Env Science

• Photic Zone


  Upper layer of the ocean where sunlight penetrates, allowing photosynthesis to occur. Extends to a depth of about 200 meters.
• Organisms in the Photic Zone

  • Phytoplankton
  • Various fish
  • Marine mammals like dolphins
• Bathyal Zone


  Zone extending from the edge of the photic zone down to about 2000 meters. Receives very little light, has cooler temperatures and higher pressure.
• Organisms in the Bathyal Zone


  • Bioluminescent fish
  • Certain species of squid
• Abyssal Zone


  Deep ocean zone, starting from 2000 meters down to the ocean floor, typically around 6000 meters. Completely dark, cold, and has high pressure.
• Organisms in the Abyssal Zone

  • Deep-sea anglerfish
  • Giant squid
  • Various benthic invertebrates
• Seawater


  Water from the ocean with a high salt concentration (approximately 35 parts per thousand)
• Examples of Seawater


  • Water from the Atlantic Ocean
  • Water from the Mediterranean Sea
• Brackish Water


  Water with a salinity between seawater and freshwater, often found in estuaries where freshwater mixes with seawater
• Examples of Brackish Water

  • Water in the Baltic Sea
  • Water in Chesapeake Bay
• Freshwater


  Water with very low salt concentration (typically less than 0.5 parts per thousand)
• Examples of Freshwater


  • Rivers
  • Lakes
  • Ponds such as the Mississippi River or Lake Victoria
• Interception


  The process by which precipitation is caught and held by vegetation, leaves, and other surfaces before it reaches the ground
• Example of Interception


  • Rainwater caught by tree leaves during a storm
• Infiltration


  The process by which water on the ground surface enters the soil
• Example of Infiltration


  • Rainwater seeping into the soil of a garden
• Percolation


  The movement of water through the soil layers, typically reaching deeper underground layers
• Example of Percolation


  • Groundwater moving through the soil to recharge an aquifer
• Mean Sea Level Aquifer

  An aquifer that is at or near the mean sea level, typically found along coastlines. Can be influenced by sea levels and tides.
• Example of Mean Sea Level Aquifer

  • The Floridan aquifer in the southeastern United States
• Perched Aquifer


  An aquifer that is above the main water table due to an underlying layer of impermeable rock or clay. Isolated from the main groundwater flow.
• Example of Perched Aquifer


  • A small groundwater reservoir found on top of an impermeable layer of shale in a hilly region
• Oceanic Crust


  The crust found beneath the ocean floors. Thinner (about 5-10 km thick), denser, and primarily composed of basaltic rocks. Younger than continental crust due to continuous formation at mid-ocean ridges and recycling into the mantle at subduction zones.
• Continental Crust


  The crust found under the continents and continental shelves. Thicker (about 30-50 km thick), less dense, and primarily composed of granitic rocks. Older than oceanic crust and forms the landmasses we live on.
• Earthquakes


  Occur due to the sudden release of energy in the Earth's crust that creates seismic waves. This release of energy usually happens when stress that has built up along geological faults or by volcanic activity becomes too great, causing the rocks to break or slip along fault lines.
• Earthquake Risk Factors


  • Places on Earth near tectonic plate boundaries (divergent, convergent, and transform boundaries) are more prone to earthquakes, such as the Pacific Ring of Fire.
• Earthquake Magnitude vs. Intensity


  Earthquakes of the same magnitude can result in different intensities at two different sites due to factors such as the distance from the earthquake's epicenter, local geological conditions, and the depth of the earthquake. Soft soils can amplify seismic waves, leading to stronger shaking, while rockier areas may experience less intense shaking.
• Human Activities Increasing Earthquake Risks

  • Hydraulic fracturing (fracking), reservoir-induced seismicity from filling large dams, and the extraction of minerals or fossil fuels can increase the likelihood and severity of earthquakes. Negligence in enforcing building codes and poor urban planning can exacerbate the life-threatening potential of earthquakes by increasing the vulnerability of structures and infrastructure.
• Deforestation


  Disrupts the carbon cycle by reducing the number of trees available to absorb carbon dioxide (CO2) during photosynthesis, leading to increased CO2 levels in the atmosphere. This contributes to global warming and climate change. Additionally, deforestation destroys habitats, leading to a loss of biodiversity.
• Fossil Fuel Combustion


  Significantly impacts the carbon cycle by releasing large amounts of carbon dioxide (CO2) and other greenhouse gases into the atmosphere. This accelerates the natural carbon cycle, leading to an increase in atmospheric CO2 levels, which enhances the greenhouse effect, resulting in global warming and climate change. The increased CO2 also affects ocean chemistry, leading to ocean acidification, which can harm marine life.
• Mitigating Imbalances in the Carbon Cycle


  • Reforestation and Afforestation: Planting trees in deforested areas (reforestation) or creating new forests (afforestation) can help absorb CO2 from the atmosphere, restoring the balance in the carbon cycle and providing habitats for wildlife, thereby enhancing biodiversity.
  • Transition to Renewable Energy: Reducing reliance on fossil fuels by adopting renewable energy sources such as solar, wind, and hydroelectric power can significantly lower CO2 emissions. This helps mitigate climate change and reduces the overall impact on the carbon cycle.
• Demography


  The statistical study of human populations, including the analysis of size, structure, distribution, and trends in birth, death, migration, and aging.
• Developments Leading to Exponential Population Growth

  • Neolithic Period: The advent of agriculture allowed for more stable food supplies, leading to population growth as people could support larger families and communities.
  • Industrial Revolution: Technological advancements and improved living standards, including innovations in medicine, sanitation, and transportation, along with increased food production and economic opportunities, resulted in a dramatic increase in the human population.
• LEDC (Less Economically Developed Country)

  Generally has lower life expectancy due to poorer healthcare, nutrition, and living conditions. Higher dependency ratio with a larger proportion of young dependents due to higher birth rates and sometimes older dependents due to inadequate pension systems.
• MEDC (More Economically Developed Country)


  Generally has higher life expectancy due to better access to healthcare, nutrition, and living conditions. Lower dependency ratio with more balanced proportions of working-age individuals and dependents due to lower birth rates and more robust social security systems.
• Pyramids of Energy


  Depict the energy flow through each trophic level in an ecosystem, always showing a regular shape because energy decreases at each successive level due to the second law of thermodynamics, where energy is lost as heat during metabolic processes.
• Food Chains


  Rarely longer than five trophic levels because energy transfer between trophic levels is inefficient, with only about 10% of energy being passed on to the next level. This inefficiency means that there is insufficient energy to support more than five trophic levels, leading to shorter food chains.
• Pyramids of Numbers


  Represent the number of organisms at each trophic level, and can have irregular shapes because the number of organisms doesn't always decrease at higher trophic levels.
• Food Webs


  Illustrate multiple feeding relationships and interactions among different organisms within an ecosystem, providing a more comprehensive understanding of the complex interdependencies compared to simple food chains.
• The producer in a food chain is not always a plant. Producers are organisms that produce their own food through photosynthesis or chemosynthesis, which can include algae and certain bacteria in aquatic ecosystems.