The
only explanation that occurs to me is that the smallest pieces
attract shell accreting organisms that naturally change the specific
gravity of the particle and down it goes. One presumes then that this
process will essentially strip all the debris out of the ocean and if
true that is excellent news. That the load has declined alone is
excellent news.
There
is support for this in the form of accreted masses with plastic waste
mixed in.
Thus
the real challenge facing us is to discover methods to intercept all
plastic waste in the first place so that it rarely ends up in the
ocean and a large part of that problem has been brought under
control.One reason I would like to see the universal adoption of
double lung incineration for all waste streams is that all organics
are consumed then and there and never end up in a land fill.
4 Theories On Why
The Ocean's Floating Plastic Is Disappearing
By Leslie Baehr
An increasing amount
of plastic has been entering our oceans since the 1980s. However,
when researchers attempted to map all of this ocean garbage, they
found that the amount of trash floating on the water's surface was
smaller than expected.
https://ca.finance.yahoo.com/news/4-theories-why-oceans-floating-155100548.html
"Plastic debris
in the open ocean." Cózar et. al.
A world map shows
concentrations of plastic in the ocean.
A new study reveals
that plastic in our oceans is disappearing, but scientists aren't
sure where the debris is going.
"These studies
suggest that surface waters are not the final destination for buoyant
plastic debris in the ocean," researchers wrote in a study
published on Monday, June 30, in the journal Proceedings of the
National Academy of Sciences.
Where is the plastic
going?
Most plastics that
enter the ocean tend to get broken down by the sun and waves into
smaller particles around 1 centimeter or less. For this reason,
scientists expected to find the tiniest pieces, 1 millimeter or less,
in the greatest abundance. But, in most of the samples they took,
these tiny pieces were missing.
In the chart below,
you can see what scientists expected (orange) versus what they
actually observed (blue). While smaller plastic was expected to be
found in larger abundance, actual observations showed a
mysterious drop off (left) in the smaller-sized plastics. The size of
the plastics increase as you move right on the graph.
Scientists aren't sure
where the plastic is going or the mechanism that's causing it to
move, but they have a few theories:
Theory 1
Washed ashore: One
possibility is that the small plastics head for land.
The
problem: Scientists think this is unlikely since there is no
reason to suspect only smaller things would wash ashore.
Theory 2
Broken down: The
small plastics could be continuously degrading into smaller,
undetectable pieces.
The problem: While
plastic pieces are continually being broken down in the ocean, there
is no reason to believe that the rate at which plastic is being
degraded has increased, the authors said. Plus, degradation of
plastic can take hundreds to thousands of years. Other degrading
factors could be at play though, such as small bacteria helping to
break down the plastics.
Theory 3
Sinking: Oceanic
epipyphytes — nonparasitic plants that usually grow on other plants
— will often latch onto anything that floats. For a particle with a
lot of surface area for its size, plant growth on the outside of the
plastic would make it heavy, causing it to sink.
The problem: Previous
studies have shown that when a plant-ballasted plastic sinks in the
open ocean, the plants growing on it die and fall off, causing the
object to pop back up.
Theory 4
Someone's
dinner: Zooplankton, tiny animals about the same size as the
missing plastic, make up the bottom of the ocean food chain. Fish
that eat zooplankton might mistake the plastic as food.
The ocean is full of
zooplankton-eating mesopelagic fish, or fish that live between 200
and 1,000 feet deep. These fish tend to migrate to the surface —
where the plastic is — at night for feeding. The researchers
believe that, if consumed, the plastic could stay inside the fish for
anywhere from a day to a year. The garbage can be transferred to
larger predators if the smaller fish is eaten. Ingested plastic could
easily sink to the seafloor if the fish dies, or if it's removed in
the animal's excrement, which is known to sink quickly.
"These
microplastics have an influence on the behavior and the food chain of
marine organisms," lead researcher Andres Cózar Cabañas of the
Universidad de Cadiz at Puerto Real (Spain) said in a press
release. The small plastics contain contaminants that can be passed
onto to the organisms who eat them or, perhaps worse, get lodged
inside them, he said. "Small oceanic fishes are the main trophic
linkage between the plankton and marine vertebrates, and serves as
staple food for many commercial fish such as tuna or swordfish,"
he said in an email.
Unfortunately, more
research is needed to crack the case of the disappearing plastic.
The beginning
The question first
occurred to the study authors while examining data taken from
the 2010/2011 Malaspina circumnavigation research trip that
sampled water from thousands of sites across the world.
"This task was
not initially in our objectives for the circumnavigation, but the
plastic presence in the first samples was striking," Cózar told
Business Insider. They found that 88% of their samples contained
plastic.
The also discovered
that the plastic appeared to be most abundant in areas where the
subtropical gyres — giant ocean-wide currents — converged. Where
these gyres come together they make huge "conveyor belts,"
bringing trash from shores into the surface of the open ocean.
The world's five major
gyres are illustrated in this map.
Based on the data
collected, the scientists expect the surface of the open ocean holds
anywhere between 7,000 and 35,000 tons of plastic, which is "far
less than expected," they wrote.
The Plastic Age
The missing plastic is
only a small part of the problem. "Our estimates indicate that
the tens of thousands of plastic tons floating on the surface waters
could represent only 1% of the plastic pollution into the oceans,"
Cózar said. More could be hiding below the surface.
