The role of biogenic structures on the biogeochemical functioning of mangrove constructed wetlands sediments--a mesocosm approach.
Benthic metabolism (measured as CO(2) production) and carbon oxidation pathways were evaluated in 4 mangrove mesocosms subjected daily to seawater or 60% sewage in the absence or presence of mangrove trees and biogenic structures (pneumatophores and crab burrows). Total CO(2) emission from darkened sediments devoid of biogenic structures at pristine conditions was comparable during inundation (immersion) and air exposure (emersion), although increased 2-7 times in sewage contaminated mesocosms. Biogenic structures increased low tide carbon gas emissions at contaminated (30%) and particularly pristine conditions (60%). When sewage was loaded into the mesocosms under unvegetated and planted conditions, iron reduction was substituted by sulfate reduction and contribution of aerobic respiration to total metabolism remained above 50%. Our results clearly show impacts of sewage on the partitioning of electron acceptors in mangrove sediment and confirm the importance of biogenic structures for biogeochemical functioning but also on greenhouse gases emission.
Penha-Lopes
Gil
G
Centro de Oceanografia, Laboratório Marítimo da Guia, Faculdade de Ciências da Universidade de Lisboa, Avenida Na Senhora do Cabo, 939, 2750-374 Cascais, Portugal. gil.penha-lopes@fc.ul.pt
Kristensen
Erik
E
Flindt
Mogens
M
Mangion
Perrine
P
Bouillon
Steven
S
Paula
José
J
D000818:Animals; D032407:Avicennia / Q000502:physiology*; D003386:Brachyura / Q000502:physiology; D002245:Carbon Dioxide / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods*; D019015:Geologic Sediments; D008697:Methane / Q000737:chemistry; D014873:Water Pollutants / Q000737:chemistry*; D053833:Wetlands
D014873:Water Pollutants; D002245:Carbon Dioxide; D008697:Methane