Blok 4: The Natural Environment

Question 1

describe integrated indicators and their use: What is the AMOEBA method?

Answer 1

General Method for Ecological Description

a semi-quantitative method for describing and assessing the quality of aquatic ecosystems.

A circle represents the target image formulated for indicators (e.g. indicator species) for the long term, while the slices (as in a pie-like radar diagram) represent the target variables.

			□ These target variables have been chosen for policy reasons rather than on the basis of scientific  argument, employing three main criteria:   it should (1) be related to water quality,  ® (2) be readily recognizable by non-experts, and  ® (3) be quantifiable (countable, measurable, etc.).

			□  This does not necessarily mean these target species are the most important in terms of optimum ecosystem functioning.

		§ Figure 10.13 shows the AMOEBA for the coastal waters and estuaries of the Netherlands along the southern North Sea. The circle of this so-called radar diagram represents the target image formulated for the long term (2010–2020). The slices of this pie-like radar diagram represent the target variables, i.e. the indicator species or communities. As can be seen, the Sandwich tern (Grote stern) stands at 61% of its target.

Question 2

What is biodegradation?

Answer 2

The chemical and biological breakdown of inorganic and organic complexes.

Question 3

What are biochemical cycles?

Answer 3

Cycling of chemical elements within and between the atmosphere, hydrosphere, lithosphere and biosphere.

Question 4

Energy balance

Answer 4

The movement of energy (i.e. the ability to do work) and changes in its form can be tracked by means of an energy balance, analogous to a mass balance.

The first law of thermodynamics states that in an isolated closed system, energy will be conserved and can be neither created nor destroyed.

		§ These concepts are useful to make an energy balance of the atmosphere and sun (a radiation balance)
			□ The radiation balance is deduced from experimental data and is written down as an average over the globe and over the year.

				a) The sunlight entering the atmosphere comprises visible light as well as infrared and ultraviolet radiation.
				b) A fraction is scattered back to outer space. Clouds, gases and particles in the air cause this scattering and reflection.
				c) Another fraction is absorbed by the atmosphere,
				d) leaving a transmission to reaching the Earth surface, where most of the sunlight is absorbed
				e) but a fraction is scattered back, much of it by snow and ice, but part of it also by forests and crops.

f) Part of the absorbed energy is used for evaporation, resulting in latent heat within the atmosphere
another part heats the lower part of the atmosphere, resulting in sensible heat and rising air, a phenomenon called convection.

(See image detailing the exchange in onenote)

Question 5

Enthalpy

Answer 5

The energy of the inter- and intra-molecular bonds that bind the system’s atoms and molecules together

Question 6

Eutrophication

Answer 6

§ The enrichment of terrestrial and aquatic systems with nutrients, in particular nitrogen and phosphorus.

Question 7

identify and describe basic principles of biology relevant to environmental sciences: genetic drift?

Answer 7

The chance that a genetically fixed characteristic will disappear from the population, leading to a more uniform and hence more vulnerable population.

Cause: Any decline in population and increase in isolation

Question 8

identify and describe basic principles of biology relevant to environmental sciences: genetic erosion?

Answer 8

Decrease in genetic variability

Cause: Any decline in population and increase in isolation

Question 9

identify and describe basic principles of biology relevant to environmental sciences: genetic variability?

Answer 9

Variation in genetically fixed characteristics

influences chance of survival

Question 10

describe integrated indicators and their use: Index of biotic integrity – IBI

Answer 10

An composite index incorporating a number of biological attributes within an ecosystem and comparing these metrics with a relatively undisturbed situation. This index is typically used for water ecosystems.

		§ Combines dozen biological attributes into a single index 
			□ total number of native fish, number and identity of sunfish species, proportion of individuals that are carnivores, etc.
		§ The strength of the index is that the biological attributes used are expressed in numerical values permitting objective comparison with future situations:
		§  The values can be compared to the values expected for a relatively undisturbed stream of
		similar size in a similar geographic region (reference image).

Question 11

Mass balance

Answer 11

The law of conservation of mass states that mass can be neither created nor destroyed.

The notion of mass balance means that if there is an increase in the amount of a chemical present in a given environment, this chemical must either have been transported from elsewhere or produced by a chemical or biological reaction from other compounds (law of conservation).

