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Division: Rhodophyta

Part II

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- advanced reds

- always multicellular: filaments or psuedoparenchymatous

-marine, freshwater

-almost always multinucleate

-many discoid chloroplasts

-primary and secondary pit plugs

- triphasic life history

Division: Rhodophyta- 6504 species Class: Florideophycidae-6199 species

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3 2N tetrasporophyte

1N gametophytes

mitosis

2N carposporophyte on 1N female gametophyte

growth

2N

1N

1N

2N

1N Carpogonium on a carpogonial branch

Multiple 2N carpospores produced through mitosis in gominoblast filaments

2N carpospores

meiosis

1N tetraspores

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Connecting filament or Ooblast filament = tube that carries the zygote nucleus from fertilized egg to internal auxiliary cell where it is cloned and differentiates into carpospores (in some Orders!)

Auxiliary cell = vegetative cell (N) that receives the 2N zygote nucleus after fertilization (in some Orders!)

Gonimoblast = 2N filaments bearing carposporangia in the carposporophyte (ALL Florideophyceans have this)

Triphasic Life Histories :Terminology

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Post- fertilization Events Distinguishing between Orders of Florideophycidae

Auxiliary cell absent Gominoblast initiated from carpogonium Auxiliary cell present

Ooblast filament transfers zygote nucleus to auxiliary cell Gominoblast initiated from auxiliary cell

Auxiliary cell present Auxiliary branch & carpogonial branch arise from same supporting cell Gominoblast initiated from a fused carpogonium & auxiliary cell

cp

oo

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Division: Rhodophyta- 6504 species 3.Class: Florideophycidae-6199 species Order: 29 orders but we will focus on 5 1. Nemaliales -255 species 2. Rhodomeniales-357 species 3. Ceramiales- 2478 species 4. Gigartinales- 806 species 5. Corallinales- 649 species

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1.Order: Nemaliales Auxiliary cell absent Gominoblasts initiated from carpogonium Pit plugs characterized by 2 cap layers

Carpogonial branch

Carpogonium

Tricogyne

Spermatium

1N female gametophyte

2N carpospores on gonimoblast filaments

2N carposporophyte on 1N female gametophyte

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- cylindrical with branchlets - multiaxial - saxicolous - intertidal

3.Class: Florideophycidae 1.Order Nemaliales Genus: Cumagloia

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2.Order: Rhodymeniales Auxiliary cell formed before fertilization Auxiliary branch & carpogonial branch arise from same supporting cell Gominoblast initiated from a fused carpogonium & auxiliary cell

S A S

Carpogonium

Supporting Cell

Auxiliary Cell

Carpogonial branch

2N carpospores on gonimoblast filaments

Spermatium

1N female gametophyte 2N carposporophyte on 1N female gametophyte

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-Subtidal, saxicolous - Associated with juvenile fish - Dichotomous branching - Multiaxial

3.Class: Florideophycidae 2. OrderRhodomeniales Genus: Rhodomenia

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-Subtidal, saxicolous - Mucus-filled sacs - Multiaxial - “sea grapes”

3.Class: Florideophycidae 2. OrderRhodomeniales Genus: Botryocladia

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3.Order: Ceramiales

S S A S A

After fertilization

Auxiliary cell develops from supporting cell of carpogonial branch after fertilization Ooblast filament forms between carpogonium & auxiliary cell Gominoblast initiated from axiliary cell

2N carposporophyte on 1N female gametophyte

1N female gametophyte

Supporting cell

Carpogonium

Tricogyne

Carpogonial Branch

Spermatium

Ooblast filament trasfers

zygote nucleus

2N carpospores on gonimoblast filaments

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- Prominent trichoblasts which leave scars after they fall off. - Number of pericentral cells helps to identify to species - Polysiphonous

3.Class: Florideophycidae 3. Order Ceramiales Genus Polysiphonia

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- saxicolous or ephiphytic -fully or partially corticated - uniaxial

3.Class: Florideophycidae 3. Order Ceramiales Genus Ceramium

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- saxicolous or epiphytic - fully corticated - distichous - uniaxial

alternate

pectinate

3.Class: Florideophycidae 3. Order Ceramiales Genus Microcladia

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4.Order: Gigartinales (former Cryptonemiales)

Auxiliary cell present BEFORE fertilization but on a distant branch Ooblast filament transfers zygote nucleus to auxiliary cell Gominoblast initiated from auxiliary cell

A

2N carposporophyte on 1N female gametophyte 1N female gametophyte

A Supporting Cell

Auxiliary Cell

Spermatium

Ooblast filament trasfers

zygote nucleus

2N carpospores on gonimoblast filaments

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Common local species: •M. flaccida – yellow/green; mid to upper intertidal •M. splendens – red/purple; low intertidal Iridescence • Proteinaceous cuticle • Multiple layers • Alternating opaque and translucent layers • Layering produces light interference patterns that give iridescent appearance when submerged • Adaptive advantage unknown

3.Class: Florideophycidae-6199 species 4. Order Gigartinales- 806 species Genera Mazzaella

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Gametophyte Carposporophyte TetrasporophyteGametophyte Carposporophyte Tetrasporophyte

- multiaxial - filamentous medulla

3.Class: Florideophycidae-6199 species 4. Order Gigartinales- 806 species Genera Mazzaella

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19 2N tetrasporophyte

1N gametophytes

2N carposporophytes on female gametophyte

3.Class: Florideophycidae-6199 species 4. Order Gigartinales- 806 species Genus Mastocarpus species complex

