bio 207 chapter 6: multicellular primary producers - seaweeds and plants

seaweeds

macrophyte or macro algae, show a ride range of growth forms and complexity of structures, lack true leaves, stems and roots

thallus

the complete body of an algae, could be filamentous, a thin leafy sheet or a giant kelp

blades

the leaf-like flattened portions of the thallus, the main photosynthetic regions

pneumatocysts

gas filled chambers along the blades, keep the blades near the surface and are filled with a mixture of gases including CO

stipe

a general stem-like structure for support, long and tough in large kelps

holdfast

a root-like structure that anchors an alga to a substrate, well developed in kelps, not involved in absorption of water or nutrients and anchor best to hard bottom substrate

Phylum Chlorophyta

green algae
multicellular species dominate salinity range environments
evolved into land plants

green algae characteristics

simple thallus
photosynthetic pigments: chlorophylls a and b, carotenoids (xanthophyll and carotene)
glucose: starch
cell walls: cellulose

Enteromorpha

filamentous, common on rocks in shallow water/rocky shore tide pools, thin thallus is a hollow tube, flourishes in polluted areas

Ulva

common sea lettuce, consists of paper-thin sheets, widespread from polar to tropical waters

Valonia

forms large spheres or clusters of spheres, only found in tropical and subtropical waters

Caulerpa

consists of thin filaments or tubes formed by a single giant cell with many nuclei, restricted to sub/tropics

Codium

dead man’s fingers, consists of multi-nucleated filaments woven into a spongy, branching thallus, tropical to temperate waters

Halimeda

calcareous green algae, consists of numerous segments of CaCO3 deposits, the accumulation of its dead, calcified segments play a role in the formation of coral reefs

Phylum Phaeophyta

brown algae
olive green to dark brown, yellow-brown pigments are more abundant than chlorophylls
dominant primary producers on temperature and polar rocky coasts
largest and structurally most complex seaweeds

brown algae characteristics

photosynthetic pigment: fucoxanthin (carotenoid)
glucose: laminarin
cell walls: algin

Ectocarpus

simplest brown algae, consists of a fine, filamentous thallus and widely distributed

Dictyota

thallus is flat and branched, sub/tropical

Padina

thallus is fan-shaped and lightly calcified, sub/tropical

Desmarestia

thallus that is branched in many ways, found in cold waters ranging from Antarctica to temperate shores

Fucus

found on the Atlantic and Pacific shores of North America and temperate shores, can have very visible pneumatocysts

Ascophyllum

the knotted seaweed, found along temperate North Atlantic coast of North America and Europe

Sargassum

the sargasso weed, spherical air bladders that keep small blades afloat, grown on rocks or float offshore in huge masses, common in Gulf of Mexico and California, Sargasso Sea

kelps

most complex and largest of all brown algae, found below tide level in temperate and subpolar latitudes, can occur in great abundance

kelp forest

provides food and shelter for many other organisms

Laminaria

large blades up to 3 meters, harvested for food, blades can be split or branched, many blades per holdfast

Postelsia

the sea palm, grows on intertidal rocks, exposed to heavy waves, occurs in thick clusters from central California to British Columbia

Macrocystis

giant kelp, largest kelp and world’s largest bottom dwelling organism's, holdfast anchored at depths of 25 m or more, several long stipes with elongated blades with a pneumatocyst at its base, can reach 100 m in length, grow 14 cm in a day

Phylum Rhodophyta

red algae
inhabit shallow water marine environments
harvested for food or extraction of select products
can be parasitic to other algal species
filamentous

red algae characteristics

photosynthetic pigment: phycobilins
glucose: Floridean starch
cell walls: agar

phycobilins

red pigments that mask chlorophyll

Porphyra

common on rocky shores above lowest tide mark, ranges from polar to tropical waters, used to make nori

Chondrus

Irish moss, common in North Atlantic, blades reach 1 m in length, tolerate wide ranges of temperature, salinity, light availability

Corallina

coralline red algae, deposits CaCO3 in cell walls, varies from light red to intense reddish-pink, warm water species involved in coral reef formation

fragmentation

algal asexual reproduction, pieces of thalli can break away and become new individuals, some species produce spores

zoospores

flagellated spores

sexual reproduction

varies greatly, always involves meiosis and fertilization, produces genetic variation within a species, 4 possible cycles

phycocolloids

gelatinous chemicals used in food processing and in the manufacture of different products

algin

from brown algae

algin uses

stabilizer and emulsifier in ice cream and cheese, frosting to prevent drying, shampoo, shaving creams, rubber, paper, paint and cosmetics

carrageenan

from red algae

carrageenan uses

emulsifier, gives body to dairy products and other processed foods, instant puddings

agar

from red algae

agar uses

adds jelly-like quality to canning of ham, fish and meats, laxatives and cosmetics, solidifying medium to culture bacteria

flowering plants

true leaves, stems and roots, reproduction involves dominant sporophyte to produce flowers, sea grasses are truly marine

sea grasses

submerged and rarely exposed at low tides, not related to grass, small flowers, pollen released in water

rhizomes

horizontal stems in sea grass that grows beneath sediment, possess roots and erect stems

Zostera

eelgrass, temperate to tropical regions, shallow coastal waters of bays and estuaries, oxygen poor sediments

salt marsh plants

cordgrasses, true grasses, land dwelling and adapted to salinity, live in soft bottoms coastal regions, protect against erosion, water purification systems, Spartina alterniflora

mangroves

trees and shrubs adapted to live along sub/tropical shores, varying salinity, flourish in muddy/sandy shores protected from wave action

mangals

mangrove forests

Rhizophora mangle

red mangrove, thick leaves to reduce water loss, seedlings germinate on parent plant