Eukarya
• Eukarya includes all organisms with eukaryotic
cells
• Examples:
– plants
– animals
– fungi
– algae
– single-celled animal-like protozoa
Protists
• Eukaryotic; but comprises its own Kingdom Protista
– Algae - aquatic, photosynthetic organisms
– Diatoms
– Dinoflagellates
– Protozoans – Foraminiferans, Radiolarians, Ciliates
• Single and multi-cellular
Unicellular Algae
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Green Algae
– Mostly freshwater and terrestrial
– 10% of species are marine
Brown Algae
– Almost all species are marine
– Sargassum (Sargasso seaweed)
– Macrocystis (Giant Kelp)
• plants grow up to 300 ft
• can grow 20”/day
• form kelp beds or kelp forests
• Harvested for Algin (used in cosmetics and ice cream).
Red Algae
– Agar and carrageenan: gelling and thickening agents
Diatoms
• Extremely diverse and distinct
members of marine phytoplankton
– Unicellular
• Diatom structure
– Enclosed in a box-shaped
organic cell wall with silica
(SiO2), called a frustule
– Holes in cell wall allow
cholorplast to capture light and
dissolved gases to enter.
Dinoflagellates
– Unicellular protists with 2 flagella (used for motility)
– Globular, plated outer “shell” that is made of cellulose
– Photosynthetic, but also can absorb nutrients
– Most are planktonic (primary producers)
– Can be bioluminescent – Bioluminescent Bay, Puerto Rico (pg. 97)
• Red tides – produce toxin in water when in Harmful Algal Blooms (HABs)
Amoeboid Protozoans
• Unicellular Protists
• All have an organelle called a pseudopod—an extension of the
cell surface that can change shape and is used for locomotion
and food capture
• Are heterotrophs consuming bacteria and other small organisms
Amoeboid Protozoans
Amoeboid Protozoans
• Major Protozoans:
– Foraminiferans
– Radiolarians
– Ciliates
Amoeboid Protozoans
• Foraminiferans (forams)
– have branched pseudopods that form elaborate,
net-like structures used to:
• snare prey
• crawl
• reduce sinking rate (pelagic)
– consume bacteria and diatoms
– some harbor symbiotic green and red algae and
zooxanthellae
– Have shell (test) made from CaCO3
– Bottom of the ocean (benthic)
Foraminiferans
Foraminiferans
• White Cliffs of Dover
Radiolarians
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Unicellular protists
Planktonic (primary producers)
Shells make of silica (glass)
Contains a needle-like pseudopodia
Dead remains cover large portions of the
ocean bottom as radiolarian ooze.
Radiolarians
Ciliates
• Ciliates
– protozoans that have cilia (hair-like growths) for
locomotion and for gathering food
• membranelles—tufts or long rows of fused adjacent cilia
• Heterotrophs – cytostome—an organelle serving as a
permanent site for phagocytosis of food
– planktonic major links in marine food chains
– form symbiotic and parasitic relationships
– Paramecium
Ciliates
Fungi
• General features of fungi
– eukaryotes with cell walls of chitin
– filamentous fungi grow into long, multi-cellular
filaments called hyphae that can branch to produce a
tangled mass called a mycelium
– Important to marine ecosystems as heterotrophic
decomposers that recycle organic material
Maritime Lichens
• Lichens: mutualistic associations between a
fungus and an alga
– fungi are usually ascomycotes
– algae are usually green or blue-green bacteria
• The fungus provides attachment, general
structure, minerals, moisture
• The alga produces organic matter through
photosynthesis
Marine Viruses
• Viruses are diverse and are more abundant than
any other organism in the sea
• Have significance for marine food webs,
population biology and diseases of marine
organisms
• Viruses of marine eukaryotic hosts first reported
in the 1970s
Biodiversity and Distribution
of Marine Viruses
• 10 times more abundant than marine
prokaryotes, may reach 1010 virons per liter of
seawater, 1013 per kilogram of sediment
• Estimated 100 to 10,000 genotypes
• Most planktonic viruses are icosahdral or binal
bacteriophages (“bacteria eaters”) with lytic
life cycles
• Sediment viruses are typically helical and
lysogenic
Marine Microbes
• http://www.youtube.com/watch?v=1TmHlcM
DIOQ