Question 12

Photochemical transformations

Answer 12

When a chemical compound (an organic pollutant in the aquatic environment, for example) absorbs light it may undergo photochemical transformation, either directly or indirectly.

Question 13

Population

Answer 13

A group of individuals of one species in an area, though the size and nature of that area is defined, often arbitrarily, for the purpose of the study being undertaken.

Question 14

TRIAD method

Answer 14

§ Integrates methods from several sciences

		§ To assess the quality of a habitat

		§ Combines
			□ Field observation (view of the biological diversity)
			□ Chemical analysis (all relevant toxic substances thought to be present)
			□ Bioassays (yield absolute mortality figures per unit time for selected species exposed to contaminated samples of habitat, like sediment)

		§ The data are compared to a clean reference area and is then plotted onto a TRIAD diagram, the larger the triangle the further away it is from the reference area (see P168)

Question 15

(Environmental distribution of chemicals) Ecotoxicology

Answer 15

□ The science concerned with the fate and toxic effects of chemicals in natural and disturbed ecosystems.

Question 16

(Environmental distribution of chemicals) Bioavailability

Answer 16

The ability of a substance to affect organisms; it is a measure of the physicochemical access that a toxicant has to the biological processes of an organism.

Question 17

(Environmental distribution of chemicals) Biomonitoring

Answer 17

refers particularly to the study of changes in the levels of toxics in selected organisms over time, or changes in (groups of) individuals from plant and animal populations exposed to harmful physical or chemical conditions.

Question 18

What is environmental quality? What are some ways to measure it?

Answer 18

is taken to comprise the structural and functional properties of the environment in the context of human appreciation, either positive or negative

There are a number of indicators for environmental quality: Index of biotic integrity, The TRIAD method, ecosystem health and the AMOEBA method

Question 19

identify and describe basic principles of chemistry relevant to environmental sciences: Thermodynamics

Answer 19

□ To identify the fate of a chemical pollutant in the environment or assess the effectiveness of a treatment process either a kinetic approach or an equilibrium approach can be adopted, focusing respectively on chemical reaction rates and the ultimate, steady-state result of such reactions.

			□ The equilibrium approach is based on the fundamental principles of thermodynamics. Thermodynamics provides a well-defined set of laws that determine:
				® first, whether or not a reaction can occur and
				® second, in which direction it will proceed: forward or reverse.

Equilibrium, as defined by thermodynamics, is a condition that can be predicted. Thermodynamics is concerned with the conversion of energy from one form to another.

Question 20

identify and describe basic principles of chemistry relevant to environmental sciences: Gibbs free energy

Answer 20

The energy available within a given system for doing work.

Gibbs free energy (G) is related to the system’s enthalpy (H), entropy (S) and temperature (T). G = H − T x S.

					◊ Enthalpy (H)
						◊ enthalpy
							– designates the energy of the inter- and intra-molecular bonds that bind  the system’s atoms and molecules together
					◊ entropy (S) 
						◊ refers to the ‘disorder’ of the system
						◊  The Equation (10.5) indicates that the more disorder there is, i.e. the larger the value of S, the less energy there will be available for doing work
						◊ the more disorganized a system, the more work will be required to impose order on it. temperature (T).

			□ Conversely,  any chemical reaction resulting in conversion of a liquid or solid to gaseous form will lead to a large increase
			in entropy.  An increase in entropy is therefore equivalent  to a decrease in the free energy of the system, or a decrease in the amount of work accomplished. 

See page 150 in the book for some examples with processes with changes in enthalpy

Question 21

perform basic calculations on the enthalpy and energy released in chemical reactions

Answer 21

○ See page 150 in the book for some examples with processes with changes in enthalpy

Question 22

identify and describe basic principles of chemistry relevant to environmental sciences: chemical equilibrium processes

Answer 22

§ Various equilibrium processes can take place: sublimation, condensation, evaporation,
§ These are important in environmental problems because they rarely are confined to just one medium
§ Example:
mercury is emitted mainly as an air pollutant, its most damaging effects occur after it has passed through the atmosphere and been deposited in lakes, where it undergoes a biological transformation process called methylation

Question 23

identify and describe basic principles of chemistry relevant to environmental sciences: photochemical transformations

