copyright © 2009 benjamin cummings is an imprint of pearson 004 environmental systems: matter,...

Copyright © 2009 Benjamin Cummings is an imprint of Pearson

004 Environmental Systems: Matter, Energy, and Ecosystems

Environment & Ecology


Central Case: The Gulf of Mexico’s “Dead Zone”

Mississippi Delta

Eutrophication

Mississippi River

Eutrophication

runoff

Eutrophication

Gulf of Mexico Dead Zone

2006 Seamap Hypoxia Map

Eutrophication

Fish kills


Eutrophication


The Earth’s systems

• System: a network of relationships among components that interact with and influence one another

• Exchange of energy, matter, or information

• Receives inputs of energy, matter, or information, processes these inputs, and produces outputs

• Feedback loop: a system’s output serves as input to that same system

• A circular process


Negative feedback loopNegative feedback loop: output resulting from a system

moving in one direction acts as an input that moves the system in the other direction

• Input and output neutralize one another

• Stabilizes the system

• Most systems in nature


Positive feedback loop

• Positive feedback loop: instead of stabilizing a system, it drives it further toward an extreme

• Examples: erosion

• Rare in nature

• But are common in natural systems altered by humans


Chemistry is crucial for understanding…Any environmental issue:

• How gases contribute to global climate change

• How pollutants cause acid rain

• The effects of chemicals on the health of wildlife and people

• Water pollution

• Wastewater treatment

• Hazardous waste

• Atmospheric ozone depletion

• Energy issues


Chemical building blocks

Matter: all material in the universe that has mass and occupies space

• Can be transformed from one type of substance into others

• But it cannot be destroyed or created, which is…

• The law of conservation of matter

• Helps us understand that the amount of matter stays constant

• Recycled in nutrient cycles and ecosystems


....

Periodic Table 112 known elements

Pure substances that cannot be broken down into simpler chemical entities by ordinary chemical reactions

An element is composed of atoms (0.1-1 nm in diameter)

Atom cluster of small particles (proton, neutron, electron)

Elements & AtomsElements & Atoms

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=QOURLVHs0YnQrM&tbnid=GVPEmzWkQVioNM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.news.com.au%2Ftechnology%2Fsci-tech%2Fnucelar-clock-100-times-more-accurate-than-atomic-clock%2Fstory-fn5fsgyc-1226297068083&ei=3tiTUYmhNIiviQLMg4GQAQ&bvm=bv.46471029,d.cGE&psig=AFQjCNHGfiPIIn-V9TT82SG_XHXTcnMvNw&ust=1368730185243640

Subatomic ParticlesSubatomic Particles

Protons (p +)

Neutrons (n o)

Electrons (e -)

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=QOURLVHs0YnQrM&tbnid=GVPEmzWkQVioNM:&ved=0CAUQjRw&url=http%3A%2F%2Fwww.news.com.au%2Ftechnology%2Fsci-tech%2Fnucelar-clock-100-times-more-accurate-than-atomic-clock%2Fstory-fn5fsgyc-1226297068083&ei=3tiTUYmhNIiviQLMg4GQAQ&bvm=bv.46471029,d.cGE&psig=AFQjCNHGfiPIIn-V9TT82SG_XHXTcnMvNw&ust=1368730185243640

