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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.


Seabed images and cored sediments from stations around Lihir(a) Drop-camera image from L1 (depth 850 m) showing seabed completely obscured by suspended particles. (b) Core from L1 with a thick orange layer of semi-fluid, freshly-deposited tailings (t) overlying more consolidated sediment. (c) Surface of a core from L5 (depth 1715 m) showing natural sediment with fine-scale biogenic relief, a small ophiuroid (o) and a xenophyophore (x). (d) Drop-camera image from L4 (depth 800 m) showing natural sediment seabed with biogenic traces. In this image the compass arm has been forced upward by accidental contact with the seabed. Image width in (a) and (d) is approximately 1 m across the lower edge. Core diameter in (b) and (c) is 10 cm.
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f2: Seabed images and cored sediments from stations around Lihir(a) Drop-camera image from L1 (depth 850 m) showing seabed completely obscured by suspended particles. (b) Core from L1 with a thick orange layer of semi-fluid, freshly-deposited tailings (t) overlying more consolidated sediment. (c) Surface of a core from L5 (depth 1715 m) showing natural sediment with fine-scale biogenic relief, a small ophiuroid (o) and a xenophyophore (x). (d) Drop-camera image from L4 (depth 800 m) showing natural sediment seabed with biogenic traces. In this image the compass arm has been forced upward by accidental contact with the seabed. Image width in (a) and (d) is approximately 1 m across the lower edge. Core diameter in (b) and (c) is 10 cm.

Mentions: Cored sediments from the two Lihir station groups were visually and geochemically distinct, with stations east of the island showing unequivocal evidence of tailings deposition. On drop-camera images from L1 the seabed was completely obscured by a dense haze of suspended particles (Fig. 2a). Cores from L1-L3 had a 3–7 cm thick surface layer of watery, fine-grained orange mud, representing freshly-deposited tailings, overlying consolidated muddy sands with thin laminations of coarser material, probably left by intermittent slumps of natural sediment and waste rock from the mine (Fig. 2b). Cores appeared devoid of biological activity. In contrast, drop-camera images from L4 showed a sediment seabed with burrow openings and other biogenic traces (Fig. 2d). Cored sediments at L4-L6 were homogeneous, moderately well-sorted muddy sands with no visible tailings layer. Core surfaces showed abundant small-scale biogenic relief and occasional small epifauna (Fig. 2c). Solid-phase metal inventories differed between stations east and west of the island (Supplementary Table S2). Cores from L1-L3 had lower solid-phase calcium, a marker for natural biogenic sedimentation (inventory to 14 cm depth, 3647–16284 g m−2) than cores from L4-L6 (range 16769–22887 g m−2). In contrast, the content of several tailings-derived trace metals was much higher in cores from L1-L3 with, for example, solid-phase lead ranging from 3.8–6.5 g m−2 at L1-L3 versus 0.6–0.7 g m−2 at L4-L6.


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

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

Seabed images and cored sediments from stations around Lihir(a) Drop-camera image from L1 (depth 850 m) showing seabed completely obscured by suspended particles. (b) Core from L1 with a thick orange layer of semi-fluid, freshly-deposited tailings (t) overlying more consolidated sediment. (c) Surface of a core from L5 (depth 1715 m) showing natural sediment with fine-scale biogenic relief, a small ophiuroid (o) and a xenophyophore (x). (d) Drop-camera image from L4 (depth 800 m) showing natural sediment seabed with biogenic traces. In this image the compass arm has been forced upward by accidental contact with the seabed. Image width in (a) and (d) is approximately 1 m across the lower edge. Core diameter in (b) and (c) is 10 cm.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

f2: Seabed images and cored sediments from stations around Lihir(a) Drop-camera image from L1 (depth 850 m) showing seabed completely obscured by suspended particles. (b) Core from L1 with a thick orange layer of semi-fluid, freshly-deposited tailings (t) overlying more consolidated sediment. (c) Surface of a core from L5 (depth 1715 m) showing natural sediment with fine-scale biogenic relief, a small ophiuroid (o) and a xenophyophore (x). (d) Drop-camera image from L4 (depth 800 m) showing natural sediment seabed with biogenic traces. In this image the compass arm has been forced upward by accidental contact with the seabed. Image width in (a) and (d) is approximately 1 m across the lower edge. Core diameter in (b) and (c) is 10 cm.
Mentions: Cored sediments from the two Lihir station groups were visually and geochemically distinct, with stations east of the island showing unequivocal evidence of tailings deposition. On drop-camera images from L1 the seabed was completely obscured by a dense haze of suspended particles (Fig. 2a). Cores from L1-L3 had a 3–7 cm thick surface layer of watery, fine-grained orange mud, representing freshly-deposited tailings, overlying consolidated muddy sands with thin laminations of coarser material, probably left by intermittent slumps of natural sediment and waste rock from the mine (Fig. 2b). Cores appeared devoid of biological activity. In contrast, drop-camera images from L4 showed a sediment seabed with burrow openings and other biogenic traces (Fig. 2d). Cored sediments at L4-L6 were homogeneous, moderately well-sorted muddy sands with no visible tailings layer. Core surfaces showed abundant small-scale biogenic relief and occasional small epifauna (Fig. 2c). Solid-phase metal inventories differed between stations east and west of the island (Supplementary Table S2). Cores from L1-L3 had lower solid-phase calcium, a marker for natural biogenic sedimentation (inventory to 14 cm depth, 3647–16284 g m−2) than cores from L4-L6 (range 16769–22887 g m−2). In contrast, the content of several tailings-derived trace metals was much higher in cores from L1-L3 with, for example, solid-phase lead ranging from 3.8–6.5 g m−2 at L1-L3 versus 0.6–0.7 g m−2 at L4-L6.

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.