1. Marine Ecosystems and Biodiversity
The relationships between organisms within ecosystems
Predator-prey relationships
The connection between environment, biodiversity and ecological niches

2. Learning Outcomes
a) Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity, and ecological niche

3. Structure and Function
Biosphere
Ecosystems
Communities
Populations
Organisms
Structure and Function
The biological organization of the ecosphere ranges from molecules and cells in organisms to the entire biological community of the Earth.
Ecology: a study of how organisms interact with each other and their environment
Layers of hierarchy (Russian nesting dolls)
Organisms  species  population  community  ecosystem  biosphere

4. Ecosystems function by the exchange of matter and energy.
An ecosystem is the totality of the environment encompassing all parts:
Chemical
Physical
Geological
Biological
Ecosystems function by the exchange of matter and energy.

5. Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Ecosystem: refers to living organisms and the physical and chemical factors which influence them
Includes both biotic and abiotic factors
A rocky shoreline (the ecosystem) includes all the organisms living there, linked together by flows of energy forming a food web and their environment.

6. Ecosystems vary in size.
They can be as small as a puddle or as large as the Earth itself.
Any group of living (biotic) and nonliving (abiotic) things interacting with each other can be considered as an ecosystem.

7. Habitat: the place where organisms live
Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Habitat: the place where organisms live
The area surrounding a hydrothermal vent provides a habitat for species of tube worms and other specialized organisms.

8. Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Population: consists of organisms of the same species, usually defined as living in the same area.
A population of ghost crabs (Ocypode saratan) living on a sandy shore.
Community: includes all the different species living in a habitat at the same time
The mollusc community on a rocky shore
Includes all the different species of molluscs living in this habitat

9. Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Species: defined as a group of similar organisms that can interbreed and produce fertile offspring.
Ex: skipjack tuna (Katsuwonus pelamis) and red mangrove trees (Rhizophora mangle).
Use a binomial system of nomenclature (each sps given a name of 2 parts)
1st name (generic) represents the genus
2nd name (specific) refers to the species

10. Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Biodiversity: takes into account the numbers of different species present and the range of habitats and ecosystems.
Coral reefs have high biodiversity with many different species present
Sandy shores have low biodiversity as there are relatively few different species in this habitat

11. Within each ecosystem, there are habitats
These may also vary in size.
A habitat is the place where a population lives.
A population is a group of living organisms of the same kind living in the same place at the same time.
All the different populations interact and form a community.

12. Explain the meaning of the terms ecosystem, habitat, population, community, species, biodiversity and ecological niche
Ecological niche: sometimes defined as the role of an organism within an ecosystem
Takes into account it’s relationship with other organisms.
In a marine ecosystem, the niche of a great white shark (Carcharinid carcharhinedae) is the top predator.
Organisms which occupy similar niches will tend to compete with each other for resources, such as food or space to live in their habitat

13. Habitat and Ecological Niche
Habitat is the area an organism lives and reproduces in.
Ecological niche is the role an organism plays in its community, including its habitat and its interactions with other organisms.
Fundamental niche - All conditions under which the organism can survive.
Realized niche - Set of conditions under which it exists in nature.

14. Fundamental vs. Realized Niche

15. Competition Between Populations
Interspecific competition occurs when members of different species try to utilize a resource in limited supply.
Competitive Exclusion Principle - No two species can occupy the same niche at the same time.
Resource Partitioning decreases competition.
Can lead to character displacement.

16. Competition Between Barnacle Species

17. Feeding Niches for Wading Birds

18. Learning Outcomes
b) Describe each of the following types of interrelationships within a marine ecosystem
Symbiosis
Parasitism

19. Describe each of the following types of interrelationships within a marine ecosystem
Symbiosis: refers to a relationship between two different organisms where both derive some benefit from the relationship
Ex: coral and zooxanthellae
Ex: cleaner fish and grouper
Ex: chemosynthetic bacteria and tube worms

20. Parasites obtain nutrients from their host
Describe each of the following types of interrelationships within a marine ecosystem
Parasitism: relationship between 2 organisms where one (parasite) obtains benefit at the expense of the other (host) which is usually harmed by the relationship
Parasites obtain nutrients from their host
Ectoparasites (ex: fish lice) live on the OUTside of their host
Endoparasite (ex: nematodes, roundworms) live inside their host (usually in the digestive system)

21. Symbiosis: A close relationship between two organisms
Symbiosis: A close relationship between two organisms. Many symbiotic organisms share a living space.
Symbiont: Usually the smaller
organism in a symbiotic relationship.
Example: Algae called zooxanthellae
that often live inside the tissue of a coral.
Host: Usually the larger
organism in a symbiotic
relationship.
Example: A coral polyp.
In this case, the Symbiont lives inside of the tissues of the Host.

