Transcript Chapter 6 - Perry Local Schools

Chapter 6
Marine Microbes
Karleskint
Turner
Small
Key Concepts
• Microbial life in the sea is extremely
diverse, including members of all three
domains of life as well as viruses.
Key Concepts
• Photosynthetic and chemosynthetic
bacteria are important primary producers
in marine ecosystems.
• Heterotrophic bacteria, and fungi play
essential roles in recycling nutrients in the
marine environment.
Key Concepts
• Some Marine microbes contribute
significantly to the accumulation of deepsea sediments.
• Populations of several kinds of
photosynthetic marine microbes may form
harmful blooms that affect other marine
and maritime organisms directly and
indirectly.
Marine Viruses
• Virology—the study of 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
Ecology of Marine Viruses
• Viruses kill host cells, and thus control
populations of bacteria and other microbes
in plankton communities
• Viruses also responsible for chronic infection
and mass mortality of populations of marine
animals
Marine Bacteria
• General characteristics
– simple, prokaryotic organization: no nuclei or
membrane-bound organelles, few genes
– reproduce asexually by binary fission
– many shapes and sizes
• bacillus—rod shape
• coccus—spherical shape
Nutritional Types
• Cyanobacteria (blue-green bacteria)
– photosynthetic bacteria which are found in
environments high in dissolved oxygen, and
produce free oxygen
– primary photosynthetic pigments are
chlorophyll a and chlorophyll b
Nutritional Types
• Chemosynthetic bacteria
– use energy derived from chemical reactions
that involve substances such as ammonium
ion, sulfides and elemental sulfur, nitrites,
hydrogen, and ferrous ion
– chemosynthesis is less efficient than
photosynthesis, so rates of cell growth and
division are slower
– found around hydrothermal vents and some
shallower habitats where needed materials
are available in abundance
Chemosynthetic bacteria (in animal tissues, in water, and on rocks)
Carbon
dioxide (CO2)
Produce
Water
(H2O)
Carbohydrates
Hydrogen
sulfide (H2S)
Animal
community
Carbon
dioxide (CO2)
Hydrogen
sulfide (H2S)
Elemental
sulfur (S)
Carbon
dioxide (CO2)
Stepped Art
Magma (molten rock)
Fig. 6-10, p. 134
Nutritional Types
• Heterotrophic bacteria
– decomposers that obtain energy and
materials from organic matter in their
surroundings
– return many chemicals to the marine
environment through respiration and
fermentation
Nutritional Types (Heterotrophic Bacteria)
• Heterotrophic bacteria
– marine snow: large, cobweb-like drifting
structures formed by mucus secreted by many
kinds of plankton, where particles may
accumulate
Symbiotic Bacteria
• Many bacteria have evolved symbiotic
relationships with a variety of marine
organisms
• Chemosynthetic bacteria live within tube
worms and clams
• Some deep-sea or nocturnal animals host
helpful bioluminescent bacteria
– photophores
– embedded in the ink sacs of squid
Archaea
• General characteristics
– small (0.1 to 15 micrometers)
– prokaryotic
– adapted to extreme environmental conditions:
high and low temperatures, high salinities, low
pH, and high pressure
– differences from bacteria
• cell walls lack special sugar-amino acid compounds in
bacterial cell walls
• cell membranes contain different lipids, which help
stabilize them under extreme conditions
Archaea
• Nutritional Types
– photosynthesizers, chemosynthesizers and
heterotrophs
– most are methanogens: anaerobic organisms
that metabolize organic matter for energy,
producing methane as a waste product
– halobacteria thrive at high salinities
Archaea
• Hyperthermophiles
– organisms that can survive at temperatures
exceeding 100o C, such as near deep-sea vents
– Potential for biomedical and industrial
application
Eukarya
• Eukarya includes all organisms with
eukaryotic cells
• Examples:
– plants
– animals
– fungi
– algae
– single-celled animal-like protozoa
Fungi
• important in marine ecosystems as
decomposers, prey, pathogens and
symbionts
Fungi
• General features of fungi
– heterotrohic decomposers that recycle organic
material
• can digest lignin (major component of wood)
Fungi
• Ecology and physiology of marine fungi
– salinity is toxic to fungi, so they must devote
energy to removing sodium
– most marine fungi live on wood from land
– some live on grass in salt marshes
– others live on algae, mangroves or sand
Maritime Lichens
• Lichens: mutualistic associations between
a fungus and an alga
– algae are usually green or blue-green bacteria
• The fungus provides attachment, general
structure, minerals, moisture
• The alga produces organic matter through
photosynthesis
Diatoms
• Diatom structure
– 2 basic diatom shapes:
• radially symmetrical valves (generally planktonic)
• bilaterally symmetrical valves (generally benthic)
Diatoms
• Diatomaceous sediments
– frustules of dead diatoms sink and collect on
the seafloor to form siliceous oozes
– accumulations form sedimentary rock
– these deposits, called diatomaceous earth, are
mined for use as filtering material, a mild
abrasive, and for soundproofing and insulation
products
– nutrient reserves, stored as lipids, accumulate
in siliceous oozes accounting for most of the
worlds petroleum reserves
Alveolates
• Dinoflagellates
– globular, unicellular (sometimes colonial) with
2 flagella
– Most are planktonic, some are benthic and
others parasitic, also can be bioluminescent –
Bioluminescent Bay, Puerto Rico
Alveolates (Dinoflagellates)
• Dinoflagellate structure
– simple flagellum encircles the cell in the
horizontal groove and produces a spinning
motion
– longer flagellum with hair-like filaments trails
down the longitudinal groove and imparts most
of the forward motion to the cell
– number, size and shapes of plates are used to
identify different species
Alveolates (Dinoflagellates)
• Ecological roles of dinoflagellates
– major component of phytoplankton
– some are parasites of copepods (crustaceans)
– zooxanthellae: species lacking flagella which
are symbionts of jellyfish, corals and molluscs
– photosynthetic zooxanthellae provide food for
hosts
– hosts provide carbon dioxide, other nutrients,
and shelter
Alveolates (Dinoflagellates)
• Harmful Algal Blooms (HABs)
– occur when photosynthetic dinoflagellates
undergo a population explosion
– colors the water red, orange or brown
– dinoflagellates that cause HABs produce toxins
• paralytic shellfish poisoning (PSP) occurs in humans
who consume shellfish contaminated with these toxins
• toxins cannot be destroyed by cooking
– oxygen content of the water may be reduced to
deadly levels as bacteria decompose animals
killed by dinoflagellate toxins