1 / 29

The Oceanic Carbon Cycle: Biological Pump

The Oceanic Carbon Cycle: Biological Pump. Primary producers: who are they? How does the pump work: transport to the bottom Open ocean ecosystems. high diversity: DEEP SEA. Deep-Sea : diverse life forms.

caden
Download Presentation

The Oceanic Carbon Cycle: Biological Pump

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Oceanic Carbon Cycle:Biological Pump • Primary producers: who are they? • How does the pump work: transport to the bottom • Open ocean ecosystems

  2. high diversity:DEEP SEA

  3. Deep-Sea : diverse life forms • Deep-sea thought to be without life (‘azoic’) until 19th century deep-sea exploration expeditions • ‘Erebus’and‘Terror’, 1839-1843, James Ross Clark • ‘Lightning’ and ‘Porcupine’, 1868-1869, Wyville Thompson • ‘Challenger’, 1872-1876, Wyville Thompson, J. W. Murray (Foraminifera:H .B. Brady, 1884)

  4. SURFACE OCEAN PRIMARY PRODUCTIVITY Satellite data (CZCS, SeaWIFS) High productivity: input of nutrients (N, P) from land Seasonality

  5. Oceanic spring bloom (high-mid latitudes) • Winter: light limitation (insolation, storms mix phytoplankton below photic zone) • Nutrients not (fully) used; accumulate • Spring: more light, warming causes stratification, keeps plankton within photic zone • Bloom (until nutrients used up, zooplankton eats phytoplankton)

  6. ‘PROTISTS’: EUKARYOTES (unicellular) LIFE ON EARTH EUKARYOTES(multicellular):FungiAnimaliaPlantae Molecular phylogenies: Protein sequences Small subunit RNA PROKARYOTES

  7. Oceanic primary producers: • Prokaryotes (unicellular, ‘simple’ cell, asexual reproduction; 0.6 mm) - cyanobacteria Prochlorococcus, Synechococcus): up to ~2/3 of primary productivity in the oceans • Eukaryotes (complex cell - nucleus - sexual and asexual reproduction; tens of mm) • Bacillariophyceae - Opaline Silica skeleton: Diatoms • Haptophyceaea • Calcium-carbonate skeleton: Calcareous Nannoplankton • No skeleton: Phaeocystis • Dinophyceae - organic -walled cysts: Dinoflagellates

  8. COCCOLITHOPHORES CALCAREOUS NANNOPLANKTON • Polysaccharide gels (transparent exopolymer particles) (Haptophyte Algae) Diameter ~20-30 mm

  9. Planktonic foraminifer

  10. Prymnesiophytes (Haptophytes) -Phaeocystis • Polysaccharide gels (transparent exopolymer particles)

  11. Transparent Exopolymer Particles • Phaeocystis blooms at high latitudes (survive in sea ice) • ~10% of annual global marine primary productivity • Much of this in form of gels - major part of dissolved organic carbon in oceans • Secrete dimethylsulfide - add sulfur to atmosphere

  12. Diatoms • Today up to 20-40% net primary production, ~ 50% organic carbon exported

  13. Diatoms • Rapid delivery of diatoms to sea floor in frontal zones (Kemp et al., 2006) • ‘giant diatoms’ in mats e.g., Fragilariopsis, Thalassiothrix, Rhizosolenia

  14. Dinoflagellates • Dinophyceae

  15. Dinoflagellates: harmful algal blooms (HABs)

  16. Type of primary producers/productivity of oceans: • Open ocean, low productivity (central gyres): prokaryotes, some dinoflagellates • Open ocean, higher productivity: calcareous nannoplankton • Open ocean, highest productivity: diatoms, Phaeocystis • Coastal ocean, high productivity: dinoflagellates, Phaeocystis

  17. Oceanic primary productivity: different dominant producers - ‘fertility’ ANNUAL

  18. Deep-sea environment:cold, dark,high pressure,very little food. Food supplied by surface productivity, miles up: biological pump

  19. How much food reaches the bottom?Not very much (<1 to few % of PP) e.g., Martin et al., 1987; north-east Pacific stations F=1.53(z/100)-0.858 z=depth

  20. Oceanic food chain

  21. Food from surface to bottom:biological pumphow does it work? • Marine snow (~4 mm particle, dead and dying phytoplankton, zooplankton exoskeletons, fecal matter) • 102-103 m/day

  22. Organic matter from surface to bottom:biological pump • Ballasted by • silica (diatoms) • carbonate (foraminifera, nannoplankton) • terrigenous dust • In fecal pellets • Stuck together by polysaccharides (Phaeocystis, diatoms, cyanobacteria, calcareous nannoplankton) • In ‘giant balls of mucus’ - larvacean houses • Carrion falls (‘dead whales’) • Lateral transport (refractory organic matter) Discrepancy between food requirements of faunas and supply in sediment traps: faunas need more than what is delivered

  23. Larvacean ‘houses’ (tunicates)2-3 feet diameter • Tunicates are Chordates (related to us vertebrates - lancelet fish)

  24. We do not understand transport of organic matter to the sea floor in the present ocean, nor importance of prokaryotic productivity • We can not predict the effects of global warming and increased nutrients on carbon cycle in the oceans

  25. Oceanic primary productivity - how limited? Transport to sea floor - how limited? Can we manipulate (carbon sequestration)?

  26. In some regions N and P are NOT limiting • "high-nutrient, low-chlorophyll” (HNLC) regions, e.g. equatorial Pacific • Not enough iron (Fe)

More Related