Spatio-temporal variability in suspended particulate matter concentration and the role of aggregation on size distribution in a coral reef lagoon

This paper presents the concentration and size distribution of suspended particles in the South-West Coral reef lagoon of the island of New Caledonia. Data are provided by filtration techniques, Optical BackScattering (OBS) measurements and in situ laser diffraction particle sizing. The concentration of suspended particles increased from reef to land. A bottom nepheloid layer occurred over the entire lagoon, and was more distinct on the nearshore area. Small particles were more abundant in the bottom nepheloid layer than in the overlying water column. The concentration of suspended particles showed more variability over space than over time. Conversely, the particle size distribution of suspended particles showed more variability at a given location over a month (time variability) than at a given moment over the lagoon (space variability). Analysis showed that aggregates represented a large fraction of suspended particles. Microscope visualization and chemical analysis of a sample suggest the inclusion of a transparent exopolymeric matrix. The relative abundance of aggregates over suspended particle volume concentration was found to increase as the quantity of suspended particle decreased. The spatial distribution of the relative abundance of aggregates suggests more aggregates proximal to coral reefs. The high concentration of aggregates at low turbidity and the spatial distribution of the relative abundance, infer that aggregation is induced by the presence of organic ligands. Unlike optical backscattering and light attenuation measurements that are size sensitive measurements of suspended particle concentration, in situ laser diffraction particle sizing provides a relevant optical measurement of suspended particulate matter in such an aggregate-dominated system.

[1]  N. Gratiot,et al.  On the determination of the settling flux of cohesive sediments in a turbulent fluid , 2005 .

[2]  James D. Irish,et al.  Determining suspended sediment particle size information from acoustical and optical backscatter measurements , 1994 .

[3]  Joanna C. Ellison,et al.  Impacts of Sediment Burial on Mangroves , 1999 .

[4]  D. Walling,et al.  High temporal resolution in situ measurement of the effective particle size characteristics of fluvial suspended sediment. , 2007, Water research.

[5]  N. Gratiot,et al.  An experimental investigation of floc characteristics in a diffusive turbulent flow , 2004 .

[6]  M. Pejrup,et al.  The use of a LISST-100 laser particle sizer for in-situ estimates of floc size, density and settling velocity , 2001 .

[7]  E. Creed,et al.  Inter-comparison of turbidity and sediment concentration measurements from an ADP, an OBS-3, and a LISST , 2001, MTS/IEEE Oceans 2001. An Ocean Odyssey. Conference Proceedings (IEEE Cat. No.01CH37295).

[8]  Patrick Gentien,et al.  In-situ depth profiling of particle sizes , 1995 .

[9]  E. Wolanski,et al.  Water and fine sediment dynamics in transient river plumes in a small, reef-fringed bay, Guam , 2003 .

[10]  C. Friedrichs,et al.  Controls on suspended aggregate size in partially mixed estuaries , 2003 .

[11]  G. Voulgaris,et al.  Temporal variability of hydrodynamics, sediment concentration and sediment settling velocity in a tidal creek , 2004 .

[12]  S. Ouillon,et al.  Suspended sediment transport in a semiarid watershed, Wadi Abd, Algeria (1973–1995) , 2007 .

[13]  S. Ouillon,et al.  Tidal modulation of wave-setup and wave-induced currents on the Aboré coral reef, New Caledonia. , 2007 .

[14]  O. V. D. Plassche,et al.  Coastal evolution -- Late Quaternary shoreline morphodynamics , 1995 .

[15]  R. T. Cheng,et al.  Laboratory and field evaluations of the LISST-100 instrument for suspended particle size determinations , 2001 .

[16]  K. Park,et al.  Monitoring of suspended sediment concentration using vessels and remote sensing , 2000 .

[17]  U. Passow,et al.  Ascending marine particles: Significance of transparent exopolymer particles (TEP) in the upper ocean , 2004 .

[18]  I. Droppo.  Rethinking what constitutes suspended sediment , 2001 .

[19]  James D. Irish,et al.  A laboratory evaluation of the laser in situ scattering and transmissometery instrument using natural sediments , 1999 .

[20]  N. Tixier.  Approche des propriétés rhéologiques de suspensions biologiques floculées , 2003 .

[21]  E. Wolanski,et al.  The effect of flocs on optical backscattering measurements of suspended material concentration , 1992 .

[22]  William H. McAnally,et al.  Coastal and estuarine fine sediment processes , 2001 .

[23]  L. Muscatine,et al.  Wax in coral mucus: Energy transfer from corals to reef fishes1 , 1974 .

[24]  C. Friedrichs,et al.  DETERMINING CONCENTRATION AND FALL VELOCITY OF ESTUARINE PARTICLE POPULATIONS USING ADV, OBS AND LISST , 2002 .

[25]  D. Bowers,et al.  A study of the temporal variability in particle size in a high-energy regime , 2004 .

[26]  E. Bird,et al.  The impacts of opencast mining on the rivers and coasts of New Caledonia , 1984 .

[27]  Sean G. Herring,et al.  Shape of the particulate beam attenuation spectrum and its inversion to obtain the shape of the particulate size distribution. , 2001, Applied optics.

[28]  A. B. Hayward.  Coral reefs in a clastic sedimentary environment: Fossil (Miocene, S.W. Turkey) and modern (Recent, Red Sea) analogues , 1982, Coral Reefs.

