Types of Energy Resources

There are many types of energy available for human use, but man tends to overuse some of them which leads to environmental problems.

1. Fossil Fuels: by far the most exploited energy resource but not for much longer. (Coal, Oil, Natural gas)
2. Nuclear Energy: highly productive, but comes with hazardous issues.
3. Hydroelectric Energy: harnesses the kinetic energy of flowing water. Sounds great but what happens to the river? And what if there is no river nearby?
4. Solar energy: just like plants have been doing for millions of years! Renewable because the sun will be around for a few billion years more! But if solar energy is so great, why are we not all using it?
5. Wind: Works great! As long as there is wind. Kind of noisy though.
6. Geothermal: harnessing the thermal energy beneath the Earth’s crust! Nees to find an opening though.
7. Tidal: using the moon’s gravitational energy that the oceans convert to kinetic energy.
8. Hydrogen Fuel Cells

Energy Budget of Food Production

Farming's Energy Budget

When farming and producing food, one needs to examine the inputs, outputs, flows and storages in order to determine the energy budget.

e.g. fuels, chemicals, labor, materials, transports, wastes, energetic content of products.

Also consider that the marketable product which is produced is only a % of the total output, which may not be marketable.

For every watt of input I get ___ watts of product (dairying, cereals, etc.)

Comparing Aquatic vs. Terrestrial Food Production

Terrestrial:

• Food harvested from 1st or 2nd trophic levels thus more energetically efficient.
• Solar energy capture (GPP) more efficient.
• Energy transfers between trophic levels not as efficient.

Aquatic:

• Most food is harvested from higher trophic levels, thus not as efficient
• Solar capture (GPP) not as efficient due to absorption of sunlight by water
• Energy transfers between trophic levels fairly efficient.

Farming and Food Production

Types of Farming Systems

1. Subsistence: provision of food for family and their community; little or no surplus; mixed crops; extensive use of human labor; low use of fossil fuels, chemicals, and capital; little technology.

2. Commercial: large profit generating scale; maximized yields, monocultures; high levels of technology, energy, and chemical inputs.

Farming can also be described as:

1. Extensive: uses more land with a lower density of animals or crops; lower inputs and outputs.

2. Intensive: intensive use of land; high inputs and outputs

And as:

i. Pastoral

ii. Arable

iii. Mixed

Demographic Transition Models

A Demographic Transition Model describes the pattern of decline in mortality and natality (fertility) of a country due to social and economic development.

Can be describes as a 5-stage model:

1. Pre-industrial
2. LEDC
3. Wealthier LEDC
4. MEDC stable
5. MEDC population decline.

MEDCs vs LEDCs

• In many MEDCs, the cost of staple food items is relatively cheap.
• Most people make purchases based on taste and preference.
• Produce seasonality has mostly disappeared due to globalization. T
• his has also allowed for a greater international variety in most supermarkets.

• In LEDCs, many staple food items may not be always affordable as prices fluctuate.
• People tend to make purchases based on nutritional need and affordability.
• Political and economic agendas can affect food production (e.g. cash cropping)
• Even if food crops are not used as cash crops, food production is still impacted since arable land is being occupied all the same.
  

Population Pyramids

Population pyramids show how many individuals are alive in different age groups of a certain region in a given year. These are made up of bars, and the x-axis shows the population numbers while the y-axis shows the age group. The length of the bars shows relative proportion, shown as a percentage of the total population.

These pyramids shows population distribution and can help make predictions on population change.

Types of Pyramid Shapes
There are four stages in the population pyramids.

• Stage 1: Expanding - High CBR, rapid fall in each upwardage group due to high CDR, short life expectancy.
• Stage 2: Expanding - High CBR, fall in CDR as more individuals live to middle age, slightly longer life expectancy.
• Stage 3: Stationary - Declining CBR, low CDR, more individuals live to old age.
• Stage 4: Contracting - low CBR, low CDR, higher dependency ratio (those that cannot work), longer life expectancy.

LEDCs tend to be stage 1 or 2

MEDCs tend to be stage 3 or 4

Food and Food Supply

1. Define food security and food insecurity.
Food security refers to the people in an area having access each day to sufficient food with sufficient nutrients. It depends on countries having the means to produce or import enough food for its population. Also, a country must make sure that there are no harmful environmental effects that can affect its ability to produce food. Food insecurity means not being able to have either enough food or food with enough nutrients each day.

