Towards environmental management of water turbidity within open coastal waters of the Great Barrier Reef

Macdonald, Rachael K.; Ridd, Peter V.; Whinney, James; Larcombe, Piers; Neil, D. T.

doi:10.1016/j.marpolbul.2013.07.026

Cited by 30 publications

(32 citation statements)

References 28 publications

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“…1) from 14 July to 22 August 2014. The sensor recorded measurements *30 cm from the seafloor, *2-3 m from Middle Reef, and was programmed to self-clean every 1 h. The sensor was deployed beside an instrument platform which included a sideways-mounted nephelometer, upwards-facing 2p quantum PAR sensor, water temperature sensor and a pressure sensor (Macdonald et al 2013). Each sensor reading is an average of 250 measurements over a 1-s period.…”

Section: Field Testsmentioning

confidence: 99%

“…Measurements were made in Cleveland Bay in the inshore turbid reef zone of the central GBR, which has been the subject of many studies associated with understanding sedimentary processes, sediment transport and fate, and the effects of watershed development on reef growth in marginal, turbid environments (Carter et al 1993;Larcombe et al 1995Larcombe et al , 2001Jing and Ridd 1996;Orpin et al 1999Orpin et al , 2004Browne et al 2010Browne et al , 2012Browne et al , 2013Lambrechts et al 2010;Bainbridge et al 2012;Browne 2012;Orpin and Ridd 2012;Perry et al 2012;Macdonald et al 2013;Delandmeter et al 2015).…”

Section: In Situ Deployment Of the Deposition Sensormentioning

confidence: 99%

“…For the first half of the deployment, where SSCs varied from \1 to 28 mg L -1 , which are typical for the Cleveland Bay area (Larcombe et al 1995;Orpin et al 2004;Macdonald et al 2013), the deposition rates averaged only 8 ± 5 mg cm -2 d -1 . This value is very similar to net deposition rates of 3-7 mg cm -2 d -1 measured over the course of a year at the same site using shallow trays, which also do not limit sediment resuspension (averaging *50 mg cm -2 d -1 ; Mapstone et al 1992).…”

Section: In Situ Deployment Of the Deposition Sensormentioning

confidence: 99%

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Continuous in situ monitoring of sediment deposition in shallow benthic environments

et al. 2017

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Sedimentation is considered the most widespread contemporary, human-induced perturbation on reefs, and yet if the problems associated with its estimation using sediment traps are recognized, there have been few reliable measurements made over time frames relevant to the local organisms. This study describes the design, calibration and testing of an in situ optical backscatter sediment deposition sensor capable of measuring sedimentation over intervals of a few hours. The instrument has been reconfigured from an earlier version to include 15 measurement points instead of one, and to have a more rugose measuring surface with a microtopography similar to a coral. Laboratory tests of the instrument with different sediment types, colours, particle sizes and under different flow regimes gave similar accumulation estimates to SedPods, but lower estimates than sediment traps. At higher flow rates (9-17 cm s -1 ), the deposition sensor and SedPods gave estimates[109 lower than trap accumulation rates. The instrument was deployed for 39 d in a highly turbid inshore area in the Great Barrier Reef. Sediment deposition varied by several orders of magnitude, occurring in either a relatively uniform (constant) pattern or a pulsed pattern characterized by short-term (4-6 h) periods of 'enhanced' deposition, occurring daily or twice daily and modulated by the tidal phase. For the whole deployment, which included several very high wind events and suspended sediment concentrations (SSCs)[100 mg L . For the first half of the deployment, where SSCs varied from\1 to 28 mg L -1 which is more typical for the study area, the deposition rate averaged only 8 ± 5 mg cm. The capacity to measure sedimentation rates over a few hours is discussed in terms of examining the risk from sediment deposition associated with catchment run-off, natural wind/wave events and dredging activities.

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Section: Field Testsmentioning

confidence: 99%

Section: In Situ Deployment Of the Deposition Sensormentioning

confidence: 99%

Section: In Situ Deployment Of the Deposition Sensormentioning

confidence: 99%

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Continuous in situ monitoring of sediment deposition in shallow benthic environments

et al. 2017

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“…The health of water systems is typically determined from a key indicator, the water clarity (turbidity) which is influenced by the amount of dissolved matter and total suspended solids (TSS) comprising organic matter such as algae and other micro-organisms and inorganic particulate matter from minerals [2]. Monitoring TSS along with other water quality parameters is crucial for coastal ecology because TSS can directly affect the turbidity and color of water [3] and turbidity determines the amount of light availability at depth for primary production [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

A Quantitative Comparison of Total Suspended Sediment Algorithms: A Case Study of the Last Decade for MODIS and Landsat-Based Sensors

