BIOL 204: 30: Global Ecology

Seasonality

refers to the periodic fluctuations in environmental conditions and biological phenomena that occur at regular intervals, typically influenced by the seasons of the year.

The importance of seasonality

1. Sunlight and temperature drive primary productivity which affect trophic levels and seasonality effects sunlight and temperature

What causes seasonality

Tilt of the Earth (23.5 degrees) and the annual rotation around the sun

Latitudinal Gradients

refers to the variation in biodiversity and ecological processes that occur along different latitudes, typically influenced by climatic factors such as temperature and precipitation.

Explanations for latitudinal gradients

Variation in climate (cooler on poles, warmer in tropics)

Tropics more productive than poles

Biogeographic reasons as well

Water Cycle

The continuous process of water movement through the environment, involving evaporation, condensation, precipitation, infiltration, and runoff.

The importance of the water cycle

• Nutrients organisms need to survive are transported through water cycle

• Helps drive ecological processes and structure ecosystems

Ogallala Aquifer

A vast underground water reservoir in the Great Plains region of the United States, crucial for irrigation and drinking water. Currently losing water

Importance of nutrient cycles

• C, H, N, O, S crucial elements to all life forms that circulate through ecosystems, supporting biological processes and maintaining ecological balance.

Carbon cycle

The series of processes by which carbon compounds are interconverted in the environment, involving absorption by plants during photosynthesis and release through respiration and decomposition.

Nitrogen Cycle

The process by which nitrogen is converted between its various chemical forms, crucial for plant and animal life, involving fixation, nitrification, and denitrification. Bacteria run this cycle.

Ocean Upwelling

The process where cold, nutrient-rich water rises from the ocean depths to the surface, supporting high levels of primary productivity and influencing marine ecosystems.

Consequences of ocean upwelling

Include increased nutrient availability, boosts in fish populations, and significant impacts on local fisheries and ecosystems.

Problem with Synthetic fertilizers

We are increasing the amount of Nitrogen in the environment which can lead to soil degradation, water pollution, and disruption of local ecosystems. Excess nitrogen can cause algal blooms and dead zones in water bodies. Loss of O2 and increased algae and cyanobacteria Ex: Missisippi Basin = Dead zone

Biomagnification

The process by which the concentration of toxic substances increases in organisms at each successive level of the food chain, leading to higher levels of pollutants in predators.

Effects of Mercury on Terrestrial Birds

Decrease in reproduction, suppression of immune system, increase in stress hormone, alteration in song, decrease in flight performance