2. Distinguish between undernutrition, malnutrition, and overnutrition.
Undernutrition occurs when the food an individual eats is not enough to meet its basic energy needs. Malnutrition occurs when the food an individual eats does not contain enough proteins or key nutrients. Overnutrition occurs when the food an individual eats contains more calories or more nutrients than those that are necessary.

3. Describe the effects of diet deficiencies in Vitamin A.
A lack of Vitamin A can cause increased susceptibility to common childhood infectious diseases. Children under 6 who do not get enough Vitamin A can go blind and even die.

4. What is famine? How may it affect: societies, the environment?
Famine is a severe shortage of food in a certain area. There is mass starvation, deaths, and social disruption. Societies become chaotic and many starving people migrate to other areas and there is a frantic search for food and water. Individuals also eat their reserves of grains for future years and they will kill their breeding livestock. This will have an impact on the sustainable yield of an environment, affecting its ability to provide enough food for the population in the future.

5. What three systems provide most of the world’s food?
Wheat rice and corn provide more than half of the calories consumed by the world population.

6. Distinguish among industrialized agriculture and plantation agriculture.
Industrialized agriculture or high-input agriculture is that that uses high amounts of energy such as fossil fuels, a large amount of water, uses commercial fertilizers, pesticides and produces single crops (monocultures) and raises livestock.
Plantation agriculture is a form of industrialized agriculture used in tropical developing countries. It involves growing cash crops on large monoculture plantations that will later be sold to developing countries. Forests are cleared to make room for these plantations and biodiversity is reduced.

7. What is a green revolution? What limits could these have?
The green revolution is a process that helped increase crop yields. It involved three steps: First, monocultures would consist of selectively bred or genetically engineered key crops. Second, use of large amounts of fertilizer, pesticides and water to improve yields. Third, multiple cropping would allow an increase in the amount of crops. The green revolution limits biodiversity and could have adverse effects on the soil profile of an area, thus affecting its ability to yield crops in the future.

Population Growth

Population growth can be defined in terms of birth rate, death, doubling time, migration, and fertility rate.

The total fertility rate (TFR) is the average number of children that each woman has over her lifetime. Calculating this helps show the potential for population change in a country.

TFR > 2.0 = population increase
TFR < 2.0 = population decrease
TFR = 2.0 = stable population

Factors that impact our environment apart from population size, is the amount and distribution of wealth as well as the resource desire and need.

Population Growth and Food Shortages

There are two opposing theories on this subject: one by Thomas Malthus, and the other by Ester Boserup. Malthus states that the population is increasing geometrically while the food supply increases aritmethically. This means that the population will surpass the amount of food available, causing excess individuals to die off.
Boserup on the other hand states that while the population keeps growing it will develop the technology needed to meed the food demand. While Malthus is too pessimistic, Boserup is too optimistic. I think we need to find a middle ground. Also, population keeps growing and each country's demands are different. Will the population grow so much that it will cause a dramatic dieback? Have we surpassed our carrying capacity?

Measuring Population Change

There are 4 main factors affecting population size:

1. Birth rate
2. Death rate
3. Immigration
4. Emigration

To measure population change one needs to know:

1. Crude Birth Rate
2. Crude Death Rate
3. Doubling Rate
4. Natural Increase Rate

The Crude Birth Rate (CBR) is the number of births per one thousand individuals in a population per year. It is calculating by dividing the number of births by the total population size and multiplying by 1000.

CBR=[(Number of Births)/(Population Size)]*1000

The Crude Death Rate (CDR) is the number of deaths per 1000 individuals. It is calculated the same as the CBR.

CDR=[(Number of Deaths)/(Population Size)]*1000

The Natural Increase Rate (NIR) is a percentage found by calculating

NIR=(CBR-CDR)/10

Doubling Time is the time in years it takes for a population to double its size.

Doubling Time= 70/NIR

Human Development Index

The Human Development Index is a measure adopted by the United Nations Development Program as a way of calculating a country's well-being. It combines measurements of life expectancy, standards of living, education and GDP into one single value, which can be used to rank countries.

