Most Phytoplankton Are Photosynthetic Autotrophs      Diatoms Apart from cyanobacteria, the most productive photosynthetic organisms in the plankton are the diatoms. Diatoms have transparent silica frustules that allow for both protection and light penetration into the cell. Diatoms store energy as fatty acids and oils, compounds that are lighter than their equivalent volume of water and assist in flotation. When diatoms die, their valves fall to the seafloor to accumulate as layers of siliceous ooze. (RIGHT) Photographs of various diatoms.
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  DIVISIONS OF ALGAE (Continued) Diatoms: Unicellular or filamentous algae with complex cell walls with silica or calcium.  Two parts of cell wall fit together like Petri dish. Distinctive patterns are used for identification. Store energy in form of oil.  Some diatoms can cause neurological disease (memory loss and diarrhea) in people who eat mussels, due to domoic acid intoxication.  Fossil deposits of diatoms (diatomaceous earth) are used as filtering agents and abrasives in several industries.
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• Diatoms contain many organelles that enable them to exist under potentially harsh conditions. • Most diatoms constist of strikingly delicate outter shells of SiO2 (frustules) which provide limited protection and light penetration.
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 Diatoms  Pectin and silica cell walls  Unicellular  Fossilized diatoms formed oil Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Figure 12.13
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Chrysophyta (Golden algae and Diatoms) • • Are eukaryotic Has pigments chlorophylls a and c and carotenoids – Two Class: • Golden Algae Ex. Mallomonas • Diatoms -Have frustules made of silica ex.. Fragillaria, Asterionella , and Tabellaria
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 Building of cell walls, or frustules, in diatoms   Increased diatom diversity in Cenozoic Era Diatoms     Unicellular Producers One of the Most common types of phytoplankton Eaten by Krill  Krill then eaten by whales  Short food chain (efficient in supporting apex predator)
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In Miocene (32 to 14 mya), Antarctica remained about 20° C warmer than today, with tundra and beech tree (Nothofagus) forests, similar to Patagonia in South America today. Evidence in Dry Valleys show presence of desiccated aquatic plants, algae, moss, and diatoms Dry Valley discovery Climate change at ~14 mya cooled Antarctica to what it is today
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Abyssal Seafloor • Chert: remains from diatoms • Fe oxides: oxidized meteorite dust • CCD: carbonate compensation depth (> 1km)
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Figure 26.21 Eukarya Land plants Green algae Cellular slime molds Dinoflagellates Forams Ciliates Red algae Diatoms Amoebas Euglena Trypanosomes Leishmania Animals Fungi Green nonsulfur bacteria Sulfolobus Thermophiles (Mitochondrion) Spirochetes Halophiles COMMON ANCESTOR OF ALL LIFE Methanobacterium Archaea Chlamydia Green sulfur bacteria Bacteria Cyanobacteria (Plastids, including chloroplasts)
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Unicellular Algae • Being composed of one cell isn’t an evolutionary dead end. • Alagae, Diatoms, Dinoflagellates, and Radiolarans all have been aound for millions of years (if not billions). • Being eukaryotic, unicellular organisms such as these use a variety of methods to eat, metabolize, and reproduce. • As a group these organisms are known as Protist!
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Diatoms reproduce asexually (cell division) and sexually (auxospore), depending on external conditions.
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Parabasalids Euglenozoans Excavata Diplomonads Apicomplexans Ciliates Diatoms Stramenopiles Golden algae Chromalveolata Alveolates Dinoflagellates Brown algae SAR clade (10th ed) Oomycetes Forams Radiolarians Green algae Chlorophytes Charophytes Land plants Archaeplastida Red algae Rhizaria Cercozoans Gymnamoebas Entamoebas Opisthokonts Nucleariids Fungi Unikonta Amoebozoans Slime molds Choanoflagellates Animals Figure 28.2
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Figure 28.2 Parabasalids Euglenozoans Excavata Diplomonads Apicomplexans Ciliates Diatoms Stramenopiles Golden algae Chromalveolata Alveolates Dinoflagellates Brown algae Oomycetes Forams Radiolarians Green algae Chlorophytes Charophytes Land plants Archaeplastida Red algae Rhizaria Cercozoans Gymnamoebas Entamoebas Opisthokonts Nucleariids Fungi Choanoflagellates Animals Unikonta Amoebozoans Slime molds SAR clade (10th ed)
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Diatoms Stramenopiles subclade (some stage with “hairy” flagellum) • • Photoautotrophic (phytoplankton) Silica cell wall – Glass-like – Two halves like a petri plate • Shells sink after death and accumulate as sediments • Diatomaceaous earth • Diatom reproduction • • • • Unique to cell structure Mitotically divide the halves Secretes the smaller half Nucleus triggers meiosis when too small
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Chapter 14 Six Main Concepts  Plankton drift or swim weakly, going where the ocean goes, unable to move consistently against waves or current flow.  Plankton is an artificial category; a category not based on a phylogenetic (evolutionary) relationship but rather on a shared lifestyle.  Phytoplankton are autotrophic, that is, they make their own food, usually by photosynthesis. Plankton productivity depends on largely on light and nutrient availability.  The ocean’s most productive phytoplankters are very small cyanobacteria working in a “microbial loop.”  Zooplankton – drifting animals – consume phytoplankton species (diatoms, dinoflagellates, coccolithophores), forming a food web that eventually supports larger animals like fishes.  Not all producers are drifters. Seaweeds and mangroves are also important contributors.
