Elevated rates of organic carbon, nitrogen, and phosphorus accumulation in a highly impacted mangrove wetland

Abstract

The effect of nutrient enrichment on mangrove sediment accretion and carbon accumulation rates is poorly understood. Here we quantify sediment accretion through radionuclide tracers to determine organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) accumulation rates during the previous 60 years in both a nutrient-enriched and a pristine mangrove forest within the same geomorphological region of southeastern Brazil. The forest receiving high nutrient loads has accumulated OC, TN, and TP at rates that are fourfold, twofold, and eightfold respectively, higher than those from the undisturbed mangrove. Organic carbon and TN stable isotopes (δ 13 C and δ 15 N) reflect an increased presence of organic matter (OM) originating with either phytoplankton, benthic algae, or another allochthonous source within the more rapidly accumulated sediments of the impacted mangrove. This suggests that the accumulation rate of OM in eutrophic mangrove systems may be enhanced through the addition of autochthonous and allochthonous nonmangrove material.

Historic carbon burial spike in an Amazon floodplain lake linked to riparian deforestation near Santarém, Brazil

“…The leaching was conducted overnight at 80 • C with added 242 Pu yield tracer (NIST 4334g, 19 picograms). Acid leaching (as opposed to complete dissolution with HF) is known to solubilize stratospheric fallout Pu, and there is little possibility that "refractory" HNO 3 -insoluble Pu exists in South America (Sanders et al, 2014). The leachates were diluted to 100 mL, filtered to remove solids and the aqueous solutions were processed with TEVA ® Resin (EIChrom, Lisle, IL, USA) in order to chemically isolate 3.0 mL Pu fractions in aqueous ammonium oxalate solution suitable for measurements by sector ICPMS (inductively coupled plasma mass spectrometry).…”

Examining 239+240 Pu, 210 Pb and historical events to determine carbon, nitrogen and phosphorus burial in mangrove sediments of Moreton Bay, Australia

“…(Everett et al, 2008;Sanders et al, 2006;Tims et al, 2010). Even with the approximately fourfold lower inventories of bomb-test fallout (Kelley et al, 1999;Ketterer et al, 2004;Sanders et al, 2010b), advances in technology now allow accurate measurements of the low anthropogenic Pu activities in the coastal sediments of the Southern Hemisphere (Everett et al, 2008;Leslie and Hancock, 2008;Sanders et al, 2014aSanders et al, , 2014bSanders et al, , 2010bTims et al, 2010;Tims et al, 2013). Pu, with half-lives of 24,110 and 6561 years respectively (http:// www.nucleide.org/DDEP.htm), may be used as a marker of sediment deposited since the early 1950s.…”

“…In addition, burial rates contribute to understanding potential impacts on this sink capacity due to climate change, local hydrological regimes, and widespread eutrophication (Alongi, 2008). Indeed, the associated nitrogen (N) and total phosphorus (TP) burial in mangrove sediments may partially offset anthropogenic nutrient loads and eutrophication in the increasingly developed coastal regions of the tropics and subtropics (Sanders et al, 2014b). Carbon and nitrogen stable isotope signatures (d 13 C and d 15 N) may also be used to identify the sources of buried organic matter (Sanders et al, 2014b).…”

Improving Silvofishery Management Through Seedling Growth – Environment Quality Dynamic Relation Analysis

“…Another source of organic matter would be the decomposition of mangrove litter by microorganism associated with mangrove roots. Sanders et al (2014) also noted that the enhanced organic matter accumulation rate was not only supported by litter decomposition and sediment trapping. Various microorganisms which lived in the mangrove roots also become the source of organic matter in the mangrove ecosystem.…”