Download Effects of Artificial Light

Temperature
Temperature


Average kinetic energy of a system
Arguably the most important aspect of
the physical environment for life


Influences geographic distributions of species
Influences interspecific competition
Temperature Ranges
 For
most living, active
animals:
 -2
°C (polar aquatic species) to
50 ° C (desert spp.)
 Few species can survive entire
range
Terminology of Thermal Biology

Various terms used to describe
thermal biology of animals:
1.
2.
3.
Cold-blooded vs. Warm-blooded
Poikilothermic vs Homeothermic
Ectothermic vs. Endothermic
Cold-blooded vs. Warm-blooded


Description of relative body temperature
 “Warm-blooded” = high body temperature
 Mammals and birds
 “Cold-blooded” = low body temperature
 Reptiles, amphibians, fish, invertebrates
Tend to be inaccurate
 Many “cold-blooded” animals have high body
temperatures (e.g. desert reptiles and
invertebrates)
 Many “warm-blooded” animals may have low
body temperatures (e.g. hibernating mammals)
Homeothermic vs. Poikilothermic

Description of variation in body
temperature

Homeothermic – body temp. strictly regulated


Poikilothermic – body temp. may fluctuate
widely


Mammals and birds
“Lower” vertebrates and invertebrates
Problems


Many “poikilotherms” normally have stable
body temperatures under natural conditions
Some “homeotherms” have broad seasonal
changes in body temperature (hibernation,
etc.)
Endothermic vs. Ectothermic

Description of heat production



Endothermic – most body heat is
physiologically generated (muscle
contraction)
Ectothermic – most body heat derived
from the environment (solar radiation,
etc.)
Problems

Some animals generate lots of heat but
do not use it to regulate body
temperature
Determinants of Body
Temperature

Temperature depends on the amount of
heat (calories) contained per unit mass
tissue


Amount of heat in body depends on…
1.
2.
3.

# calories contained per °C determined by
the heat capacity of the tissues (~ 0.8
cal*°C-1*g-1)
Rate of heat production
Rate of external heat gain
Rate of heat loss to the environment
Body heat = heat produced + heat
transferred
Heat Transfer
Three ways of transferring heat
1.
Conduction – transfer of heat between
objects in contact with one another
2.
Radiation – transfer of heat by
electromagnetic radiation
3.
Evaporation – transfer of heat to water
as it changes from liquid to gaseous
phase
Conduction



Transfer of kinetic energy between two
objects in contact
Heat moves from warmer region to cooler
region
Rate of transfer: T1 – T2
H=k×
X

H = rate of heat transfer per cross sectional area

k = thermal conductivity of the conductor

d = distance between two points

T1 and T2 = temperature at points 1 and 2
Conduction and Convection

Conduction rate is increased by
convection


Movement of gas or liquid over the surface of
transfer
Continuous replacement of fluid maximizes
temperature difference and facilitates heat
transfer
Radiation



Transfer of heat via electromagnetic
emission
Objects do not require contact
Stefan-Boltzmann law:





H = εσTs4
H = rate of heat exchange per unit area
ε = emissivity (wavelengths at which EM
radiation is emitted,~3-4 μm for most
objects on earth)
σ = Stefan-Boltzmann constant
Ts = surface temperature of the object
Net heat exchange is from the object
with the higher Ts to the one with the
Evaporation


Only means by which heat can be
lost to a hot environment
Vaporization of water requires heat


~ 2400 kJ per g water absorbed from
the surface of the animal
Evaporative cooling used to dissipate
heat

Sweating, panting
Heat Storage


Animals can store heat in their
bodies by moderating heat transfer
to the environment
Factors Affecting Heat Transfer

Surface Area/Volume Ratio


Larger animals have proportionately lower
heat flux
Temperature Gradient
Between body and environment
 Lower gradient, slower heat transfer


Specific Heat Conductance

Insulation – reduces heat conductance
Total Body Heat
Htotal = Hv + Hc + Hr + He + Hs
Hv = heat produced by metabolism (+)
Hc = heat loss/gain by conduction and
convection (+/-)
Hr = heat transfer via radiation (+/-)
He = heat loss by evaporation (-)
Hs = stored heat (+)
Effects of Body
Temperature Change

