1. Open Ocean Communities
- Ecology and Marine Communities
- Blue Water and Midwater Communities
- The Deep Sea Floor
Reading:
4th Ed: Ch 16 Sec 16-17, Ch 15 Sec 19-20,24
5th Ed: Ch 16 Sec 16-17, Ch 15 Sec 20-21, 25
Graphic: (top) Tube worms, Riftia pachyptila photo by C. Van Dover OAR/National
Undersea Research Program, Coll. of William and Mary. (bottom) Lion-mane
jellyfish. K.Evans, photographer, Monterey Bay National Marine Sanctuary
Collection.
2. Ecology - Organisms and Their Environment
Ecology: How organisms interact with each other and with their environment
Habitat: Place where an organism lives
Niche: An organism's role in its habitat
Community: The populations of all species that occupy a particular habitat
Graphic: (top) Hermit crab in its natural environment. NOAA National Estuarine
Research Reserve Collection, (bottom) Giant sea spider, photo obtained during
the NORFANZ expedition, copyright by the Commonwealth of Australia, 2001.
3. Success in Marine Communities
Physical, biological and chemical factors determine the composition of marine
communities
The success of an organism within a community depends on
- its tolerance for the conditions of its environment
- the range of variability of physical, chemical and biological factors in its
habitat
4. Population - Growth and Controls
J Shaped - Population growth without control
S Shaped - Population growth with control
Many different processes affect the size of the population that can be sustained
in an environment (the “carrying capacity”)
Graphic: Garrison, 4th Ed., Fig. 16.3. pg 418, 5th Ed., Fig. 16.4, pg 394.
5.. Biological Factors
Biological factors arise due to interactions among organisms
Interactions can be among:
- members of the same species
- members of different species
Examples:
- crowding
- predation
- availability of food
- availability of a mate
Graphic: Sponge colony, D.Blackwood and P.Valentine, photographers, courtesy of
USGS.
6. Competition
Competition occurs when organisms require a resource that is in limited supply
Competition can occur among members of the same species or between members of
different species
Competition can restrict the range of a population
Graphic: Garrison, 4th Ed., Fig. 16.2, pg 417, 5th Ed., see Fig. 16.3, pg 394.
7. Predator-Prey Interaction
A species' distribution may be controlled by predation
Predation strategies:
- foraging
- ambushing (“sit and wait”)
- scavenging
- filter feeding
- deposit feeding
Graphic: (top) polychaete worm, Cordell Bank National Marine Sanctuary, (center)
nurse shark, (bottom) moray eel, courtesy of NOAA Photo Library.
8. Making a Living in the Open Ocean
Food is limited in most areas of the open ocean
Below the sunlit zone, most open ocean consumers depend on the productivity of
organisms in the water column above
Graphic: Image provided by the SeaWiFS project, NASA/Goddard Space Flight Center
and Orbimage.
9. Types of Communities
Photosynthetic – sustained by production of new plant material within the
community
Detrital – sustained by export of organic matter from the euphotic zone
Chemosynthetic – sustained by production of organic matter via
non-photosynthetic chemical reactions (chemosynthesis)
Graphics:(top) Kelp community, M.Golden, photographer, courtesy of NOAA
Restoration Center. (bottom) Octopus on the muddy sea bottom. Courtesy of OAR/NURP
and North Carolina State University.
10. Where is Each Type of Marine Community Found?
Photosynthetic
- Coastal or estuary
- Open ocean (shallow)
- Coral reef
Detrital
- Open ocean (deeper)
- Deep sea floor
Chemosynthetic
- Hydrothermal vent
- Cold seep
- Brine pool
Graphic: Garrison, 4th Ed., Fig. 13.19, pg 342, 5th Ed., Fig. 13.18, pg 321.
