A combined modelling and geochemical study of the fate of terrigenous inputs from mixed natural and mining sources in a coral reef lagoon (New Caledonia)

Fernandez, Jean-Michel; Ouillon, Sylvain; Chevillon, Christine; Douillet, Pascal; Fichez, Renaud; Gendre, Romain Le

doi:10.1016/j.marpolbul.2005.09.010

Cited by 76 publications

(55 citation statements)

References 25 publications

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“…284 water exchanges proceed from both the south and the east of Sta. SM (Fernandez et al, 2006). Note 286 also that Trichodesmium density and environmental parameter variations at Sta.…”

Section: General Environmental Conditions and Causes Of Bloom Developmentioning

confidence: 90%

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Rodier

Borgne²

2008

Journal of Experimental Marine Biology and Ecology

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Abstract. The present description of Trichodesmium spp. population dynamics and associated 1 environmental variables is the first one using a very short sampling interval (2-3 days). Such a 2 strategy allows a fine description of changes involving the population density and characteristics. It 3 also lends itself to interpreting those changes from past environmental conditions. During the two 4 surveys, 2 and 5 month-long, T. erythraeum dominated the Trichodesmium population, with 5 temporary occurrence of T. thiebautii and five blooms could be described. These events appeared at 6 temperatures > 24°C and followed, in all cases, nitrate, soluble reactive phosphorus and chlorophyll 7 a enrichments, with a 3-7 day time lag. Low wind speed (< 4m s -1 ) was not a prerequisite for 8Trichodesmium bloom developments as long as temperatures exceeded 26°C. As abundance 9 increased during the bloom, so did the number of filaments (trichomes) in colonies and their 10 buoyancy, leading to a clear positive biomass gradient from the bottom to the surface. A simple 11 model, using variable growth rates, showed trichome ascent would be responsible for 87-99% of 12 concentrations at 0.5m, with Trichodesmium net growth rates ranging from 0.11 to 0.38 d -1 . Finally, 13 rapid trichome density declines could be ascribed to nutrient depletion and massive surface death 14 following ascent. 15 16 17

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“…284 water exchanges proceed from both the south and the east of Sta. SM (Fernandez et al, 2006). Note 286 also that Trichodesmium density and environmental parameter variations at Sta.…”

Section: General Environmental Conditions and Causes Of Bloom Developmentioning

confidence: 90%

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Rodier

Borgne²

2008

Journal of Experimental Marine Biology and Ecology

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“…The present data suggest the strong impact of winds on currents in Boulari Bay, and the formation of a In Boulari Bay, the neap/spring tide cycles had a non-significant influence on the currents measured 3 m above the seabed (Figure 2). In the absence of trade winds (periods C and E), a strong westward flow was observed during several days and may indicate the development of a cyclonic gyre circulation along the isobaths from Mont-Dore (SW of Boulari Bay) towards Nouméa (as described by Fernandez et al [27]). This gyre results from the conjunction of the propagation of the tide along the coastline of the bay.…”

Section: Hydrodynamicsmentioning

confidence: 64%

“…This has led to the mobilization and transport of approximately 300 million m 3 of soil material (laterites). Opencast Ni mines have enhanced soil erosion and transportation of sediments and metals into the lagoon [19,[24][25][26][27] with several consequences on the lagoonal ecosystems, including increased sedimentation rates; decreased light penetration and dissolved oxygen levels; and an increased metal contamination in the food web which may affect humans [23,28,29]. The Ni mining industry has flourished for over 25 years, and New Caledonia will remain one of the major worldwide Ni producers for the foreseeable future, with global Ni reserves estimated at around 20-25% [30].…”

Section: Introductionmentioning

confidence: 99%

“…Numerous studies of the south-western lagoon of New Caledonia have been conducted investigating hydrodynamics, sediment transport, sedimentation dynamics, metal fluxes, accumulation zones, and particle sources [23,27,[31][32][33][34][35][36][37]. In complement to these works, this paper aims at characterizing the suspended sediment mineralogy and geochemistry (including metals) in three bays; analysing the relationships between their composition and the mining activities; determining how hydrodynamics forced by wind regimes affect the transportation of particulate metals bounded to the lateritic Suspended Particulate Matter (SPM) into the lagoon.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of Suspended Sediments during a Dry Season and Their Consequences on Metal Transportation in a Coral Reef Lagoon Impacted by Mining Activities, New Caledonia

