Notes, summaries, assignments, exams, and problems for Geology

Trophic Interactions and Food Webs

Trophic interactions are known as a food web. In a food web, herring typically receives about 0.68% of primary production, compared to 1% in a linear food chain. Ecosystems with fewer trophic levels often exhibit greater fish production.

The Biological Pump

The biological pump refers to the removal of organic matter (specifically organic carbon, fixed by phytoplankton during photosynthesis) from the euphotic zone to deeper waters and ultimately to the ocean floor (sediments).

Biogeochemistry and Trace Metals

Biogeochemistry involves the biological mediation of geochemistry. It encompasses major element cycles such as Carbon (C), Nitrogen (N), Phosphorus (P), and Sulfur (S). These cycles are intimately linked to... Continue reading "Ocean Dynamics and Climate Science Fundamentals" »

Near Earth Asteroids (NEAs)

Asteroids that cross the orbits of inner planets.

Comets

Icy counterparts to asteroids, formed beyond the frostline.

Kuiper Belt

Objects outside the orbit of Neptune to the beginning of the Oort Cloud.

Asteroids

• Small, naturally formed solid bodies that orbit the Sun.
• Airless and show no detectable outflow of gas or dust.
• 18 different compositional types, ranging from solid metal to soggy dirt clods.
• Most are"rocky" consisting of common minerals and free metal. -"Iron" composed of almost pure metal (mostly iron and nickel). -"Carbonaceous Chondrite" composed of rocky material and carbon-rich compounds.

Asteroid Facts

• Rocky leftovers of planet formation.
• Largest is Ceres, diameter ~1,000 km.
• 150,000 in catalogs, and probably over

Conditions for Life

Several key factors make life on Earth possible:

• Water
• A magnetic field
• A protective atmosphere
• Carbon compounds
• An energy source

Biotic and Abiotic Factors

Biotope: The non-living part of an environment, including all abiotic factors.

Biocenosis: All living things from every species within a defined area that provides the necessities for survival.

Ecosystem: A natural environment where living things interact with each other and their surroundings.

Trophic Levels

Ecosystems often have distinct trophic levels:

• Tertiary consumers
• Secondary consumers
• Primary consumers
• Producers

Predation

Predation is an interspecific relationship where one living thing kills another for food.

Soil Composition

Topsoil: Composed of partially decomposed organic matter... Continue reading "Understanding Our Ecosystem" »

Continental Environments

Fluvial (River) Environments

• Stream/river channels
• Sand bars
• Levees
• Floodplains

Lacustrine (Lake) Environments

• Vary in depth, salinity, biological activity, and sediment
• Source sand and mud

Aeolian (Desert) Environments

• Little to no annual precipitation
• Low vegetation
• High wind
• Transport of sand grains
• Dunes contain well-sorted, well-rounded, and frosted (scratched during wind transport) sand grains sand and dust

Paludal (Swamp) Environments

• Area of anoxic (deoxygenated) water where plant material accumulates but cannot decompose (coal)
• Very low energy environment

Glacial Environments

• Glacial meltwater and sediment transport
• Sand, mud, gravel

Transitional Environments

Deltas

• Fan-shaped deposits of sediment
• Coarser sediment is commonly deposited

Non-Conventional Power Plants

The environmental problems caused by conventional power plants have led to the creation and development of non-conventional or alternative energy power plants. These include:

• Wind farms
• Solar power plants
• Geothermal power plants
• Biomass power plants
• Ocean power plants

Combined Cycle Power Plant

Electricity is generated as the result of two combined cycles. In the first cycle, a mixture of air and gas is used to heat the water in the boiler, similar to a conventional thermal cycle. The combustion gases from the first cycle are then transported to another boiler, where they transfer their energy.

Nuclear Power Plants

This type of plant includes a nuclear fission reactor that produces heat to generate the pressurized steam... Continue reading "Alternative Energy Power Generation Methods" »

Energy Resources

Nonrenewable Energy

Nonrenewable energy is a source of energy that exists in limited quantities and, once used, cannot be replaced except over millions of years.

