Seaweed and Plants:

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Seaweed and Plants Multicellular Primary
Producers
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Types of Algae Classes

• Chlorophyta Green
• Phaeophyta Brown
• Rhodophyta Red

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Seaweeds

• Seaweeds are another class of primary producers.
• Techincally they are not weeds, but algae.
• Most biologists agree that macrophyte is a much
  better name.
• Some also call them macroalgae.

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Seaweeds Green algae

• Have the same pigments
• as land plants (chlorophyll)
• More than 7,000 species
• Marine algae are macro
• Alteration of generations

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Thalus
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• Filamentus algae such as Ulva forms paper thin
  sheets.

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• Dead mans fingers, Codium fragile and
  several spp. of
• Culerpa are know for there tube-like
  structures.

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Phaeophyta

• Largest (size) and most complex of the algae
• Nearly all are marine (1500 spp.)
• Brown color comes from accessory pigments
  (fucoxanthin)

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• Fucus sprialis a common brown algae can be found
  on
• rocky shores. Unlike other algae in this
  category, its thallus
• lacks gas bladders.

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• Knotted rockweed, Ascophyllum nodosum, is
  common to
• N. America and Europe.

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Kelps!

• Kelps are the largest seaweek we encounter in the
  ocean. They are also the most complex.
• Due to this large size, many of the kelps are
  harvested for food!
• Who knows where we will find seaweed next?

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Sea plam (Postelsia palmaeformis)
containsinternal support structures that help
them withstand wave action! Its also eated on a
regular basis as sea noodles.
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Macrocystis pyrifera, the largest of the kelps
anchors itself to the sea floor by use a massive
holdfast. Here we can see not only the large
blades, but the extensive pneumatocysts used for
buoyancy.Rem Pneumatocystsdeveloped as a
means to maximize energyproduction through
photosynthesis by keeping the seaweedclose to
the surface.
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These kelp obtain huge proportions growing as
much as 0.5m/day!These when large kelp group
together a kelp forest is develops.Kelp forest
are great for shelteringall sorts of marine
life, including Garabaldi, scallops, seals and
sharks.They also provide an oportunity for
selective harvesting of the upper sections of
the blades for food.
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Members of the species Rhodophyta red algae,
are more numerous than the green and brown
algae combined.

• Although many red algae are in fact
• red due to the prescence of red
• pigments known as phycobilins,
• which mask chlorophyll, these algae
• may display an even greater intensity
• when exposed to sunlight!
• Nearly 4,000 species exist and many are
• used for food or other specialty products.

Porphya, a red algae
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Corallina, a coralline algae, deposits CaCO3
within its cell walls which provides structural
support and often encrusting many surrounding
surfaces.
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Sexual Reproduction, or not

• Sexual reproduction is expensive both
  energetically and physiologically.
• Sometimes its better to reproduce by asexual
  means from fragments, spores, or buds.
• Sometimes algae use both sexual and asexual
  reproduction depending on environmental
  conditions.

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Products from Seaweed
Phycocolloidsform gels and increase viscosity of
liquids Alginstabilizer in ice cream
(Macrocystis) Carageenanemulsifier (Irish Moss,
Chondrus) Agarjellies (and of course all your
plates in microbiology, Gelidium,
Pterocladiella)
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Seagrasses (lillies) reproduce through rhizomes,
or horizontal stems which grow beneath the
sediment.
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Mangroves
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Mangroves

• Mangroves thrive in salty environments and are
  able to obtain freshwater from saltwater.
• Some spp. secrete excess salt through their
  leaves while other block absorption of salt at
  their roots.

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Magrove Impacts

• At one time, nearly 0.5 million acres of magroves
  surrounded Floridas coastal zone contributing to
  ecosystem health in a variety of ways.
• -Trap and cycle organics, chemical elements,
  sediment and minerals.
• -Provide shelter for marine organisms.

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Plate 9. Black Mangrove, Avecennia germinans.
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Plate 8. Red Mangrove, Rhizophora mangle.
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Red Mangrove
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Plate 10. White Mangrove, Laguncularia racemosa.