Refractory organic matter in coastal salt marshes-effect on C sequestration calculations.

摘要: Abstract The age and ability of salt marshes to accumulate sequester carbon is often assessed using the isotopic signatures (Δ14C δ13C) sedimentary organic matter. However, transfers allochthonous refractory (CRF) from watershed would not represent new C sequestration. To better understand how inputs affect assessments marsh sequestration, Δ14C δ13C both total (TOC), CRF, non-CRF matter fractions were measured in four contrasting systems on North Atlantic coast. our knowledge, no sediment study has considered or budget calculations impact chronologies. Stable radiogenic isotope data suggest that while TOC was dominated by autochthonous plant inputs, CRF locally recycled C, delivery which controlled size slope each watershed. Steep-gradient rivers analyzed delivered Δ14C-depleted their estuarine marshes, site located low-gradient river associated with larger content. Finally, isolated riverine input contained least fraction as CRF. Laterally transported caused only a small offset relation (average −44.4 −24.2‰ at location). presence sediments steep-gradient led large overestimates time deposition (i.e. apparent older than ‘true’ deposition) ranged −170.6 −528.9‰). Further, reliance loss ignition analyses calculate sequestration might produce much 10 20% since neither account for lateral transport carbon.