phaeophyta and rhodophyta lecture 9: kelp habitats

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.