Estuarine Suspended Sediment Dynamics: Observations Derived from over a Decade of Satellite Data

Abstract

Suspended sediment dynamics of Corpus Christi Bay, Texas, USA, a shallow-water wind-driven estuary, were investigated by combining field and satellite measurements of total suspended solids (TSS). An algorithm was developed to transform 500-m Moderate Resolution Imaging Spectroradiometer (MODIS) Aqua satellite reflectance data into estimated TSS values. The algorithm was developed using a reflectance ratio regression of MODIS Band 1 (red) and Band 3 (green) with TSS measurements (n = 54) collected by the Texas Commission on Environmental Quality for Corpus Christi Bay and other Texas estuaries. The algorithm was validated by independently collected TSS measurements during the period of 2011-2014 with an uncertainty estimate of 13%. The algorithm was applied to the period of 2002-2014 to create a synoptic time series of TSS for Corpus Christi Bay. Potential drivers of long-term variability in suspended sediment were investigated. Median and IQR composites of suspended sediments were generated for seasonal wind regimes. From this analysis it was determined that long-term, spatial patterns of suspended sediment in the estuary are related to wind-wave resuspension during the predominant northerly and prevalent southeasterly seasonal wind regimes. The impact of dredging is also apparent in long-term patterns of Corpus Christi Bay as concentrations of suspended sediments over dredge spoil disposal sites are higher and more variable than surrounding areas, which is most likely due to their less consolidated sediments and shallower depths requiring less wave energy for sediment resuspension. This study highlights the advantage of how long-synoptic time series of TSS can be used to elucidate the major drivers of suspended sediments in estuaries.

Long-term changes on estuarine ciliates linked with modifications on wind patterns and water turbidity

“…Among estuaries with strong interaction across coastal forms (i.e. saltmarshes and flood-plains) and the water column, wind attributes capable of producing wind waves are thereby better descriptors of water turbidity than wind velocity alone (Cho 2007, Reisinger et al 2017. The simultaneous intensification of bottom shear stress due to the expansion of the dredged area may additionally amplify the effect of changing wind patterns on water turbidity (López-Abbate et al 2017).…”

Microbial Processing of Sediment‐Derived Dissolved Organic Matter: Implications for Its Subsequent Biogeochemical Cycling in Overlying Seawater

“…In addition, the dissolved organic carbon (DOC) concentration of coastal sediment pore water has been reported to be up to an order of magnitude higher than in the overlying water (Burdige & Gardner, 1998). Understanding the intrinsic bioavailability and subsequent biogeochemical effects of SDOM in overlying seawater is important because mobilization of SDOM commonly occurs in coastal and estuarine areas through diffusion and resuspension by natural and anthropogenic activities (e.g., tidal currents, wind energy and storms, fishing, dredging, and the rotation of ships' propellers) (Burdige & Komada, 2015;Eggleton & Thomas, 2004;Reisinger et al, 2017;Superville et al, 2014;Zuo et al, 2016).…”

Long‐Term Trends in Chesapeake Bay Remote Sensing Reflectance: Implications for Water Clarity

“…Red-to-green ratio algorithms are often helpful in optically complex coastal waters because they minimize the interference by non-algal particle absorption and CDOM absorption in the blue bands (Abbas et al, 2019;Ioannou et al, 2014;Le et al, 2013;Tzortziou et al, 2007). For example, the red-to-green ratio Rrs(645)/Rrs(555) has been employed to estimate TSS (Reisinger et al, 2017) and turbidity (J. Wang et al, 2021) in the coastal Gulf of Mexico and Pearl River Estuary, respectively.…”

“…MODIS is well suited for time series analysis despite the potential sensor drift and/or increased noise associated with its extended time in orbit. MODIS has been used for time series analysis in estuaries, lakes, and coastal waters such as, to name just a few: the Columbia River Estuary (Hudson et al, 2017), the coastal waters of the northern Gulf of Mexico (Reisinger et al, 2017), the Patos Lagoon in Brazil (Tavora et al, 2019), fjords in Svalbard (Payne & Roesler, 2019), coastal waters in the Arctic (Chaves et al, 2015), the Bohai Sea (Shang et al, 2016), and Minnesota lakes (Knight & Voth, 2012). To correct for potential drift, MODIS-Aqua is calibrated onboard regularly using scheduled solar diffuser measurements and lunar observations (Wu et al, 2013).…”