Temperature affects the rate of
chemical reactions


Affects chemical reactions needed to
maintain homeostasis
Too low


metabolism not fast enough to maintain
homeostasis
Too high

reactions in metabolic pathways
uncouple, enzymes denature, etc.
Changes in Metabolism with Body
Temperature

Temperature Coefficient (Q10) –
factorial increase in a rate with a 10 °C
increase in temperature
Q10 = (R2/R1)

R2 and R1



10/T2-T1
reaction rates at temperatures T2 and T1
respectively
If T2 and T1 differ by 10 °C, Q10 = (R2/R1)
Typical Q10 values for biological rates
(metabolic rate, etc) range from 2 to 3
(doubling or tripling of rate)
Changes in Metabolism with
Temperature


Q10 values often change across a range
of temperatures
Performance curves

Initial large increase, followed by smaller
increases
Light
Effects of Artificial Light:
- Orientation and Attraction/Repulsion
- Reproduction
- Communication
- Competition
- Predation
- Ecosystem disruption
Complex Ecosystem
Effects of Artificial Light
Living things respond in a variety of ways to
impacts on the environment. Some examples of
the effect of light at night are well known moths gathering around a street lamp, or the
harvesting of fish with spotlights. These changes
can have a dramatic effect on humans - as for
example the negative impact of light at night on
the salmon fishery.
Terrestrial Mammals
Terrestrial Mammals
Possible effects:
- disruption of foraging behaviour
- increased risk of predation
- disruption of biological clocks, affecting mating
success and group-mediated anti-predator vigilance
- increased road deaths due to blinding and
disorientation
- disruption of dispersal movements and corridors
Increased highway lighting is not effective in reducing deercar collisions.
Terrestrial Mammals
Many mammals (small carnivores, rodents) are nocturnal.
These are affected by light at night.
Night-adapted animals have a rod-based retina, which
provides the necessary sensitivity for night vision but
blinds the animal in bright light. Light (moonlight)
increases the risk of predation, so small mammals stay
hidden.
A light level of 0.2 lux was sufficient to suppress
melatonin production in rats and enhance tumor production.
Bats
Bats
Insects are attracted to lights, bats then gather in
the lights to feed on these insects.
Moths evade bats by detecting their ultrasound,
but moths do not use this warning in bright light, so
they are an easy target.
Bats
In several mountain valleys in switzerland, the
lesser horseshoe bat became locally extinct after
streetlights were installed. They were replaced by
pipistrelle bats, who feed at streetlights
Migrating Birds
Migrating Birds
Migrating Birds
Migrating birds tend to move toward light
and are reluctant to leave the
lighted area.
- delays migration
- mortality due to exhaustion and
collision with structures.
Floodlit structures attract and kill birds,
particularly in misty weather.
Sea Turtles
Sea Turtles
Hatching turtles are disoriented by artificial light,
causing them to go inland instead of to the sea. Artificial
light also aids predation of the hatchlings.
A number of measures have been taken with some
success. These include shielding of luminaires, reducing
light output, installing motion detectors and light
curfews, and LED lighting embedded in roadways. All
coastal buildings must now have a lighting plan. However,
problems continue with
population growth and lighting further inland that
creates sky glow. Local lighting controls are not a
complete solution.
Reptiles
Gecko
Reptiles
Rattle snakes and water snakes hunt in the
dark of the new moon. These species have
declined in areas of heavy light pollution.
Gecko mating is curtailed in artificial light.
Frogs and Toads
Frogs and Toads
Frogs and toads have extremely sensitive night
vision, and can see in light levels of 10^-6
(10000000) to 10^-5 (1000000) lux. (Moonlight is
typically about 1 lux). They are nocturnal, so light at
night affects them and their predator-prey
relationship. Some species are attracted to light,
which acts as an 'evolutionary trap'.
Mating behaviour (chorusing) and fertility (in toads)
are inhibited under artificial light. After exposure
to bright light (along a highway, for example) frog
night vision can take hours to restore to night
vision sensitivity.
Salamanders
Newt
Salamanders
Salamanders are aquatic animals. Newts rely on
the day-night transition to initiate foraging,
and rely on the characteristics of natural light
for navigation.
Artificial light interferes with both these
activities, and may be one factor in their
population decline.
Fishes
Sea Trout
Fishes
Some fish species are attracted to light, and
fishing vessels use high-intensity lamps to
attract their prey. Mercury-vapour lamps have