Answer 23

§ When a chemical absorbs light and transforms.
§ Can be direct (like CFC breaking down in the atmosphere due to sunlight, and going on to rip apart ozone molecules)
Can be indirect: light-induced processes in water due to the presence of organic pollutants. These processes are initiated by the absorption of light by other chemicals present in the system. (photolysis)

Question 24

identify and describe basic principles of chemistry relevant to environmental sciences: ○ biochemical transformations including biodegradation, ecotoxicology and bioavailability

Answer 24

§ Reactionss mediated by natural organisms.
§ Biodegradation: the chemical and biological breakdown of inorganic and organic substances.
§ Oil spills will eventually biodegrade
§ Ecotoxicology (Section 10.5.2)
§ The science concerned with the environmental fate and toxic effects of chemicals in natural and disturbed ecosystems.
§ Bioavailability (Section 10.5.2)
The ability of a substance to affect organisms; it is a measure of the physicochemical access that a toxicant has to the biological processes of an organism.

Question 25

identify and describe basic principles of biology relevant to environmental sciences: ○ inter- and intra-specific competition over limited resources,

Answer 25

§ Plants and animals are in continuous interaction with members of their own and other species. This interaction is competition over limited resources
□ Intraspecific competition
® Occurs between individuals of the same species
□ Interspecific competition
® Occurs between individuals of separate species
This type of competition can be aggravated by human disturbance (pollution/habitat loss,…) as it favors aggressive, colonizing species.

Question 26

identify and describe basic principles of biology relevant to environmental sciences: ecosystem

Answer 26

§ Def: An ecosystem: is a plant and animal community in its physical environment together with all the relationships between them, i.e. considered as a system.

		§ Function: The ecosystem concept, the idea that flora and fauna interact with their environment to form an ecological complex, has long been central to the public perception of ecology and to a growing awareness of ongoing environmental degradation
		§ Structure: 
		The biotic components of an ecosystem can be conceptually organized in terms of species, populations  and communities. 
			□ A biotic community is any assemblage  of populations living in a given area or physical habitat. 
			□ communities can be conveniently named and classifyed according to 
				® their major structural features (e.g. dominant or ‘indicator’ species)
				® The physical habitat of the community
				® Functional attributes such as the type of community processes (e.g.production and respiration, see Energy flow).

Question 27

identify and describe basic principles of biology relevant to environmental sciences: disturbance, resources and biodiversity

Answer 27

See p 155

Question 28

identify and describe basic principles of biology relevant to environmental sciences: ◊
species richness, species diversity and biodiversity,

Answer 28

§ Species richness: refers to the number of species present in a particular community (does not differentiate between rare and abundant species)
§ Species diversity: takes into account both species richness and relative abundances
Biodiversity: a term that embraces more structural components, taking into account the qualitative and quantitative variability in the biosphere (or a part of it) covering genes, species, communities, ecosystems and landscapes.

Question 29

identify and describe basic principles of biology relevant to environmental sciences: flows and losses of energy across trophic levels,

Answer 29

§ Energy does not move in a cycle but flows through ecosystems, being dissipated as heat and lost as useful energy forever. Chemical elements, in contrast, are used over and over again in ecosystems during processes of growth and decomposition.
§ biogeochemical cycles:
□ The cycles of chemical elements through living organisms and through the abiotic environment
□ Important cycles:
® carbon, oxygen, nitrogen, phosphorus and sulphur, and those of sodium, potassium, calcium and magnesium. The hydrological cycle, or water cycle, is also of major importance because of its crucial role in transporting chemical elements through the biosphere.
□ Nitrogen cycle (in the marine environment)
® Nitrogen fixation
◊ the conversion of N from atmospheric nitrogen gas into organic nitrogen by a variety of micro-organisms
◊ Another source is run-off from land via rivers, which are often ‘enriched’ with effluents from sewage treatment plants
◊ Plants and animals grow by feeding on sources of inorganic and organic nitrogen, in addition to other elements. As a result of egestion during lifetime and final decay after death a range of nitrogen- containing derivates become available in the environment
◊ Figure 10.6 shows the conversion of organic derivates to ammonium (ammonification), the conversion of ammonium (NH4) to nitrate (NO3) (nitrification) and finally nitrate reduction (denitrifi -cation), by means of which N03 is converted into gaseous N2. In short, this step closes the nitrogen cycle in the marine environment.
® eutrophication, the enrichment of surface waters with plant nutrients, in particular
nitrogen and phosphorus
In the case of marine and coastal waters, excessive nutrient influx from rivers and land run-off can readily trigger a series of unwanted environmental changes: primary production increases, the waters become turbid, macrophytes (i.e. macroscopic plant species) disappear, benthic (i.e. bottom-living) fauna die off and finally the ecosystem as a whole may collapse.

