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Particle (ecology)

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Title: Particle (ecology)  
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Subject: Marine pollution, Environmental impact of shipping, Outline of water, Marine habitats, Eutrophication
Publisher: World Heritage Encyclopedia

Particle (ecology)

In marine and freshwater filter particles out of the water with unique filtration mechanisms (filter feeders). Particles are often associated with high loads of toxins which attach to the surface. As these toxins are passed up the food chain they 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 dredging. They can remain floating in the water and drift over long distances. The decomposition of some particles by bacteria consumes a lot of oxygen and can cause the water to become hypoxic.

Particle analysis

Particle levels in water (or air) can be measured with a turbidity meter and analyzed with a particle counter. They can also be scanned with an underwater microscope, such as ecoSCOPE. Collected particles of size 20 - 200 micrometers hovering in the free water in the vicinity of a harbor had the following contaminant levels (table). Many of those contaminants are carcinogenic.

Particles scanned with the ecoSCOPE microscope. The blue frame is a 1 mm contrast grid.
Particles in the vicinity of a harbor
Contaminant Mass of contaminant relative to total particle dry weight
Arsenic 8.17 mg/kg
Lead 80.1 mg/kg
Cadmium 0.61 mg/kg
Chromium 31.2 mg/kg
Copper 44 mg/kg
Nickel 20.6 mg/kg
mercury 0.86 mg/kg
Zinc 156 mg/kg
EOX 0.79 mg/kg
Anthracene 602 µg/kg
Fluoranthene 5947 µg/kg
Pyrene 5549 µg/kg
Benzo(a)anthracene 5296 µg/kg
Benzo(b)fluoranthene 2499 µg/kg
Benzo(k)fluoranthene 1652 µg/kg
Benzo(a)pyrene 1895 µg/kg
Dibenzo(ah)anthracene 200 µg/kg
Benzo(ghi)perylene 1533 µg/kg
Dichloromethane 66 µg/kg
Chloroform 11 µg/kg
Carbon tetrachloride 5 µg/kg
1,1,1-Trichloroethane 4 µg/kg
Pentachlorophenol 22 µg/kg
1,2,3-Trichlorobenzene 0.4 µg/kg
1,3,5-Trichlorobenzene 0.4 µg/kg
1,2,4-Trichlorobenzene 1.4 µg/kg
1,2,3/4,5-Tetrachlorobenzene 1.2 µg/kg
1,2,3,4-Tetrachlorobenzene 0.4 µg/kg
Pentachlorobenzene 0.8 µg/kg
Hexachlorobenzene 3.9 µg/kg
Total PCBs 2205 µg/kg
PCB 28 598 µg/kg
PCB 52 331 µg/kg
PCB 101 205 µg/kg
PCB 138 414 µg/kg
PCB 153 432 µg/kg
PCB 180 225 µg/kg
Benzene 108 µg/kg
Toluene 655 µg/kg
o,-m,-p-Xylene 247 µg/kg
2,3,7,8-TCDF (dioxin) 0.8 ng/kg

Contaminant kinetics

It takes a few days until 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.

Many 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. The milk of mothers (Homo sapiens) consuming fish and related products like margarine and eggs in such areas have so high toxin levels that it would be impossible to sell such milk on markets - their babies have much more birth-defects and/or retarded brains and have later difficulties to learn and/or reproduce. Many die at an early age.

Filter of krill

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 particle filtration structure one would have to tile 7500 times this image.

Filter basket of a mysid.

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