Electron Shell Configurations of Atoms

proton

neutron

electron

hydrogenatom

heliumatom

carbonatom

1p, 0n, 1e- 2p, 2n, 2e- 6p, 6n, 6e-


proton

neutron

electron

hydrogenatom

heliumatom

carbonatom

1p, 0n, 1e- 2p, 2n, 2e- 6p, 6n, 6e-


atomic number: number of p; #p = #e-

2He2e- and 2p

He


atomic mass (atomic wt.): sum of masses of p+nHe 2p + 2n, atomic mass = 4

4

2He

He

p + n e-


p = n = e- = Atomic number = Atomic mass =

C

Carbon Atom


O16 O17 O18

stable isotopes

Atoms that differ in the number of neutrons

16

8 O

18

8 O17

8 O#p

#p+n

O


Two or more atoms held together by chemical bondsOxygenOxygen OO2 2

NitrogenNitrogen NN22

AmmoniaAmmonia NHNH33

Carbon DioxideCarbon Dioxide COCO22

WaterWater HH22OO

MethaneMethane CHCH44

GlucoseGlucose CC66HH1212OO66

Major Organic ElementsMajor Organic Elements

• CCarbonarbon• HHydrogenydrogen• OOxygenxygen• NNitrogenitrogen• PPhosphorushosphorus• SSulfurulfur


• Carbohydrates: C6H12O6 (glucose)

• Lipids: C3H8O3 (glycerol) + 3C16H32O2 (fatty acids)

• Proteins: COOH-NH2

• Nucleic Acids: sugar, PO4, N2 containing base


Binding two or more different kinds of elements together

NaClNaCl

CHCH44

CC66HH1212OO66

CC66HH1212OO66 + 6O + 6O2 2 6CO 6CO22 + 6H + 6H22O + energyO + energy

6CO6CO22 + 6H + 6H22O + energy O + energy C C66HH1212OO66 + 6O + 6O22

Acids

HCL H+ + Cl-

Proton donor, i.e., they donate H+ ions

HCl is a strong acid with a pH 1-2

Bases

Na+ + OH- NaOHNH3 + H+ NH4

OH - + H+ H2O

HCO3 +H+ H2CO3

Proton acceptor, i.e., they take up H+ ions

NaOH is a strong base ~pH 12

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NeutralizationHCl + NaOH H2O + NaCl

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Buffer- resists dramatic changes in pH; ex. tums, rolaids…buffers stomach acid

pH Scale

Neutral 7Acidic 0-6Basic (alkaline) 8-14

Type of Solution pH Value

0-14

pH Scale

Logarithmic scale

Causes of Acid RainCauses of Acid Rain

Air pollution• Burning of fossil fuels

- Power plants- Cars, trucks, airplanes

The main chemicals• Sulfur dioxide• Nitrogen oxides

Acid RainAcid RainNormal Rain

• H2O + CO2 H+ + HCO3-

• A pH of 5.6• Water + carbon dioxide proton + bicarbonate

Acid Rain• Form of water pollution• More acidic than normal rain• Has pH < 5.6• nitrous dioxide + water nitrous acid + nitric

acid 2NO2 + H2O HNO2+ HNO3

• sulfur dioxide + water sulfuric acidSO2 + H2O H2SO4

Ecological Effects from Ecological Effects from Acid Rain in Lake SystemAcid Rain in Lake System

Changes begin to occur as soon as a lake starts to lose it natural bases or alkalinity.

1. A large reduction in the number of plankton & invertebrates.

2. The rate of decomposition of organic matter decreases

3. Direct effects on fishes reproductive cycles.4. A calcium deficiency in fish leads to bone

malformation.5. Fish can suffocate as their gills become clogged

with aluminum hydroxide.6. Songbirds are effected by eating insects

contaminated with toxic metals.

Acid Rain on ForestsAcid Rain on Forests

VOG on CropsVOG on Crops

Table 2. Soil pH range for optimum growth of some crops.Crop pH Alfalfa 6.5-7.5 Avocado 6.0-6.5 Azalea 4.5-5.0 Ginger 6.0-7.0 Macadamia 5.0-6.5 Pineapple 4.7-5.7 Sugarcane 6.0-7.0 Taro 5.5-6.5