"Indeed, the
quantity of plastic floating in the ocean and its final destination
are still unknown," the researchers concluded
The
only explanation that occurs to me is that the smallest pieces
attract shell accreting organisms that naturally change the specific
gravity of the particle and down it goes. One presumes then that this
process will essentially strip all the debris out of the ocean and if
true that is excellent news. That the load has declined alone is
excellent news.
There
is support for this in the form of accreted masses with plastic waste
mixed in.
Thus
the real challenge facing us is to discover methods to intercept all
plastic waste in the first place so that it rarely ends up in the
ocean and a large part of that problem has been brought under
control.One reason I would like to see the universal adoption of
double lung incineration for all waste streams is that all organics
are consumed then and there and never end up in a land fill.
4 Theories On Why
The Ocean's Floating Plastic Is Disappearing
By Leslie Baehr
An increasing amount
of plastic has been entering our oceans since the 1980s. However,
when researchers attempted to map all of this ocean garbage, they
found that the amount of trash floating on the water's surface was
smaller than expected.
https://ca.finance.yahoo.com/news/4-theories-why-oceans-floating-155100548.html
"Plastic debris
in the open ocean." Cózar et. al.
A world map shows
concentrations of plastic in the ocean.
A new study reveals
that plastic in our oceans is disappearing, but scientists aren't
sure where the debris is going.
"These studies
suggest that surface waters are not the final destination for buoyant
plastic debris in the ocean," researchers wrote in a study
published on Monday, June 30, in the journal Proceedings of the
National Academy of Sciences.
Where is the plastic
going?
Most plastics that
enter the ocean tend to get broken down by the sun and waves into
smaller particles around 1 centimeter or less. For this reason,
scientists expected to find the tiniest pieces, 1 millimeter or less,
in the greatest abundance. But, in most of the samples they took,
these tiny pieces were missing.
In the chart below,
you can see what scientists expected (orange) versus what they
actually observed (blue). While smaller plastic was expected to be
found in larger abundance, actual observations showed a
mysterious drop off (left) in the smaller-sized plastics. The size of
the plastics increase as you move right on the graph.
Scientists aren't sure
where the plastic is going or the mechanism that's causing it to
move, but they have a few theories:
Theory 1
Washed ashore: One
possibility is that the small plastics head for land.
The
problem: Scientists think this is unlikely since there is no
reason to suspect only smaller things would wash ashore.
Theory 2
Broken down: The
small plastics could be continuously degrading into smaller,
undetectable pieces.
The problem: While
plastic pieces are continually being broken down in the ocean, there
is no reason to believe that the rate at which plastic is being
degraded has increased, the authors said. Plus, degradation of
plastic can take hundreds to thousands of years. Other degrading
factors could be at play though, such as small bacteria helping to
break down the plastics.
Theory 3
Sinking: Oceanic
epipyphytes — nonparasitic plants that usually grow on other plants
— will often latch onto anything that floats. For a particle with a
lot of surface area for its size, plant growth on the outside of the
plastic would make it heavy, causing it to sink.
The problem: Previous
studies have shown that when a plant-ballasted plastic sinks in the
open ocean, the plants growing on it die and fall off, causing the
object to pop back up.
Theory 4
Someone's
dinner: Zooplankton, tiny animals about the same size as the
missing plastic, make up the bottom of the ocean food chain. Fish
that eat zooplankton might mistake the plastic as food.
The ocean is full of
zooplankton-eating mesopelagic fish, or fish that live between 200
and 1,000 feet deep. These fish tend to migrate to the surface —
where the plastic is — at night for feeding. The researchers
believe that, if consumed, the plastic could stay inside the fish for
anywhere from a day to a year. The garbage can be transferred to
larger predators if the smaller fish is eaten. Ingested plastic could
easily sink to the seafloor if the fish dies, or if it's removed in
the animal's excrement, which is known to sink quickly.
"These
microplastics have an influence on the behavior and the food chain of
marine organisms," lead researcher Andres Cózar Cabañas of the
Universidad de Cadiz at Puerto Real (Spain) said in a press
release. The small plastics contain contaminants that can be passed
onto to the organisms who eat them or, perhaps worse, get lodged
inside them, he said. "Small oceanic fishes are the main trophic
linkage between the plankton and marine vertebrates, and serves as
staple food for many commercial fish such as tuna or swordfish,"
he said in an email.
Unfortunately, more
research is needed to crack the case of the disappearing plastic.
The beginning
The question first
occurred to the study authors while examining data taken from
the 2010/2011 Malaspina circumnavigation research trip that
sampled water from thousands of sites across the world.
"This task was
not initially in our objectives for the circumnavigation, but the
plastic presence in the first samples was striking," Cózar told
Business Insider. They found that 88% of their samples contained
plastic.
The also discovered
that the plastic appeared to be most abundant in areas where the
subtropical gyres — giant ocean-wide currents — converged. Where
these gyres come together they make huge "conveyor belts,"
bringing trash from shores into the surface of the open ocean.
The world's five major
gyres are illustrated in this map.
Based on the data
collected, the scientists expect the surface of the open ocean holds
anywhere between 7,000 and 35,000 tons of plastic, which is "far
less than expected," they wrote.
The Plastic Age
The missing plastic is
only a small part of the problem. "Our estimates indicate that
the tens of thousands of plastic tons floating on the surface waters
could represent only 1% of the plastic pollution into the oceans,"
Cózar said. More could be hiding below the surface.
"Indeed, the
quantity of plastic floating in the ocean and its final destination
are still unknown," the researchers concluded
No comments:
Post a Comment