Chapter 10Chapter 10

Marine EcologyMarine Ecology

Marine EcologyMarine Ecology• _____ is the interaction between organisms and their _____ is the interaction between organisms and their

environment.environment.

• These interactions affect the survival and distribution These interactions affect the survival and distribution of these organisms.of these organisms.

• Organisms within a community interact with each Organisms within a community interact with each other in very complex ways.other in very complex ways.

______________All populations of organisms living in a All populations of organisms living in a

defined area.defined area.

______ ______ The physical place where an organism lives.The physical place where an organism lives.

Niche Niche The resources (biotic & abiotic) an organism The resources (biotic & abiotic) an organism uses for survival, growth and reproduction.uses for survival, growth and reproduction.

Needs of a SpeciesNeeds of a Species

• Populations demand specific Populations demand specific resources to survive.resources to survive.

• These resources can affect These resources can affect population growth if they are in short population growth if they are in short supply.supply.

• These resources that have the ability These resources that have the ability to affect the growth of a population to affect the growth of a population are called are called limiting resourceslimiting resources..

Needs of a SpeciesNeeds of a Species

• The limiting resources can include, The limiting resources can include, but are not limited to:but are not limited to:– NutrientsNutrients– LightLight– Space (habitat)Space (habitat)– Oxygen or carbon dioxideOxygen or carbon dioxide– Inorganic compoundsInorganic compounds

Needs of a SpeciesNeeds of a Species

• Even if an organism is able to acquire a Even if an organism is able to acquire a limiting resource, there is a maximum limiting resource, there is a maximum number of organisms that any habitat number of organisms that any habitat can support. can support.

• This number is known as the This number is known as the carrying carrying capacitycapacity. .

• As a population becomes more As a population becomes more “crowded,” the growth rate of that “crowded,” the growth rate of that population will decrease.population will decrease.

Marine EcologyMarine Ecology

Ways that Species can Interact:Ways that Species can Interact:

1.1. CompetitionCompetition

2.2. Predator-Prey InteractionsPredator-Prey Interactions

3.3. SymbiosisSymbiosis

CompetitionCompetition

• Competition occurs when organisms Competition occurs when organisms must “fight” with one another over a must “fight” with one another over a limiting resource they both require for limiting resource they both require for survival.survival.

• Organisms can compete with members Organisms can compete with members of their own species – intraspecific of their own species – intraspecific competition – or members of other competition – or members of other species – interspecific competition.species – interspecific competition.

Purple _____ exhibiting _____ competition andPurple _____ exhibiting _____ competition andRed (dark in photo)_____ exhibiting _____ with a ____Red (dark in photo)_____ exhibiting _____ with a ____

_____ competition between two hermit crabs _____ competition between two hermit crabs fighting over a mollusk shellfighting over a mollusk shell

CompetitionCompetition

• An organism can use a resource at An organism can use a resource at the expense of another organism. the expense of another organism.

• This may result in reduced ability of This may result in reduced ability of that individual to reproduce or even that individual to reproduce or even survive.survive.

• Poorer competitors may die out due Poorer competitors may die out due to this competition.to this competition.

• Interspecific CompetitionInterspecific CompetitionIndividuals of different species compete for Individuals of different species compete for

same resources (food, shelter, space).same resources (food, shelter, space).

What are possible outcomes of interspecific What are possible outcomes of interspecific competition?competition?• one individual one individual excludesexcludes the other (principle of the other (principle of

competitive exclusion) Ex. Two fish species competitive exclusion) Ex. Two fish species feed on seaweed and one feeds faster and has feed on seaweed and one feeds faster and has more offspring until the second species is gonemore offspring until the second species is gone• they they coexistcoexist (resource partitioning) (resource partitioning)

Resource partitioning - Resource partitioning -

Competing species can coexist if they Competing species can coexist if they use the same resource in a slightly use the same resource in a slightly different way or at a different time.different way or at a different time.