Taking this into consideration, two broad classifications can be used into which countries can be placed:

• MEDCs: Most economically developed countries
  
• LEDCs: Least economically developed countries

MEDCs are industrialized countries that have high GDPs. Their population is relatively rich and has a relatively low growth rate. These countries also have a high level of resource use.

On the other hand, LEDCs are less or not at all industrialized. These countries may have high natural capital, but it is usually exported to MEDCs where it is processed. LEDCs have lower GDPs and have higher poverty rates. Their population is large and has poor standards of living along with a high population growth rate.

Limiting Factors and Population Growth

Populations can change over time due to many different variables, known as limiting factors. These keep populations in check and can be classified into

• Density dependent factors
• Density independent factors

Density dependent factors are those that, as its name implies, depend on population density. This means that the impact these factors have depends on how many individuals there are. These are usually biotic factors, such as biomass, predation, competition.

Density independent factors are those that affect a population regardless of its size. These are usually abiotic factors. Some examples are pH, temperature, salinity, and also natural disasters such as tornadoes, earthquakes, volcanic explosions.

GROWTH CURVES

Growth rate can be graphed. There are two different types of curves:

• J-curve
• S-curve

Each shows a different type of population growth.

J-curves show exponential growth. The population grows exponentially and then crashes or suffers what is known as a dieback. This is because the population overshoots and exceeds the carrying capacity (K), which is the maximum amount of individuals an ecosystem can support without being affected. This is known as a boom and bust pattern. This growth rate is common in organisms.

S-curves start out as exponential growth, but then stabilize as the population reaches its carrying capacity. This growth rate is consistent with density dependent factors. This is known as a logistic curve.

S- and J-curves are idealized. In nature, both types of limiting factors act on the same population and the result is a combination of both curves.

And what about humans?

Human population seems to be growing exponentially, but in my opinion, seeing the conditions our planet is in, it seems as if we have surpassed our carrying capacity. Is the human population heading for a dieback? How much longer before the population crashes?

Quick notes on Sustainable Yield

Sustainable Yield (SY) refers to the increase in natural capital. It is the natural income that can be exploited each year without depleting the original stock or affecting its potential for replenishment.

If you see it as a business, you could consider sustainable yield as the 'retained profit' of a company. It is the amount that one has left over and can use to invest in other aspects of the business. That money can be used to expand and grow or to improve the business in any other way. It is the same with Sustainable Yield, that increase in natural capital is what is available for use and would not affect the environment. It is like the money a company can use to make itself better without going into debt.

* MSY means the maximum sustainable yield, and it is the one that is of interest commercially speaking.

Some important aspects to consider when calculating sustainable yield are:

• carrying capacity
• population size
• total biomass or energy at a given time
• Rates of change of population, biomass, and energy.

However, there is a convenient formula for calculating Sustainable Yield:

SY= Annual Growth and Recruitment - Annual Death and Emigration

Basically, what this calculates is how many organisms are there at a given point in time. It considers new individuals that came in, and individuals that died or left.

Sustainable Yield can also be calculated by

SY= (Total Biomass or energy at a Time T)+1 - (Total Biomass or energy at a Time T)

This is useful when calculating the changes in SY over a period of time. It would be used when comparing biomass in 2009 and biomass in 2010.


Here is an example on how sustainable yield is important for economic systems. It is a report on the commercial value of estuaries in Australia.
http://www.ozcoasts.org.au/indicators/econ_value_commercial_fisheries.jsp

Also, here is an ecological assessment of rivers and estuaries (also in Australia). This is the type of information that is useful when evaluating an ecosystem and its natural resources.
http://www.anra.gov.au/topics/coasts/pubs/estuary_assessment/est_ass_int_wpdd.html

Economy and Systems

An economic system produces and distributes goods and services by using natural, human and manufactured resources. It works just like an environmental system: it is made up of certain components, require inputs (resources) and produces outputs (good and services).

Economic systems seek to satisfy people's needs and wants in the most efficient and effective way. The success or failure of an economic system is based on how efficiently and effectively it carries out its activities. An economic system is also in charge of the distribution of wealth.

As in any system, there needs to be an input of resources. In an economic system, these resources are known as capital, and it is used to produce goods and services.

Capital can be divided into three categories:

1. Natural Capital
2. Human Capital
3. Manufactured Capital

Natural capital and natural income include natural resources that have value. These are resources that support life. Examples include trees, soil, water, living organisms, etc. Natural capital also includes processes such as photosynthesis and biogeochemical cycles, because these help promote life.

