Introduction

What is Environmental Science?

Environmental Science is the study of organisms and the their surroundings. The goal of environmentalists is to create a sustainable society where humans can live in good conditions without depleting resources and doom our future generations. 

There are many problems with society right now. We have various forms of pollution, overpopulation, over-harvesting our resources, global warming, and much more. 

In order for humans to survive in the long run, and not be the source of its own undoing, we must figure out ways to live sustainably.

Cycles

Everyone should know a little bit about the difference cycles in the environment

The water cycle consists of the evaporation of water from the ocean, the condensation of water into clouds, the precipitation of the water on the land, into runoff towards the ocean.

Other less known parts include the infiltration and percolation of water into the soil and the slow groundwater movement along with transpiration from plants.

The nitrogen cycle consists of nitrogen fixation of atmospheric N2 into NH3, nitrification of NH4 to NO2 to NO3, and denitrification into atmospheric N2 again.

Other steps include ammonification of dead matter into NH3.

The Phosphorus Cycle is mainly a sedimentary cycle. Phosphate is usually the limiting factor for plants and lake populations.

The main parts of the phosphorus cycle include uplifting, sediments, fertilizing, and runoff.

The sulfur cycle is a mainly anthropogenic cycle, but most of it is inside the earth in rocks and minerals.

The important parts of the sulfur cycle include acid rain deposition, sulfate salt composition, and hydrogen sulfide emissions from industries.









QUIZ QUESTION: Through what process does atmospheric nitrogen get converted into NH3?

Weather and Climate

Weather is short term conditions of a place while climate is long term conditions. Upwelling occurs when the surface waters move away from the west coast, causing a massive rush of cool, deep, nutrient-rich water to rise from the bottom.

The El Nino Southern Oscillation is an important weather phenomenon in the Pacific Ocean. Usually, tropical trade winds blow from east to west and this causes upwelling off the west coast of the Americas. Anyways, during an ENSO, these westerly winds weaken, and sometimes reverse in direction preventing the normal upwelling, which stops crucial nutrients from reaching populations, leading to a decline in biodiversity of the ocean. This is becoming a major concern for us because these ENSOs are happening more and more often. No one knows why, but scientists suspect human actions and pollution are behind this enigma.

EXTRAPOLATING QUESTION: What is the reverse of an El Nino called?

Biomes

Population Ecology

Exponential growth is when a population grows at a fixed rate. This is what occurs in the early stages of a population's development. The population takes in all the resources and multiply in numbers. There are no limiting factors and the population will continue to grow until it is unable to sustain itself.

This is a logistic growth curve, or an S-shaped curve. This occurs when a population reaches a carrying capacity (k) where k is the maximum number of organisms that the environment can sustain. Once the population overshoots, a dieback occurs because the population has run out of resources and can not support that many organisms. 

Scientists have classified species into r-selected and k-selected species.
R-SELECTED SPECIES                                              K-SELECTED SPECIES
1. Many offspring                                                           Few offspring
2. Minimum parental care                                               High parental care
3. Reproduce early and many times                                Reproduce late and few times
4. High population growth rate                                       Low population growth rate
5. Generalist species                                                       Specialist species

Furthermore, scientists have come up with three general survivorship curves: early loss, constant loss, and late loss.

The graph has age of the organism on the x-axis and percentage of organisms surviving on a log scale on the y-axis. The red line represents late loss because most of the organisms survive longer. The black line represents constant loss where organisms die off regularly. The blue line represents early loss where the survival rate of the young is low, but those who survive tend to live a long time. Examples of late loss are humans and rhinos, constant loss are squirrels and birds, early loss are fish.




QUIZ QUESTION: Are humans k-selected or r-selected species?

Preserving Biodiversity

What's so important about having biodiversity anyways?
           Well, some people argue that species have instrumental value, or that species are advantageous to humans because of the goods and services that it provides like food, fuel, medicine, etc. Species can provide revenue for humans, for example, eco-tourism gains half a trillion dollars each year. They can also provide useful genetic information and code for scientists to make genetically modified assets.
           Other people argue that species have intrinsic/existence value, which means that everything has a right to live regardless of its advantages because everything has that fundamental right be it cockroach, insect, or human. Famed biologist E. O. Wilson goes even further and says that people have a natural affinity for nature and want to protect it, a phenomenon known as biophila.
           I would argue that the intrinsic people are the nicer people and the instrumental people are the sadistic exploiting type. But that's just my opinion.

What are the threats to biodiversity?
Remember this useful acronym HIPPO
H: habitat destruction and fragmentation, the greatest threat to biodiversity.
I: invasive species, these (mostly generalist species) are introduced into foreign environments and more often than not displace existing species that are unable to compete. Example: quagga mussel, kudzu vine
P: population growth of humans
P: pollution, more on that later down
O: over-harvesting, coming soon!

How do we protect biodiversity?
Important legislation and treaties include…
Convention on International Trade in Endangered Species (CITES): A treaty signed by the vast majority of countries and it prohibits the trading of listed endangered species.
Lacey Act of 1900: It prohibits the movement of wild animals across state borders.
Endangered Species Act of 1973: Holds National Marine Fisheries Service and US Fish and Wildlife Services responsible for identifying and listing endangered and threatened species, and prohibits projects that would risk the extinction of an endangered or threatened species.

Food

Everyone loves food. Food is the one great bliss of life. But how do we get our food?
We raise animals and livestock on croplands, rangelands, and ocean fisheries. Of the 30,000 edible plant species, 90% of our daily intake of food comes from only 14 plant and 8 terrestrial animal species. Wheat, rice, and corn provide more than 50% of the calories we eat. Such concentrated eating habits lead to the development of industrialized plantation agriculture. This is when farmers take a plot of land and only grow one type of plant species on it like acres devoted to the production of wheat. Such monoculture wears down the land and degrades the soil. It also becomes quite susceptible to invasive species and is expensive to maintain.
In order to produce good food, we need good soil. There are three main nutrients that plants need: Nitrogen, Phosphorus, and Potassium. You can find the N-P-K numbers on any bag of fertilizer and it will tell you the varying concentrations each has in the bag. Soil salinization and erosion are huge problems in the US. Soil salinization occurs when there is too much irrigation water in the soil and when the water evaporates, leaves behind a thin crust of salts called the duracrust. Too much salt eventually causes the death of plants. Did you know that soil in the US is eroding 16 times faster than it's being replenished? At this rate, we might not have enough land to produce our food with.

How can YOU help?  :)
We can install drip irrigation systems that deliver precise amounts of water to targeted crops so that soil salinization doesn't occur.
We can also grow our own food in our backyards with no pesticides and being organic, healthier.
We can support local organic farms by purchasing their products in local farmer's markets.