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- multiaxial - filamentous medulla - smells like chlorine (antiherbivory) - often has epiphytes

3.Class: Florideophycidae-6199 species 4. Order Gigartinales- 806 species Genus Prionitis

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- uniaxial - thallus covered with bumps (antiherbivory) - very high intertidal - saxicolous - can facilitate recruitment of other algae (Fucoids)

3.Class: Florideophycidae-6199 species 4. Order Gigartinales- 806 species Genus Endocladia

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Division: Rhodophyta- 6504 species 5. Order Corallinales- 649 species

• Cell walls impregnated with CaCO3 • Isomorphic alternation of generation • Reproductive structures in conceptacles • Ecological importance: stabilize reefs, induce invert settlement

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How do coralline algae become calcified?

• Sequestering of Calcium ions from the water column, synthesis of calcium carbonate (CaC03) in cell wall

• Synthesis of calcium carbonate(precipitation) requires a high pH

• High rates of photosynthesis correlated with high rates of calcification

• Calcification 2-3x faster in light than dark

• Highest in young tissue

•Photosynthesis may raise the pH immediately outside a cell

What is known:

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Coralline Algae and Global Warming

• Global warming likely to lead to a lower in pH (raise in acidity of the world’s oceans

• Acidic environment is bad for calcification process big (complicated) trouble for calcified critters and algae!!

• Lots of current research on this

CO2 + H20 H2C03 HCO3 + H+ CO3 + H+

more acidic more basic

Carbon reaction in seawater:

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Carbonic acid Bicarbonate Carbonate

Increasing CO2

pushes RXN in this

direction

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Order: Corallinales (used to part of Cryptonemiales) Supporting cell acts as an auxiliary cell Carpogonial branches located in conceptacles Gominoblast initiated from a fusion of cells in carpogonial branch

2N carposporophyte on 1N female gametophyte

1N female gametophyte

2N carpospores on gonimoblast filaments

Supporting Cell

Carpogonial Branch Tricogyne

Carpogonium

Spermatium

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Geniculate corallines

• upright •articulated

Non-geniculate corallines

Crustose or Unattached Encrusting Branching

Geniculum (flexible joint) Intergeniculum (hard part between genicula)

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- Common intertidally - Conceptacles on tips -Finely branched, more so than Bossiella or Calliarthron - Intergenicula are thin and tubular and smaller than those on Bossiella or Calliarthron

3.Class: Florideophycidae-6199 species 5. Order Corallinales- 649 species Genera Corallina

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- Common intertidaly - Intergenicula typically “heart-shaped” - Conceptacles in pairs on the face of a segment, not margins - Intergenicula are larger than Corallina

3.Class: Florideophycidae-6199 species 5. Order Corallinales- 649 species Genus Bossiella

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-Common intertidally

-Intergenicula typically “wingnut-shaped”

- Conceptacles mainly on margins of segments - Calcareous sections are larger than Corallina

3.Class: Florideophycidae-6199 species 5. Order Corallinales- 649 species Genus Caliarthron

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• rhodolith •unattached • free-living • non- geniculate form • biogenic habitat for lots of inverts!

3.Class: Florideophycidae-6199 species 5. Order Corallinales- 649 species Genus Lithothamnion

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Foster 2001

Rhodolith Beds

New Report

World Rhodolith Distribution

Distributional Limits

•Depth -light limited in deep, dessicated in shallows

•Water motion-need intermediate amount of hydraulic energy

•Sedimentation -smothered by fine sediments

‘reduced’ size, cover

sand ‘intact’ rhodolith

bed

low high

buried by siltation

DISTURBANCE

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Biogenic Ecosystems – Foundation Species

Kelp Forests

Seagrass Meadows Rhodolith Beds

Coral Reefs

Rhodolith beds, reefs that rock and roll

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What are other important features of rhodolith beds?

Form complex habitat for a variety of orgamisms

Cover extensive ares of the seafloor, globally distributed

Cryptofauna/Infauna Epifauna/Epiflora

• hard bottom species

• soft bottom species

Rhodolith Bed Community

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Seasonal Macroalgal Species

Scinaia confusa

Kallymenia pertursa

Halymenia hollenbergii

Sporochnus bolleanus

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New

growth

Growth Rate

L. muellerii 0.6 mm/yr

L. margaritae 5.6 mm/yr

S. trichotomum 7-8 mm/yr

Catalina rhodoliths

1.6 mm/yr

Internal Banding

0

5

10

15

20

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Lo

ng

itu

d (

mm

)

0 20 40 60 80 100

Número de bandas

Lcal= 1.62 + 0.27 (X)

r2= 0.86

P=0.000

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Coralline algae as global palaeothermometers

Lithothamnion glaciale Kamenos et al. 2008

Banding reflects sea surface temperature

signal using SrCO3 and MgCO3

They are found

in Pleistocene

and Pleiocene

fossil deposits

Baja California

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auxiliary cell?

Yes No

Ooblast? Yes. Gigartinales – Auxiliary cell is anywhere in thallus No. Rhodymeniales – Fusion with carpegonium

Before After

Ceramiales – (has ooblast)

Nemaliales – Gonimoblasts from carpegonium

Corallinales – Fusion of carpegonium with carpegonial branch * Supporting cell acts as auxiliary cell

Post-fertilization in a nutshell