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Ecological impacts of large-scale disposal of mining waste in the deep sea.

Hughes DJ, Shimmield TM, Black KD, Howe JA - Sci Rep (2015)

Bottom Line: At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations.At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion.Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

View Article: PubMed Central - PubMed

Affiliation: Scottish Association for Marine Science, Oban, Argyll PA37 1QA, United Kingdom.

ABSTRACT
Deep-Sea Tailings Placement (DSTP) from terrestrial mines is one of several large-scale industrial activities now taking place in the deep sea. The scale and persistence of its impacts on seabed biota are unknown. We sampled around the Lihir and Misima island mines in Papua New Guinea to measure the impacts of ongoing DSTP and assess the state of benthic infaunal communities after its conclusion. At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations. At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion. Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

No MeSH data available.


Abundance of metazoans (>250 μm) at stations around MisimaBars represent means (±SD) of replicate corer drops (n = 3 drops station−1, except for M3, where n = 6 drops), with densities standardised to individuals m−2. Stations are arranged along the X-axis in order of increasing water depth, and colour-coded according to the geochemical evidence for presence of tailings in cored sediments.
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f5: Abundance of metazoans (>250 μm) at stations around MisimaBars represent means (±SD) of replicate corer drops (n = 3 drops station−1, except for M3, where n = 6 drops), with densities standardised to individuals m−2. Stations are arranged along the X-axis in order of increasing water depth, and colour-coded according to the geochemical evidence for presence of tailings in cored sediments.

Mentions: Stations M1-M3 showed very low densities of total metazoan meiofauna in comparison with the tailings-free M6 station (Fig. 5a). Values at M4 and M5 showed the expected depth-related decline22 relative to M6, but were not significantly different (α = 0.05) from each other (Mann-Whitney U-test M4 ≠ M5, U = 12.0, P = 0.6625). Metazoan meiofaunal density therefore showed no evidence of a tailings effect at M4. Higher-taxon representation at M1 followed the pattern of the Lihir tailings stations, with harpacticoid copepods comprising 71% of the metazoan meiofauna. The copepod percentage declined to 52% at M2 and 38% at M3, while the relative abundance of nematodes increased. Stations M4-M6 grouped together closely in terms of meiofaunal composition, with 21–23% copepods and 72–76% nematodes (Supplementary Table S5). Total macrofaunal abundance was similarly highest at M6, lower at M4 and M5 and uniformly lowest at M1-M3 (Fig. 5b). Macrofaunal abundance at M4 (low tailings content) was not significantly different from the tailings-free station M5 at very similar water depth (Mann-Whitney U-test, U = 6.0, P = 0.0809). Macrofaunal higher-taxon structure at M1 was distinctive (Supplementary Table S6), with similar representation of polychaetes (43% total individuals) and bivalves (36%) and a high abundance (18%) of echiuran worms, a group which is usually a very minor component of the deep-sea macrofauna21. Stations M2 and M3 were almost identical in higher-taxon composition with 72–73% polychaetes, 19–20% bivalves and very few (<1%) echiurans. Stations M4-M6 had 54–68% polychaetes, 15–17% bivalves and no echiurans. The Bwagaoia Basin tailings stations (M1-M3) were united by the extreme rarity of peracarid crustaceans (amphipods, isopods and tanaidaceans), which accounted for only 0–2% of the macrofaunal individuals. Outside the basin (M4-M6) peracarids made up 11–24% of the total community, proportions much more typical of natural deep-sea sediments23. Metazoan meio- and macrofauna therefore showed reduced densities and anomalous community structure in the main tailings depocentre. No tailings impacts were apparent at M4-M6.


Ecological impacts of large-scale disposal of mining waste in the deep sea.

Hughes DJ, Shimmield TM, Black KD, Howe JA - Sci Rep (2015)

Abundance of metazoans (>250 μm) at stations around MisimaBars represent means (±SD) of replicate corer drops (n = 3 drops station−1, except for M3, where n = 6 drops), with densities standardised to individuals m−2. Stations are arranged along the X-axis in order of increasing water depth, and colour-coded according to the geochemical evidence for presence of tailings in cored sediments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4419517&req=5

f5: Abundance of metazoans (>250 μm) at stations around MisimaBars represent means (±SD) of replicate corer drops (n = 3 drops station−1, except for M3, where n = 6 drops), with densities standardised to individuals m−2. Stations are arranged along the X-axis in order of increasing water depth, and colour-coded according to the geochemical evidence for presence of tailings in cored sediments.
Mentions: Stations M1-M3 showed very low densities of total metazoan meiofauna in comparison with the tailings-free M6 station (Fig. 5a). Values at M4 and M5 showed the expected depth-related decline22 relative to M6, but were not significantly different (α = 0.05) from each other (Mann-Whitney U-test M4 ≠ M5, U = 12.0, P = 0.6625). Metazoan meiofaunal density therefore showed no evidence of a tailings effect at M4. Higher-taxon representation at M1 followed the pattern of the Lihir tailings stations, with harpacticoid copepods comprising 71% of the metazoan meiofauna. The copepod percentage declined to 52% at M2 and 38% at M3, while the relative abundance of nematodes increased. Stations M4-M6 grouped together closely in terms of meiofaunal composition, with 21–23% copepods and 72–76% nematodes (Supplementary Table S5). Total macrofaunal abundance was similarly highest at M6, lower at M4 and M5 and uniformly lowest at M1-M3 (Fig. 5b). Macrofaunal abundance at M4 (low tailings content) was not significantly different from the tailings-free station M5 at very similar water depth (Mann-Whitney U-test, U = 6.0, P = 0.0809). Macrofaunal higher-taxon structure at M1 was distinctive (Supplementary Table S6), with similar representation of polychaetes (43% total individuals) and bivalves (36%) and a high abundance (18%) of echiuran worms, a group which is usually a very minor component of the deep-sea macrofauna21. Stations M2 and M3 were almost identical in higher-taxon composition with 72–73% polychaetes, 19–20% bivalves and very few (<1%) echiurans. Stations M4-M6 had 54–68% polychaetes, 15–17% bivalves and no echiurans. The Bwagaoia Basin tailings stations (M1-M3) were united by the extreme rarity of peracarid crustaceans (amphipods, isopods and tanaidaceans), which accounted for only 0–2% of the macrofaunal individuals. Outside the basin (M4-M6) peracarids made up 11–24% of the total community, proportions much more typical of natural deep-sea sediments23. Metazoan meio- and macrofauna therefore showed reduced densities and anomalous community structure in the main tailings depocentre. No tailings impacts were apparent at M4-M6.

Bottom Line: At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations.At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion.Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

View Article: PubMed Central - PubMed

Affiliation: Scottish Association for Marine Science, Oban, Argyll PA37 1QA, United Kingdom.

ABSTRACT
Deep-Sea Tailings Placement (DSTP) from terrestrial mines is one of several large-scale industrial activities now taking place in the deep sea. The scale and persistence of its impacts on seabed biota are unknown. We sampled around the Lihir and Misima island mines in Papua New Guinea to measure the impacts of ongoing DSTP and assess the state of benthic infaunal communities after its conclusion. At Lihir, where DSTP has operated continuously since 1996, abundance of sediment infauna was substantially reduced across the sampled depth range (800-2020 m), accompanied by changes in higher-taxon community structure, in comparison with unimpacted reference stations. At Misima, where DSTP took place for 15 years, ending in 2004, effects on community composition persisted 3.5 years after its conclusion. Active tailings deposition has severe impacts on deep-sea infaunal communities and these impacts are detectable at a coarse level of taxonomic resolution.

No MeSH data available.