Natural capital in economic systems is extremely important since natural capital yields natural income. In fact, the World Bank calculates a country's wealth by also considering the way it administers its natural resources, along with the other criteria.

Natural resources can be classified into 4 categories by their availability or depending on how long it takes for them to be renewed.

1. Renewable
   
2. Non-renewable
   
3. Replenishable
4. Recyclable

It is possible for a certain resource to fall into more that one category, and there may be ideas that differ depending on each person's point of view.

My Ecological Footprint

The ecological footprint is a measure of how many planets an individual, a family, a community, a city, a country, etc. would need if everyone on Earth lived the way he/she/they did. It takes into account aspects such as your home, your transportation, food, and extra stuff.
There are many ecological footprint test, however I did the one on the WWF page: http://footprint.wwf.org.uk

Here is my result:


If everyone on Earth lived the way I did, we would need 2.16 planets.

Sustainability is....

• Recognizing that you form part of a system, and that your actions have an impact on whether or not you can carry on with that way of life.
• Using only what you need.
• Using resources responsibly.
  
• Respecting nature, not abusing it.
• Meeting your needs without harming nature.
• Living in such a way that you ensure that life will carry on and that quality of life will be maintained.
• Being able to maintain your living conditions because of the fact that the environment is not being abused, and thus can keep providing the necessary resources.
• Making sure that future generations will have a world to live in and care for.
  
• Teaching future generations what it means to form part of an ecosystem.

This and many more things define sustainability. Sustainability is not a simple concept that can be defined in two or three sentences. It is a way of life. It is something that should be applied in all aspects of life. It should be a way of measuring our actions.

Measuring Biomass

Biomass refers to the total number of living organisms in a certain area. It is the amount of energy that is available for the next trophic level. It is important to measure biomass because it gives an idea of the state of the ecosystem. By knowing the amount of energy available, one can know how many species it can support.

One way to measure biomass is to obtain the dry weight of an organism (since it is a rough approximation to the amount of biomass) and multiply it by the number of those organisms in a given area. The units are grams per meter squared (or cubed if it is an aquatic ecosystem). This is a commonly used method. However, the difficulty here is knowing with accuracy the total number of individuals, particularly if one wants to measure biomass in a wide area.

The way to get the 'most accurate' biomass measurement would require counting absolutely every organism. However, there are ways to get an estimate. One method is by making a transect, which means tracing an imaginary line across the selected ecosystem, and counting the organisms that are in the quadrants following the transect. That data can then be extrapolated to the rest of the ecosystem, or several transects can be made, to get a more accurate estimate.

Quadrats are another method in which a rectangular area is selected and biomass is counted in that specific place only. Random quadrats can be selected, and as with the transect, the more measurements (quadrats) you select, the better the estimate.

There is also a remote sensing technique that surveys the earth's surface from the air or using satellites. Images generated are analyzed to determine total biomass productivity. However, this is only used with producers, and works mostly on dense woodlands.

In the future, more technological tools will be developed and improved in order to measure biomass easily. This could include better imaging to determine biomass, as well as a technological tool that will help get an accurate number of the individuals of a species in an area. The main benefit is that the measurement will be non-destructive, harming no ecosystem.

After biomass is collected at different trophic levels, a biomass pyramid can be made. Here's an example of an estuary, more specifically, Chesapeake Bay. Taking the following food chain:

phytoplankton -> clams -> blue crabs -> sandbar sharks

Firstly, the units will be measured in kg per cubic kilometer, since it is a aquatic ecosystem. We can calculate the amount of each species in the food chain, and we get the following information:

There are 31,333,333 units of phytoplankton in 2320 cubic km of water in Chesapeake Bay.
There are 9,200,000 clams in that same area.
There are 278,666 blue crabs.
There is one sandbar shark.

Then, considering the weight of each specie and the area, we can calculate biomass, which then can be shown in what is known as a biomass pyramid. Results are shown below.

Bibliography:
Rosillo Callé, Francisco. The biomass assessment handbook. Illustrated ed. Earthscan, 2007. Print.

Kimball, John W. "Food Chains." Biology Pages. N.p., 23 Apr 2010. Web. 27 Aug 2010. .

