macro algae bioaccumulation of copper


Well-Known Member
reference world health organization report on copper and marine life:
4.2.2 Aquatic plants
Bioaccumulation factors have been calculated for over 20 species
of marine macroalgae showing maximum values up to 27 000, depending on
the exposure concentration (Bryan & Hummerstone, 1973; Phillips,
1977; Malea et al., 1994; Correa et al., 1996).
Hall et al. (1979) found that a nontolerant strain of the brown
alga Ectocarpus siliculosus exposed to various copper concentrations
(up to 250 µg/litre) displayed higher accumulation values than did a
tolerant strain. At 72 h incubation, the tolerant strain accumulated
mean copper values of 20 mg/kg (wet weight) with no added copper and
234 µg/kg at 250 µg Cu/litre in the medium (Hall, 1981). The same
strain incubated for 14 days displayed accumulation values of 13 mg/kg
with no added copper and 1075 mg/kg at 250 µg Cu/litre in the medium
Reed & Moffat (1983) exposed the green alga Enteromorpha compressa
to copper concentrations of up to 610 µg/litre (9.6 µmol/litre) for 6
days. Copper accumulation was linearly dependent on the exposure
concentration and the pattern was similar in both the tolerant and
non-tolerant strains. Mean maximum concentrations in the algae were
22.2 mg Cu/kg (0.35 µmol/g) (fresh weight) for the nontolerant strain
and 25.4 mg Cu/kg (0.4 µmol/g) for the tolerant strain. Equilibrium
was not reached within the experimental time period.
250ppm or less of copper was reported at the faucets of 80% of the major cities in the US.
So 425 pounds of water at .00025ppm copper has about .1 pounds of copper
The macros exposed to that level (bolded and underlined above) increased 1000ppm copper in that time.
So 1000ppm of copper *pounds of macros=.1 pounds of copper. so the pounds of macros= .1/.001=100 pounds of macros.
Which is a lot. If the copper level through copper treatment was 1/10 of that then 10 pounds of macros and if 1/100 then 1 pound of macros.
So macros can remove copper but it can take time. But if you are constantly harvesting a pound of macros each week eventually the copper level will come down to reef safe levels. But it can take time. Not to mention the effort of keeping the bioload high enough to constantly provide the nutrients to keep the macros thriving.
But if you treated the tank to say .20ppm copper then the macros could bring that level down to reef safe levels in a short time.
But even with that Paul_B for other boards has kept a reef tank in operation for 40 years now. Until 1990 or so it was with straight tap water. And his corals did just fine until he had a problem. He found out that the water company had added a zinc compound which was affecting his corals. And switched to RO/di after that. Obviously there are things other then copper to consider.
Plus other compounds (strontium, iodine, potassium) are also bioaccmulated by the macros for which I have seen no data on. So perhaps those things are depleted along with nutrients by the macros. Plus corals do need light and food also.
My point here is that perhaps copper is not the biggest thing to worry about.
my .02