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Primary Production OCN201 Fall 2008
Zackary Johnson Department of Oceanography http://www.soest.hawaii.edu/oceanography/zij/education/ocn201
• Molecular evidence (i.e. DNA sequence) suggests that phylogenies are not always hierarchical • There are mechanisms that account for this (sex, viruses, random upp/take/incor poration of DNA) • Complicated!
William 1999
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• Molecular evidence suggests genomes have fused and have resulted in different life stages
Williamson and Vickers American Scientist Nov/Dec 2007
Major Concepts
9 Primary production is the first link in converting “environmental” energy to biological energy 9 Oceanic primary production is dominated by single celled “plants” called phytoplankton 9 Phytoplankton are exceptionally diverse 9 Primary production is typically limited by light or nutrients
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What is primary production?
Primary = first, initial PdProducti on = ffiormation / creation of something
Primary production = the first conversion of energy from the environment into “biological” energy
What types of organisms are primary producers in the ocean?
What is primary production?
Photosynthesizers (plants): use sunlight energy to convert carbon dioxide into simple sugars
H2O + CO2 Æ CH2O + O2
Chemosynthesis (some types of bacteria): use chemical energy to create simple sugars ex. H2S + 2O2 + CO2 Æ CH2O + SO4 ex. hydrothermal vent bacteria in worms
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Facts about marine primary production
What fraction of primary production is done by photosynthesizers?
(A)1%
(B)50%
(C)99%
Facts about marine primary production 9 Photosynthesizers contribute >99% of the total primary production in the ocean
Chemosynthesis is important in certain areas (especially in areas where there is not light –ex. deep sea, deep sea vents, etc.), but is a small fraction of total primary production of the ocean.
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Facts about marine primary production
About what fraction of the earth’s primary production occurs in the ocean?
(A) 1%
(B) 50%
(C) 99%
Facts about marine primary production 9 Marine photosynthesis is about equal to terrestrial (land) photosynthesis (~50Gt/yr), even though the ocean is “blue”
9 The ocean is much larger than ldland (70% vs 30%) 9 Marine plants double every 2‐3 days, terrestrial plants average years 9 Thus, even though there is less “plant” material in the ocean, as a whole the ocean is about as productive as land. Sometimes called the “invisible forest.”
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Facts about marine primary production
What types of organisms are responsible for most marine primary production (photosynthesis)?
(A) Phytoplankton
(B) Seaweed
(C) Benthic (bottom attached) Algae
Facts about marine primary production *Photosynthesizers in the ocean are dominated by single celled “plants” called phytoplankton phyto = plant plankton = free floating
SdSeaweed and bthibenthic algae are regionally important (ex. coasts) but contribute only a fraction of the total marine primary production
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Phytoplankton Diversity Phytoplankton are exceptionally diverse major groups of importance to marine ecosystems:
9 diatoms 9 Only one algal class, the Charophyceae, gave rise to 9 dinoflagellates land plants 9 cyanobacteria 9 include both prokaryotes and eukaryotes 9 prymnesiophytes 9 many taxa have unique properties 9 prasinophytes 9 this diversity has implications for the functioning of 9 silicoflagellates the ecosystem and biogeochemical cycles
Blackenship, 2002
Phytoplankton Diversity Diatoms ‐ Dominant primary producers in high latitude, coastal, and upwelling environments ‐ (high nutrient) ‐ siliceous oozes ‐ high latitude sediments
Centric – radial symmetry (pelagic, benthic)
Coscinodiscus Corethron Thalassiosira Chaetoceros
Pennate – bilateral symmetry (pelagic, benthic)
Asterionella Nitzschia
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Phytoplankton Diversity
Dinoflagellates Important producers at high & low latitudes Toxic blooms ‐ "red tides", paralytic shell‐fish poisoning Zooxanthellae ‐ symbiotic in corals & some protozoans Bioluminescence
Alexandrium Gymnodinium Ceratium
Phytoplankton Diversity Cyanobacteria Ubiquitous in temperate & warm‐water open ocean particularly important in oligotrophic (nutrient poor) oceans
CHARACTERISTICS: Prokaryotic ‐ no organelles ShSynechococcus ‐ small, coccoid pilkticoplankters (~1 μm) Prochlorococcus – recently discovered, most abundant throughout the water column (107‐108 cells/liter) Very small (0.6‐1.0 μm in diameter) Responsible for ~50% chlorophyll / primary production in the oligotrophic waters Some use N2 (gas) as a source of nitrogen
Synechococcus Trichodesmium Prochlorococcus
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Phytoplankton Diversity
Prymnesiophytes Carbonate rich blooms (high latitudes) – coccolithophorids Antibacterial activity ‐ acrylic acid (Phaeocyctis) Calcareous deposits in ocean sediments
Emiliania huxleyi Phaeocystis (gel matrix)
Regulation of Primary Production (Photosynthesis)
What is required for photosynthesis to occur?
Light (energy) + Nutrients (substrate)
What can limit primary production in the ocean?
Light or nutrients!
(phytoplankton get consumed too, but we’ll get to that later…)
Phytoplankton in the Black Sea
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Types of Light Limitation Æ Light Decreases with Depth
0 0 light primary production Euphotic 10 1250 Zone (m) (m)
100 2500 Depth Depth
1000 Aphotic 3750 Zone
10000 5000
Light decreases exponentially with depth, so most of ocean (at depth) is light‐limited
Types of Light Limitation Æ Mixing
Little Mixing Lots of Mixing 0
Euphotic 50 Zone (m) Light OK 100 Depth
150 Aphotic Zone
200 Light Limited
If phytoplankton mix out of light layer (euphotic zone) they become light limited
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Types of Light Limitation Æ Time (Daily / Seasonal), Latitude
DilDaily solar cycle (th’(earth’s spii)inning) and seasonal cycle ((th’earth’s rotation around sun / axis tilt) cause changes in light availability
ex. Half the year the North (and South Pole) receive no sun!
Types of Nutrient Limitation Æ Nutrients Increase at Depth
0 0 1o Prod. Euphotic 10 1250 Zone (m) (m)
100 2500 Depth “nutrients” Depth “nutrients” 1000 Aphotic 3750 Zone
10000 5000
Nutrients (ex. PO4, NO3) accumulate at depth, so most of ocean (at surface) is nutrient‐limited!
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Types of Nutrient Limitation Æ Spatial Patterns (ex. PO4)
Nutrients (ex. PO4, NO3) are abundant in certain regions (high latitudes, equator, coastal areas) because of physical forces (upwelling, mixing)
Pulse of a Planet
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Major Concepts redux
9 Primary production is the first link in converting “environmental” energy to biological energy 9 Oceanic primary production is dominated by single celled “plants” called phytoplankton 9 Phytoplankton are exceptionally diverse 9 Primary production is typically limited by light or nutrients
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