Chapter Chapter 1010

Marine Marine EcologyEcology

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Marine EcologyMarine Ecology

• Ecology is the interaction between Ecology is the interaction between organisms and their environment.organisms and their environment.

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

• Interactions can be very complex.Interactions can be very complex.

CommunityCommunityAll populations of organisms living in a All populations of organisms living in a

defined area.defined area.

Habitat Habitat 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 Even if an organism is able to acquire a limiting resource, there is a acquire a limiting resource, there is a maximum number of organisms that maximum number of organisms that any habitat can support. any habitat 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 limiting resource they both require for survival.for survival.

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

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 Individuals of different species

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

What are possible outcomes of What are possible outcomes of interspecific competition?interspecific competition?• one individual excludes the other one individual excludes the other

(principle of competitive exclusion)(principle of competitive exclusion)• they coexist (resource partitioning) they coexist (resource partitioning)

More on NichesMore on Niches

– Fundamental nicheFundamental niche - all resources a - all resources a species is capable of using.species is capable of using.

– Realized nicheRealized niche - all resources a species - all resources a species actually uses in a community.actually uses in a community.

– The realized niche may be different due The realized niche may be different due to specific interactions with competitors.to specific interactions with competitors.

Resource partitioning - Resource partitioning -

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

Symbiosis - one species Symbiosis - one species living in or on another.living in or on another.Types of Symbiosis:Types of Symbiosis:1. Mutualism - both species benefit (example: 1. Mutualism - both species benefit (example:

cleaning associations).cleaning associations).

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

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

More on SymbiosisMore on Symbiosis

• If partners if a symbiotic relationship If partners if a symbiotic relationship can live without one another, this is can live without one another, this is known as facultative symbiosis.known as facultative symbiosis.

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

• In all cases, the smaller partner is In all cases, the smaller partner is known as the symbiont and the known as the symbiont and the larger partner is called the host.larger partner is called the host.

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

• Camouflage

• Mimicry

EcosystemEcosystemAll the biotic (living) and abiotic All the biotic (living) and abiotic

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

input of energy.input of energy.• Chemicals and nutrients are Chemicals and nutrients are

cycled within ecosystems.cycled 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 trophic ecosystem’s trophic structure.structure.

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

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

On average, ~10% On average, ~10% (5 - 20%)(5 - 20%) is transferred to is transferred to the next level of the food chain.the next level of the 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 tide (therefore, between high and low tide (therefore, this is exposed at least once a day – this is exposed at least once a day – twice in NC!)twice in NC!)

– 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 This zone, too, can be subdivided into

different areas:different areas:– Epipelagic zoneEpipelagic zone- extends from the water’s - extends from the water’s

surface to 100-200 m; plenty of sunlight surface to 100-200 m; plenty of sunlight available to support primary productionavailable to support primary production

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

– The The bathypelagic, abyssopelagic and bathypelagic, abyssopelagic and hadopelagic zoneshadopelagic zones are deep sea zones where are deep sea zones where light does not penetrate. These will be covered light does not penetrate. These will be covered in the chapter on deep sea organisms.in the chapter on deep sea organisms.

Measuring Primary Measuring Primary ProductivityProductivity

• The total amount of primary production is The total amount of primary production is known as the gross primary production.known as the gross primary production.

• The organic matter left over after the The organic matter left over after the primary producers meet their own needs primary producers meet their own needs is the net primary production. This forms is the net primary production. This forms the base of the trophic pyramid.the base of the trophic pyramid.

• The total amount of phytoplankton in the The total amount of phytoplankton in the water is called the standing stock water is called the standing stock (phytoplankton are the main primary (phytoplankton are the main primary producers).producers).

The Carbon CycleThe Carbon Cycle

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

• This carbon is cycled through an This carbon is cycled through an ecosystem.ecosystem.

Nitrogen and PhosphorusNitrogen and Phosphorus

• Nitrogen and phosphorous are also Nitrogen and phosphorous are also required for primary production and required for primary production and must be cycled through an must be cycled through an ecosystem. ecosystem.

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

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

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