Fernandez

Meunier

Ouillon

et al. 2017

Water

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Coral reef lagoons of New Caledonia form the second longest barrier reef in the world. The island of New Caledonia is also one of the main producers of nickel (Ni) worldwide. Therefore, understanding the fate of metals in its lagoon waters generated from mining production is essential to improving the management of the mining activities and to preserve the ecosystems. In this paper, the vertical fluxes of suspended particulate matter (SPM) and metals were quantified in three bays during a dry season. The vertical particulate flux (on average 37.70 ± 14.60 g·m 2 ·d −1 ) showed fractions rich in fine particles. In Boulari Bay (moderately impacted by the mining activities), fluxes were mostly influenced by winds and SPM loads. In the highly impacted bay of St Vincent and in the weakly impacted bay of Dumbéa, tide cycles clearly constrained the SPM and metal dynamics. Metals were associated with clay and iron minerals transported by rivers and lagoonal minerals, such as carbonates, and possibly neoformed clay as suggested by an unusually Ni-rich serpentine. Particle aggregation phenomena led to a reduction in the metal concentrations in the SPM, as identified by the decline in the metal distribution constants (K d ).

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“…The mangrove studied here does not develop downstream an ultramafic watershed. However, due to coastal current [43], some of these minerals may have been deposited in the mangrove, explaining the high concentrations of Fe measured in the solid phase. Within the salt-flat, reduced dissolved iron (Fe precipitated as ferrihydrite and lepidocrocite [44].…”

Section: Distribution and Speciation Of Redox Sensitive Elements: Iromentioning

confidence: 99%

Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

Deborde

Marchand

Molnar

et al. 2015

JMSE

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Abstract:In mangrove ecosystems, strong reciprocal interactions exist between plant and substrate. Under semi-arid climate, Rhizophora spp. are usually predominant, colonizing the seashore, and Avicennia marina develops at the edge of salt-flats, which is the highest zone in the intertidal range. Along this zonation, distribution and speciation of C, Fe, S, N, and P in sediments and pore-waters were investigated. From the land-side to the sea-side of the mangrove, sediments were characterized by I/ increase in: (i) water content; (ii) TOC; (iii) mangrove-derived OM; II/ and decrease in: (i) salinity; (ii) redox; (iii) pH; (iv) solid Fe and solid P. Beneath Avicennia and Rhizophora, TS accumulated at depth, probably as a result of reduction of iron oxides and sulfate. The loss of total Fe observed towards the sea-side may be related to sulfur oxidation and to more intense tidal flushing of dissolved components. Except the organic forms, dissolved N and P concentrations were very low OPEN ACCESSJ. Mar. Sci. Eng. 2015, 3 53beneath Avicennia and Rhizophora stands, probably as a result of their uptake by the root systems. However, in the unvegetated salt-flat, NH4 + can accumulate in organic rich and anoxic layers. This study shows: (i) the evolution of mangrove sediment biogeochemistry along the intertidal zone as a result of the different duration of tidal inundation and organic enrichment; and (ii) the strong links between the distribution and speciation of the different elements.

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A combined modelling and geochemical study of the fate of terrigenous inputs from mixed natural and mining sources in a coral reef lagoon (New Caledonia)

Cited by 76 publications

References 25 publications

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Population dynamics and environmental conditions affecting Trichodesmium spp. (filamentous cyanobacteria) blooms in the south–west lagoon of New Caledonia

Dynamics of Suspended Sediments during a Dry Season and Their Consequences on Metal Transportation in a Coral Reef Lagoon Impacted by Mining Activities, New Caledonia

Concentrations and Fractionation of Carbon, Iron, Sulfur, Nitrogen and Phosphorus in Mangrove Sediments Along an Intertidal Gradient (Semi-Arid Climate, New Caledonia)

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