[29]  Y. C. Agrawal,et al.  Instruments for particle size and settling velocity observations in sediment transport , 2000 .

[30]  A. Hoitink.  Tidally-induced clouds of suspended sediment connected to shallow-water coral reefs , 2004 .

[31]  J. Debenay.  Sedimentology in the Southwestern Lagoon of New Caledonia, SW Pacific , 1987 .

[32]  Markus Huettel,et al.  Coral mucus functions as an energy carrier and particle trap in the reef ecosystem , 2004, Nature.

[33]  Paul S. Hill,et al.  Settling velocity, effective density, and mass composition of suspended sediment in a coastal bottom boundary layer, Gulf of Lions, France , 2007 .

[34]  P. Ridd,et al.  Factors controlling suspended sediment on inner-shelf coral reefs, Townsville, Australia , 1995, Coral Reefs.

[35]  K. Keiding,et al.  The shear sensitivity of activated sludge: an evaluation of the possibility for a standardised floc strength test. , 2002, Water research.

[36]  C. Rogers.  Responses of coral reefs and reef organisms to sedimentation , 1990 .

[37]  P. Larcombe,et al.  Quantifying the response of optical backscatter devices and transmissometers to variations in suspended particulate matter , 1999 .

[38]  J. C. Winterwerp,et al.  On the flocculation and settling velocity of estuarine mud , 2002 .

[39]  D. Thornton.  Diatom aggregation in the sea: mechanisms and ecological implications , 2002 .

[40]  S. Ouillon,et al.  A numerical model for fine suspended sediment transport in the southwest lagoon of New Caledonia , 2001, Coral Reefs.

[41]  Eric Wolanski,et al.  Effects of transparent exopolymer particles and muddy terrigenous sediments on the survival of hard coral recruits , 2003 .

[42]  Measuring physical characteristics of particles: a new method of simultaneous measurement for size, settling velocity and density of constituent matter , 1992 .

[43]  Andrew H. Barnard,et al.  Spectral particulate attenuation and particle size distribution in the bottom boundary layer of a continental shelf , 2001 .

[44]  K. Keiding,et al.  Physico-chemical characteristics of full scale sewage sludges with implications to dewatering. , 2002, Water research.

[45]  S. Ouillon,et al.  Enhancement of regional variations in salinity and temperature in a coral reef lagoon, New Caledonia , 2005 .

[46]  Philippe Forget,et al.  Inversion of reflectance spectra of nonchlorophyllous turbid coastal waters , 1999 .

[47]  Hanqing Yu,et al.  Stability of sludge flocs under shear conditions , 2008 .

[48]  S. Ouillon,et al.  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). , 2006, Marine pollution bulletin.

[49]  C. Mustin,et al.  Evolution of size distribution and transfer of mineral particles between flocs in activated sludges: an insight into floc exchange dynamics. , 2002, Water research.

[50]  R. Chant,et al.  In situ particle size distributions and volume concentrations from a LISST-100 laser particle sizer and a digital floc camera , 2005 .

[51]  C. Migon,et al.  Water residence time: A regulatory factor of the DOM to POM transfer efficiency , 2007 .

[52]  Pascal Douillet,et al.  Correspondence between the distribution of hydrodynamic time parameters and the distribution of biological and chemical variables in a semi-enclosed coral reef lagoon , 2007 .

[53]  A. Alldredge,et al.  The physical strength of marine snow and its implications for particle disaggregation in the ocean , 1990 .

[54]  S. Andréfouët,et al.  Coupling satellite data with in situ measurements and numerical modeling to study fine suspended-sediment transport: a study for the lagoon of New Caledonia , 2004, Coral Reefs.

[55]  P. Chardy,et al.  Sedimentation of particulate matter in the south-west lagoon of New Caledonia: Spatial and temporal patterns , 1995 .

[56]  Russ Babcock,et al.  Effects of sedimentation on settlement of Acropora millepora , 2004, Coral Reefs.

[57]  E. Wolanski,et al.  Nepheloid layer dynamics in coastal waters of the great Barrier Reef, Australia , 2003 .

[58]  C. Mobley.  Light and Water: Radiative Transfer in Natural Waters , 1994 .

[59]  Philippe Fraunié,et al.  Calculations of hydrodynamic time parameters in a semi-opened coastal zone using a 3D hydrodynamic model , 2006 .

[60]  M. Pejrup,et al.  In situ particle size spectra and density of particle aggregates in a dredging plume , 2000 .

[61]  C. Chevillon,et al.  Major benthic communities of the south-west lagoon of New Caledonia , 1988, Coral Reefs.

[62]  P. Douillet.  Tidal dynamics of the south-west lagoon of New Caledonia: observations and 2D numerical modelling , 1998 .

[63]  S. Ouillon,et al.  Geochemical and hydrodynamic constraints on the distribution of trace metal concentrations in the lagoon of Noumea, New Caledonia , 2007 .

[64]  R. E. Johannes.  ECOLOGY OF ORGANIC AGGREGATES IN THE VICINITY OF A CORAL REEF1 , 1967 .

[65]  E. Baker,et al.  The effect of particle size on the light attenuation coefficient of natural suspensions , 1984 .

[66]  Graham J.L. Leeks,et al.  Monitoring and preliminary interpretation of in-river turbidity and remote sensed imagery for suspended sediment transport studies in the Humber catchment , 1997 .