Marine Producers (Ch.7)
part 2
• Seaweeds
• Seagrasses & other
marine flowering plants
3 Types of Seaweed
• Phylum Chlorophyta (greens)
• Phylum Rhodophyta (reds)
• Phylum Phaeophyta (browns)
• Largely distinguished based on ________
(pigments, cell wall comp, and food reserves)
Seaweed distribution
• Governed by environmental factors:
– _____
– __________
– Duration of tidal exposure
– Wave action
– Salinity
– Availability of mineral nutrients
Seaweed reproduction
• ___________________
Chlorophyta: Green Algae
• Class Ulvophyceae (green seaweeds)
• 1100 spp (13% of green algae)
• Provides seasonal source of food for
marine animals
• Help form coral reefs
• High growth response in nutrient-polluted
waters
• Part of “__________” = live on docks,
wharf pilings, hulls of boats etc.
Chlorophyta: Green Algae
Common local greens:
Chlorophyta: Green Algae
• Role in: ____________
• Halimeda (calcareous)
• Deposits of > 50m depth in GBR!
Rhodophyta: Red Algae
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Whole phyla are mainly marine
98% of 6000 sp are marine
___________________________
Mostly benthic
Survive at greatest depths (____m)
Multicellular and small structure
Often branched, delicate
Can form turfs (on rocks or sediments)
Rhodophyta: Red Algae
Rhodophyta: Red Algae
• Ecological role: sometimes “_______”=
grow on other algae or plants
• Commercial use:
– Stiffening/gelling agents in cell walls
• ____ – used in labs as culture medium
– Also used as thickening agent in
pharmaceuticals and foods
• __________ – ice cream, salad dressings,
cosmetics
Phaeophyta: Brown Algae
• Multicellular (Stramenopiles)
• 1500 spp are almost all marine
• More diverse than greens, but less than
reds
• Mostly benthic
• ____________ (microscopic to giant kelps
of 100m)
Phaeophyta: Brown Algae
Phaeophyta: Brown Algae
• _________ = gas-filled
structures on larger
brown algae that help
to buoy the blades
closer to sunlight
• Fucus (rockweed) – a
common local intertidal
species
Marine Flowering Plants
Kingdom Plantae:
• Phylum ________ (flowering plants)
– Marine habitats defined by their dominant
plants:
• Seagrass Beds
• Salt Marshes
• Mangrove Forests
Seagrass beds
• Hydrophytes = live beneath water
• 66 spp (only 0.02% of all flowering plants)
Local families:
• Eelgrasses (Zostera)
• Surfgrasses
(Phyllospadix)
Ecological Role of Seagrasses
• Habitat – nursery for young fish and
inverts
• Stabilizes sediments – reduces ________
• Mitigates wave action
• Absorbs metals and other pollutants
• Primary producers
• Food for many inverts, birds, mammals
Impact of Dugong grazing on
seagrasses
Salt marshes
• _______ only! Must be exposed to air to
flourish
• Mainly _______
• Biological filters for runoff
• Store water – prevent flooding
• Provide habitat; feeding & nesting grounds
• Found in river deltas, estuaries, shores of
lagoons and bays
Salt marshes
Mangrove Forests
• Tropical equivalent to salt marsh
• Have more __________ (not grasses and
herbs)
• Very little is submerged by tide
• Red and Black Mangroves have roots that
descend to or rise from sediments
• Thrive along protected tropical shores:
– Low wave action, high salinity, anoxic
sediments such as in _________
Mangrove Forests