Coller Marine ScienceColler Marine ScienceIntro to Ecological Principles Intro to Ecological Principles

in the in the Marine EnvironmentMarine Environment

Marine Ecology

• Define ecology and give examples of the differences between ecology and environmentalism.

• Give examples of research targets in ecological studies.• Define, recognize and describe any type of interaction between organisms using

appropriate terminology.• Understand and be able to develop food webs, trophic pyramids and to make

predictions regarding the effects of disturbances on these, based on data, observations and descriptions of communities, (e.g. trophic cascades).

• Be able to describe nutrient / biogeochemical cycles and evaluate the effects of human impact on these cycles.

• Discuss the factors that affect population growth and distribution.• Explain the various levels of organization as defined ecologically i.e. community,

ecosystem, biome, etc. . .

Objectives:

What is Ecology??• Ecology is the study of the interactions between organisms and the environment.• Ecology is the study of the relative stability, distribution and density of populations

and the measurable relationships to abiotic factors in their environment.• There are three major disciplines in ecology.

– Population Ecology– Community Ecology– System Ecology

NOAA Marine Ecologist Lisa Ballance

What Ecology is Not!!• Ecology is not an ideology regarding the rights of living things.• Ecology is not environmentalism or any other political movement.• Ecology is not a religious or moral guide.• Ecology is not in opposition to technological advancement, the accrual of wealth or

the use (exploitation) of natural resources.

Exempli Gratia• Ecologists cannot say that it is wrong to fish in a particular

manner or that it is immoral to kill an octopus.

• Ecologists can say that a particular manner of fishing will not be sustainable and will lead to a loss of resources and jobs, or tell us that octopuses demonstrate high levels of intelligence compared with other invertebrates.

Defining the Ecological DiscussionBiotic or Abiotic

• Biotic Factor are those that are alive or are the result of actions by living organisms.– All living things– The products of their bodies e.g. bone, hair, droppings, fallen leaves, burrows

• Abiotic Factors are those that are not alive or the result of actions by living things.– Temperature, pH, humidity, wind speed, altitude, incline, light, salinity, water density,

pressure, PO2 , etc.

Question• Give two examples of abiotic factors which are more significant in

rocky intertidal ecosystems (tide pools) than in the open ocean.

Organizational Hierarchy• Ecologists study different aspects of the interactions that take place in living

systems. To that end they look at living systems using various scales to help them understand the dynamics of life on earth.

• These levels can be delineated generally by the following categories.– Biosphere– Biomes– Ecosystems – Communities– Populations

• Species Subset– Individuals

Organizational Hierarchy• What is the distinction between the community and the ecosystem within a given

area?• Describe the make-up of a kelp forest community.

Individual

Population

Community

Ecological Interactions• Competition

– Interspecies– Intraspecies

• Heterotrophic (Consumers)– Predator/Prey– Planktonivorous (insectivorous) – Herbivorous– Scavengers, Detritivores, Decomposers, D.O.M.– Parasitism– Photo-heterotrophy (bacterial light-mediated ATP synthesis)

• Autotrophic (Producers)– Photo-autotrophy– Chemo-autotrophy

• Symbiosis– Endo/Ecto(epi)-symbiosis– Parasitism– Commensalism (e.g. epiphytes)– Mutualism– Mimicry (Batesian and Mulerian)

Interspecies Competition

Intraspecies Competition

Predation

Commensalism• Relationship that involves two organisms wherein one organism benefits from the

relationship and the other is not harmed nor does it benefit. Symbolically (+ : 0 )

Mutualism• Relationship (often symbiotic) that involves two organisms both of which benefit

from the relationship. Symbolically ( + : + )

Parasitism• Relationship (often symbiotic) that involves two organisms one of which benefits

from the relationship at the expense of the other. Symbolically ( + : – )

MimicryBatesian: One organism mimics Batesian: One organism mimics another to gain the benefit of itanother to gain the benefit of it’’s s characteristic. For example; if the characteristic. For example; if the Mimic Octopus mimics a sea snake it Mimic Octopus mimics a sea snake it gains the benefit of the threat posed gains the benefit of the threat posed by sea snakes.by sea snakes.

Mullerian: Groups of organisms Mullerian: Groups of organisms share appearance in order to benefit share appearance in order to benefit from the reinforcement of deterence.from the reinforcement of deterence.

Population EcologyLogistic Growth Exponential Growth

Carrying Capacity/Limiting ResourcesCarrying Capacity:Carrying Capacity:• In any system there is a finite supply of resources. In any system there is a finite supply of resources. • Even seemingly limitless resources such as sunlight require surface area for Even seemingly limitless resources such as sunlight require surface area for

organisms to be able to exploit them and so there is a maximum number of organisms to be able to exploit them and so there is a maximum number of organisms that can acquire that resourceorganisms that can acquire that resource. .

