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Chapter 5- The Microbial World

• Bacteria• Unicellular algae• Protists• The Microbial Loop

Picoplankton

Nanoplankton

Microplankton

Mesoplankton

Macroplankton

Megaplankton

Fill in the blank…

A. FemtoplanktonB. MesoplanktonC. NanoplanktonD. Microplankton

A

Primary Productivity

• 6CO2 + 6H2O = C6H12O6 + 6O2

• With rare (relatively) exceptions, all energy comes into the system via this pathway.

• Gross PP – respiration = Net Production• Many different measurement techniques for

PP

Global Net PP

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Limiting Factors

• Light (irradiance or intensity)- graph

• Mixing- good and bad…

• Nutrient availability• Grazing- fast growth vs. fast food

Two Main Classes of Cells

• Prokaryotic (Bacteria and Archaea)– Pro = “Before”; Karyon = “Kernel”– No nucleus, DNA coiled up inside cell

• Eukaryotic (Everything else)– Eu = “True”– DNA inside membrane bound organelle inside

cell, the nucleus

3 DomainTaxonomy of life Eukaryotic Cell (non bacterial)

Prokaryotic Cell (bacteria)

Major Groups of Phytoplankton

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Why are they* all small?* Planktonic producers

Kelp Paddies

SargassumSargassum

The Microbial Web

Net Phytoplankton

Net Zooplankton

Nekton

DissolvedOrganic Matter(DOM)

Nano and Pico Phytoplankton

ProtozoanGrazers

Heterotrophic Bacteria

OLD NEW

Prokaryotes

• Domain Eubacteria and Archaea• “Bacteria” important in PP, as well as in

decay/recycling of nutrients ProchlorococcusProchlorococcus(0.7 microns)(0.7 microns)

Possibly they are also the most plentiful species on Earth: a single ml of surface seawater may contain 1.000,000 cells or more. Worldwide, there are estimated to be 100 octillion individuals… 1029

“Blue-green algae” orCyanobacteria

• Some of the first life on Earth• Important nitrogen fixers in

the marine system• Heterocysts

Their other BIG claim to fame?

The Microbial Web

Net Phytoplankton

Net Zooplankton

Nekton

DissolvedOrganic Matter(DOM)

Nano and Pico Phytoplankton

ProtozoanGrazers

Heterotrophic Bacteria

OLD NEW

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Diatoms- class Bacillariophyta

• Unicellular• Centric and Pennate• Shell (Frustule) walls made of

Silica (SiO2)– Epitheca and hypotheca

• Reproduction (asexual and sexual)

• Auxospores• Diatomaceous/Siliceous Ooze

Diatom Reproduction I am going:

A. Too s l o wB. Just rightC. Too fast

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Dinoflagellata

• Two flagella, often cell has cellulose armored plates

• Cingulum and Sulcus

• Both photosyn. and not

• Zooxanthellae

Swimming with bioluminescent dinoflagellates

CoccolithophoresCalcium Carbonate

White Cliffs of Dover

Diatoms are made of:

A. Calcium CarbonateB. CaCO3

C. Silica DioxideD. Cellulose

The Microbial Web

Net Phytoplankton

Net Zooplankton

Nekton

DissolvedOrganic Matter(DOM)

Nano and Pico Phytoplankton

ProtozoanGrazers

Heterotrophic Bacteria

OLD NEW “Protistan” plankton

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Foraminiferans and Radiolarians• Shell (test) of calcium

carbonate (CaCO3)• Feed with pseudopods• Foraminiferan ooze

• Glass tests (Silica) plus others

• Pseudopods• Radiolarian ooze

(deep water)

Chapter 6The Macroscopic Algae

General Environment

• Waves, currents, tides, upwelling all create turbulence which greatly affects the physical environment

• Little Stratification-Uniformly high nutrients.• In shallow waters, wave/swell action impacts

the bottom flora and Fauna• Four main types of shallow-water benthos

- Unvegetated sedimentary - Hard substrate- Kelp forest - Seagrass beds

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Food webs in So. Cal. Kelp Forest The Macroscopic Algae

• Plant evolution begins in the sea• Single celled Multicelled colonies

– But still have very little specialization between cells

• Three divisions of algae- all can be seen in tide pools

– Rhodophyta- Red Algae– Phaeophyta- Brown Algae– Chlorophyta- Green Algae

The 3 groups of Algae

• Rhodophyta- Red Algae– Chl. a, other accessory

pigments, storage is Floridean starch

• Phaeophyta- Brown Algae– Chl. a & c, other pigments,

storage is Laminarin• Chlorophyta- Green Algae

– Chl. a & b, other pigments, storage is Starch

“Typical” Algae structure

(Pneumatocyst)

Algae structureBlade: which of these is algae?

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Algae structurePneumatocysts:N2, O2, and Co2 gasSingular and large, or small and many

Algae structureStipe:Flexible and strong (in some ways) Some with conductive tissues which move photosynthatedown to lower parts

Phaeophyta and the Evolutionary Adaptations of Seaweeds to a Physically

Stressful Environment• Multicellular with a minor degree of

specialization• Structural adaptations of thallus:

holdfast, stipe, blades, gas bladders (pneumatocysts)

• Chemical adaptations:– Cellulose walls w/ polysaccharides– may incorporate calcium carbonate

• 3 Reproductive Cycles: Haplontic(zygotic), Diplontic (gametic) or Alternation of Generations (diplohaplontic,sporic cycle)

Phaeophyta

• largest and most complex• chlorophyll a, c,

carotinoids and fucoxanthin, homology to diatoms and golden algae

• Flagellated spores• storage is laminarin• cell wall= cellulose and

algin• heteromorphic

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Kelp Beds and Forests

• Found in cold, temperate regions only.• Large brown algae= kelp.• Kelps obtain nutrients from water, so

depend on turbulence to renew waters to avoid depletion.

• Form extensive 3-D habitat with several vertical layers= High species diversity

Kelp Harvesting

Rhodophyta: distant relatives to Phaeophyta…a separate kingdom?

• No flagellated stage• mostly marine, tropical• Chlorophyll a, carotinoids,

phycobilins (phycoerythrin)– Primary endosymbiosis

• storage = floridean starch• cell walls are cellulose with agar

and carageenan• Broad coastal distribution• Alternation of generations is

common, rely on water currents

Chlorophyta: share a common ancestor with terrestrial plants

• Cyanobacteria and primary endosymbiotic theory…Chlorophyll a, b, carotinoids,

• Marine, FW, soil, freeliving and symbiotic

• Diverse body plans, colonial, multicellular

• storage=starch• cell wall = cellulose• Ulva: isomorphic alt of gen

– Biflagellated gametes– conjugation

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Epibionts Islands in the stream

• Numerous single-celled and colonial diatoms and other algae use large macroscopic algae as a home

• Floating Sargassum are true macroscopic pelagic seaweeds…why are there not more who use this strategy?

• Kelp Rafts- Natural FADs

Life cycles of most algae

• 2 multicellular phases- Alternation of Generation

• 2n n 2n n….etc.• Sporophyte and Gametophyte• One phase may be dominant in structure• Examples…

Alternation of generations: a generalized scheme

The life cycle of Laminaria: an example of alternation of generations

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