Futuristic Research Division, National Centre for Sustainable Coastal Management, Ministry of Environment, Forest and Climate Change, Anna University Campus, Chennai, India.
Département des Sciences Biologiques, Groupe de Recherche Interuniversitaire en Limnologie, Université du Québec à Montréal, Montréal, QC, Canada.
Environ Sci Pollut Res Int. 2021 Aug;28(31):42051-42069. doi: 10.1007/s11356-021-13638-7. Epub 2021 Apr 1.
Efficient nutrient cycling and adequate sediment bioavailable nutrient supply are considered to be the two most important factors regulating the high productivity and subsequent carbon sequestration by mangrove ecosystems. We assessed spatial variability and the possible regulating factors of sediment bioavailable nutrients (nitrogen (N) and phosphorus (P)) and surface water-dissolved nutrients (N, P and silicate (Si)) in the five ecologically important mangrove ecosystems along the east and west coast of India during dry season. Higher bioavailable nitrogen concentrations in the sediments were recorded in Coringa mangroves (36.27 ± 14.7 μg g) and Bhitarkanika (18.54 ± 5.9 μg g) mangroves in the east coast followed by Karnataka (15.51 ± 8.26 μg g), Goa, (10.18 ± 9.96 μg g) and Kerala (6.36 ± 5.05 μg g) mangroves in the west coast. The dissolved inorganic nutrients in the mangrove waters ranged between 5.1 and 220.9 μmol l for N and 0.07 and 3.9 μmol l for P. These results indicated that terrestrial inputs, in situ remineralization and prevalent anoxic conditions regulated sediment nutrient content in these ecosystems, whereas the higher ammonium in the sediments was attributed to the greater nutrient adsorption by finer particles. The stoichiometry of the bioavailable nutrients (N, P) in the mangrove sediments deviated drastically from the Redfield ratio, and strong P limitation was recorded in most of the ecosystems. The results highlighted the potential role of sediment particle size and physiochemical (salinity and pH) properties in regulating bioavailable nutrient dynamics in mangrove sediments.
高效的养分循环和充足的沉积物可利用养分供应被认为是调节红树林生态系统高生产力和随后碳固存的两个最重要因素。本研究评估了印度东、西海岸五个生态重要的红树林生态系统在旱季期间沉积物可利用养分（氮（N）和磷（P））和表层水溶解养分（N、P 和硅酸盐（Si））的空间变异性及其可能的调节因子。在东海岸，科林加红树林（36.27 ± 14.7 μg g）和比塔克那卡红树林（18.54 ± 5.9 μg g）的沉积物中可利用氮浓度较高，其次是卡纳塔克邦（15.51 ± 8.26 μg g）、果阿（10.18 ± 9.96 μg g）和喀拉拉邦（6.36 ± 5.05 μg g）的红树林。红树林水中的溶解无机养分在 N 为 5.1 至 220.9 μmol l 之间，在 P 为 0.07 至 3.9 μmol l 之间。这些结果表明，陆地输入、原地再矿化和普遍存在的缺氧条件调节了这些生态系统中的沉积物养分含量，而沉积物中较高的铵则归因于较细颗粒对养分的更强吸附。红树林沉积物中可利用养分（N、P）的化学计量明显偏离了雷德菲尔德比，并且在大多数生态系统中都记录到了强烈的磷限制。研究结果强调了沉积物颗粒大小和理化性质（盐度和 pH 值）在调节红树林沉积物中可利用养分动态方面的潜在作用。