Protea flower crop Big Island


Effects from Acid RainEffects from Acid Rain

Acid RainAcid Rain


Ocean Acidity


Global Ocean Acidity


Consequences of Ocean Acidity

Animals with CaCO3 skeletons affected• Plankton• Corals• Mollusks • Fish

http://news.bbc.co.uk/2/hi/science/nature/7933589.stm

Fisheries

Acid Rain in Marine EnvironmentAcid Rain in Marine Environment

• reduces ability of marine organisms to utilize calcium carbonate

• Coral calcification rate reduced 15-20%

• Skeletal density decreased, branches thinner


Photosynthesis

• Chloroplasts: organelles where photosynthesis occurs

• Contain chlorophyll: a light-absorbing pigment

6CO2 + 6H20 + the sun’s energy C6H12O6 + 6O2

Autotrophs (producers): produce their own food from the sun’s energy by photosynthesis

Green plants, algae, and cyanobacteria


Cellular respiration releases chemical energy

• Heterotrophs (consumers): organisms that gain energy by feeding on others

• Animals, fungi, microbes

C6H12O6 + 6O2 6CO2 + 6H20 + energy

mitochondria


Energy and matter in ecosystems

Energy Flow Nutrient Cycling


Energy is converted to biomass

Primary production: conversion of solar energy to chemical energy by autotrophs

• Gross primary production: assimilation of energy by autotrophs

• Net primary production (NPP): energy remaining after respiration, used to generate biomass

• Available for heterotrophs

Productivity: rate at which autotrophs convert energy to biomass


Net primary productivity of ecosystems

High net primary productivity: ecosystems whose plants rapidly convert solar energy to biomass


A global map of NPP

NPP increases with temperature and precipitation on land, and with light and nutrients in aquatic ecosystems.


Nutrients can limit productivity

Nutrients: elements and compounds that organisms consume and require for survival

• Stimulate plant production

• Lack of nutrients can limit production.

• Nitrogen and phosphorus are important for plant and algal growth.

Oceanic primary productivity is highest in water near shore.

• Over 200 dead zones now exist due to nutrient pollution.


Nutrient runoff devastates aquatic systems

• Aquatic dead zones result from nutrient pollution from farms, cities, and industry.

• Most dead zones are located near Europe and the eastern U.S.

• Scientists are investigating innovative and economical ways to reduce nutrient runoff.

Phytoplankton blooms off the Louisiana coast.


Ecosystems come in different sizes

• Ecosystems vary greatly in size.

• The term “ecosystem” is most often applied to self-contained systems of moderate geographic extent.

• Adjacent ecosystems may interact extensively.

• Ecotones: transitional zones between two ecosystems in which elements of each ecosystem mix


• Landscape ecology: the study of how landscape structure affects the abundance, distribution, and interaction of organisms• Helpful for sustainable regional development• Useful for studying migrating birds, fish, mammals

• Patches: ecosystems, communities, or habitat form the landscape and are distributed in complex patterns (a mosaic)

Landscape ecology

This landscape consists of a mosaic of patches of 5 ecosystems.


Conservation biology

• If a habitat is distributed in patches, organisms face danger in traveling from one patch to another.

• Patches spaced too far apart prevent travel• Conservation biologists: study the loss,

protection, and restoration of biodiversity

• Humans are dividing habitat into small, isolated patches.

• Corridors of habitat can link patches.


Conservation biology• Geographic information systems (GIS): computer

software that layers multiple types of satellite data to create a complete picture of a landscape

• Geology, vegetation, animal species, and human development

Biogeographic assessment for NWHI


Nutrients circulate through ecosystems

• Physical matter is circulated continually in an ecosystem.

• Nutrient (biogeochemical) cycle: the movement of nutrients through ecosystems

• Pools (reservoirs): where nutrients remain for varying amounts of time

• Flux: movement of nutrients among pools

• Can change over time

Carbon CycleCARBON CYCLE


Humans affect the carbon cycle

• Burning fossil fuels moves carbon from the ground to the air.

• Cutting forests and burning fields moves carbon from organisms to the air.

• Today’s atmospheric carbon dioxide reservoir is the largest in the past 800,000 years.

• The driving force behind climate change


The phosphorus cycle


Humans affect the phosphorus cycle

• Mining rocks for fertilizer moves phosphorus from the soil to water systems.

