Particle (ecology)
Particle (ecology) is the term for small objects of nonbiological kind.
Particles can remain in suspension in the ocean or freshwater, however they eventually settle (rate determined by Stoke's law) and accumulate as sediment. Some can enter the atmosphere through wave action where they can act as Cloud Condensing Nucleii (CCN). Many organisms can filter particles out of the water with unique filtration mechanisms (filter feeders). Particles are often associated with toxins which can attach to the surface functional groups. As these toxins are passed up the food chain they can accumulate in fatty tissue and become increasingly concentrated in predators (see bioaccumulation. Very little is known about the dynamics of particles, especially when they are re-suspended by storms or dredging. They can remain suspended in water for and drift over long distances. Non-living particles contribute to the detrital pool, where they are acted upon by bacteria and detritivores. This process consumes oxygen, and can cause oxygen depletion.
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Particlekils.gif
Image:Particlekils.gif
Particles scanned with a new underwater microscope (ecoSCOPE) in a polluted estuary hovering in the free water, size 20 - 200 micrometer (blue frame is a 1 mm contrast grid). Particles collected in the vicinity had the following toxin levels (milligram per unit dry weight):
arsenic ............................................ 8.17 mg kg-1
lead ............................................. 80.1 mg kg-1
cadmium ...................................... 0.61 mg kg-1
chrom ........................................ 31.2 mg kg-1
copper ....................................... 44 mg kg-1
nickel ....................................... 20.6 mg kg-1
mercury ................................ 0.86 mg kg-1
zinc .......................................... 156 mg kg-1
EOX ........................................ ..... 0.79 mg kg-1
anthracen ..................................602 myg kg-1
fluoranthen ............................ 5947 myg kg-1
pyren ...................................... 5549 myg kg-1
benzo(a)anthracen ................ 5296 myg kg-1
benzo(b)fluoranthen ............. 2499 myg kg-1
benzo(k)fluoranthen ............. 1652 myg kg-1
benzo(a)pyren ....................... 1895 myg kg-1
dibenz(ah)anthracen ...............200 myg kg-1
benzo(ghi)perylen ................ 1533 myg kg-1
dichlormethan ........................... 66 myg kg-1
trichlormethan ........................... 11 myg kg-1
tetrachlormethan ......................... 5 myg kg-1
1, 1, 1- trichlorethan ................... 4 myg kg-1
pentachlorphenol ....................... 22 myg kg-1
1, 2, 3-trichlorbenzol .................. 0.4 myg kg-1
1, 3, 5- trichlorbenzol ................. 0.4 myg kg-1
1, 2, 4- trichlorbenzol ................. 1.4 myg kg-1
1, 2, 3/4, 5-tetrachlorbenzol ....... 1.2 myg kg-1
1, 2, 3, 4-tetrachlorbenzol ........... 0.4 myg kg-1
pentachlorbenzol ........................... 0.8 myg kg-1
hexachlorbenzol ............................ 3.9 myg kg-1
PCB 28 ....................................... 598 myg kg-1
PCB 52 ....................................... 331 myg kg-1
PCB 101 ..................................... 205 myg kg-1
PCB 138 ..................................... 414 myg kg-1
PCB 153 ..................................... 432 myg kg-1
PCB 180 ..................................... 225 myg kg-1
total PCB ................................ 2205 myg kg-1
benzol ........................................ 108 myg kg-1
toluol ......................................... 655 myg kg-1
o,-m,-p-Xylol ............................. 247 myg kg-1
2,3,7,8-Tetra-CDF (dioxin) .......... 0.8 ng kg-1
It takes a few days until plankton organisms have filtered the particles and incorporated the toxins into their body fat and tissue: In the southwards flow of the waters of the Hudson off the coast of New Jersey, the highest levels of mercury in copepods have not been found directly in front of the river off New York but 150 km south, off Atlantic City.
Some copepods are then captured by mysidae, krill and smallest fish like the juveniles of atlantic herring - and in each step of the foodchain the toxin concentrations increase by the factor of 10 (ca.) (the milk of mothers (Homo sapiens) consuming fish or related products in such areas have toxin levels which would make it impossible to sell such milk on some european markets - their babies have much more defects and retarded brains or later difficulties to learn / reproduce).
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Mercuryk.gif
image:mercuryk.gif
mercury in zooplankton (copepods) in the open ocean off New York and Atlantic City USA New Jersey
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Krillfilter2kils.jpg
Image:Krillfilter2kils.jpg
Filter of krill: The first degree filter setae carry in v-form two rows of second degree setae, pointing towards the inside of the feeding basket. The purple ball is one micrometer in size. To display the total area of this fascinating partical filtration structure one would have to tile 7500 times this image.