients?
- through cell wall over entire surface
What are the 3 major groups of seaweed? And what is the most obvious distinction?
- Green, Red, Brown
- Visible distinction in pigments
Division Chlorophyta, and where common, and form
- Green algae
- Vivid green colour from chlorophylls
- Only 10% species are marine, common in estuaries, low salinity
- Very thin forms, 1-2 cell layers thick
Division Phaeophyta , and where common and form
- Brown Algae (tan-brown)
- Kingdom Protista
- Brown pigment fucoxanthin
- Large seaweeds of temperate waters
- Kelps
- Usually perennial
Kelps: how big can they get, what kind of algae, and name a species?
- Often brown algae
- Can form entire marine habitats, like forests
- Giant kelp, Macrocystis can grow down to 40m, up to 1m/day
Division Rhodophyta, pigments, distribution, form
- Red Algae (red-purplish colours)
- Phycoerythrin (red)
- Phycocyanin (blueish)
- Most numerous seaweed, wide distribution to warmer waters and greater depth
- Mostly blades, and small fine forms, some rigid calcified forms
Seaweed life cycle
- Complex with alternation of generations with different reproductive phases
Accessory pigments and light filtration
- Not chlorophyll
- Absorb different wavelengths of light to transfer to photosynthetic system
- Light filtered out by water, longer wavelengths first
- Can show distinct growth zonation in depth of water
- More distinct where light is limiting
Main human uses of seaweed
- Food
- Carageenan, agar
- Animal feed
Seaweed as food
- Dulse in East coast Canada, a red algae
- Kelps common in China, Japan, Korea, as nori, Porphyra, a red
- Porphyra also harvest by local FN
- Historically important in Asia for inland populations as a dietary source of iodine
What important dietary feature makes seaweed consumption important for inland populations of Asia?
- Iodine
Porphyra
- Red algae
- Important food source in Asia and for FN
Colloid polysaccharides
- Alginic acid, carrageenan, agar
- Colloid keeps molecules in fluid in suspension
Alginic acid
- From kelps
- Used as a thickening agent in food and other products
Carageenan
- From red algae
- Emulsifier, gelling agent in creamy texture foods and cosmetics
- Ice cream, chocolate milk, yogurt, pudding, toothpaste
Agar
- From red algae
- Polysaccharides
- Gelling agent in laboratory research
- Make culture medium gels for bacteria, fungi, plants
- Agarose gels for DNA mapping
Shortage of Agar
- Currently supply is short
- Cannot be replaced synthetically
- Cannot be cultivated in large scale at present time
- Biotechnology is dependent on some types of seaweeds!
Seaweed in cow feed does what?
- Reduces methane emission almost entirely
Methane and cows
- Methane significant green-house gas
- Cow releases btwn 70-120kgs/year through burping
- Estimate 1.3-1.5 billion cows in the world
How was seaweed identified as a benefit to cow diet?
- Prince Edward Island dairy farmer noticed cows grazing on washed-up seaweeds were healthier and more productive
Australian study in 2015 showed that what kind of seaweed was particularly effective in cow diet?
- Red Alga, Asparagopsis
- With production of bromoform which interferes with rumen enzymes
