Ecosystem Impacts on the Oceans

Question 1

describe ecosystem services

Answer 1

• a service is a benefit that is provided to humans, in a direct or indirect way
• includes: food production (fisheries); absorption of the excess heat caused by anthropogenic forcings in the atmosphere; absorption of CO2 from the atmosphere (carbon sink); reservoir of biological diversity (coral reefs); cultural, recreational services (tourism, recreational fishing)

Question 2

ecosystem stressors

Answer 2

• pollution of air, water, and soil
• deforestation and land use change, largely driven by agriculture
• fragmentation of habitats, loss of biodiversity

Question 3

effects of ecosystem stressors on the ocean

Answer 3

• overfishing, increase in bycatches, ecological extinctions
• habitat degradation in coastal regions
• invasive species
• sea level rise threats to coastal ecosystems
• loss of sea-ice habitats
• ocean acidification

Question 4

describe the ocean warming trends

Answer 4

• most of the surface is warming up, but there are important regional differences
• warming is stronger in the North Atlantic Ocean
• warming is stronger in the surface of the ocean, weaker in the deep ocean –> increases the stratification
• more stratified = less distribution of nutrients –> changes in ocean productivity

Question 5

describe the changes in ocean oxygen

Answer 5

• warming of the surface water & increase in ocean stratification will also affect the oxygen content of the ocean
• warm water holds less oxygen –> warming will decrease oxygen in the ocean
• as ocean warms and becomes more stratified, the transport of oxygen from the atmosphere to the ocean interior will decrease

Question 6

deoxygenation

Answer 6

decline in ocean oxygen due to climate change & warming temps

Question 7

what factors contribute to sea level rise

Answer 7

• thermal expansion of sea water
• melting of mountain glaciers & ice sheets
• release of water from groundwater aquifers

Question 8

describe thermal expansion’s effect on sea level rise

Answer 8

• water expands as it gets warmer –> sea level rises

Question 9

describe how the ocean acidifies

Answer 9

• once CO2 dissolves, it undergoes a chemical reaction with water & is converted to carbonic acid
• hydrogen atom in carbonic acid dissociates in aqueous solution
• as more CO2 dissolves in the ocean, the ocean becomes more acidic

Question 10

what organisms are vulnerable to small pH changes

Answer 10

• calcifying organisms, their shells contain calcium carbonate
• ex: corals, crustaceans, mollusks

Question 11

what is a lightly protected marine area

Answer 11

• some protection exists, but significant extractive activity is allowed

Question 12

what is a strongly protected marine area

Answer 12

• all commercial activity prohibited, only light recreational and subsistence fishing allowed

Question 13

what is a fully protected marine area

Answer 13

• no extractive activities allowed

- also called “marine reserves”

Question 14

describe coral bleaching

Answer 14

• when coral is under stress, it will eject the algae which removes its color (bleaches it)
• ejection increases the corals’ chance of surviving short-term stress as they can later regain the algae
• if stressful conditions persist, the coral eventually dies of starvation