11. Open Ocean Habitats
Blue Water:
- sunlit zone in non-coastal regions
- limited availability of plant material
Midwater:
- no photosynthesis
- vision is used for hunting in the upper part of this zone
Seafloor:
- most consumers depend on the export of food from higher in the water column
Graphic:(top) Humpback whale and calf, D.Glickman, courtesy of NOAA, (middle)
Cyanea jellyfish, P.Auster, NOAA/OAR/NURP and Univ. of Ct., (bottom) wolf eel,
V.O'Connell, NOAA/OAR/NURP and Alaska Dept. of Fish and Game.
12. Blue Water Communities
Even in the sunlit zone, food is limited in most parts of the open ocean
Predation and competition provide important evolutionary pressure
Graphics: A school of jacks in the open ocean. Photo by Dr. J.P.McVey, courtesy
of NOAA.
13. Blue Water Predators - Built for Speed
Many blue water predators are cruisers
- constantly searching for prey
- forked tails and narrow fins provide speed
Cooperative hunting:
- school of predators encircles or herds prey
- schooling helps these hunters avoid predation
Graphics: (top) Bonito, Historic NMFS Collection, NOAA, (bottom) yellow fin
tuna, OAR/NURP, NOAA.
14. Schooling
School - massed group of similar individuals, closely packed and moving as a
unit
- Deter predators
- Reduce chance interactions between predator and prey
- Enhanced mating opportunities
About 25% of fish species school
Graphic: Northern anchovy school, OAR/NURP, Courtesy of NOAA.
15. More Predator Avoidance Strategies
Sunlit zone:
- countershading
- "fly" out of the water on large fins
- large size
Midwater:
- silver or black (fish)
- red or purple (invertebrates)
- transparency
- bioluminescence can camouflage
Deep dwellers:
- colorless (no pigment) or black fish
Graphics: (top) Flying fish, S.Rankin, NMFS, SWFSC, (bottom) Jellyfish,
M.Youngbluth, OAR/NURP, both courtesy of NOAA.
16. Between Sunlight and Darkness - The Deep Scattering Layer of the Disphotic
Zone
The DSL is composed of millions of organisms.
Many:
- migrate toward the surface at night to feed
- descend deeper during the day for protection from predators
Members of this community include shrimp, squid, and many species of small fish
Graphic: (top) Siphonophore, OAR/NURP Collection, courtesy of NOAA.
17. Below the DSL, Life in Darkness
Making the most of scarce food…
Deep-sea fish require specific adaptations to survive in areas where the food
supply is poor, and the availability of food is unpredictable
Making the most of infrequent mating opportunities…
- "parasitic" males
- hermaphroditism
- some are simultaneously male and female
- some change gender depending on community composition
Graphics: (left) Hagfish, courtesy of NOAA, (right) Brittle stars in the deep
sea off Cape Hatteras. S. Stancyk, photographer. Courtesy of NOAA NURP and Univ.
of S.Carolina.
18. Deep Sea Floor Communities
- Slow metabolic rates reduce the need for food
- Appendages or fins can lift bodies above the ooze
- Other animals burrow
- Mobile species quickly colonize any potential food source
Community members:
- crustaceans
- worms
- sea cucumbers
- sea stars
- fish
Graphic: (top) Deep sea crab and anemone, R.Cooper, OAR/NURP and Univ. of Ct.
courtesy of NOAA, (bottom) mobile community members, OAR/NURP and Univ. of
Hawaii at Manoa.
19. Vacuum Cleaners of the Deep
Up to 80% of animals on the deep sea floor are deposit feeders
- feed on organic matter this is mixed within the sediment
A very effective strategy...
- there is little plant material for herbivores
- few live animals for carnivores
- slow currents carry little food to suspension feeders
Graphic: Sea cucumber, . E.Williams, photographer. Courtesy of National Undersea
Research Program and NOAA.
20. Preview of Next Lecture
Coastal Marine Communities
Reading:
4th Ed., Ch 16 Sec 10, 12-13
5th Ed., Ch 16 Sec 10-12
Graphic: Egret at the Weeks Bay National Estuarine Research Reserve. Courtesy of
NOAA.