11.4 What marine environmental problems are associated with non-point source pollution, including trash?

through intentional and unintentional actions, humans release a vast amount of trash into oceans.

Non-point source pollution and trash

non-point source pollution (poison runoff) = any type of pollution entering the ocean from multiple sources rather than from a single discrete source, point, or location. in most urban areas, non-point source pollution arrives at the ocean via runoff from storm drains, many of which now have labels indicating that they lead to the ocean.

**many people believe that storm drain runoff is processed by sewage treatment plants but ANY material that enters storm drains goes directly into streams or the ocean.

  • difficult to pinpoint where NPS pollution originates but the cause of the pollution may already be apparent i.e.

    • Ex. trash washed down storm drains to ocean then washes up on beaches

    • Ex. pesticides, fertizilers from agriculture

    • Ex. oil from automobiles that are washed to the ocean whenever it rains

  • trash enters ocean as a result of ocean dumping

    • existing laws allow certain types of trash i.e. glass, metal, rags, and food to be legally dumped in ocean as long as they’re dumped far enough away from shore or ground up small enough

      • mostly biodegrades and doesn’t accumulate at surface

**always illegal to dump plastic

Plastics as Marine Debris

plastics constitude vast majority of marine debris

80% marine debris comes from land-based sources, and most of that is plastics

  • when plastics enter ocean, they float and aren’t easily biodegradable —> plastics can remain in marine environment almost indefinitely, affecting marine organisms through entanglement and ingestion

    • many times fish are strangled, marine birds ingest so much plastic that their stomachs fill and then they die of starvation, marine turtles die when they eat floating plastic bags

**>700 species have been reported to become entangled in or eaten plastic

  • entanglement and ingestion not the worst problems

  • floating plastic pieces have a high affinity for non-water-soluble toxic compounds i.e. DDT, PCBs, and other oily pollutants —> plastics accumulate poisons to levels as high as a million times their conc. in seawater —> marine organisms eat them

Plastics = one of the few things illegal to dump anywhere in the ocean

Brief History of Plastics

  • debuted 1862 at Great International Exhibition in London

  • commercial development in WWII when shortages of rubber and other materials created great demand

  • plastic = lightweight, strong, durable, and expensive = many advantages over other stuff

  • by 1970s, plastic products made their way into everything

  • disadvantagesL

    • disposing of plastics has strained the capacity of land-based solid-waste disposal system

    • plastic waste now increasingly abundant component of oceanic trash

  • very same properties that make plastics so advantageous also make them unusually persistent and damaging when released into marine environment

    • lightweight —> float and conc. at surface

    • strong —> entangle marine organisms

    • durable —> don’t biodegrade easily, last almost indefinitely

    • inexpensive —> mass produced, used in everything

Plastic nurdles in the marine environment

today nearly all plastic products produced from small pre-production plastic pellets called nurdles that range in size from a BB to a pea

  • nurdles transported in bulk abroad commercial vessels and found throughout oceans

  • bc of ocean surface currents that wash plastic ashore, plastic nurdles and other trash can be found on most beaches, even in remote areas

Microplastics

microplastics (microbeads): small plastic particles between 1mm-5mm in diameter

  • used as cleaners and scrubbers in hand cleaners, exfoliating facial scrubs, toothpastes, air blasting technology

    • in some cosmetics, combined microplastics in the product contain more plastic than the container they came in

  • enter ocean via runoff from land, washed down drains, transported unaltered through waste water treatment plants bc of micro size

  • transport pollutants and eaten by fish

  • also generated as larger pieces of plastic break down over time

  • floating plastics photodegrade: sunlight breaks them down into progressively smaller pieces —> facilitates ingestion of plastics by all types of marine organisms

The issue of plastics in the ocean

accumulates a lot in middle of 5 major subtropical gyres

  • gyres far from population centers and slowly rotate —> floating debris accumulate in calm centers

  • in every marine environment where scientists have looked, they’ve found plastic

    • found plastic in stomachs of tiny sea creatures living in Pacific Ocean trenches nearly 11km deep

  • floating plastic trash so abundant it’s being used as an artificial habitat in the open ocean by marine creatures from microbes that use it as floating platforms, to fish that are protected within the floating debris —> beginning to alter comp. of marine ecosystems

    • Ex. water strider lays eggs on floating objects in open ocean —> as trash increases, water strider eggs increase

  • half the plastic ever made was made in the last 15 years

  • where does all this trash go?

    • some washes up on beaches bc of surface currents

    • some eaten by marine animals

    • some encrusted nby marine life and sinks to sea floor

    • plastic trash pervasive throughout sea floor and found in mariana trench even

    • large portion remains at sea

Eastern pacific garbage patch = twice the size of texas, just floating pieces of trash

Reducing the amount of plastics in the ocean

what can be done to limit the amount of plastics in the marine environment?

  • limit use of single-use plastic

  • recycle plastic material

  • dispose of plastic trash properly (don’t dump in ocean)

MARPOL: 1988 International Convention for the prevention of Pollution from Ships (short for marine pollution) proposed a treaty banning the disposal of all plastics and regulating the dumping of most other garbage at sea

  • studies say MARPOL has reduced marine debris and entanglements by discarded fishing nets in some places i.e. alaska and california BUT

  • other studies show no improvement in areas i.e. Southern Ocean, South Atlantic, Hawaiian Islands

RECAP

although some plastics wash up on beaches, the vast majority of plastics don’t ever leave the ocean. instead, they break down into smaller pieces and enter marine food webs at progressively lower levels.

CONCEPT CHECK 11.4

(1) what is non-point source pollution and how does it get into the ocean? what other ways does trash get into the ocean?

  • NPS pollution = pollution that can’t be pinpointed back to a specific origin point, enters the ocean in many different ways

  • enters ocean through storm drains, sewage dumping, runoff, drains

(2) what properties contributed to plastics being considered a miracle substance? how do those same properties cause them to be unusually persistent and damaging in the marine environment?

  • inexpensive —> mass produced and everywhere, more likely to end up in ocean

  • durable —> lasts forever in the ocean, extremely pervasive

  • lightweight —> floats on top of the ocean, can be photodegraded into even smaller pieces

  • strong —> entangle marine organisms