22. There are three main trends observed with organisms that participate in symbiotic relationships.
Mutualism: A relationship between two organisms (host and symbiont) in which both benefit from the interaction.
Parasitism: A relationship between two organisms in which one organism benefits at the other organism's expense.
Commensalism: A relationship between two organisms in which the host neither benefits nor is hurt by the relationship.
Host
Symbiont
Host
Symbiont
Host
Symbiont

23. The grouper fish allows the cleaner fish to eat food trapped between its teeth: a free lunch in exchange for some dental hygiene.

25. Learning Outcomes
c) Explain the meaning of the terms producer, consumer, predator, prey and trophic level in the context of food chains and food webs

26. Green plants, algae, and some types of bacteria are referred to as producers as they are able to synthesize organic substances from simple organic compounds , using light energy from the sun, in the process of photosynthesis.
Plants are autotrophs and the primary producers in most ecosystems.

27. Plants use chlorophyll in photosynthesis:
to convert inorganic material into organic compounds
to store energy for growth and reproduction

29. As the primary producers, plants require for photosynthesis :
Sunlight
Nutrients
Water
Carbon dioxide
The formula for photosynthesis is:
Sunlight + 6 CO2 + 6 H2O  C6H12O6 (sugar) + 6 O2

30. The term consumer refers to an organism that obtains its energy requirements by feeding on other organisms.
Primary consumers (known as herbivores) feed on plant material;
Secondary consumers (or carnivores) feed on herbivores.
There also may be tertiary consumers, feeding on secondary consumers in a food chain

31. Herbivores eat plants and carnivores eat animals.
All other organisms are heterotrophs, the consumers and decomposers in ecosystems.
Herbivores eat plants and carnivores eat animals.
Material is constantly recycled in the ecosystem.
Energy gradually dissipates as heat and is lost.

32. Animals must consume pre-existing organic material to survive
Animals break down the organic compounds into their inorganic components to obtain the stored energy.
The chemical formula for respiration is:
C6H12O6 (sugar) + 6 O2  6 CO2 + 6 H2O + Energy

33. The recovered energy is used for:
Movement
Reproduction
Growth
The food consumed by most organisms is proportional to their body size (exceptions occur).
Smaller animals eat smaller food
Larger animals eat larger food

34. Chemosynthetic bacteria, such as those found associated with hydrothermal vents, are able to produce organic substances by oxidizing hydrogen sulphide. In a hydrothermal vent community, these chemosynthetic bacteria are the producers that provide food for other organisms in the community

36. FIGURE 10.02a: Simple food chain.
A food chain is the succession of organisms within an ecosystem based upon trophic dynamics.
Who is eaten by whom.
FIGURE 10.02a: Simple food chain.

37. A food web consists of interconnected and interdependent food chains
FIGURE 10.02b: Food web.

38. FIGURE 10.01: Ecosystem model.

39. FIGURE 10.02c: Energy pyramid.
An energy pyramid represents a food chain in terms of the energy contained at each trophic level.
The size of each level in an energy pyramid is controlled by the size of the level immediately below.
FIGURE 10.02c: Energy pyramid.

40. The word “trophic” refers to nutrition
Trophic dynamics is the study of the nutritional interconnections among organisms within an ecosystem.
In food chains and webs the  represents the direction in which energy and biomass are transferred
Trophic level is the position of an organism within the trophic structure of an ecosystem.
Autotrophs form the first trophic level.
Herbivores are the second trophic level.
Carnivores occupy the third and higher trophic levels.
Decomposers form the terminal level.

41. Sunlight and nutrients are the limiting factors in marine ecosystems.
Phytoplankton blooms are the rapid expansion of a phytoplankton population because sunlight and nutrients are abundant.

42. The basic feeding strategies of animals are:
Grazing
Predation
Scavenging
filter feeding
deposit feeding
Population size is dependent upon food supply and grazing pressure.

43. FIGURE 10.03e: Feather duster worms.
Feeding Strategies
Predator
FIGURE 10.03c: Barracuda.
Filter Feeder
Courtesy of Florida Keys National Marine Sancutary/NOAA
Scavenger
FIGURE 10.03e: Feather duster worms.
© Frank & Joyce Burek/age fotostock
FIGURE 10.03d: Crab.
Courtesy of George Harrison/U.S. Fish & Wildlife Service

44. Bacteria are decomposers.
They break down organic material and release nutrients for recycling.
FIGURE 10.05a: Nutrient cycling.
FIGURE 10.05b: Sediment geochemistry.

45. Energy Transfer Between Trophic Levels
FIGURE 10.06: Energy transfer between trophic levels.
Adapted from Russel-Hunter, W.D. Aquatic Productivity. Macmillan, 1979.

