TY - JOUR

T1 - Soil organic carbon stocks in estuarine and marine mangrove ecosystems are driven by nutrient colimitation of P and N

AU - Weiss, Christian

AU - Weiss, Joanna

AU - Boy, Jens

AU - Iskandar, Issi

AU - Mikutta, Robert

AU - Guggenberger, Georg

N1 - Funding information: We would like to thank the Federal Ministry of Education and Research (BMBF) for funding of this subproject in the frame of the German Indonesian joint research project SPICE III (funding code 030F0644C). We furthermore thank our partners from the Leibniz Center for Tropical Marine Ecology (ZMT Bremen) for valuable information on the Segara Anakan Lagoon based on their local working experience of many years, as well as all other partners from the SPICE III joint research project (Science for the Protection of Indonesian Coastal Marine Ecosystems) for their valuable contribution. We thank Dani from Malenge for the boat service during sampling on the Togian Islands, Darjon from Derawan for logistical support during sampling of Berau estuary, and Aditya Windardi for his local knowledge of mangroves at Segara Anakan. For his help in CFA analysis André Specht from the Institute for Plant Nutrition (Leibniz University of Hannover) is thanked for. Finally, we appreciate the help of Axel Steinhof from the Max-Planck-Institute for Biogeochemistry in Jena for the

PY - 2016/7/19

Y1 - 2016/7/19

N2 - Mangroves play an important role in carbon sequestration, but soil organic carbon (SOC) stocks differ between marine and estuarine mangroves, suggesting differing processes and drivers of SOC accumulation. Here, we compared undegraded and degraded marine and estuarine mangroves in a regional approach across the Indonesian archipelago for their SOC stocks and evaluated possible drivers imposed by nutrient limitations along the land-to-sea gradients. SOC stocks in natural marine mangroves (271–572 Mg ha−1 m−1) were much higher than under estuarine mangroves (100–315 Mg ha−1 m−1) with a further decrease caused by degradation to 80–132 Mg ha−1 m−1. Soils differed in C/N ratio (marine: 29–64; estuarine: 9–28), δ15N (marine: −0.6 to 0.7‰; estuarine: 2.5 to 7.2‰), and plant-available P (marine: 2.3–6.3 mg kg−1; estuarine: 0.16–1.8 mg kg−1). We found N and P supply of sea-oriented mangroves primarily met by dominating symbiotic N2 fixation from air and P import from sea, while mangroves on the landward gradient increasingly covered their demand in N and P from allochthonous sources and SOM recycling. Pioneer plants favored by degradation further increased nutrient recycling from soil resulting in smaller SOC stocks in the topsoil. These processes explained the differences in SOC stocks along the land-to-sea gradient in each mangrove type as well as the SOC stock differences observed between estuarine and marine mangrove ecosystems. This first large-scale evaluation of drivers of SOC stocks under mangroves thus suggests a continuum in mangrove functioning across scales and ecotypes and additionally provides viable proxies for carbon stock estimations in PES or REDD schemes.

AB - Mangroves play an important role in carbon sequestration, but soil organic carbon (SOC) stocks differ between marine and estuarine mangroves, suggesting differing processes and drivers of SOC accumulation. Here, we compared undegraded and degraded marine and estuarine mangroves in a regional approach across the Indonesian archipelago for their SOC stocks and evaluated possible drivers imposed by nutrient limitations along the land-to-sea gradients. SOC stocks in natural marine mangroves (271–572 Mg ha−1 m−1) were much higher than under estuarine mangroves (100–315 Mg ha−1 m−1) with a further decrease caused by degradation to 80–132 Mg ha−1 m−1. Soils differed in C/N ratio (marine: 29–64; estuarine: 9–28), δ15N (marine: −0.6 to 0.7‰; estuarine: 2.5 to 7.2‰), and plant-available P (marine: 2.3–6.3 mg kg−1; estuarine: 0.16–1.8 mg kg−1). We found N and P supply of sea-oriented mangroves primarily met by dominating symbiotic N2 fixation from air and P import from sea, while mangroves on the landward gradient increasingly covered their demand in N and P from allochthonous sources and SOM recycling. Pioneer plants favored by degradation further increased nutrient recycling from soil resulting in smaller SOC stocks in the topsoil. These processes explained the differences in SOC stocks along the land-to-sea gradient in each mangrove type as well as the SOC stock differences observed between estuarine and marine mangrove ecosystems. This first large-scale evaluation of drivers of SOC stocks under mangroves thus suggests a continuum in mangrove functioning across scales and ecotypes and additionally provides viable proxies for carbon stock estimations in PES or REDD schemes.

KW - Ecosystem functioning

KW - global change

KW - Indonesia

KW - marine and estuarine mangroves

KW - nitrogen

KW - phosphorus

KW - soil organic carbon

KW - stable isotopes

UR - http://www.scopus.com/inward/record.url?scp=84977118081&partnerID=8YFLogxK

U2 - 10.1002/ece3.2258

DO - 10.1002/ece3.2258

M3 - Article

AN - SCOPUS:84977118081

VL - 6

SP - 5043

EP - 5056

JO - Ecology and evolution

JF - Ecology and evolution

SN - 2045-7758

IS - 14

ER -