• Wastewater discharge also releases phosphorus, which boosts algal growth and causes eutrophication.

• May be present in detergents

• Consumers should purchase phosphate-free detergents.

Nitrogen Cycle


Humans affect the nitrogen cycle• Excess nitrogen leads to hypoxia in coastal areas.

• Synthetic fertilizers doubled the rate of Earth’s nitrogen fixation.

• Burning forests and fossil fuels leads to acid precipitation.

• Wetland destruction and increased planting of legumes has increased nitrogen-rich compounds on land and in water.

• Increased emissions of nitrogen-containing greenhouse gases

• Calcium and potassium in soil are washed out by fertilizers.

• Reduced biodiversity of plants adapted to low-nitrogen soils.

• Changed estuaries and coastal ecosystems and fisheries


Human inputs of nitrogen into the environmentFully half of nitrogen entering the environment is of human origin.


A law addressing hypoxia in the Gulf

• The Harmful Algal Bloom and Hypoxia Research and Control Act (1998) called for an assessment of hypoxia in the Gulf and to:

• Reduce nitrogen fertilizer use in Midwestern farms

• Change timing of fertilizer applications to minimize runoff

• Use alternative crops

• Manage livestock manure

• Restore wetlands and create artificial ones

• Improve sewage-treatment technologies

• Evaluate these approaches

• This Act has worked, and was reauthorized in 2003.


The hydrologic cycle• Water is essential for biochemical reactions and is

involved in nearly every environmental system.

• Hydrologic cycle: summarizes how liquid, gaseous, and solid water flows through the environment

• Oceans are the main reservoir.

• Less than 1% is available as fresh water.

• Evaporation: water moves from aquatic and land systems to air

• Transpiration: release of water vapor by plants

• Precipitation: condensation of water vapor as rain or snow returns water from the air to Earth’s surface


Groundwater

• Aquifers: underground reservoirs of sponge-like regions of rock and soil that hold water

• Groundwater: water found underground beneath layers of soil

• Water table: the upper limit of groundwater held in an aquifer

• Water may be ancient (thousands of years old).


The hydrologic cycle


Water Cycle in Hawaii


Human impacts on hydrologic cycle

• Damming rivers increases evaporation and infiltration into aquifers.

• Altering the surface and vegetation increases runoff and erosion.

• Spreading water on agricultural fields depletes rivers, lakes, and streams and increases evaporation.

• Overdrawing groundwater for drinking, irrigation, and industrial uses depletes groundwater resources.

• Removing forests and vegetation reduces transpiration and lowers water tables.

• Emitting pollutants changes the nature of precipitation.


QUESTION: Review

Which of the following part of an atom has a positive charge?

a) Proton

b) Neutron

c) Electron

d) Hydrogen

e) Neutreno


QUESTION: Review

Which of the following organisms is an autotroph?

a) Deep-sea tubeworm

b) Horse

c) Pine tree

d) Human

e) None of these


QUESTION: Review

A transitional zone between two ecosystems is a(n):

a) Conservation zone

b) Corridor

c) Reservoir

d) Ecotone

e) Patch


QUESTION: Review

Humans have affected the nitrogen cycle in all of the following ways EXCEPT:

a) Doubling the rate of nitrogen fixation

b) Increasing emissions of greenhouse gases

c) Lowering water tables

d) Changing estuaries and coastal ecosystems

e) Reducing diversity of plants adapted to nitrogen-poor soils


QUESTION: Interpreting Graphs and Data

Which is the most basic material?

a) Lemon juice

b) Acid rain

c) Rainwater

d) Seawater

e) Soft soap


QUESTION: Interpreting Graphs and Data

According to this graph, which ecosystem has the lowest amount of biomass?

a) Temperate grassland

b) Boreal forest c) Savannad) Tropical

rainforest

copyright © 2009 benjamin cummings is an imprint of pearson 004 environmental systems: matter,...

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