46. Food chains transfer energy from one trophic level to another
Biomass is the quantity of living matter per unit area or per volume of water.
With each higher trophic level:
the size of organisms generally increases
the reproductive rate decreases
The number of organismsdecreases
the total biomass decreases

47. The two major food chains in the ocean are:
the grazing food chain
the Detritus food chain (non-living wastes form the base of the food chain)
Only about 10-20% of energy is transferred between trophic levels.
This produces a rapid decline in biomass at each successive trophic level.

48. Primary production is the total amount of carbon (C) converted into organic material per square meter of sea surface per year
(gm C/m2/yr)

49. Factors that limit plant growth and reduce primary production include:
Major Factors:
solar radiation
nutrients
Secondary Factors:
Upwelling
Turbulence
grazing intensity
turbidity
Only 0.1 to 0.2% of solar radiation is used for photosynthesis, and its energy stored in organic compounds.

50. d) Explain how populations of predator and prey may be interrelated
Learning Outcomes
d) Explain how populations of predator and prey may be interrelated
Predation occurs when one living organism, the predator, feeds on another, the prey.
Presence of predators can decrease prey densities, and vice-versa.

51. Lynx-Snowshoe Hare Interactions

52. Explain how populations of predator and prey may be interrelated
The availability of food is a major factor which will affect the numbers of predators in an ecosystem
If the availability of food increases, the number of predators may correspondingly increase.
The converse is also true
The numbers of prey/predators show a series of fluctuations, where the number of predators lags behind the prey

53. Prey-Predator Relationships
FIGURE 10.04: Prey-predator relationships.

55. Prey Defenses
Prey defenses are mechanisms that thwart the possibility of being eaten by a predator.
Spines
Tough Epidermis
Poisonous Chemicals
Camouflage
Bright Coloration
Flocking Behavior

56. Camouflage in the Anglerfish

57. Mimicry
Mimicry occurs when one species resembles another that possesses an overt antipredator defense.
Batesian - Mimic lacks defense of the organism it resembles.
Müllerian - Mimic shares same protective defense.

58. Learning Outcomes
Describe shoaling and explain why shoaling may be a successful strategy for feeding, reproduction and predator avoidance, with reference to tuna and sardines

59. Shoal - any group of fishes that remains together for social reasons
School - a polarized, synchronized shoal (has coordinated, directed movements)
schooling is an extreme form of shoaling
fish move into and out of schools all the time

60. Shoaling and commercial fish
Many commercially important fish shoal and this behavior makes them more vulnerable to fishing pressure and capture in large numbers
In many commercial species the largest shoaling occurs during migrations, when smaller shoals join together.
Some North Atlantic herring shoals have been measured to be 279 million to 4,580 million m3 with densities of fish per/m3
Migrating mullet shoals in the Caspian Sea have been documented 100 km long

61. One strategy is to attack at low light levels
Shoals and Predators
One strategy is to attack at low light levels
Another strategy is to swim along shoal and pick off fish that are sick, don’t stay in form, or make an error in responding
More effective is the to attack in schools – schooling fish cannot avoid another school as effectively as they can a lone predator
Shoaling fish favorite of pelagic predators – hunting strategies have developed to overcome defenses of shoals –

63. How do Schools Work?
Requires great deal of coordination among individuals in the school
Vision is primary sensory cue for coordinating movement
Use of optomotor reaction - individual movement is coordinated with movement of some other visually distinctive object - e.g. a spot or a stripe

64. Functions of Schooling Behavior
increased hydrodynamic efficiency
increased efficiency finding food
increased reproductive success
reduced risk of predation
Dilution and confusion effect
More eyes to detect danger

65. Functions of Schooling Behavior
Hydrodynamic efficiency
individuals obtain reduction in drag by following in “slip-stream” of neighbors
limited evidence in support of this

66. Functions of Schooling Behavior
Reduced predation risk
creates patchy distribution of prey - large areas with no prey
once school is found, individual risk of being captured is reduced by dilution
confusion of prey by protean displays, encirclement, other behaviors

67. Functions of Schooling Behavior
Feeding
increases effective search space for the individual (more eyes, separated by greater distance)
coordinated movements to help break up schools of prey - analogous to pack behavior in wolves - by tunas, jacks

68. Functions of Schooling Behavior
Reproduction
increases likelihood of finding a mate
facilitates coordination of preparedness (behavioral and pheromonal cues)
facilitates arriving at right spawning site at right time

69. Fish Behavior & Communication
Shoaling • A social grouping of fish • Occurs throughout life in about 25% of fish species • Half of all fish shoal at some time
Benefits of Shoaling • Gives a predator many moving targets – Confuses predators – Increases chances at the individual level – Increases food finding ability • Keeps potential mates in close proximity

70. Fish Behavior & Communication
Pods • Tightly grouped school • Move as a single unit (including making quick turns) • Makes the school appear like one large organism – Protection from predators

71. Liabilities of Grouping Behavior
• Increased likelihood of disease & parasite transmission • Becoming more conspicuous to some predators – Harvested more easily by man