Soil Urease Activity of Sundarban Mangrove Ecosystem, India

Subhajit Das,Sabyasachi Chakraborty,Abhishek Mukherjee,Tarun Kumar De,Dipnarayan Ganguly

doi:10.4236/aim.2017.78048

Abstract

Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region (No tidal action and wave attack occurs as it is furthest from river shore and it contains maximum content of organic carbon and minimum soil salinity and silicate concentration. In this zone plenty of pneumatophores, below ground root and dense vegetation are found), Rooted region (It is situated in between Deep forest region and Un-rooted region. This region contains only pneumatophores but it is devoid of long roots and vegetations. It faces wave attack and tidal action less than that of Un-rooted region) and Un-rooted region (It is closest to river shore and faces maximum wave attack and tidal action; it contains minimum organic carbon but maximum soil salinity and silicate concentration. This zone is totally devoid of any roots, pneumatophores and vegetations) of Sundarban mangrove forest ecosystem, India revealed an interesting explanation. Soil urease activity showed a decreasing pattern with increase in depth from the deep forest region of the Sundarban forest ecosystem. Soil urease activity was found to be more sensitive to soil temperature and pH rather than soil salinity. This ensured that soil urease along with the microbes present in the Sundarban forest ecosystem are more tolerant to fluctuation in salinity than that of temperature. Soil ammonia concentration was found to be directly governed by the soil urease activity [The regression equation is Ammonia in soil = -1.64 + 0.0402 Urease Activity (R-Sq = 62.9%, P < 0.001, n = 41)].

Highlights

Mangroves accounting for 0.7% of the tropical forest area are highly productive [1] [2] [3] and afford territory for rich biodiversity [4]
Vertical occurrence of soil urease activity along with ammonia content from three distinct regions viz. Deep forest region
The present study explored seasonal, spatial and vertical abundance of soil urease activity along with ammonia content and their correlative interaction relating to Nitrogen mineralization and probable influences of soil parameters on soil urease activity

Summary

Introduction

Mangroves accounting for 0.7% of the tropical forest area are highly productive [1] [2] [3] and afford territory for rich biodiversity [4]. The vast majority of the nutrient pool of mangrove forests is stored in the soil and many mangrove soils have extremely low nutrient availability [5]. Nutrient dynamics along with soil enzyme activity of Sundarban mangrove forest is highly influenced by periodic seasonal change, sedimentation rate, water level, leaf fall, etc. In a tropical mangrove forest of Brazil significant sediment accumulation rate was observed to control nutrient status of mangrove sediment [6]. Previous research works reported that mangrove sediments may act as a vast reservoir of organic matter as it initiates the production and rapid burial of the organic matters and it was influenced by sea level rise [7]

Methods

Findings

Discussion

Conclusion