Biogeochemistry of Mangrove Ecosystems

The biodiversity of Mangrove ecosystems is the most profound in the islands and coastline of the Indo-West-Pacific region, where the occurrence of 44 varieties has been reported. In the Atlantic Ocean coast Mangrove ecosystems are especially widespread in the Caribbean region. The chemical composition of plant species and soils of Mangrove ecosystems have been recently discussed (Dobrovolsky, 1994). 

The total ash content accounts for 11-23% from the dry weight of plant biomass. We can remember for comparison, that these values for the terrestrial forest ecosystems on the similar limestone soils are 5-6% only. These differences can be attributed to the adaptation of Mangrove ecosystems to saline marine waters. 

The common biogeochemical feature of the Mangrove ecosystems is connected with small fluxes of trace metals (Table 43). 

The Mangrove ecosystems are the example of one of the most productive ecosystems of the World. The biomass pool is in excess of 100 ton/ha of dry matter and annual NPP varies from 10 to 30 ton/ha, including leaf litter production of 8-15 ton/ha. Using average data on annual net primary production and content of various elements, we can estimate the values of biogeochemical cycles (Table 44). 

The comparison of biogeochemical fluxes in the Mangrove and Tropical Rain Forest ecosystems shows that the total mass of ash elements per unit area is similar. However, the proportion of various elements is markedly different. The Mangrove plant uptake of Fe and Mn is less and that of Sr is higher than the uptake of these elements in Tropical Rain Forest ecosystems. 

---