phaeophyta and rhodophyta lecture 9: kelp habitats
TRANSCRIPT
Phaeophyta and Rhodophyta
Lecture 9: Kelp Habitats
Fan-Shaped Phylogenetic Tree
Algal pigments
Algal pigments
Pigment Molecules
Fucoxanthin Phycobilins
Accessory Pigments• “Chromatic adaptation”• Action spectra• Chlorophylls 440, 670nm)• Fucoxanthin (440-460nm)• Phycobilins –
phycoerythrin(540nm) & phycocyanin(620nm)
Div Phaeophyta
– Taxonomically maybe placed as a Class Phaeophyceae in Div Chromophyta/ Chrysophyta/ Heterokontophyta!!!
– Phaeophyta (brown) – 997 spp (almost exclusively marine.
– Chl a + c, B-carotene, fucoxanthin, neofucoxanthin, carotenoids
– Size: filamentous(mm) to kelps(m)– 14 Orders: e.g. Ectocarpales, Sporochnales,
Dicytotales, Fucales, Laminariales – Temperate, few tropicals
Sargassum Padina
Dictyota Laminaria
Div Rhodophyta
• Rhodophyta (red) – 4000-6000 spp• 97% are marine• No flagellae, pit connections (in Florideophyc)• Chl a, a + B-carotene, xanthophylls,
phycobiliproteins (red)• Filamentous (mm) to corticated (dm), crustose
(CaCO3)• 2 Classes (Dixon 1973): Bangiophyceae
(Porphyra) + Florideophyceae (Polysiphonia, Ceramium, Chondrus)
• Temperate and tropical.
CaloglossaLaurencia
Polysiphonia
FalkenbergiaKallymenia
Phaeophyte taxonomy
• Single class: Phaeophyceae. • Almost exclusively marine, only 5-6
genera FW.• Primarily temperate, some tropicals• Lithophytes – requires hard substrate• Sargassum are free-floating – Sargasso
sea• 14 Orders, e.g. Ectocarpales, Fucales,
Laminariales
Thallus organization
• Filamentous – Ectocarpus• Multiseriate filaments – Sphacelaria• Crustose - Ralfsia• Parenchymatous – Dictyota, Padina• Morphologically differentiate – Laminaria, Fucus
• Taxonomy based on reproductive structures and life cycles
THALLUS
SHEET
COARSLEY - BRANCHED
JOINTED -CALCAREOUS
THICK -LEATHERY
FILAMENT
ENCRUSTING
Macroalgae - Phaeophyta
ClassPhaeophyceae
taxonomy
Dawes, pg 135
Ectocarpus:Unilocular
vsPleurilocular
sporangia
Or. EctocarpalesEctocarpus Pilayella
Or. Sphacelariales
Sphacelaria
Or. Ralfsiales
Ralfsia verrucosa
Or. Dictyotales – 16 genera
Dictyota dichotoma
Dicytopteris sp – mid rib
Or. Dictyotales
Padina - calcified
Stypopodium – fish deterrant
Or. Dictyotales – Lobophora
Decumbent form
Crust form
Ruffled form
Grazing pressure
Or. Chordariales
Cladosiphon
Or. Sporochnales - GoM
S. apodus S. moorei S. radiciformis
Or. Desmarestiales
Desmarestia ligulata
Sulfuric acid
Or. ScytosiphonalesF. Chnoosporaceae F. Scytosiphonaceae
Scytosiphon lomentaria
Colpomenia sinuosa (sea corn-flakes)
Hydroclathrus
Or. Laminariales• “Kelps”• Northern hemisphere• 4 families:
– Chordaceae– Laminariaceae
(Laminaria, Agarum)– Lessoniaceae
(Macrocystis, Postelsia)– Alariaceae
(Alaria, Egragia)
http://seaweed.ucg.ie/Algae/laminaria.htmlLaminaria digitata
Or. Fucales
• Southern Hemisphere• Wrack or Rockweed• 4 Families
– Fucaceae (Fucus, Ascophyllum)
– Sargassaceae (Sargassum, Turbinaria)
– Cystoseiraceae– Hormosiraceae
(Hormosira)
http://seaweed.ucg.ie/Algae/fucus.html Fucus vesiculosis
Or. Fucales
• Southern Hemisphere• Wrack or Rockweed• 4 Families
– Fucaceae (Fucus, Ascophyllum)
– Sargassaceae (Sargassum, Turbinaria)
– Cystoseiraceae– Hormosiraceae
(Hormosira)
Turbinaria ornata
Sargassum
MS Phaeophyta (1957)
• Ectocarpales – Ectocarpus (6sp)
• Sphacelariales - Sphacelaria
• Dictyotales – Dictyota (2), Padina
• Fucales – Sargassum (3)
• about 13 species…
Rhodophyte taxonomy
Bangiophycidae1. Uninucleate cells
2. Single stellate, central plastid
3. Intercalary (diffuse) cell division
4. Absence of pit connections
5. Mostly asexual reproduction
6. Simple unicell – multicell thallus forms
7. 3 Orders
Florideophycidae1. multinucleate cells in many
species
2. Several to many discoid chloroplasts per cell
3. Cell division is atypical
4. Presence of pit plugs
5. Sexual reproduction common
6. Only multicell thalli
7. 9 Orders
Two subclasses: Bangiophycidae and Florideophycidae (Dawes 1998).
