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11/5/2007

Major Concepts 9 Primary production is the first link in converting OCN201 Fall 2007 “environmental” energy to biological energy 9 Oceanic primary production is dominated by single Zackary Johnson celled “” called Department of Oceanography http://www.soest.hawaii.edu/oceanography/zij/education.html 9 Phytoplankton are exceptionally diverse 9 Primary production is typically limited by light or nutrients

What is primary production? What is primary production? Photosynthesizers (plants): use sunlight energy to Primary = first, initial convert into simple sugars Production = formation / creation of something

H2O + CO2 Æ CH2O + O2 Primary production = the first conversion of energy from the environment into “biological” energy Chemosynthesis (some types of bacteria): use What types of organisms are primary producers in the chemical energy to create simple sugars ? ex. H2S + 2O2 + CO2 Æ CH2O + SO4

ex. hydrothermal vent bacteria in worms

Facts about marine primary production Facts about marine primary production What fraction of primary production is done by 9 Photosynthesizers contribute >99% of the total primary photosynthesizers? production in the ocean

(A)1%

(B)50%

(C)99%

Chemosynthesis is important in certain areas (especially in areas where there is not light –ex. deep , 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 Facts about marine primary production

About what fraction of the earth’s primary production occurs in 9 Marine is about equal to terrestrial (land) the ocean? photosynthesis (~50Gt/yr), even though the ocean is “blue”

(A) 1%

(B) 50%

(C) 99%

9 The ocean is much larger than land (70% vs 30%) 9 Marine plants double every 2‐3 days, terrestrial plants average years 9 Thus, even though there is less “” material in the ocean, as a whole the ocean is about as productive as land. Sometimes called the “invisible forest.”

Facts about marine primary production Facts about marine primary production

What types of organisms are responsible for most marine *Photosynthesizers in the ocean are dominated by single celled primary production (photosynthesis)? “plants” called phytoplankton phyto = plant = free floating (A) Phytoplankton

(B) Seaweed

(C) Benthic (bottom attached)

Seaweed and benthic algae are regionally important (ex. ) but contribute only a fraction of the total marine primary production

Phytoplankton Diversity Phytoplankton Diversity Phytoplankton are exceptionally diverse ‐ Dominant primary producers in high latitude, coastal, and upwelling environments major groups of importance to marine ecosystems: ‐ (high nutrient) ‐ siliceous oozes ‐ high latitude sediments 9 diatoms 9 Only one algal class, the Charophyceae, gave rise to 9 land plants Centric –radial symmetry (pelagic, benthic) 9 9 include both prokaryotes and 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

Coscinodiscus Corethron Thalassiosira

Pennate – bilateral symmetry (pelagic, benthic)

Asterionella Nitzschia Blackenship, 2002

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Phytoplankton Diversity Phytoplankton Diversity Cyanobacteria Dinoflagellates Ubiquitous in temperate & warm‐water open ocean Important producers at high & low latitudes particularly important in oligotrophic (nutrient poor) Toxic blooms ‐ "red tides", paralytic shell‐ poisoning Zooxanthellae ‐ symbiotic in corals & some protozoans CHARACTERISTICS: Prokaryotic ‐ no organelles Bioluminescence Synechococcus ‐ small, coccoid picoplankters (~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

Alexandrium Gymnodinium Ceratium

Synechococcus Trichodesmium Prochlorococcus

Phytoplankton Diversity Regulation of Primary Production

Prymnesiophytes (Photosynthesis) Carbonate rich blooms (high latitudes) – coccolithophorids Antibacterial activity ‐ acrylic acid (Phaeocyctis) What is required for photosynthesis to occur? Calcareous deposits in ocean sediments

Light (energy) + Nutrients (substrate)

What can lim it primary proddiuction in the ocean?

Light or nutrients! Phaeocystis (gel matrix) (phytoplankton get consumed too, but we’ll get to that later…)

Phytoplankton in the Black Sea

Types of Light Limitation Æ Light Decreases with Depth Types of Light Limitation Æ Mixing

Little Mixing Lots of Mixing 0 0 0 light primary production Euphotic Euphotic 10 1250 50 Zone Zone (m) (m) (m)

h h

h Light OK t t 100 2500 100 Dep Dep Dept

1000 Aphotic 3750 150 Aphotic Zone Zone

10000 5000 200 Light Limited

Light decreases exponentially with depth, If phytoplankton mix out of light layer (euphotic zone) so most of ocean (at depth) is light‐limited they become light limited

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Types of Light Limitation Æ Time (Daily / Seasonal), Latitude Types of Nutrient Limitation Æ Nutrients Increase at Depth

0 0 1o Prod. Euphotic 10 1250 Zone (m) (m)

h h t 100 2500 Dep “nutrients” Dept “nutrients” 1000 Aphotic 3750 Daily solar cycle (earth’s spinning) and seasonal cycle (earth’s Zone rotation around sun / axis tilt) cause changes in light availability 10000 5000 ex. Half the year the North (and South Pole) receive no sun! Nutrients (ex. PO4, NO3) accumulate at depth, so most of ocean (at surface) is nutrient‐limited!

Æ Types of Nutrient Limitation Spatial Patterns (ex. PO4) Pulse of a Planet

Nutrients (ex. PO4, NO3) are abundant in certain regions (high latitudes, equator, coastal areas) because of physical forces (upwelling, mixing)

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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