Examples:

• Coal (fossil fuel)
• Oil (fossil fuel)
• Natural gas (fossil fuel)
• Uranium (rock)

Renewable Energy

Renewable energy is a source of energy that can be replaced in a relatively short period of time.

Examples:

• Hydroelectric
• Solar
• Geothermal
• Wind
• Biomass
• Nuclear fusion (potentially in the future)

Most renewable energy originates from the sun.

Fossil Fuels

Oil, natural gas, and coal are known as fossil fuels because they were formed underground from the remains of once-living organisms. Fossil fuels are relatively inexpensive and are usually readily available, but their use creates... Continue reading "Renewable & Non-Renewable Energy Resources: A Comprehensive Guide" »

The Hydrosphere

Definition

All the water that exists on our planet is collectively known as the hydrosphere. This includes water found on the ground, surrounding us, and underground.

Forms of Water

• Solid: Ice, glaciers, snow, and ice caps.
• Liquid: Rivers, seas, oceans, and rain.
• Gas: Steam and water vapor.

Distribution of Water

• Planet: 71% water
• Marine Water: 97%
• Fresh Water: 3%

Water Uses

Water is essential for various purposes, including agriculture, industries, homes, public services, energy production, transportation, and recreation.

Waters of Mexico

Mexico's water resources include marine and fresh water, with diverse classifications, uses, and locations.

Marine Water

Mexico has a vast coastline with access to the Pacific Ocean, the Gulf of California,... Continue reading "Understanding the Hydrosphere, Atmosphere, and Climate" »

Radioactive Decay: Principles and Equations

If the decay rate is equal to λ, the probability that a given nucleus will decay in a small time interval dt is λdt. Therefore, if at any time we have P parent nuclei, the number that decay in the next moment is P(λdt).

The rate of change of parent nuclei (dP/dt) is proportional to the number of parent nuclei present:

dP/dt = -λP

This differential equation can be solved as follows:

• Separate variables: dP/P = -λdt
• Integrate both sides: ∫(dP/P) = -λ∫dt
• Resulting in: ln(P) = -λt + C

The boundary condition is found because we know that when t = 0, P = P₀ (the initial number of parent nuclei). Therefore, C = ln(P₀), and we can write the equation as:

ln(P) = ln(P₀) - λt

Rearranging this equation:

• ln(P)

Coastal Dynamics: Waves and Marine Erosion

Waves are fundamental forces shaping our coastlines. Their interaction with the shore involves two primary movements: swash and backwash.

Understanding Wave Dynamics

Swash and Backwash: The Basics

• Swash: When water rushes up the beach.
• Backwash: When water drains back down the beach.

Destructive Waves: Shaping Coastlines

Destructive waves are powerful forces that remove material from the beach. They are characterized by a weak swash and a strong backwash, pulling sand and pebbles back down the beach as the water retreats.

• Often steep, high waves that are close together.
• Crash down onto the beach.
• Come in very quickly, at a rate of 10 to 15 waves per minute.
• Also known as plunging waves.

Constructive Waves: Building

Climograma

Un Climograma é un gráfico no que representamos simultaneamente os valores da temperatura media mensual, mediante unha liña, e os de precipitación media mensual, mediante barras verticais, dos doce meses do ano. No eixe vertical esquerdo situaremos as frecuencias de temperatura en oC (Graos Centígrados), tendo en conta se hai temperaturas inferiores a 0oC, pois nese caso haberá que deixar un espazo para representalas. As temperaturas medias mensuais están unidas por unha liña vermella 1.No eixe vertical dereito representaremos as precipitacións (en mm), tendo en conta as proporcións que debemos utilizar en función do total, sabendo que será necesario indicar o dobre do valor empregado no eixe vertical esquerdo. A diferenza... Continue reading "Climograma and Pollution: Environmental Impact in Spain" »