Tackenberg, Oliver. "A New Method for Non-destructive Measurement of Biomass, Growth Rates, Vertical Biomass Distribution and Dry Matter Content Based on Digital Image Analysis." Oxford Journals (2007): n. pag. Web. 27 Aug 2010. .

Measuring Biodiversity

Biodiversity is the total amount of different species that are found in a given ecosystem, biome or the entire planet. It is an indicator of the health of an area. The greater biodiversity there is, the healthier the ecosystem is.

There are several ways to measure the biodiversity of a given area. The two most popular indices are the Shannon Index and the Simpson Index.

However, before we can talk about measuring biodiversity, two key terms we should know are richness and evenness.

Richness: Number of species per sample.

Evenness: Relative abundance of the different species making up the richness of the area.

The Shannon Index

H= Shannon Diversity Index

S= Total # of species in a community (richness)

Pi= Proportion of S made up of ith species

Eh= Equitability (evenness)

Equitability is measured H/Hmax. Hmax=lnS

To learn more about the Shannon Index go here: http://www.tiem.utk.edu/~mbeals/shannonDI.html

The Simpson's Index

It measures the probability that two individuals randomly selected belong to the same species (or other category)

n= total # of organisms of a particular species (in plants, the % of coverage is measured)

N= total # of organisms of all species

There is also Simpson's Index of Diversity, which measures the probability that 2 randomly selected individuals in a zone belong to different subspecies.

The formula is 1-D.

Finally there is the Simpson's Reciprocal Index, which measures the number of equally common subspecies that will produce the observed Simpson's index.

The formula is 1/D

For more information: http://www.countrysideinfo.co.uk/simpsons.htm

The Key to Classifying

We know that organisms are classified using the Linneaen taxonomic system, and they are named using binomial nomenclature. However, what do we do when we encounter an unknown organism? How can we name an organism found in the wild?

A dichotomous key is a tool used to identify organisms in a systematic way. It can be used to identify organisms parting from a certain taxonomic level. These keys are organized in such a way that the user has to make certain choices according to certain characteristics of the organism. Each step of the dichotomous key offers two choices (thus the name; dichotomous means: divided in two parts) until it points to a specific organism that has all the characteristics previously chosen.

Dichotomous keys are useful for identifying organisms in the field, or even in the lab when there is no other information available about the organism. Keys make come in diagram or in written form.

Here are two examples:

MLA: McGraw Hill. "Taxonomic Classification and Phylogenetic Trees." McGraw Hill Higher Education. The McGraw-Hill Companies, 2001. Web. 12 Aug 2010. .

Species Classification

There are so many different species on the planet that it's difficult to keep track of all of them. Scientists needed to find a way to classify each of them, and so taxonomy emerged.
Taxonomy is the science of identifying, describing, naming, and classifying living things. There are various ways of classifying organisms, but scientists currently rely on the Linnaean taxonomic system, created by Carl Linnaeus, a swedish biologist.

The Linnaean taxonomic system divides organisms into 7 major taxonomic levels called taxa: Kingdom, Phylum, Class, Order, Family, Genus, Species. However, there may be subdivisions like: subclass, suborder, etc. Each taxon becomes more specific as you move down the hierarchy of taxa. For example, many organisms may belong to the same kingdom, but not as many belong to the same phylum. Also, one is able to appreciate relationships between organisms using the taxonomic classification of each. Two species that share the same Order and Family are more closely related than two that only belong to the same order.

However, when naming an organism a binomial nomenclature. This means that when referring scientifically to a certain organism, one simply has to name the genus and species. For example, one would not write Atlantic salmon in a research paper, but would write Salmo salar.


MLA: Nixon, Joshua. "Scientific Names." Taxonomy. Michigan State University, n.d. Web. 12 Aug 2010. .

Chesapeake Bay

Chesapeake Bay is an estuary located in the west coast of the United States. It receives water from over 100,000 streams and rivers and empties in the Atlantic Ocean. It is home to around 350 species of fish, dozens of species of shellfish and crabs, 16 species of underwater grasses. Waterfowl, ospreys, and shorebirds also inhabit nearby areas.

All of these species interact in this ecosystem, and form a very complex food web (made up of many food chains). As explained previously, the food chain begins with a producer, which in this case is the phytoplankton, which is then eaten by a number of first consumers, which are then eaten by other predators.

