Early growth responses of mangroves to different rates of nitrogen and phosphorus supply

• Published in: Journal of experimental marine biology and ecology Vol. 397; no. 2; pp. 85 - 93
• Main Author: Alongi, D.M.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.02.2011; Elsevier
• Subjects: ammonium compounds; Animal and plant ecology; Animal, plant and microbial ecology; Avicennia marina; Biological and medical sciences; biomass; Brackish water ecosystems; Bruguiera gymnorhiza; Bruguiera gymnorrhiza; Ceriops; Ceriops tagal; dissolved inorganic nitrogen; equations; Fundamental and applied biological sciences. Psychology; leaves; Mangrove; mangrove forests; mangrove soils; Marine; mineralization; Nitrogen; Nutrient limitation; Nutrient utilization; Phosphorus; Plant–soil relations; recruitment; Rhizophora apiculata; roots; Sea water ecosystems; stem elongation; Synecology; toxicity; tree growth; Xylocarpus; Xylocarpus granatum; Xylocarpus moluccensis; Phosphorus; Plant–soil relations; Nutrient utilization; Nitrogen; Nutrient limitation; Mangrove; Marine environment; Growth; Limiting factor; Nutrient; Soil plant relation; Plant-soil relations
• ISSN: 0022-0981; 1879-1697
• DOI: 10.1016/j.jembe.2010.11.021

Experiments were conducted in an outdoor facility to quantify growth responses of six mangrove species to rates of dissolved inorganic nitrogen and phosphorus supply mimicking the range of N and P mineralization rates in natural soils. Growth of all six species on nitrogen was nonlinear. Stem extension rates of Rhizophora apiculata and Xylocarpus granatum were enhanced to the highest rate of N supply (50 mmol m − 2 d − 1 ); Bruguiera gymnorrhiza, Avicennia marina, and Xylocarpus moluccensis stem growth leveled off by 10 mmol m − 2 d − 1 . Stem growth of Ceriops tagal peaked at 24–26 mmol N m − 2 d − 1 . Except for A. marina and C. tagal, rates of biomass increase declined at the highest supply rate, indicating NH 4 + toxicity. At different rates of P supply, stem extension rates and rates of biomass increase of R. apiculata and C. tagal best-fit Gaussian curves and B. gymnorrhiza stem growth and biomass increase best-fit sigmoidal and Gaussian curves, respectively; X. moluccensis stem and biomass growth increased linearly, but stem and biomass growth rates of A. marina did not vary in relation to P supply. Stem growth of X. granatum was Gaussian but rates of biomass increase best-fit a quadratic equation. Changes in leaf and root N and P content mirrored the growth responses. As rates of N and P mineralization in natural mangrove soils overlap with the lowest rates of N and P supplied in these experiments, the growth responses imply that mangroves are intrinsically nutrient-limited at mineralization rates often encountered in nature. Such species specificity may have significant implications for recruitment success and the establishment of species gradients within mangrove forests. ► Growth of six mangrove species on nitrogen was nonlinear. ► At different rates of P supply, growth responses of mangroves were complex; growth rates of A. marina did not vary with P supply. ► These growth responses imply that mangroves are nutrient-limited at mineralization rates encountered in nature. ► Such species specificity may have implications for recruitment success and the establishment of species gradients.