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Most Phytoplankton Are Photosynthetic Autotrophs Major types of phytoplankton? • Picoplankton – this category encompasses most other plankton types, which are very small. • Diatoms – the dominant and most productive of the photosynthetic plankton. • Dinoflagellates – widely distributed singlecelled phytoplankton; use flagella to move. • Coccolithophores – small single-celled autotrophs.
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Pelagic Sediments Vary in Composition and Thickness • Turbidites – deposits made by turbidity currents • Oozes – sediment containing at least 30% biogenous material – Siliceous oozes are formed by organisms that contain silica in their shells. Diatoms are one type of organism whose remains contribute to siliceous ooze. – Calcareous oozes are formed by organisms, such as foraminifera, which contain calcium carbonate in their shells. • Hydrogenous sediments - originate from chemical reactions that occur in the existing sediment. – Are often found in the form of nodules containing manganese and iron oxides – Evaporites are salts that precipitate as evaporation occurs and include many salts with economic importance.
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Food Webs Disperse Energy through Communities Diatoms, and other primary producers, convert the energy from the sun into food used by the rest of the oceanic community. A simplified food web, illustrating the major trophic relationships leading to an adult blue whale.
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Biogenous sediment composition Microscopic biogenous tests are composed of 2 main chemical compounds: 1. Silica (SiO2) including opal (SiO2 · nH2O) Diatoms (algae) Radiolarians (protozoan) 2. Calcium carbonate or calcite (CaCO3) Coccolithophores (algae) Foraminifers (protozoan)
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 Deep ocean sediments comprise  biogenic oozes   siliceous oozes that mainly form from diatoms and radiolaria, and calcarious oozes (e.g., form from coccolithophores and foramini-fera) below the carbonate compensation depth (CCD); and  abyssal clays that are often windtransported, particularly in the tropical oceans.
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Siliceous ooze forms from diatoms and radiolaria Diatom
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 Deep ocean sediments comprise  biogenic oozes   siliceous oozes that mainly form from diatoms and radiolaria, and calcarious oozes (e.g., form from coccolithophores and foramini-fera) below the carbonate compensation depth (CCD); and  abyssal clays that are often windtransported, particularly in the tropical oceans.
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Life of the Cretaceous • Plankton – Diatoms radiated – Foraminifera diversified – Calcareous nannoplankton radiated – Ammonoids and belemnoids persisted
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Deep Sea Environments • Siliceous ooze – Diatoms – Radiolarians • Common in upwelling regions • Accumulations can alter to opal then chert 45
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Sedimentary Rocks Biochemical Rocks Chert, like chalk, is composed of tiny shells from planktonic life, but the organisms involved secrete SiO2 shells. Diatoms and radiolaria have microscopic SiO2 shells
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13. More Diatoms
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14. Spiny Diatoms
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Foulants • Soft Foulants (algae and seweed) • Hard Foulants (barnacles and diatoms)
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Antifoulants • Used to control the growth of marine organisms (algae and seaweed-soft foulants; barnacles and diatoms-hard foulants) • Usually mixed with the paint as it is applied to the hull • Slowly leach form the surface of the hull
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Photosymbiosis in forams • Early suggestions of photosymbiosis in living forams (1880s — 1950s) • Lee et al. (1965) established first unequivocal evidence for photosymbiosis in living forams • Photosymbionts now confirmed in 12 extant families o Symbionts include diatoms, dinoflagellates, unicellular green algae, unicellular red algae and cyanobacteria
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Cynobacteria are phototrophic bacteria that can fix nitrogen from the atmosphere. The mats are comprised of cynobacteria, bacteria, and diatoms and form layers These mats often occur in extreme and fluctuating environments http://huey.colorado.edu/cyanobacteria/about/ cyanobacteria.php http://www.nhm.ac.uk/natureplus/blogs/Antarcticcyanob acteria/2010/12/23/cyanobacterial-mat-communities-inlake-hoare
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Beaver Lake is about 7 miles long with a permanent ice cover Receives glacial melt water with more dense marine water below Biota includes strictly marine species of fish at the bottom with freshwater diatoms in surface waters Still little known on carbon cycling and species diversity in these lakes
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Salientia Life History and Reproduction Explosive Breeding Tadpoles scape algae and diatoms from substrate
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Stream-breeding frogs in North America • Rocky Mountain Tailed Frog (Ascaphus montanus) • Found in small (1st - 3rd order), cold streams in the northern Rockies • Males don’t call • Internal fertilization with cloacal “tail” • Lay eggs under rocks • Tadpoles develop for 3 yrs. – suck onto rocks with mouth, scrape off diatoms and insect larvae • Adults in stream during day, forage along bank at night
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Major Primary Producers in Fresh Water • Algae • Diatoms • Cyanobacteria (aka, blue-green algae)
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General physiological requirements • Light of specific wavelength • Nutrients: - N and P - Si for diatoms - Mg for chlorophyll • Carbon forms: - CO2 - Carbonic acid: H2CO3 - Hydrogen carbonate: HCO3- Carbonate: CO32-
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