Evidence of mercury biomagnification in the food chain of the cardinal tetra Paracheirodon axelrodi ( O steichthyes: C haracidae) in the R io N egro, central A mazon, B razil
In this study, nitrogen stable isotope ( δ 15 N ) and total mercury ( THg ) analyses were conducted on algae, submersed and emergent macrophytes, shrubs and trees, Macrobrachium sp. and Paracheirodon axelrodi collected in three streams that drain a large interfluvial region in the middle Rio Negro,...
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Veröffentlicht in: | Journal of fish biology 2016-07, Vol.89 (1), p.220-240 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | In this study, nitrogen stable isotope (
δ
15
N
) and total mercury (
THg
) analyses were conducted on algae, submersed and emergent macrophytes, shrubs and trees,
Macrobrachium
sp. and
Paracheirodon axelrodi
collected in three streams that drain a large interfluvial region in the middle Rio Negro, Amazonas State, Brazil. Samples were collected during different hydrological periods over 12 months in lower stream reaches and their headwaters; the latter being characterized by shallow, open‐canopy swamps. Additionally,
δ
15
N
values and mercury concentrations of
Paracheirodon simulans
and
Cichla
spp. from the middle Rio Negro were analysed to demonstrate
THg
biomagnification in the food web. The highest mercury levels of
P. axelrodi
were found in small individuals, which were collected principally in the low water period. The log
10
THg–δ
15
N
relationship of vascular plants and algae,
Macrobrachium
sp.,
Paracheirodon
spp. and
Cichla
spp. showed significant mercury biomagnification among trophic levels, with regression slopes of 0·15 and 0·25 for the entire food web and heterotrophs‐only food web, respectively. The mean ±
s.d
.
THg
concentrations for
Macrobrachium
sp.,
P. axelrodi
,
P. simulans
and
Cichla
spp. were 63·6 ± 23·7, 104·5 ± 40·0, 112·3 ± 31·4 and 418·5 ± 188·1 ng g
−1
wet mass, respectively. Elevated levels of mercury found in
Paracheirodon
spp. and top predators such as
Cichla
spp. in a remote area far from anthropogenic inputs provide evidence that high mercury concentrations occur naturally in Rio Negro aquatic food webs. |
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ISSN: | 0022-1112 1095-8649 |
DOI: | 10.1111/jfb.12952 |