Marine Pollution Flashcards
Main categories of marine pollution
- Toxic substances
- Solid waste inc. plastic debris
- Sewage and eutrophication
- Warm water sources
- Noise
- Light
Acute pollution discharge
catastrophic but a relativley quick event, short term
Chronic pollution discharge
continuous input of toxic substance or other anthropogenic factor (causes degredation of the environment) long term
Acute effect of oil spills
e.g. Oiling
Chronic effect of oil spills
e.g Changes
in community structure
Point pollution sources
Point source – discrete entry point
* E.g. oil spills, sewage outflow, factory
wastewater pipe
Diffuse pollution sources
Diffuse – variety of geographic points
* E.g. rainfall run-off, CO2, plastic pollution
*Biomagnification
An increase in the
biological concentration of a chemical with increasing trophic position
Bioaccumulation
Corresponds to the
process by which the intake of a chemical, via dietary or environmental
exposure routes, exceeds elimination
Toxic substances (Heavy metals) - Sources
Sources:
*Mining e.g. Mercury (Hg) and gold mines
* Manufacturing e.g. Hg from pulp mills (prior to regulation) and Cadmium (Cd) from battery factories
* Coal-burning powerplants (Hg as aerosols)
* Sewage e.g. Cd
* Agriculture e.g. insecticides and fungicides
Toxic substances (Heavy metals) - Effects
- Methyl-mercury bioaccumulates in food chain and causes Minimata disease in humans
- Denature proteins e.g. Zinc (Zn) and Cu
- Bind to blood pigments e.g Cu
- Renal function e.g. Cd in sea turtles and dugongs consumed by humans
Persistent Organic Pollutants (POPs) - Sources
- Agricultural run-off e.g. pesticides and herbicides
- Anti-fouling paint e.g. Tributyltin (TBT)
- Industrial additives e.g. Polychlorinated biphenyls (PCBs)
Persistent Organic Pollutants (POPs) - Effects
- Slow degradation
- Biomagnification and bioaccumulation
- Eggshell thinning e.g. DTT
- Carcinomas
- Reproductive failure
- Impacts on immune, endocrine (hormones) and nervous system function
Oil and Polycyclic aromatic hydrocarbons (PAHs) - Sources
- Small amount of natural release (seeps)
- Human activity e.g.
- Leaks from marine terminals, harbours, offshore drilling, tankers and barges
- Washout from land via drains & rivers
- Intentional washing of tanks
Oil and Polycyclic aromatic hydrocarbons (PAHs) - Effects
- Oil fouling – ingestion, suffocation and hypothermia
- Cascading effects e.g. Coastal vegetation die-off -> increased turbidity
- PHAs (lipophilic) – Cancers, tissue abnormalities and
reduced reproductive rates - Chemical dispersants (Surfactants) also toxic
Carbon dioxide (CO2) - Sources
Rising CO2 emissions due to burning of fossil fuels
Carbon dioxide (CO2) - Effects
- Reduction in seawater pH - Acidification
- Reduced availability of calcium carbonate for
exoskeletons of marine organisms - e.g. Corals, molluscs, echinoderms, crustacea,
foraminifera - Increases in sea-surface temperature
- Reduction in sea ice
- Coral bleaching
Debris (inc. plastic) - Sources
- ~80% is plastic
- Huge variety of sources e.g. waste
mismanagement, sewage outflows and fishing - Larger items (macroplastics >5mm) are broken
down to microplastics (<5mm) - Microplastics are also purpose-made e.g.
microbeads and industrial abrasives - Easily transported and accumulates in gyres and
coastal regions
Debris (inc. plastic) - Effects
- Ingestion
- Chemical contaminants e.g. PCBs and plasticizers
- Entanglement
- Smothering
Nitrogen - Sources
- Sewage and fertilizers (rivers and run-off)
- Atmospheric nitrogen emissions from
burning of fossil fuels
Nitrogen - Effects
- Eutrophication
- Phytoplankton blooms
- Detritus sinks
- Microbial respiration: hypoxia and
- Anoxia -> fish die offs and dead zones
- Harmful Algal Blooms (‘red tides’)
- Paralytic shellfish poisoning
Warm water sources (thermal pollution) - Sources
- Power stations
- Use water in heat dissipation
- Warm water pumped directly into the
sea (up to +15°C)
Warm water sources (thermal pollution) - Effects
- Can kill local species
- Primary producers replaced
- Primary production reduced
- Changes in zooplankton and fish communities
- Increased numbers of alien species e.g
Pacific oysters in Sweden
Noise - Sources
- Vessel traffic
- Oil and gas exploration e.g. seismic surveys
- Construction e.g. pile driving offshore structures
- Sonar e.g. military vessels
Noise - Effects
- Hearing damage
- Stress
- Behavioural changes
- Disturbance
- Masking
Light - Sources
- Coastal development
- Offshore industries e.g. oil and gas, marine
renewables - Shipping
Light - Effects
- Disruption to movement patterns
- Greater exposure to other threats e.g. predation
- Reduces reproductive success