Dorji

Fearns

2016

Remote Sensing

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A quantitative comparative study was performed to assess the relative applicability of Total Suspended Solids (TSS) models published in the last decade for the Moderate Resolution Imaging Spectroradiometer (MODIS) and Landsat-based sensors. The quantitative comparison was performed using a suite of statistical tests and HydroLight simulated data for waters ranging from clear open ocean case-1 to turbid coastal case-2 waters. The quantitative comparison shows that there are clearly some high performing TSS models that can potentially be applied in mapping TSS concentration for regions of uncertain water type. The highest performing TSS models tested were robust enough to retrieve TSS from different water types with Mean Absolute Relative Errors (MARE) of 69.96%-481.82% for HydroLight simulated data. The models were also compared in regional waters of northern Western Australia where the highest performing TSS models yielded a MARE in the range of 43.11%-102.59%. The range of Smallest Relative Error (SRE) and Largest Relative Error (LRE) between the highest and the lowest performing TSS models spanned three orders of magnitude, suggesting users must be cautious in selecting appropriate models for unknown water types.

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“…This suggests that Y desorbed from particulates in the estuarine mixing zone effectively traces the extent of discharge plumes due to the strong solution complexation of Y (and to a lesser extent HREEs) with carbonate ions (dissolved) compared with LREE covalent complexation to particulates in sea water Nozaki, 1996, Quinn et al, 2004 (Macdonald et al, 2013) suggesting the peaks observed in FRI 12.1 are likely reflecting localised resuspension at this site. Increased localised resuspension of sediments at FRI 12.1 could be due to either tidal current attenuation through the inter-reef passage, (Fig.…”

Section: Water Quality Gradient; σRee σRey and Y/homentioning

confidence: 91%

Holocene sea level and climate variability on the Great Barrier Reef, Australia

Leonard¹

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The Great Barrier Reef (GBR) is a natural, social and economic asset synonymous with Australia; however, there are concerns regarding both the frequency and extent of modern reef decline, especially in regions within close proximity to the coastline. With the future of coral reefs uncertain, elucidating the controls on reef growth and decline in the recent geological past prior to anthropogenic impacts is imperative to future management strategies. Numerous reef cores have revealed a substantial hiatus period or reef "turn-off" event during the mid-Holocene (~4600 years before present; yBP 1950) clearly prior to anthropogenic influence. Previously published research has suggested that changes in sea level, climate, and/or environmental conditions caused this reef "turn-off", but the exact cause is still tentative.Whether sea level varied significantly during the Holocene has been debated for over half a century, with oscillations generally dismissed as dating artefacts due to large age errors or to the misinterpretation or inaccuracies of the sea level indicator. Coral microatolls, one of the most reliable sea level indicators, were used to test whether relative (RSL) oscillations could be detected during the Holocene. Elevation surveys of sub-fossil coral microatolls (n=32) and non-microatoll reef flat corals (n=10) were conducted on three separate sites in the Keppel Islands, southern GBR and dated using high precision uranium thorium (U-Th) techniques. The resultant palaeo-sea-level reconstruction revealed a rapid lowering of RSL of at least 0.4 m from 5500 to 5300 yBP following a RSL highstand of ~0.75 m above present from ~6500 to 5500 yBP. RSL then returned to higher levels before a 2000-yr hiatus in reef flat corals after 4600 yBP.To determine if this was a local scale response, or part of a broader regional signal, the same methodology was applied to another 8 sites from a wide latitudinal range along the GBR (11˚S to 20˚S). The 94 U-Th dates of sub-fossil microatolls from this research adds support to the RSL lowering event at 5500 yBP, with microatolls close to present sea level found at ~5100 yBP. A second oscillation of ~ -0.3m at 4600 yBP was also detected in the northern GBR, with microatolls at three sites close to modern SL between 4600 -4000 yBP. The RSL oscillations at 5500 yBP and 4600 yBP coincide with both substantial reduction in reef accretion and wide spread reef "turn-off", respectively, thereby suggesting that oscillating sea level was the primary driver of reef shut down on the GBR.Understanding the coeval palaeo-climate and -environmental conditions may reveal both the cause of these sea level oscillations and further modes of stress placed on coral reefs prior to the midHolocene hiatus. In the first instance one of the simplest and most efficient methods of extracting information from the annual bands of massive Porites sp. coral cores is by using the growth characteristics (i.e. linear extension) and ultra violet (UV) luminescent intensity which are linked to II sea surface ...

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Towards environmental management of water turbidity within open coastal waters of the Great Barrier Reef

Cited by 30 publications

References 28 publications

Continuous in situ monitoring of sediment deposition in shallow benthic environments

Continuous in situ monitoring of sediment deposition in shallow benthic environments

A Quantitative Comparison of Total Suspended Sediment Algorithms: A Case Study of the Last Decade for MODIS and Landsat-Based Sensors

Holocene sea level and climate variability on the Great Barrier Reef, Australia

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