lec 28: macroplastics and microplastics

Question 1

just how big is the impact of plastic on a historical scale

Answer 1

VERY big, it is one of the main things that defines our era.

Question 2

what is the anthropocene defined by

Answer 2

the great acceleration of human activity
growing biological invasions

In absolutely all spheres of life and resources

endless economic growth
anthropocentic

Question 3

why is the arctic said to become a future hub for biological invasions

Answer 3

because with climate change, it will become a transport route (commerce but also for leisure)

Question 4

how have humans co-opted the hydrological cycle

Answer 4

one of the ways was by damming runoffs , of rivers

Question 5

T or F: Plastics production increased X20 over the last 50 years (more than that now)

Answer 5

True

Question 6

T or F: plastics in the marine environment can be found in enormous densities

Answer 6

true

Question 7

How does the small and colorful aspect of plastics impact the marine environment

Answer 7

animals triggered by certain colors will be enticed into consuming them

fish, seabirds, turtles (mistaking plastic bags for jellyfish)

Question 8

give an example of how far plastic can be found

Answer 8

in the mariana trench a place even human cant get to

Question 9

How do plastics interact with the major ocean gyres

Answer 9

they accumulate in gyres, collected of the coast and swept up, they can travel far because they are resistent and so they end up where the currents take them

ex: Plastic accumulation in the North Atlantic subtropical gyre

Question 10

what can be said about the rafting of marine species on ocean litter

Answer 10

20 to 80% of debris was human-made (persisting longer than natural debris)

attached invertebrates: barnacles, bryozoans, hydroids, worms, molluscs

floating trash enables raft dispersal by marine species to double in the tropics and triple in high latitudes

Question 11

what makes plastic debris such a problem, what makes it worse than natural debris

Answer 11

the problem with plastic debris is that they can transport organisms with distances much larger than natural debris due to their resistance. This can lead to non-native species invasions

they have become a strong vector !

Question 12

what are microplastics

Answer 12

small (<5mm) polymer particles: beads, pellets, flakes, fibres

Question 13

where do microplastics come from?

Answer 13

• products of fragmentation of larger plastic debris
• manufactured for industrial use or domestic use

Question 14

how do microplastics end up in deep sea sediments

Answer 14

they get flushed into the ocean and rivers
floating for long times
they gain bacterial filth
and settle up

Question 15

why are rivers sinks for microplastics

Answer 15

because they settle there at a much quicker rate

Question 16

what are the findings of the st-lawrence study

Answer 16

1. Size, shape and chemical composition of the beads suggest that most originate from cosmetic produts
2. some microbeads originate from industrial sources
3. microbeads occur at nearly every site sampled across a 320 km section of the river
4. local abundances are as high as those recorded in marine sediments
5. Rivers can act as a sink for microplastic pollution

Question 17

T or F: wastewater treatment plants cannot filter microplastics

Answer 17

True

Question 18

why is it a concern?

Answer 18

small enough to be ingested by aquatic animals

impacts on animal physiology and behaviour

readily absorb toxic contaminants (e.g PCBs) and can transfer these to animals that ingest them

possible transfer to humans (e.g through marine shellfish consumption)

Question 19

what are nanoplastics

Answer 19

plastic particles that are small enough they can pass through membranes