Marine plastics

Question 1

Describe the global trends in plastic production since its inception

Answer 1

• Mass plastic production only began in 1950
• Since then, production has increased from 2 Mt to 380 Mt in 2015

Question 2

Give some data on plastic waste

Answer 2

• Most plastic ever produced (6,300 Mt) has become waste
• No commonly used plastics are biodegradable
• Almost 80% of waste accumulates in landfills/ natural environ
• ~12,000 million tonnes of plastic waste will be in landfills or natural environ by 2050 (Geyer et al. 2017)

Question 3

Where do most marine plastics come from?

Answer 3

• Fishing and aquaculture
• Most significantly, improperly managed waste

Question 4

How does mismanaged waste contribute to ocean pollution?

Answer 4

• Waste is improperly disposed of in dumps or open landfills.
• It can enter oceans via inland waterways, wastewater outflows, or be transported by wind/tides.

Jambeck et al. (2015) Estimate:
- 2,500 Mt of municipal waste generated by people living in 192 coastal countries (11% of of this was plastic)
- 1.7 - 4.6% of the total plastic waste from these countries was mismanaged and entered the ocean

Question 5

How much mismanaged plastic waste was there in the UK in 2010, how is this expected to change?

Answer 5

67,500t mismanaged plastic waste in 2010, expected to rise by 39.26% by 2025

Question 6

what are the ecological effects of plastic on beaches and in the ocean?

Answer 6

• Physical barrier (e.g turtle egg laying)
• Lowers diversity of shoreline invert communities
• Increases hazard of entanglement
• Death by ingestion
• Smother coral assemblages
• But, bottles/ jars increased diversity and abundance in soft sediment habitat

Question 7

Describe findings into how hermit crabs can utilise plastic debris

Answer 7

• Common (observed in 10/16 terrestrial hermit crabs)
• Mechanisms: sexual signaling, lightness of artificial shells, odour cues, and camouflage in a polluted environment.

Question 8

What is the effects of exposure to microplastics on fish and aquatic inverts?

Answer 8

• There is evidence that macrodebris is bad for marine life
• The evidence that microplastics are important at organism-ecological scales remains scarce.
• But absence of evidence does not equate to evidence of absence.

Question 9

What is a major issue with some attempts to solve the plastic problem, like the Ocean Cleanup project?

Answer 9

• Huge publicity surrounds well-meaning attempts
• E.g The Ocean Cleanup project, trapped 100s of animals
• Criticised for not understanding the source of the problem or ecosystems affected.

Question 10

What are some ways the source of plastic pollution has been addressed?

Answer 10

• National bans on single use products e.g microbeads in cosmetics
• Significant campaigns on banning products e.g straws

Question 11

Describe the critics of the plastic panic

Answer 11

• Conservationists argue that climate change is the big threat to oceans
• And that plastics are insignificant compared to that
• Also argue that people making a big deal about plastics gives us carte blanche to engange in other, more damaging, behaviours