been used to attract fish into special channels
around dams and power stations.
Other fish species avoid light. In Scotland,
lights from a tennis court eliminated sea trout
from a nearby river.
Fishes
Juvenile rainbow trout are inhibited from foraging by moonlight
or artificial light. Darkness is essential for fish to avoid
predation. Harbour seals have learned to use artificial light to
outmigrating smolts.
Salmon fry are inhibited from
migration by light levels in
excess of 1 lux.
Several species are inhibited
from spawning (laying eggs) by
light at night
Insects and Streetlamps
Insects are critically important as pollinators and
members of food webs in an ecosystem.
Lamp Effects on beetles, moths, flies, caddisflies:
Fixation or Capture Insect cannot escape near zone of
the light.
Crash Barrier Flight path is interrupted so insects
cannot migrate
Vacuum Cleaner Insects are removed from the area
local to the lamp.
Insects and Streetlamps
Insects and Streetlamps
Radius of attraction: 400 to 600 metres under full
darkness, 40 to 60 metres under full moon.
In dark zones, the attraction has been 2000 to 11000
insects per night. In a rural village with lighting, 400
to 1600 insects per night per lamp. Approximately
1/3 of the insects are killed or incapacitated.
In order, worst to best, are high-pressure mercury,
high-pressure sodium and low-pressure sodium lamps.
Insect attraction can be reduced with a UV filter.
Insects and Streetlamps
Mayflies
Moths
Moths
Areas around artificial lights function as bat, bird,
gecko and spider feeding stations. Some bats live
only a few days, so any disruption of their
behaviour has an effect on the population. Light
interferes with dispersal, which inhibits resistance
to habitat fragmentation.
Light greater than 0.05 lux inhibits mating in one
species of moth.
Moths
Lamp with ultraviolet component (mercury vapour,
LED) is a strong attractant. Low pressure sodium
vapour rarely attracts moths. Individual lamps
attract more strongly than an aggregate of lamps.
One lamp trap collected 50,000 moths in a single
evening. A typical catch rate is 4 to 10,000 insects
per year.
Artificial light can inhibit moth parasites.
Fireflies
Artificial light swamps
the luminescent mating
communications of
fireflies. Continuous light
(due to skyglow) may
affect the timing of
development from
pupa to fly. Artificial
light inhibits the
resettlement of
fragmented habitat (light
barrier effect).
Freshwater Habitats
Plankton
Daphnia
Freshwater Habitats
Zooplankton are at the bottom of the food chain, so
their health impacts the marine ecosystem. Nocturnal
marine organisms respond to light of full moon (0.05
to 0.1 lux). Zooplankton rise to the surface at night.
Artificial light suppresses zooplankton migration.
Cued by low light, stream insects (eg, caddisfly
larvae) migrate downstreamat night while foraging.
Plant Responses to Artificial
Lighting
Plant Responses to Artificial
Lighting
There are four photoreceptor families. These have
different spectrum responses in order to control the timing
of growth (eg, germination) under various conditions (direct
sun, open sky, shade).
Photoperiodism: some plants are sensitive to the length of
the day.
Daylight extension inhibits the flowering of some plants and
encourages it in others. A brief exposure to light will inhibit
the cockleburr from flowering. Some trees exposed to
lighting exhibited late season growth followed by severe
winter dieback. Security lighting around prisons prevents
soybeans from growing, within 30 metres of the source.
Minimizing the Impact of Artificial
Light on an Ecosystem
Turn lights off when they are not needed
Reduces the impact on nocturnal insects, animals and on
plants.
Limit the extent of lighting
Minimizes environmental impact and sky glow
Use new lighting methods:
Example: buried LED lamps in coastal highway
Consider the impact of spectrum
Example: some insects are particularly sensitive to ultraviolet
WATER POLLUTION EFFECTS
State of water
•
Natural Water has,
–
–
–
Physical attributes ( Temperature, smell,
Colour )
Chemical attributes – pH, DO, ions
Biological attributes – microorganisms
Organisms and users will adapt to
water with particular physical,
chemical and biological attributes
–
–
•
Salty sea
Fresh Water
Water Pollution
–
Alteration of the water features/attributes to
the detriment of its inhabitants and users
State of water cont;
Water Quality
– The degree of pollution from the point of
view of organisms living in or using the
water.
Pollution Sources
1.
Point sources
•
•
2.
Piped (sewage,oils)
Stormwater drains
Non- Point sources
•
•
•
Agricultural runoff
Atmospheric pollution
Seepage from mine/urban areas
What is water pollution ?