• The maximum number of organisms, of a single species, that any ecosystem can The maximum number of organisms, of a single species, that any ecosystem can support is called the support is called the carrying capacitycarrying capacity..

• If the population exceeds the carrying capacity some of the members of the If the population exceeds the carrying capacity some of the members of the population will not receive the necessary resources to survive and they will die.population will not receive the necessary resources to survive and they will die.

Limiting Resources:Limiting Resources:• The resource that determines the carrying capacity and therefore The resource that determines the carrying capacity and therefore ““limitslimits”” the growth the growth

of a population is called a of a population is called a limiting resourcelimiting resource..• Limiting resources can be obvious types such as space or food. Or they can be subtle Limiting resources can be obvious types such as space or food. Or they can be subtle

such as the presence of trace elements or other nutrients.such as the presence of trace elements or other nutrients.Limiting Factors:Limiting Factors:• Other elements within an ecosystem may affect the size of a population these may be Other elements within an ecosystem may affect the size of a population these may be

obvious such as predation and disease, or more subtle such a tolerances to obvious such as predation and disease, or more subtle such a tolerances to environmental conditions such as incubation temperatures.environmental conditions such as incubation temperatures.

Carrying Capacity• Generalized graph depicting the population Generalized graph depicting the population

of a species relative to its carrying capacity. of a species relative to its carrying capacity. This shows a logistic growth rate common to This shows a logistic growth rate common to stable systems.stable systems.

• Environmental factors can cause the carrying capacity to change, for example a Environmental factors can cause the carrying capacity to change, for example a particularly rainy year may result in more forage for herbivores and alter the particularly rainy year may result in more forage for herbivores and alter the carrying capacity for a wide number of interconnected organisms in a given system.carrying capacity for a wide number of interconnected organisms in a given system.

• Environmental change and human intervention can also result in extreme cases of Environmental change and human intervention can also result in extreme cases of population growth and die-offs. One of the most classic examples of this is the case population growth and die-offs. One of the most classic examples of this is the case of the introduction of reindeer to St. Matthew Island, Alaska.of the introduction of reindeer to St. Matthew Island, Alaska.

Carrying Capacity: St. Matthew’s Island Deer a Case History

St. Matthew IslandSt. Matthew Island’’s reindeer herd provides a good example of a population explosion and crash. s reindeer herd provides a good example of a population explosion and crash. When 29 reindeer were introduced to St. Matthew in 1944, the island was covered with a thick When 29 reindeer were introduced to St. Matthew in 1944, the island was covered with a thick

mat of lichens. With the abundance of high quality forage, the herd increased dramatically, and mat of lichens. With the abundance of high quality forage, the herd increased dramatically, and by the summer of 1963 there were 6000 unmanaged reindeer on the island.There were however, by the summer of 1963 there were 6000 unmanaged reindeer on the island.There were however, less than 50 reindeer alive that next spring. less than 50 reindeer alive that next spring.

St. Matthews reindeer population increased dramatically because there was little hunting or St. Matthews reindeer population increased dramatically because there was little hunting or predation, good fawn production and an abundance of high quality forage. As the St. Matthew predation, good fawn production and an abundance of high quality forage. As the St. Matthew reindeer population grew, increasing amounts of forage (food) were required. reindeer population grew, increasing amounts of forage (food) were required.

Soon most of the lichens, (high quality winter forage) were used up, and sedges and grasses Soon most of the lichens, (high quality winter forage) were used up, and sedges and grasses (medium quality winter forage) took their place in the ground cover. At the time of the crash, (medium quality winter forage) took their place in the ground cover. At the time of the crash, deep snows limited availability of the remaining forage. Crowberry, a low quality food, was the deep snows limited availability of the remaining forage. Crowberry, a low quality food, was the only available forage. As the quantity and quality of forage declined, the condition of reindeer only available forage. As the quantity and quality of forage declined, the condition of reindeer declined as well. The reindeer lacked adequate fat reserves to survive the particularly difficult declined as well. The reindeer lacked adequate fat reserves to survive the particularly difficult winter of 1963-64 and 99% of the animals died. winter of 1963-64 and 99% of the animals died.

In 1982 the last reindeer disappeared from the island. In 1987, 22 years after the period of In 1982 the last reindeer disappeared from the island. In 1987, 22 years after the period of overgrazing, only 10 percent of the original lichen biomass had grown back, and these were overgrazing, only 10 percent of the original lichen biomass had grown back, and these were mostly lichens that are not preferred by reindeer. It will take many additional mostly lichens that are not preferred by reindeer. It will take many additional ‘‘reindeer-freereindeer-free’’ years before the island will again be capable of supporting a large population of reindeer.years before the island will again be capable of supporting a large population of reindeer.