Ex. Two fish species that both eat Ex. Two fish species that both eat seaweeds. One might specialize on seaweeds. One might specialize on brown algae while another might brown algae while another might feed on red algaefeed on red algae

Symbiosis - one species living in or on Symbiosis - one species living in or on another.another.

Types of Symbiosis:Types of Symbiosis:1. Mutualism - both species _____ (example: cleaning 1. Mutualism - both species _____ (example: cleaning

associations).associations).

2. Commensalism - one species benefits with no apparent effect 2. Commensalism - one species benefits with no apparent effect on the other (example: barnacles living on whales; hermit crab).on the other (example: barnacles living on whales; hermit crab).

3. Parasitism - one species benefits & the other is harmed 3. Parasitism - one species benefits & the other is harmed (examples: tapeworms in the guts of whales).(examples: tapeworms in the guts of whales).

More on SymbiosisMore on Symbiosis• If partners in a symbiotic relationship can If partners in a symbiotic relationship can

live without one another, this is known as live without one another, this is known as facultative symbiosis (cleaning symbiosis).facultative symbiosis (cleaning symbiosis).

• If the partners cannot survive with the If the partners cannot survive with the other partner, this is known as obligate other partner, this is known as obligate symbiosis (marine lichens).symbiosis (marine lichens).

• The smaller partner is known as the The smaller partner is known as the symbiont and the larger partner is called symbiont and the larger partner is called the host. Name each in a marine lichen.the host. Name each in a marine lichen.

PredationPredationOne species (predator) kills another One species (predator) kills another (prey) for food.(prey) for food.

• Prey species often have adaptations that Prey species often have adaptations that help them avoid being eaten such as:help them avoid being eaten such as:

• Warning coloration (lionfish we discussed Warning coloration (lionfish we discussed in Fig. 8.10)in Fig. 8.10)

• Camouflage (stonefish and flounder)Camouflage (stonefish and flounder)

• Physical adaptations (shells in mollusks)Physical adaptations (shells in mollusks)

• Behavior (schooling)Behavior (schooling)

EcosystemEcosystemAll the _____ (living) and _____ All the _____ (living) and _____

(nonliving) components in a defined (nonliving) components in a defined area.area.• Ecosystems interact.Ecosystems interact.• All ecosystems require a constant All ecosystems require a constant

inputinput of energy. of energy.• Chemicals and nutrients are Chemicals and nutrients are cycledcycled

within ecosystems.within ecosystems.

Energy FlowEnergy Flow

• Energy flows through an ecosystemEnergy flows through an ecosystem

• Route of energy flow is determined Route of energy flow is determined by an by an ecosystem’s ecosystem’s trophic trophic structure.structure.

Where Does all the Energy Where Does all the Energy Go?Go?Is Is allall of the energy stored by of the energy stored by

individuals at one trophic level individuals at one trophic level available to the next?available to the next?No No - energy needs of individual take up - energy needs of individual take up most of the energy created or consumed.most of the energy created or consumed.

On average, ~10% On average, ~10% (5-20%)(5-20%) is is transferred to the next level of the transferred to the next level of the food chain.food chain.

Food chains rarely extend beyond four trophic levels except in the ocean community. Why??????

• There is more biomass created at the There is more biomass created at the bottom of the trophic level – at the bottom of the trophic level – at the primary producer level. Think of all the primary producer level. Think of all the primary producers present in the marine primary producers present in the marine community and the VAST stretches of community and the VAST stretches of ocean that support primary production.ocean that support primary production.

• Therefore, the system can support Therefore, the system can support additional secondary consumers. additional secondary consumers.

Major Marine EnvironmentsMajor Marine Environments

• Benthic organismsBenthic organisms – live in/near – live in/near bottom featuresbottom features

• This can be subdivided by the depth This can be subdivided by the depth of the benthic zone. Examples:of the benthic zone. Examples:– Intertidal zoneIntertidal zone – benthic zone located – benthic zone located

between high and low tidebetween high and low tide– Subtidal zoneSubtidal zone – always submerged; – always submerged;

below the low tide level.below the low tide level.