Rhodophyte taxonomy
Bangiophycidae1. Uninucleate cells
2. Single stellate, central plastid
3. Intercalary (diffuse) cell division
4. Absence of pit connections
5. Mostly asexual reproduction
6. Simple unicell – multicell thallus forms
7. 3 Orders
Florideophycidae1. multinucleate cells in many
species
2. Several to many discoid chloroplasts per cell
3. Cell division is atypical
4. Presence of pit plugs
5. Sexual reproduction common
6. Only multicell thalli
7. 9 Orders
Two subclasses: Bangiophycidae and Florideophycidae (Dawes 1998).
THALLUS
SHEET
COARSLEY - BRANCHED
JOINTED -CALCAREOUS
THICK -LEATHERY
FILAMENT
ENCRUSTING
Bangiophycidae
Thallus organization
• Unicellular - Porphyridium• Filamentous – Erythrocladia, Polysiphonia• Sheet-like – Porphyra• Branching – Laurencia, Gracilaria• Encrusting calcareous – Lithothamnion,
Melobesia• Jointed Calcareous – Amphiroa, Corallina
• Taxonomy based on morphology, reproductive structures, and life cycles
Macroalgae - Rhodophyta
Macroalgae - Rhodophyta
Subclass Florideophycidae taxonomy
Dawes, pg 153
Or. Palmariales
Palmaria palmata
Dulse
Or. Nemaliales – 4 Families
Liagora
Galaxaura
Scinaia
Or. Gelidiales – 2 Families
Gelidium
Gelidiella
Or. BonnemaisonialesAsparagopsis - gametophyte Falkenbergia - sporophyte
Or. Cryptonemiales – 12 Families
Cryptonemia Halymenia
Grateloupia
Or. Corallinales – 1 Family w 35 genera
Articulated (geniculate) Non-Articulated (encrusting)
Amphiroa
JaniaCorallina
Lithothamnion
PorolithonNeogoniolithon
Melobesia
Or. Gigartinales – 28 FamiliesHypnea
Eucheuma
Gracilaria
Kallymenia
Or. Rhodymeniales – 3 FamiliesChampia Botryocladia
Chrysymenia
Or. Ceramiales – 4 FamiliesCeramiaceae (100 genera)
Callithamnion
More Fam. CeramiaceaeCeramium
More Fam. CeramiaceaeCeramium
Ceramium
Or. Ceramiales – 4 FamiliesCeramiaceae (100 genera)
CallithamnionDelesseiraceae (90 genera)
CaloglossaDasyaceae (10 genera)
Dasya
Rhodomelaceae (125 genera) - Laurencia
Or. Ceramiales – 4 FamiliesCeramiaceae (100 genera)
CallithamnionDelesseiraceae (90 genera)
Caloglossa
Polysiphonousconstruction
Dasyaceae (10 genera)Dasya
Rhodomelaceae (125 genera) - Laurencia
Polysiphonia (Fam. Rhodomelac)
Macroalgae - Rhodophyta
MS Rhodophyta (1957)
• Nemalionales – Achrochaetium (2sp)• Gelidiales – Gelidium (2)• Cryptonemiales - Grateloupia• Corallinales – Fosliella (2)• Gigartinales – Gymnogongrus, Agardhiella,
Hypnea, Gracilaria• Ceramiales – Ceramium, Spyridia, Caloglossa,
Bostrichia (2), Chondria, Herposiphonia, Polysiphonia (3), Lophosiphonia
• about 24 species…
• Bangiales – Erythrotrichia, Goniotrichum
AlgaeBase.org
Seaweeds in your diet!
