Extensive coral mortality and critical habitat loss following dredging and their association with remotely-sensed sediment plumes

Dredging poses a potential threat to coral reefs, yet quantifying impacts is often difficult due to the large spatial footprint of potential effects and co-occurrence of other disturbances. Here we analyzed in situ monitoring data and remotely-sensed sediment plumes to assess impacts of the 2013–201...

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Bibliographic Details
Published in:Marine pollution bulletin 2019-08, Vol.145, p.185-199
Main Authors: Cunning, Ross, Silverstein, Rachel N., Barnes, Brian B., Baker, Andrew C.
Format: Article
Language:English
Subjects:
Animals
Anthozoa
Benthos
Benthos collecting devices
Bleaching
Bottom trawling
Coral Reefs
Corals
Disease control
Dredging
Ecosystem
Environmental Monitoring
Florida
Geologic Sediments
Habitat loss
Mortality
Plumes
Port of Miami
Remote monitoring
Remote sensing
Sediment
Sediment traps
Sedimentation
Sediments
Spatial analysis
Spatial distribution
Spatial variations
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Summary:Dredging poses a potential threat to coral reefs, yet quantifying impacts is often difficult due to the large spatial footprint of potential effects and co-occurrence of other disturbances. Here we analyzed in situ monitoring data and remotely-sensed sediment plumes to assess impacts of the 2013–2015 Port of Miami dredging on corals and reef habitat. To control for contemporaneous bleaching and disease, we analyzed the spatial distribution of impacts in relation to the dredged channel. Areas closer to dredging experienced higher sediment trap accumulation, benthic sediment cover, coral burial, and coral mortality, and our spatial analyses indicate that >560,000 corals were killed within 0.5 km, with impacts likely extending over 5–10 km. The occurrence of sediment plumes explained ~60% of spatial variability in measured impacts, suggesting that remotely-sensed plumes, when properly calibrated against in situ monitoring data, can reliably estimate the magnitude and extent of dredging impacts. •Sediment traps accumulated up to 830 kg of fine sediment per m2 during dredging.•Sediment covered 50–90% of adjacent reefs, remained elevated 10–100 × 2 yr later.•>560,000 corals within 0.5 km of the channel were lost due to dredging.•Dredge plumes detected by satellite predict ~60% of variability in benthic impacts.•Dredging impacted corals and reef habitat at least 2.5 km and possibly >10 km away.
ISSN:0025-326X
1879-3363
DOI:10.1016/j.marpolbul.2019.05.027