Feel free to email the instructor (dpalmer@kent.edu) with any
comments about the format and ease of use of these online notes.

1. Ecology and Open Ocean Communities
- Biological Interactions
- Trophic Structure in Open Ocean Communities

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

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
Review: Physical and Chemical Factors
- light availability, temperature, exposure to air, ease of movement, suitable pH (acidity), suitable dissolved gases

4. 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

5. Tolerance for Environmental Conditions
A species' response to an environmental factor often follows a bell-shaped curve
Example:
 High abundance at intermediate temperature, lower abundance at extreme temperatures

6. Competition
Competition can occur among members of the same species or between members of different species
Competition can restrict the range of a population

7. Population - Growth and Controls
J Shaped - Population growth without control
S Shaped - Population growth with control

8. Distribution of Organisms
Random - the position of one organism does not influence other organisms (rare)
Clumped - conditions are optimal in small areas (most common)
Uniformly spaced (very rare)

9. Predator-Prey Interaction
A species' distribution may be controlled by predation
Predation strategies:
- foraging
- ambush (sit and wait)
- scavenger
- filter feeding
- deposit feeding
 

10. Symbiotic Interactions
Symbiosis is the close interaction of two species
Mutualism
- both organisms benefit
Commensalism
- one organism benefits, the other  is not helped or  harmed
Parasitism
- one organism benefits, the other is harmed

11. Building Biomass and Trophic Transfers
Biomass, the amount of carbon/g/meter squared per day or per year, varies from place to place.
The open ocean is least productive, and coastal estuaries and coral reefs are most productive.
To see what happens to productivity in communities, we can look at trophic (feeding) steps.

Each trophic step represents the ecological level at which an organism feeds
Each trophic step has a transfer efficiency of ~10%
See figures 14-2 and 14-3

12.  We often speak of the trophic Pyramid, because there are many organisms that make up
the lowest level of the feeding community, the autotrophic primary producers (the phytoplankton),
and there are progressively fewer organisms with each trophic step.  This is because energy is
continually lost in transfer, and to sustain higher levels, more energy has to be expended.

13. Trophic Webs (Food Webs)
Food webs arise from competitive and predator-prey interactions
Some organisms are more crucial to the food web than others
Figures 14-4 and 14-5

14. Structure of Marine Communities
Photosynthetic
- Open ocean
- Coral reef
Detrital
- Deep sea floor
Chemosynthetic
- Hydrothermal vent
- Cold seep
 

15. Examples of Marine Communities
Open Ocean:
- Coral reef communities
- Open ocean communities
- Deep sea floor communities
- Hydrothermal vent and cold seep communities
Coastal:
- Rocky intertidal communities
- Seaweed communities
- Sand beach and cobble beach communities
- Salt marsh and estuary communities

16. Open Ocean Communities
Food is limited in the open ocean
Consumers in the open ocean depend on the productivity of organisms in the water column above

17  •Many predators hunt in schools.
•Advantages:
•Cooperative hunting
•Avoid bigger predators!

18. Schooling
About 25% of fish species school
School - massed group of similar individuals, closely packed and moving as a unit
Deters predators (school appears as a larger "individual")
Reduces chance interactions between predator and prey
Enhances mating opportunities

19.  Other ways to avoid predation in the open ocean…
 Large Size…Too big for most predators
 Leaving the Water-e.g., the flying fish
 Diving Deep-protection in the Deep Scattering Layer (DSL)

20.  The DSL (Deep Scattering Layer) is really a mass of swimming organisms, millions of them,
that stay more or less together and move up and down in the water column to feed.
They are at the base of the photic zone during the day, and rise into shallower water at night.

21.  Below the DSL, in the dark, we see lots of adaptations to feeding on material falling from above,
and to maximizing the amount of oxygen that can be taken up.

22.Deep Sea Floor Communities
The deep sea floor is
- dark
- usually cold
- hypersaline
- highly pressurized
Slow metabolic rates and unique adapatations allow organisms to thrive
 

23.  In each community, we see the same story-lots of primary producers and primary consumers,
and fewer secondary and tertiary consumers, and fewest of all, the top predators.  As energy flows
up the trophic pyramid, some energy is lost at every step.  There is an energetic cost to sustaining top
predators, and so there are always fewer of them than of the lower trophic groups.

24. Next Lecture
Spineless wonders:  Marine Invertebrates and review for exam III

Focus question:  Why is biodiversity so high in coral reefs?