Benthos
• 235,000 animal species in the oceans - 98% live on the ocean floor
• Factors Controlling Distribution and Diversity
– Primary Productivity
– Patchy or clumped distribution
Benthos
• Factors Controlling Distribution and Diversity
– Substrate type
– Temperature, currents, wave energy
Benthic Life - Lifestyles of the slow and slimy
• Populations and communities
• Competition
– Space and resources
• Infauna and epifauna
– Sessile versus vagile
– Tiering
– Zonation
Benthic Life
• Methods of making a living
– Suspension feeding
– deposit feeding
– Grazing
– Predators
Benthic Communities - Rocky Intertidal
• A well studied community
• Environment of extremes
• Distribution
– Based on tolerance to changing conditions
– Biozones
• Supratidal
• Intertidal
– Upper, middle, & lower
• Subtidal
Benthic Communities - Rocky Intertidal
• Supratidal/Spray Zone
• Submerged only during storms and highest tides
• Most obvious inhabitant = periwinkle snail
• Lichens and algae
• limpets
Benthic Communities - Rocky Intertidal
• Intertidal Zone - upper and middle parts
• Competition for space - when does space open up?
• Barnacles
• Rockweed
• Predatory snails
• Muscles and oysters
• chitons
Benthic Communities - Rocky Intertidal
• Intertidal Zone - lower part
• Why is this zone so diverse?
• Anemones
• Sea stars and brittle stars
• Urchins (tube feet)
• Octopuses
Benthic Communities - Sandy Intertidal
• An extreme environment
• High energy - mobile substrate
• Vagile and infaunal
• Distribution
– Zones? - gradients
• Crabs
• Burrowing clams
• Where is diversity highest?
Benthic Communities - Vents and Seeps
• First discovered in 1977
• Communities based on chemosynthesis
• Bluesprints for how life began on earth?
Benthic Communities - Vents and Seeps
• Vent communities
• Hydrothermal vents
• Chemosynthesis = sulfer oxidizing bacteria
• Tube worms
Benthic Communities - Vents and Seeps
• Hydrocarbon seep communities
• 1984 - GOM
• Methane and hydrogen sulfide
• Clams and worms