Cultivation of Red Algae– carragenans, agar
Eucheuma cultivation – Zanzibar, E. Africa
Kelps for algin (thickener)
•Used in over 300 products: ice cream, paints, sauces, and toothpaste •California/Oregon – heavily regulated• 8m/20ft wide swaths• 550 metric tons/day/ship• 700’000 metric tonnes p.a. in China alone!
http://www.starthrower.org/research/kelpmisc/kelp_mp.htm
• Kelps • Coral Reefs
http://life.bio.sunysb.edu/marinebio/kelpforest.html
KELP FORESTS
Kelp: Division Phaeophyta (Brown Algae)
Parts of a kelp• Leaflike blades • Gas-filled
pneumatocysts• Long hollow stem or
stipe• Rootlike holdfast to
attach to substrate• Complex life cycle
Kelp “life history”
Kelp alternates between a large sporophyte and a tiny gametophye
- sporophyte = “plant that makes spores” (diploid, 2N, large plant-like
stage)
- gametophyte = “plant that makes gametes”(haploid, 1N, small
inconspicous stage - can be a tiny thread)
http://www.mbari.org/staff/conn/botany/browns/james/Web/lifehis.htm
Kelp forest zonation
Kelp forests occur in cool water
The ecological role of kelp• Dampen wave action• Reduce coastal erosion• Enhance recruitment of fish
and invertebrates• High productivity and
turnover of plant matter puts • many nutrients into system• High structural diversity (like
a forest on land) • provides shelter and habitat
for many species• Habitat complexity created:
– - understory with filtered light
– - canopy at surface
Kelp forests come and go…
Kelp forests are deforested by natural causes
Salinity, temperature change, storms, seasons
Can recover fairly quickly under natural conditions
Sea urchins graze on kelp
Sea otters control urchin populations by eating them
The last of the otters• 150 years after excessive hunting, by late 1800s, only 3000 otters left• International Fur Treaty established in 1911: illegal to kill sea otters, even for
indigenous Alaskans
Otters repopulate• In 1980s, census conducted: 150,000 otters on earth, mostly in Alaska• 2000 otters found in California, population was thought to be extinct there
Sea otters give birth to 1 infant per pregnancy, 6 month gestationSea otters give birth to 1 infant per pregnancy, 6 month gestation
Kelp: alternate stable foodwebs“Keystone spp”
A new threat emerges
• In 1991, first killer whale attack on Alaskan otter is witnessed
Sequential overharvesting of marine mammals
• Killer whales may have switched to otters because their normal food (whales and seals) has become rare.
Kelp foodwebs and Alternate Stable States (A.S.S.)Killer
whales
A. S. S. - Kelps
Kelp dominated, many ottersNutrient poor, few urchins
Kelp dominated, few ottersNutrient poor, few urchins
Algal dominated, many ottersNutrients elevated, lots urchins
Algal dominated, few otters, Nutrient rich, lots urchins
Small disturbance,“Natural”
Large disturbance,“Unatural”, entire food wed has changed.
A. S. S. – Coral Reefs
Algal dominated, some fishNutrient poor, some urchins
Coral dominated, many fishNutrient poor, many urchins
Algal dominated, few fishNutrient rich, few urchins
Calc Red Algae dominated, some fishNutrient rich, many urchins
Urchin die-off & Over-fishing route
Eutrophication & Over fishing route
References• Dayton, PK, Tegner MJ, Edwards PB, et al Sliding baselines, ghosts, and reduced expectations in kelp forest communities
ECOL APPL 8 (2): 309-322 MAY 1998
• Estes, JA, Duggins, DO, Rathbun, GB. The ecology of extinctions in kelp forest communities. CONSERV BIOL 3 (3): 252-264 SEP 1989
• Jackson, JBC, Sala E Unnatural oceans SCI MAR 65: 273-281 Suppl. 2 SEP 2001
• Jackson, JBC, Kirby, MX, Berger, WH, et al. Historical overfishing and the recent collapse of coastal ecosystems SCIENCE 293 (5530): 629-638 JUL 27 2001
• Jackson, JBC What was natural in the coastal oceans? P NATL ACAD SCI USA 98 (10): 5411-5418 MAY 8 2001
• Simenstad CA, Estes JA, Kenyon KW. Aleuts, sea Otters, and alternate stable-state communities SCIENCE 200 (4340): 403-411 1978
• Steneck RS, Graham MH, Bourque BJ, et al. Kelp forest ecosystems: biodiversity, stability, resilience and future ENVIRON CONSERV 29 (4): 436-459 DEC 2002
• Tegner, MJ, Dayton, PK Sea-urchins, El-Ninos, and the long-term stability of southern California kelp forest communities MAR ECOL-PROG SER 77 (1): 49-63 OCT 1991
Summary• Kelps largest protists - to 70m long! • Kelp habitats – Brown canopy, Red
understory• Browns taxonomy by reproduction and life-
history• Reds taxonomy by morphology,
reproduction, and life-history• Human uses of Kelps and Red algae for
food additives.