"Water pollution" is defined as the
addition of harmful or objectionable
material causing an alteration of
water quality.
How does water pollution occur?
Mankind through socio-economic activities
introduce pollutants to the environment.

“Then the Earth’s waters cycle, carry
and spread the pollutants all around the
planet.”
Water Cycle
Precipitation
Evaporation
Evaporation
Evapo-transpiration
Discharge
treated water
Soil
moisture
Water
Supply
Soil moisture
Infiltration
Recharge
Ocean
runoff
Extraction
Aquifer
Soil moisture
Infiltration (Art)
Extraction
Return flow
Treated water
Salt Water Intrusion
Aquifer intrusion
Precipitation
Evaporation/ET
Surface Water
Groundwater
Pollution types

Thermal Pollution (Heated factory water or cooler
water from another basin)



Warmer …less dissolved Oxygen
Cooler …More dissolved Oxygen
Suspended solids (Silts, Clay, living
organisms, dead organic Matter).



Dissolved solids (chemicals)
Acid rain water (Nox and sox) Leaching
effects
Trace elements (Heavy Metals)
Human activities that contribute to water pollution








Overgrazing
Poor agricultural land management
Removal of riparian vegetation
Sewage, industrial, and domestic
discharges
Construction, Mining
Release of gases and aerosols to the
atmosphere
Mismanagement of reservoirs
Accidental spills
Water pollutants (polluting elements)
•
•
•
•
•
•
•
•
•
•
•
•
•
Sewage/waste water;
Fertilizers/Pesticides;
Alien species
Global Warming
Atmospheric Deposition;
Pathogens; from untreated sewage, storm drains, septic
tanks, runoff from farms
Petroleum;
Radioactive substances;
Heat;
Siltation/sediments;
Salinization - Increased salinization and salt runoff from
irrigated farms causes salinization of major rivers;
Heavy metals cause unpleasant taste and odour to drinking
water;
Suspended particles like sediments
Effects of polluted water on;
1.
Effects on Agriculture; - use of wastewater and polluted
surface and groundwater which contaminate crops and
transmit disease to consumers and farm workers;
Depositions of deleterious chemicals in soil leading to
loss of soil fertility;
2. Effects on Environment/ecosystems; - pungent smell,
discolourisation; increased temps; contamination; change
the pH; decreased oxygen; detergents that create a mass
of white foam in the river waters; Enrichment of
groundwater with salts, nutrients from irrigated lands;
eutrophication/algal blooms-what is the effect on
recreational activities, water treatment plants/water
providers; loss of aesthetic value; Algae clogs our
waterways
Effects of polluted water on;
4. Domestic effects; - toxic substances
such as lead, mercury, cadmium, and
chromium or cyanide, which may affect
the use of the receiving water for
domestic use or for aquatic life.
5. Effects on industry; boiler scales,
Heavy metals cause unpleasant taste
and odour to drinking water; Suspended
particles cause unpleasant taste &
discoloration to drinking water;
Effects of polluted water on;
6. Economy
•
Unsightly color, reduced clarity, and obnoxious odour of the
receiving waters also make it unfit for recreation and other
productive uses;
•
Adverse effects of water pollution lead to economic losses
in terms of reduced health, reduced agricultural productivity, and
low-quality tourism.
•
There is also economic losses to family income due to the desire for
safe bottled water which is more expensive than unbottled water.
•
When water is polluted, fish and other aquatic resources can perish,
which leads to a decline in fisheries production.
Erosion from degraded uplands and pollution from silt and
sedimentation, as well as untreated sewerage, cause
productivity losses in fisheries. Silt and sedimentation are major
causes for losses in fishery
production.
•
High levels of turbidity leads to economic losses;
Effects of polluted water on;

