Storage and recycling of major and trace element in mangroves

Area of Science:

• Environmental Science
• Biogeochemistry
• Ecology

Background:

• Mangroves play a role in sequestering metals and nutrients in sediments.
• Knowledge gaps exist regarding element storage and recycling within mangrove plant biomass, particularly root uptake and litterfall.

Purpose of the Study:

• To investigate the storage and transport pathways of 16 elements (macro-nutrients, micro-nutrients, potential toxicants) in the Sundarbans mangrove ecosystem.
• To quantify element fluxes through root uptake and litterfall and assess their significance in mangrove biomass.

Main Methods:

• Analysis of elemental concentrations in plant organs and sediment.
• Quantification of elemental stocks in plant biomass.
• Assessment of elemental translocation, uptake, and loss via litterfall.

Main Results:

• Elemental concentrations in plant organs were generally lower than in sediment.
• Macro- and micro-nutrient stocks ranged from 60 to 2717 and 0.003 to 37.7 Mg ha⁻¹, respectively, with Sodium (Na) highest and Cadmium (Cd) lowest.
• Avicennia species showed maximal element accumulation; belowground uptake exceeded litterfall loss by 2-3 fold.
• The Sundarbans mangrove may act as a source of Manganese (Mn) to the Bay of Bengal.
• Significant retention of Molybdenum (Mo), Cadmium (Cd), and Tin (Sn) in plant biomass was observed.

Conclusions:

• Mangroves efficiently store and remobilize major and trace elements from sediments through root uptake.
• Recycling of elements back to the sediment surface occurs via litterfall.
• Observed retention of specific trace elements suggests potential applications in phytoremediation and ecosystem restoration.