Question 30

identify and describe basic principles of biology relevant to environmental sciences: flows and losses of energy across trophic levels:

Answer 30

§ To understand and manage complex ecosystems, we need to have some measure of the system’s overall performance (or ‘health’) in which both structure and functioning are represented.
§ Ecosystem health:
□ A comprehensive, multi-scale, dynamic, hierarchical measure of system vigor, organisation and resilience
® Vigor:
◊ a measure of its activity
◊ How to measure: Gross Primary Production, Net Primary Production, …
® Organisation
◊ Refers to the number and diversity of interaction between component elements off the system. It’s a measure of exchange between system components (who eats who and other exchanges)
◊ How to measure: is hard to measure but Network analysis is a potential approach to solving the problem of measuring organisation. This involves quantitative analysis of interconnections between ecosystem components (the species) and their interconnections within the larger system (their biotic environment), i.e. the total number of potential pathways of material exchange between system components
® Resilience
◊ Refers to the ability of an ecosystem to maintain its structure and behavioral patterns.
◊ Two aspects: the time it takes to recover and the amount of stress from which a system can recover

Question 31

describe integrated indicators and their use: TRIAD

Answer 31

§ Integrates methods from several sciences
§ To assess the quality of a habitat
§ Combines
□ Field observation
□ Chemical analysis (all relevant toxic substances thought to be present)
□ Bioassays (yield absolute mortality figures per unit time for selected species exposed to contaminated samples of habitat, like sediment)
The data are compared to a clean reference area and is then plotted onto a TRIAD diagram, the larger the triangle the further away it is from the reference area

Question 32

The global warming potential (GWP) (see Section 10.2.2) reflects
a the atmospheric lifetime of a greenhouse gas;
b the global temperature over a certain time period, caused by one unit
of greenhouse gas emitted, compared to that of Co2;
c the amount of warming potentially avoided by international
agreements (e.g. the Kyoto protocol);
d the potential of solar irradiation to warm the lower atmosphere.

Answer 32

B

Question 33

Based on Figure 4.1 (workbook), explain how the amount of energy
emitted by the Earth’s surface, as long-wave radiation and convection
(broadly defined here as the movement of molecules, including the
process of evaporation) can be higher than the total amount of solar
energy reaching it.

Answer 33

Because of greenhouse gases, such as Co2, and H2o vapour, which occur
naturally in the atmosphere. These absorb most (350 W/m) of the long-
wave radiation emitted by the Earth, as well as the energy emitted by
convection and a small amount of incoming solar radiation. Most of this
energy, a total of 324 W/m, is (re)emitted to the Earth’s surface. Thus,
energy is effectively being recycled between the Earth’s surface and the
atmosphere.

Question 34

See assignment 4.3 for Gibs free energy assignment

Answer 34

See assignment 4.3 for Gibs free energy assignment

Question 35

Biodegradation (see Section 10.3.4) is
a the photochemical breakdown of organic complexes;
b the physical fixation of heavy metals;
c the chemical and biological breakdown of inorganic and organic
complexes;
d the uptake of toxic compounds by plants.

Answer 35

C

Question 36

Which of the following measures could prevent genetic drift (see Section
10.4.1)?
a Connecting nature areas by ‘corridors’ to create a national network of
protected areas.
b Creating undisturbed nature reserves without recreation.
c Isolating nature reserves so that animals cannot migrate from one
area to another.
d Animal breeding programmes in zoos.

Answer 36

A

Question 37

See assignment 4.6 for assignment on ecosystems and species richness

Answer 37

See assignment 4.6 for assignment on ecosystems and species richness

Question 38

See assignment 4.7 for assignment on AMOEBA

Answer 38

See assignment 4.7 for assignment on AMOEBA