Improvement of water quality- Removal of
organic matte thru aerobic decomposition;
chlorination to remove bacteria,
suspended solids; precipitation of salts,
desalination etc during water treatment is
expensive for polluted water;

Increased salinization and salt runoff
leading to salinization of major rivers.;

Heavy metals cause unpleasant taste and
odour to drinking water;

Suspended particles cause unpleasant
taste & discoloration to drinking water;
Effects of polluted water on;

Hard water with usually high levels of
calcium and magnesium can cause a
build-up of minerals in pipelines/boiler
scales and cause erosion and blockage
problems. Water softeners and
conditioners can be used in the water to
reduce limescale but can be expensive.
Effects of polluted water on;
7. Leisure




Swimming pool water can become contaminated with a number of different pollutants
and may cause changes in water colour and odour, some pollutants may also be
harmful to human health.
Discolouration of the swimming pool water could be due to a number of reasons. It
may be dirty and cause the water to change a milky colour if the filter is inadequate
or blocked. Algae contamination can also cause discolouration, black algae cause
black spots to appear in the pool. Other forms of algae contaminate pools when
chlorine levels are too low, these often turn the water a green colour.
Chlorine is used in many swimming pools to keep them clean. There are certain
substances, such as certain types of detergents and some forms of make-up, that don’t
mix well with chlorine. These can cause adverse effects to human health such as skin
and throat irritations.
Pond water can also become polluted with different chemicals or microbes. This can
make the pond less attractive and can be harmful to aquatic life within the pond. An
overgrowth of algae and accumulation of leaf debris are often the main problems with
ponds in the home; UV filters are efficient at reducing algae levels in ponds and also
remove decaying vegetation. These are useful for long term maintenance of your
pond.
Effects of polluted water on;
8. Effects on human health;
Increased incidence of tumours, ulcers due to nitrate pollution; Increased
incidence of skin disorders due to contact with pollutants; Increased
incidence of constipation, diarrhea, and infections to intestine;
Dangerous effects on growing foetus in pregnant women; Concentration
of pollutants due to bioaccumulative pesticides through secondary and
tertiary food chains in case of non-vegeterians; Still births, abortions,
and birth of deformed children; Blue baby disease caused by
methaneglobinema-which results in asphyxia (reduced oxygen
supply);Reduced activity of immune system; Loss of memory power and
reduced mental sharpness; Water borne diseases like jaundice, hepatitis,
gasteroenteritis, will be more prevalent due to water pollution; Reduced
bone development and muscular development; Reduced male fertility;
Shifts in physiological cycles of human body.
Effects of polluted water on;
9. Effects on animal health;
 Large scale death of aquatic and terrestrial animals;
 Reduced reproduction rate;
 Increased disease incidences;
 Imbalances created in secondary foodchains;
 Accumulation of bioaccumulative and nonbiodegraddable
pollutants in animal bodies;
 Bioaccumulation eg of organochlorine pesticides;
 Biomagnification;
 Cause health hazards like impotence, cancerous tumours etc
Major water related diseases
1
2
3
4
Type
Water borne
(Disease
causing
vector
carried in
water)
Water
washed
(Resulting
from lack of
water or
improper
use of water)
Water Based
(Vector lives
in water)
Diseases
Cholera
Typhoid
Diarrhoea
Dysentery
Effects
Dehydration
Scabies
Eye
infections
Diarrhoea
Cause
 Drinking
contaminated
water
 Eating
contaminated
food
 Not washing
 Lack of enough
water for
washing
Bilharzias

Blood in stool
Pain in stomach
Insect vector Malaria
related
River
blindness


Worms from the
snails enter
through the skin
in infected
water
Mosquitoes bites
Semolina worm
Itchy lashes
Sore eyes
Blindness
Fever from lice
diseases
Prevention
 Use clean water for
drinking
 Keep flies away from
food
 Avoid unprotected
water sources
 Increase water
availability for washing
 Improve personal
hygiene


Fever
Aches
Blindness



Reduce contact with
infected snails
Control snails
Removal potential
larvae breeding sites
Use mosquito netting
Introduce fish in ponds
river water