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Classification of phytoplankton
The document discusses the diversity and productivity of plankton, classified into various groups such as phytoplankton, zooplankton, and bacterioplankton, which are crucial for marine food webs. It highlights the role of plankton in aquatic ecosystems, detailing their life history, motility, size, and spatial distribution, alongside explaining the ecological importance of these organisms in nutrient cycling and food production. Additionally, it explores mechanisms behind the patchiness of plankton distribution and the efficiency of open-ocean food webs, emphasizing the foundational role of phytoplankton in marine environments.
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Classification of phytoplankton
- 1. Plankton diversity and Productivity,Classification of plankton Presentation by C. Raja Samanth
- 2. Introduction • Plankton rangewidely in size, taxonomic diversity, and life style. • Phytoplankton are the primary producers in food web, and their productivity is limited by the scarcity of nutrients.
- 3. • Bacteria providea second base to food webs, and they allow the scarce nutrients to be efficiently recycled. • Limited primary production and food webs with several energy-wasting steps limit the number of large animals.
- 4. • Gelatinous planktonsuch as ctenophores play significant roles in open-ocean ecosystems. • Because of their efficient feeding mechanisms, reduction of nutritional quality, and provision as prey for specialist carnivores. • Several structural features and behaviors have evolved to keep afloat organisms that are not strong swimmers.
- 5. Classification of plankton •Two groups of organisms inhabit the oceanic zone: plankton and nekton Based on productivity, biomass, abundance and diversity, plankton far outweighs nekton in open ocean • Plankton can be classified into logical groups based on: Taxonomy Motility Size Life history Spatial distribution
- 6. Taxonomic groups • Seston:particles suspended in the sea, include: • Tripton: non-living seston • Phytoplankton: primary producers • Zooplankton: heterotrophic eukaryotic microbes that float in the currents • Bacterioplankton: archaeans and bacteria • Viriplankton: free viruses (the most abundant plankton of all)
- 7. Motility • Akinetic: planktonthat don’t move at all, e.g., viruses, diatoms and forms • Kinetic: plankton that can move (include majority of plankton) • Kinetic plankton move by use of flagella, jet propulsion, undulation, swimming appendages
- 8. Size • Original scheme(based on visibilty and collection method): – macroplankton – visible to the naked eye – microplankton – caught with standard plankton net – nanoplankton – concentrated by centrifugation • Newer classifications: femtoplankton, picoplankton, mesoplankton, macroplankton, megaplankton
- 10. Life history • Holoplankton:organisms that are planktonic throughout their lives, e.g., microbes, arrowworms, salps, siphonophores, comb jellies, copepods, krill • Meroplankton: planktonic larvae that will grow into non-planktonic organisms – in open ocean would include larvae of nektonic fish and squid – in coastal waters would also include larvae of benthic invertebrates
- 11. Spatial distribution • Neritic:distinguished by presence of meroplankton and diverse diatoms • Oceanic: less diverse in diatoms and invertebrate meroplankton; more salps, larvaceans, arrowworms and sea butterflies • Neuston: plankton that life close to the water’s surface • Pleuston: plankton which break the surface of the water with their gas bladders or bubbles, e.g., by- the-wind sailor
- 12. • Megaplankton – mostorganisms classified as megaplankton are animals – cnidarian zooplankton • largest members of the plankton are jellyfishes
- 14. Patchiness Plankton occur inpatches (localized aggregations), often around upwellings Patchiness can be caused by: • upwelling • localized variations in sea surface conditions • vertical mixing • downwelling • waters of different densities coming together • grazing by zooplankton
- 15. Ecology of theOpen Sea • Open sea is a pelagic ecosystem—one in which the inhabitants live in the water column basis of food chain is many species of small phytoplankton • Small, primary producing organisms have a relatively high surface area allows them to absorb more nutrients from surrounding seawater • Majority of herbivores in open ocean are zooplankton which supply food for nekton
- 16. Productivity – All higherforms of life rely on plankton – Water near the surface receives plenty of sunlight, but few nutrients from land or the sea bottom (except in rare areas of upwelling) – Phytoplankton productivity is low in tropical waters • arrangement of water in layers with little circulation between prevents nutrients from being brought from the sea bottom • low phytoplankton numbers support even fewer numbers of zooplankton
- 17. Food web Basis offood webs in open sea is formed by phytoplankton and heterotrophic bacteria Dissolved and particulate organic matter • phytoplankton release photosynthetic products as DOM into surrounding seawater • heterotrophic bacteria recycle DOM as they eat it and then are eaten by nanoflagellates • bacterial loop: process in which bacteria metabolize DOM and return it to the water in an inorganic form available to phytoplankton • lysis of bacteria by viruses releases DOM and particulate organic matter (POM)
- 18. Dissolved inorganic nutrients Shark Squid Tuna Herring Ctenophores Dolphin Toothed whale Leatherback turtle Baleen whale Jellyfish Sardines Tintinnids Heterotrophic nanoflagellates Particulateorganic matter Viruses Dissolved organic matter Free heterotrophic bacteria (to deeper waters) Meso- and Microzooplankton Phytoplankton Stepped Art Figure 17- 17, p. 481
- 19. Macrozooplankton (krill, shrimp) Nanoplankton (cyanobacteria, smalldiatoms) Microzooplankton (foraminiferans, radiolarians) Mesozooplankton (copepods) Nekton (fishes, squid, whales) Phytoplankton (nanoplankton and smaller) Mesozooplankton Macrozooplankton Large and medium fishes, squid Small fishes Phytoplankton (nanoplankton and smaller) Large and medium fishes, squid Microzooplankton Mesozooplankton Macrozooplankton Small fishes Microzooplankton Stepped Art Figure 17- 18, p. 482
- 20. • Food websin the open sea (continued) – efficiency of open-ocean food webs • pyramid of production = diagram that indicates the rate at which new biomass is produced at successive trophic levels • standing crop = amount of biomass of organisms in a given area at a given time • standing crop of phytoplankton in open ocean might be very small, giving a pyramid of production that is partly inverted • The wealth of the open sea resides in its microscopic inhabitants
- 21.