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11/17/2008 Primary Production OCN201 Fall 2008 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 phylogenies are not always hierarchical • There are mechanisms that account for this (sex, viruses, random uptake/incorporation p / p of DNA) • Complicated! William 1999 1 11/17/2008 • 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 gy g gy 9 Oceanic primary production is dominated by single celled “plants” called phytoplankton 9 Phytoplankton are exceptionally diverse Primary production is typically limited by light or 9 Primary production is typically limited by light or nutrients 2 11/17/2008 What is primary production? Primary = first, initial P d i Production = formation / creation of something f i / i f hi Primary production = the first conversion of energy from the environment into “biological” energy What types of organisms are primary producers in the 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 chemical energy to create simple sugars ex. H2S + 2O2 + CO2 Æ CH2O + SO4 ex. hydrothermal vent bacteria in worms 3 11/17/2008 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. 4 11/17/2008 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 Th The ocean is much larger than land (70% vs 30%) i hl th l d (70% 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.” 5 11/17/2008 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 SSeaweed and benthic algae are d d b thi l regionally important (ex. coasts) but contribute only a fraction of the total marine primary production 6 11/17/2008 Phytoplankton Diversity Phytoplankton are exceptionally diverse major groups of importance to marine ecosystems: 9 9 9 9 9 9 9 Only one algal class, the Charophyceae, gave rise to land plants land plants 9 include both prokaryotes and eukaryotes 9 many taxa have unique properties 9 this diversity has implications for the functioning of the ecosystem and biogeochemical cycles diatoms dinoflagellates cyanobacteria prymnesiophytes prasinophytes silicoflagellates 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 Thalassiosira Corethron Chaetoceros Pennate – bilateral symmetry (pelagic, benthic) Asterionella Nitzschia 7 11/17/2008 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 S Synechococcus ‐ h small, coccoid ll id picoplankters i l kt (~1 μm) (~1 ) 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 8 11/17/2008 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! g (phytoplankton get consumed too, but we’ll get to that later…) Phytoplankton in the Black Sea 9 11/17/2008 Types of Light Limitation Æ Light Decreases with Depth 0 0 light 1250 100 1000 2500 Aphotic Zone Depth (m) Depth (m) 10 Euphotic Zone primary production d 3750 5000 10000 Light decreases exponentially with depth, so most of ocean (at depth) is light‐limited Types of Light Limitation Æ Mixing Little Mixing 0 Depth (m) 50 Euphotic Zone Light OK 100 150 200 Lots of Mixing Aphotic Zone Light Limited If phytoplankton mix out of light layer (euphotic zone) they become light limited 10 11/17/2008 Types of Light Limitation Æ Time (Daily / Seasonal), Latitude Daily solar cycle (earth’s spinning) and seasonal cycle (earth’s D il l l ( th’ i i ) d l l ( th’ 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 1o Prod Prod. Euphotic Zone 1250 100 1000 2500 “nutrients” Aphotic Zone “nutrients” Depth (m) Depth (m) 10 0 3750 5000 10000 Nutrients (ex. PO4, NO3) accumulate at depth, so most of ocean (at surface) is nutrient‐limited! 11 11/17/2008 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 12 11/17/2008 Major Concepts redux 9 Primary production is the first link in converting “environmental” energy to biological energy gy g gy 9 Oceanic primary production is dominated by single celled “plants” called phytoplankton 9 Phytoplankton are exceptionally diverse Primary production is typically limited by light or 9 Primary production is typically limited by light or nutrients 13