Karter/University of California, Davis, Andrew J., and Robert A. Dieterich Professor of Veterinary Science, Emeritus. Population Dynamics: An Introduction for Alaskan Reindeer Herders. Population Dynamics: An Introduction for Alaskan Reindeer Herders. May 1989. University of Alaska Fairbanks. 23 Mar. 2009 <http://www.uaf.edu/snras/afes/pubs/bul/B81.pdf>.

Carrying Capacity: St. Matthew’s Island Deer a Case History

St. Matthew Island Reindeer Population

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6000

1350

29

0

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2000

3000

4000

5000

6000

7000

1940 1945 1950 1955 1960 1965 1970

Year

Popu

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Carrying Capacity and Human Population• Q: Why should population dynamics matter to us?? Q: Why should population dynamics matter to us??

• A: Human population growth has followed an exponential pattern since the dawn of A: Human population growth has followed an exponential pattern since the dawn of the industrial age and the advent of science. This is unsustainable!! i.e. bad news the industrial age and the advent of science. This is unsustainable!! i.e. bad news for all those folks who are in areas where they cannot provide for themselves.for all those folks who are in areas where they cannot provide for themselves.

• S: The rate of growth has begun to slow with education, as well as social and S: The rate of growth has begun to slow with education, as well as social and political leadership. We are smart and if we can control our growth and reverse this political leadership. We are smart and if we can control our growth and reverse this trend then we can stop a human catastrophe. The essential question is what are you trend then we can stop a human catastrophe. The essential question is what are you going to do??going to do??

Thomas MalthusEnglish economist Malthus is best known for his hugely influential theories on population growth. ‘ An Essay on the Principle of Population' was published in 1798

The main tenets of his argument were radically opposed to current thinking at the time. He argued that increases in population would eventually diminish the ability of the world to feed itself and based this conclusion on the thesis that populations expand in such a way as to overtake the development of sufficient land for crops.Believing that one could not change human nature, Malthus wrote:Must it not then be acknowledged by an attentive examiner of the histories of mankind, that in every age and in every State in which man has existed, or does now exist•That the increase of population is necessarily limited by the means of subsistence,•That population does invariably increase when the means of subsistence increase, and,•That the superior power of population is repressed, and the actual population kept equal to the means of subsistence, by misery and vice.

So was Malthus wrong? Why have we not run out of food or other essential resources?

Green Revolution

• Advances in agricultural technology lead to immense increases in productivity– Farming and irrigation techniques– Hybridization, genetic manipulation– Chemical fertilizers, insecticides, herbicides– Etc.

Ecological Succession• Succession is the natural

progression of groups flora and fauna that move into available habitat over time.

• Available habitat can arise from disturbance, (e.g. fire) or from the formation of new terrain, (e.g. volcano).

• As time passes and conditions change the make-up of the community changes through competitive exclusion.

• Eventally a “climax community” is established that will not be replaced except by some disturbance (i.e. logging, flood, etc.).

Ecological Succession

Ecological Succession• Primary succession involves previously unpopulated terrain. Which can be either

newly formed or scraped clear to reveal substrate as with landslides.

Ecological Succession• Secondary succession involves regions that were previously populated but in which

the community has undergone a significant disturbance.

Hurricanes and Floods Fallow Farms, Logging

Tornado and StormsFire Succession

Trophic Levels and Pyramids• The initial energy in ecosystems comes The initial energy in ecosystems comes

from either sunlight or chemicals used from either sunlight or chemicals used by autotrophs to generate by autotrophs to generate carbohydrates.carbohydrates.

• The initial energy to enter a system The initial energy to enter a system moves through the system via moves through the system via consumption. consumption.

• Q: What happens to that energy as it Q: What happens to that energy as it moves from one organism to another?moves from one organism to another?

• A: At each level most of the energy is A: At each level most of the energy is lost as heat and motion. Much of it is lost as heat and motion. Much of it is used for growth and reproduction.used for growth and reproduction.

• Only a small fraction (Only a small fraction (≈ 10%) ≈ 10%) of the of the energy is actually transferred up the energy is actually transferred up the food chain via consumption.food chain via consumption.

