Transcript ENVI 30 Environmental Issues

I.
Kelp Forests
Dominated by brown algae
Found in shallow open coastal settings
where water temperature usually <20 oC
Bottom depth typically <20 m
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Light readily available
Highly productive, diverse ecosystems
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Productivity related to fast kelp growth rates
Fig. 16-7
Pacific Fig. 16-8
Atlantic Fig. 16-9
I.
Kelp Forests
Atlantic
Pacific
Grazers
Urchins
Suspension
Feeders
Mussels
Urchins,
Abalones,
Limpets
Mussels
Predators
Maine
Lobsters
Sea Otters
I.
Kelp Forests
A.
Factors Affecting Kelp Forests
1.
2.
vanaqua.org
Intensity and frequency of winter storms
Presence/Absence of urchin predators (sea
otters/lobsters)
Abundance and behavior of herbivores
Winter storms can rip kelps from their holdfasts
After severe storms, portions of sea floor may be stripped
of kelp
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Urchins deprived of preferred foods (mature kelp or drift
algae) may increase mobility and eat newly recruited kelps
Grazing may prevent kelps from re-growing
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Leads to establishment of more resistant coralline algae
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Leads to urchin barrens
Fig. 16-14
hopkins.stanford.edu
I.
Kelp Forests
B.
Kelp Forest Ecology
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Sea otters/Lobsters important top-down
regulators of community structure
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Prey on important grazers like urchins (Pac/Atl) and
abalones (Pac)
Urchins, abalones, other herbivores graze on
attached seaweeds, drift kelp
Urchin populations can have a major impact on
community composition
Fig. 16-11
Fig. 16-15
II.
Plants
A.
Bryophytes
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Non-vascular plants
Dominant gametophyte
Marchantiophyta (liverworts)
Anthocerotophyta (hornworts)
Bryophyta (mosses)
bio1151.nicerweb.com
II.
Plants
B.
Pteridophytes
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Vascular plants
sierrapotomac.org
Dominant sporophyte
Lycopodiophyta (club mosses)
Pteridophyta (ferns, whisk ferns, horsetails)
malag.aes.oregonstate.edu
II.
Plants
C.
Seed Plants
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Vascular plants
Dominant sporophyte
Cycadophyta (sago palms)
Ginkgophyta (ginkgo)
Pinophyta (conifers)
Gnetophyta (gnetales)
5.
Anthophyta/Magnoliophyta (flowering plants)**
cycads
southafrica.net
ginkgo
ucmp.berkeley.edu
Welwitschia
biolib.cz
conifers
frogsonice.com
II.
Flowering Plants (Anthophyta)
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True roots, stems, leaves
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Roots
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Stems
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Elevate and separate leaves
Elevate reproductive structures
Nodes, internodes
Leaves
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Mechanical anchors
Absorb water, minerals
Often with root hairs (increase surface area for absorption)
May store carbohydrates
Main photosynthetic organ
Blade, petiole, veins
Specialized vascular tissues that transport water,
minerals, nutrients
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Xylem – Water
Phloem – Minerals, nutrients
thomson.fosterscience.com
parenchyma
collenchyma
sclerenchyma
micro.magnet.fsu.edu
II.
Flowering Plants (Anthophyta)
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Monocots vs. dicots
holganix.com