Spatio-Temporal Variation of Atmospheric Nutrient Deposition in Different Land Uses/Covers around Lake Kivu

Mashimango Bagalwa,Katcho Karume,Frank Kansiime,Harvey Bootsma,Sarah Akello,Jackson Gilbert Mwanjalolo Majaliwa

doi:10.4236/jwarp.2021.139037

Abstract

Atmospheric deposition of nutrients, particularly nitrogen and phosphorus has the capacity to significantly affect the productivity and biogeochemistry of aquatic ecosystems. The objective of this study was to assess the impact of land use/cover types on the atmospheric deposition of nutrients around Lake Kivu. Dry and wet atmospheric deposition samples were collected from four different land use/cover types (forest, wetland, agricultural and urbanized area) at four stations (Goma, Lwiro, Bukavu and Iko) around the Lake Kivu basin. The highest annual loading of dry total phosphorus (TP) was recorded at a station located in an urban area at Goma (4.4 ± 3.9 μmol/m2/yr) and the highest dry deposition of total nitrogen (TN) was recorded at Iko (84.5 ± 41.2 μmol/m2/yr). High wet TP and TN were at Bukavu (0.7 ± 1.1 μmol/m2/yr) and Iko (21.7 ± 34.7 μmol/m2/yr) respectively. High dry TP loads were recorded in the forest area of Goma and the highest dry TN at Lwiro. High wet TP loads were record in agriculture at Goma and high values of wet TN in agriculture at Iko. Phosphorus and nitrogen deposition rates around Lake Kivu were similar to those reported for other African lakes. The highest rate of TP was recorded mainly in the forest area for dry deposition while high TN was recorded in all types of land use/cover in the basin. This study found out that forest traps high concentration of nutrient than other land uses/covers.

Highlights

Atmospheric deposition is a substantial pathway for the transport of contaminants, resulting in water quality deterioration in different ecosystems across the world
The highest annual loading of dry total phosphorus (TP) was recorded at a station located in an urban area at Goma (4.4 ± 3.9 μmol/m2/yr) and the highest dry deposition of total nitrogen (TN) was recorded at Iko (84.5 ± 41.2 μmol/m2/yr)
The present study examined the effect of four main types of land use/cover on atmospheric nutrient deposition in the Lake Kivu region, namely forest, wetland, agriculture and urbanized areas in 4 stations around Lake Kivu basin

Summary

Introduction

Atmospheric deposition is a substantial pathway for the transport of contaminants, resulting in water quality deterioration in different ecosystems across the world. It can affect aquatic ecosystem functions in many ways [1] [2] [3]. Nitrogen (N) and phosphorus (P) are transported into the atmosphere through wind erosion, burning and tillage [7]. Deposition of these particles has been recognized as an important source of nutrients in receiving lakes and other water bodies [8] [9]

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