Advanced Ecology Lecture One PDF

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Summary

Taught by May Myklebust
This lecture talked about Earth's climate Systems...

Description

Ecosystem Structure and Function    

Context: ecosystem concepts, climate systems, geology and soils Mechanisms: energy and mass movement through ecosystems (trophic dynamics and species effects) Patterns: Temporal and spatial dynamics of ecosystems Spatial Distributions: Dispersal, bio-geography (Pleistocene ice ages, islands, continents and oceans)

Labs:

1. 2. 3. 4.

Loss of tree species Stable Isotope Analysis Restoration Lab Waterfowl Habitat Selection

Literature Critiques: analyze and critique two scientific reports (first one available now) Ecosystem Concepts    

ecosystem energy and mass input, output and cycling ecosystem structure and function ecosystem feedbacks human impact on Earth's ecosystems

Intro

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focuses on the interactions between physical environments and organisms (biotic and abiotic) ecosystem ecology is a preferred approach to ecosystem management and restoration

Processes occur at different scales (logging Douglas Fir)

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Patch: productivity, species diversity Regions: water supply and fire risk (Trees hold water and transpire moisture into the atmosphere) Planet: climate change

Energy Inputs/Outputs

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ecosystem energy mainly gained from sun energy and materials from the air or rocks you always need more energy coming in as it doesn't get cycled, but materials from air and rock do. Gain/lose energy and material from the environment through input/output processes such as photosynthesis and transpiration ecosystems exchange energy and materials among components through internal cycling process such as herbivory and predation

Ecosystem Components

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Producers Consumers Water Bodies Atmosphere Soil

Ecosystem Processes (measured in rates, called fluxes):

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Photosynthesis Decompostion Respiration Mineralization

Ecosystem Carbon Cycle

The Carbon Cycle Large inputs via photosynthesis Large outputs via respiration Large carbon pools in soils and veg will buffer activities of animals from temporal variability of carbon uptake by plants The Water Cycle Large inputs to ecosystem Large outputs to the environment Plants and soils have limited capacity to store water so activities of animals and decomposers are closely linked to water inputs The Nutrient Cycle Nitrogen and phosphorus cycles have small annual inputs and outputs and are tightly recycled within ecosystems Nutrient availability limits activity of animals and decomposers. Variability across Ecosystems

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pool sizes and rates of cycling carbon, water and nutrients differ among ecosystems undisturbed tropical forests have relatively large pools of carbon in plants and soil which correspond to large input and output fluxes Reduction in plant carbon pool leads to a decrease in inputs followed by a slower decrease in output (climate change) Ecosystems respond differently to environmental changes. Nitrogen deposition may or may not stimulate plant growth

Ecosystem Structure and Constraints

State Factors: independent variables that set bounds for ecosystem structure and function (climate, parent material, topography, potential biota and time) Climate: Water availability and temperature regime govern biological and chemical reactions that control ecosystem processes. Results in biomes according to climate Parent Material: Will determine the type of nutrients in soil, and soil types and the vegetation that can grow there Topography: Within regions, topography influences micro-climate and soil development Potential Biota: At a local scale, PB governs the type and diversity of organisms that actually occupy the site Time: Determines the degree of soil and ecosystem development since disturbance Inactive Factors: Resource Supply (light, chemicals and nutrients): Most soil nutrients occur near the top of a soil column and roots stabilize soil. Micro-environment: Disturbance Regime: Organisms can influence disturbance regime which can dictate ecosystem structure and process rates Biotic Community: The types of species present, their abundance and their interactions that can influence ecosystem processes. E.g. Conifers have low photosynthetic rates and low decompostition rates which results in slow nutrient cycling, this supports slow growing species. Angiosperms have higher photosynthetic and decomposition rates resulting in higher nutrient turnover Feedbacks: regulate internal dynamics of an ecosystem.

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Stabilizing: when two components of a system of opposite effects on each other (large prey have positive impacts on predator vise versa) Amplifying: when two components of a system have both positive effects or negative on each other. (more fungi more plants, more plants more fungi) Stabilizing feedbacks resist change where amplifying reinforce tendency to change

How Humans impact the Earth's Ecosystem Humans have altered the land surface Land Cover Change: Mostly due to agriculture and goods for people. This production prevents carbon and nutrients from returning to soil Habitat Loss: Geographic ranges of 1/3rd terrestrial mammal species overlap with wilderness areas. Lots of human encroachment occuring for resource extraction Invasive Species: Movement of organisms by humans have increased the occurrence of invasive species changing ecosystems. Bio-Geo-chemical Cycles: Fossil fuel burning has increased atmospheric CO2 which interferes with the energy balance of earth.

Earth's Climate Systems

Radiant Energy

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emitted by objects with a temperature above absolute zero. Transports energy but does not effect molecules until it is absorbed. Can increase the temperature of the object.

Temperature and Radiation:

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the amount of radiation energy emitted by an object is proportional to its temperature

Wavelength and Temperature

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The higher the temperature, the shorter the wavelength of radiation Cool objects release long wave radiation

The sun emits shortwave that is absorbed by Earth. Earth returns long wave back to space Energy Budget

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Most excess energy is absorbed in the ocean - water expansion causes sea levels to rise

Atmospheric Aersols Typically have short Mean Residence Time (MRT) small particles suspended in air Interact with incoming solar radiation

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reflect scatter absorb

Atmospheric mass and pressure

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mass is pulled towards surface by gravity air pressure is die to mass overlying air molecules pressure decreases with altitude

Atmospheric Temperature

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lower atmosphere is ehated from below by Earth's surface. Temperature decreases with altitude Warm air can hold more water vapour than cold air. When warm air cools, water vapour condenses (liquidizes) as cool air warms, liquid water evaporates As air rises, it expands due to lower pressure and cools. Water vapour condenses with sufficient cooling

Atmospheric Structure:

Temp profiles separate atmosphere into distinct layers. Planetary Boundary Layer: Lowest layer of troposphere where mixing of air occurs due to surface heating

the Coriolis effect*** rotates faster at the equator, due to it being wider it has larger travel time

January 13th, 2020

Surface Properties Influencing Climate

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Proximity to ocean or lake size of continent topography

Orographic Effects

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mountains cause air to rise, rising air cools, water vapour precipitates...