Predicting dredging-associated effects to coral reefs in Apra Harbor, Guam - Part 2: Potential coral effects

Deborah Shafer Nelson, John McManus, Robert H. Richmond, David B. King, Joe Z. Gailani, Tahirih C. Lackey, Duncan Bryant

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Coral reefs are in decline worldwide due to anthropogenic stressors including reductions in water and substratum quality. Dredging results in the mobilization of sediments, which can stress and kill corals via increasing turbidity, tissue damage and burial. The Particle Tracking Model (PTM) was applied to predict the potential impacts of dredging-associated sediment exposure on the coral reef ecosystems of Apra Harbor, Guam. The data were interpreted using maps of bathymetry and coral abundance and distribution in conjunction with impact parameters of suspended sediment concentration (turbidity) and sedimentation using defined coral response thresholds. The results are presented using a " stoplight" model of negligible or limited impacts to coral reefs (green), moderate stress from which some corals would be expected to recover while others would not (yellow) and severe stress resulting in mortality (red). The red conditions for sediment deposition rate and suspended sediment concentration (SSC) were defined as values exceeding 25 mg cm-2 d-1 over any 30 day window and >20 mg/l for any 18 days in any 90 day period over a column of water greater than 2 m, respectively. The yellow conditions were defined as values >10 mg cm-2 d-1 and <25 mg cm-2 d-1 over any 30 day period, and as 20% of 3 months' concentration exceeding 10 mg/l for the deposition and SSC, respectively. The model also incorporates the potential for cumulative effects on the assumption that even sub-lethal stress levels can ultimately lead to mortality in a multi-stressor system. This modeling approach can be applied by resource managers and regulatory agencies to support management decisions related to planning, site selection, damage reduction, and compensatory mitigation.

Original languageEnglish (US)
Pages (from-to)111-122
Number of pages12
JournalJournal of Environmental Management
Volume168
DOIs
StatePublished - 2016

Fingerprint

Reefs
Dredging
Ports and harbors
dredging
Suspended sediments
coral reef
coral
harbor
suspended sediment
Sediments
Turbidity
turbidity
sediment
mortality
Bathymetry
Site selection
damage
site selection
Deposition rates
Sedimentation

Keywords

  • Coral threshold responses
  • Deposition
  • Dredging
  • Sedimentation rate
  • Stoplight indicators
  • Turbidity

ASJC Scopus subject areas

  • Environmental Engineering
  • Waste Management and Disposal
  • Management, Monitoring, Policy and Law

Cite this

Predicting dredging-associated effects to coral reefs in Apra Harbor, Guam - Part 2 : Potential coral effects. / Nelson, Deborah Shafer; McManus, John; Richmond, Robert H.; King, David B.; Gailani, Joe Z.; Lackey, Tahirih C.; Bryant, Duncan.

In: Journal of Environmental Management, Vol. 168, 2016, p. 111-122.

Research output: Contribution to journalArticle

Nelson, Deborah Shafer ; McManus, John ; Richmond, Robert H. ; King, David B. ; Gailani, Joe Z. ; Lackey, Tahirih C. ; Bryant, Duncan. / Predicting dredging-associated effects to coral reefs in Apra Harbor, Guam - Part 2 : Potential coral effects. In: Journal of Environmental Management. 2016 ; Vol. 168. pp. 111-122.
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