Food Web and Food Chains

Semicossyphus pulcher

California Sheephead

Pisaster brevispinusSpiny Pink Seastar

Trophic CascadesCastro 6th ed. pp .294-295 & fig. 13.26Castro 5th ed. pp. 282-283 & fig. 13.26

Bioaccumulation & BiomagnificationBioaccumulation: Up-take and retention via any route, (diet, respiration, etc.). Although often viewed as a negative effect of man-made chemicals, bioaccumulation is in fact a necessary process for survival and relates both to man-made and naturally occuring chemicals such as those seen in H.A.B.’s. Animals bioaccumulate vitamins A, D and K, trace elements, essential fats and amino acids. Bioaccumulation is of concern when substances are present at harmful levels. The extent of bioaccumulation depends on the organism’s rates of uptake, distribution, metabolism and excretion.

Bioaccumulation & BiomagnificationBiomagnification: The increase in relative concentrations of substances (toxins) in the tissues of animals in subsequent trophic levels. The biomagnification factor (BMF) is the ratio of the concentration of a substance in the predator compared with the prey.

Case Studies: DDT• DDT DDT (dichlorodiphenyltrichloroethane) is a is a

highly effective insecticide for the eradication highly effective insecticide for the eradication of disease carrying mosquitoes.of disease carrying mosquitoes.

• Because of its persistence in the environment Because of its persistence in the environment it bio-accumulates. it bio-accumulates.

• Because of its solubility in fats it undergoes Because of its solubility in fats it undergoes bio-magnification through the food chain.bio-magnification through the food chain.

• This lead to high concentrations in fish and This lead to high concentrations in fish and subsequently harmful levels in fish eating subsequently harmful levels in fish eating birds. This led to a thinning egg shells birds. This led to a thinning egg shells causing high mortality rates in young.causing high mortality rates in young.

• DDT banned in 1972DDT banned in 1972• Additionally the wholesale eradication of Additionally the wholesale eradication of

mosquitoes brings its own harmful effects as mosquitoes brings its own harmful effects as they play a role in many ecosystems as food they play a role in many ecosystems as food for fish, birds, small mammals and other for fish, birds, small mammals and other insects as well pollinators.insects as well pollinators.

Rachel CarsonDisturbed by the profligate use of synthetic chemical pesticides after World War II, Carson reluctantly changed her focus in order to warn the public about the long term effects of misusing pesticides. In Silent Spring (1962) she challenged the practices of agricultural scientists and the government, and called for a change in the way humankind viewed the natural world.

Although DDT was popularly viewed as a miracle of modern technology—especially because it had been successfully used in World War II to kill fleas, mosquitoes, and other insects that can spread deadly diseases like malaria—biologists had begun to compile evidence of the rise of DDT-resistant strains of insect pests and of the harmful side effects of DDT on other species. Nonetheless, the U.S. Department of Agriculture and the manufacturers of DDT and similar pesticides continued to support the use of these substances. But Carson’s gripping accounts of ecological disasters were based on a meticulous search and use of scientific literature, and her conclusions were upheld by President John F. Kennedy’s Science Advisory Committee, among other authorities

Case Studies: DDT

Case Studies: Minimata Japan

http://www.youtube.com/watch?v=ihFkyPv1jtU

H.A.B.s in U.S. Coastal WatersNeurotoxic ShellfishParalytic ShellfishAmneisiac ShellfishDomoic Acid??CiguateraPfisteriaBrown Tide??Anoxia??

Primary Production & Standing Stock

Variations in Productivity with Latitude

Variations in Productivity with Latitude

Variations in Productivity with Latitude

Upwelling• Caused by seasonal prevailing winds which result in Eckmann transport of surface

water away from the coast.• Surface water is replaced by deep water which is colder and carries a large nutrient load.

Upwelling on CA Coast

El Niño la Niña• http://svs.gsfc.nasa.gov/stories/

elnino/index.html

The Layered OceanMixed Layer: Upper 100m of ocean. Well mixed due to winds, currents and wave action. This leads to nearly uniform density. At lower latitudes temperature varies seasonally.Pycnocline: Region of rapidly increasing density, due to changes in temperature and salinity.Deep Layer: Majority of the oceans mass. Density increases gradually with depth and water moves slowly; in only a few locations (usually near the bottom) are water movements fast enough to be considered currents.

The Layered Ocean

Latitudinal Ocean Variations

Latitudinal Ocean Variations

Biogeochemical Cycles• H2O-Cycle

Biogeochemical Cycles• C-Cycle

Biogeochemical Cycles• N-Cycle

Biogeochemical Cycles• P-Cycle

• The Environment “shapes” species based upon the phenotypic variations that are carried within a species genome.

• Nature is the tool which selects for traits.• Genes are the raw material upon which natural selection acts. Genes are

continuously mutating providing new materials for Nature to act upon.• Evolution, “Descent with Modification” is the result.• Ecology and Evolution are intimately connected in Nature. The Earth is a dynamic

system. Just as the clouds in the sky change, the mountains rise and fall, even the stars above change through time, so do all living things.

Evolution & Natural Selection