Major Marine EnvironmentsMajor Marine Environments• Pelagic organismsPelagic organisms – live in the water column – live in the water column• This zone, too, can be subdivided into different This zone, too, can be subdivided into different

areas:areas:– Epipelagic zoneEpipelagic zone- extends from the water’s surface to 100-- extends from the water’s surface to 100-

200 m; plenty of sunlight available to support primary 200 m; plenty of sunlight available to support primary productionproduction

– Mesopelagic zoneMesopelagic zone – extends from lower limit of epipelagic – extends from lower limit of epipelagic to about 1000 m; although sunlight is not plentiful, new to about 1000 m; although sunlight is not plentiful, new research has shown that some photosynthesis does occur research has shown that some photosynthesis does occur in this zone, although it is very reduced compared to the in this zone, although it is very reduced compared to the epipelagic zone. epipelagic zone.

– The The Deep Sea Deep Sea zoned as bathypelagic (1000-4000m), zoned as bathypelagic (1000-4000m), abyssopelagic (4000-6000m) and hadopelagic (>6000m) abyssopelagic (4000-6000m) and hadopelagic (>6000m) where light does not penetrate. These will be discussed in where light does not penetrate. These will be discussed in the chapter on deep sea organisms.the chapter on deep sea organisms.

Measuring Primary Measuring Primary ProductivityProductivity• The total amount of primary production is known as The total amount of primary production is known as

the gross primary production.the gross primary production.

• The organic matter left over after the primary The organic matter left over after the primary producers meet their own needs is the net primary producers meet their own needs is the net primary production. Can be estimated using gas detectors production. Can be estimated using gas detectors that measure carbon dioxide used or oxygen that measure carbon dioxide used or oxygen produced.produced.

• The total amount of phytoplankton in the water is The total amount of phytoplankton in the water is called the standing stock. Can be measured by called the standing stock. Can be measured by instruments that quantify chlorophyll in seawater. instruments that quantify chlorophyll in seawater. Also can be measured using satellite photographs.Also can be measured using satellite photographs.

Standing Stock (the total amount of Standing Stock (the total amount of phytoplankton) is estimated using phytoplankton) is estimated using instruments that detect chlorophyll or instruments that detect chlorophyll or satellite photographs. satellite photographs.

The Carbon CycleThe Carbon Cycle

• Carbon is required for primary Carbon is required for primary producers to create organic producers to create organic molecules. molecules.

• This carbon is cycled through an This carbon is cycled through an ecosystem. Carbon dioxide is ecosystem. Carbon dioxide is released during _____ and released during _____ and decomposition. It is used by decomposition. It is used by producers during ____. producers during ____.

Nitrogen and Phosphorus

Nitrogen and phosphorous are also required for primary production and must be cycled through an ecosystem. Figures 10.21 and 10.22 outline this cycling.Nitrogen is fixed by bacteria and archaea.Most nitrogen and phosphorous compounds are produced during decomposition and excretion.

Certain elements or compounds taken up by Certain elements or compounds taken up by organisms cannot be metabolized or excreted.organisms cannot be metabolized or excreted.

They accumulate in the organism (bioaccumulation) They accumulate in the organism (bioaccumulation) and may reach toxic levels.and may reach toxic levels.• heavy metals (lead, arsenic, mercury)heavy metals (lead, arsenic, mercury)• nonbiodegradable pesticides (DDT)nonbiodegradable pesticides (DDT)• Even toxins produced by organisms can be biomagnified like during Even toxins produced by organisms can be biomagnified like during

red tidesred tides

The effects of bioaccumulated materials are The effects of bioaccumulated materials are magnified through the food web (biomagnification).magnified through the food web (biomagnification).