The main purpose of the food chain is to see how energy is transferred from one organism to another. However, pyramids are ways to obtain more data. They represent graphically how energy, matter, and population are distributed in a system. Two of them are the pyramid of biomass and the pyramid of productivity.

The pyramid of biomass shows the amount of biomass at each trophic level, which is calculated by multiplying the mass of an organism times the amount of organisms. The dry weight of an individual is roughly the same as the energy it contains.

The pyramid of productivity shows the flow of energy over time. Since energy is lost as it moves from 1 trophic level to another, the upper levels are always smaller than the lower ones. Only 10% of the energy in one trophic level is passed on to the next one.

Trophic Levels

A trophic level is a hierarchical position that an organism occupies in an ecosystem. This is based on its source of energy. It is also known as feeding level. Trophic levels are represented through food chains, which show the flow of energy from one organism to another with the sun being the first source of energy.

Let's use as an example a food chain in a kelp forest. Here, the kelp would be the producer, which is eaten by blacksmith fish, who in turn is eaten by otters, who are then eaten by sharks.

The kelp is the producer and occupies the first trophic level. Being an autotroph, it is able to convert the Sun's energy into food for itself, and thus supporting the rest of the food chain.

Blacksmith fish would be the first consumers (herbivores), occupying the second trophic level. Otters are the second consumers (carnivore eating a herbivore), and are placed at the third trophic level. Finally, sharks are third consumers (carnivore eating a carnivore), and occupy the fourth trophic level. If we consider that when the shark dies it remains are broken down by bacteria, they would act as decomposers, placing them at a fifth trophic level.

Ecosystem Fun

An ecosystem is a community that interacts with its physical environment. This includes both biotic and abiotic factors.

Some examples of ecosystems include:

• Estuary: Found where a river meets the ocean, resulting in brackish water and a high biodiversity. Producers are submerged aquatic vegetation (SAV) and plankton. Animals consists of several species of fish, crabs, and invertebrates such as polychaetes and flatworms. Some birds, amphibians, reptiles and mammals inhabit the surrounding land areas.
  
• Coral reef: A highly productive ecosystem. Producers include phytoplankton and algae. Other organisms that can be found in a coral reef are sea anemones, sponges, clownfish, butterfly fish, flatworms, sea stars, sea urchins, shrimps, crabs, lobsters, sharks, rays, among many others.
  
• Desert: Have low precipitation. Low vegetation consisting mostly of deep-rooted shrubs. Animals are nocturnal and have adapted to the heat and scarce water availability.
  
• Rainforest: Abundant rainfall allows the growth of broadleaf trees. There are also herbaceous plants and shrubs. There is great biodiversity, serving as a habitat for a great variety of mammals, reptiles, birds, and insects. Some animals include the jaguar, chimpanzees, butterflies, lizards, macaws and boas.
  
• Grassland: The vegetation consists of a variety of grasses with a resistance to drought and animals are herbivores and some predators that feed on them.
  

What is a system?

A system is a set of components that function and interact in a certain way. Some key components of a system are:

• Inputs: These enter the system. (e.g. matter, energy)
  
• Outputs: These flow out of the system.
  
• Flows: These are materials passing through the system.
  
• Storages: These are where something, such as energy, is held in a certain part of the system.
  
• Sources: As its name states, it is where an input comes from (e.g. the sun is a source of energy)
  
• Sinks: This is where the output goes.
  

Studying the environment as a system helps us better understand the relationships between the different components and the causes and effects within that system.

Types of systems include:

• Open system: Both matter and energy are exchanged.
  
• Closed system: Energy is exchanged, but matter is not.
  
• Isolated system: Neither matter or energy are exchanged.
  

A common characteristic of all systems is synergy. It means that "the whole is greater than the sum of its parts." This occurs when two or more components or processes interact in such a way that the result is greater than the individual effect. This can be seen in things as simple as table salt and in complex systems such as the digestive or circulatory systems.

Hello ESS!

Environmental Systems and Societies is a course that challenges us to use critical thinking in order to form a well-based personal response to important environmental issues. This is achieved only through deep understanding of the interrelationships between environmental systems and societies.

As I progress in the second semester of this course, this blog will provide a space in which important and relevant topics can be discussed. It will also serve as an archive of my coursework throughout the following four to five months.