Nutrient and physicochemical properties as potential causes of stress in mangroves of the central Red Sea.

Abdullahi Bala Alhassan,Mohammed Othman Aljahdali,Jian Liu

doi:10.1371/journal.pone.0261620

Abdullahi Bala Alhassan, Mohammed Othman Aljahdali + Show 1 more

Open Access

https://doi.org/10.1371/journal.pone.0261620

Copy DOI

Journal: PloS one	Publication Date: Dec 23, 2021
Citations: 5	License type: CC BY 4.0

Affiliation: King Abdulaziz University, Ahmadu Bello University

Abstract

Mangrove ecosystems are some of the most productive and important sinks for sediment globally. Recently, there has been an increasing interest in possible causes of stress in mangroves, such as nutrient limitation, high salinity, solar radiation and temperature. We measured different factors casing stress and determined how they influenced oxidative stress and growth biomarkers in six study sites dominated by mangroves; Al Lith, South Jeddah, Dahban, Thuwal, Rabigh and Mastorah. Significant differences (P < 0.05) were recorded in water salinities and temperatures, nitrogen and phosphorus content in sediments, and antioxidant enzyme activities in different study sites. The highest salinity (40.75 ‰) and temperature (29.32°C) were recorded in the Rabigh mangrove stand, which corresponds to the lowest dissolved oxygen (5.21 mg/L). Total organic carbon, total nitrogen and total phosphorus in sediment across the study areas were in the order Rabigh>Thuwal>Dahban>Al Lith>South Jeddah>Mastorah. Total nitrogen in mangrove leaves at Rabigh was the highest and about 1.3 times higher than the total nitrogen in South Jeddah mangrove ecosystem, very different from the ratio of total nitrogen in the sediments at Rabigh and South Jeddah mangrove ecosystems. The average values of δ13C (-17.60‰) and δ15N (2.84‰) in the six mangrove ecosystems, and the highest δ13C (-13.62‰) and δ15N (4.39‰) at Rabigh in the sediments suggest that nutrient input differed among study sites. Higher nutrient levels at Rabigh mangrove ecosystem were attributed to restricted circulation, camel grazing and land runoff with agricultural waste during seasonal flooding events. However, N limitation and possibly salinity contributed to stress in Al Lith, South Jeddah, Dahban, Thuwal, Rabigh, and Mastorah mangrove ecosystems. Salinity (r = 0.9012) contribute more to stress at Rabigh.

Highlights

Mangrove ecosystems in marine environments are some of the most productive and important sinks for sediment globally, with shoreline characteristics that provide protection from seasonal flooding [1,2,3,4,5]
Changes in environmental parameters and percentage of mud and sand in study sites Physicochemical parameters such as salinity, temperature, dissolved oxygen (DO), pH and density vary across the six different sites in this study selected at the central Red Sea (Table 2)
There exists no significant difference in DO values recorded at Al lith, South Jeddah, Dahaban, Thuwal and Mastorah

Summary

Introduction

Mangrove ecosystems in marine environments are some of the most productive and important sinks for sediment globally, with shoreline characteristics that provide protection from seasonal flooding [1,2,3,4,5] They provide substantially greater gross primary production and sediment carbon and nutrient accumulation relative to environments lacking vegetation cover in marine ecosystems [5,6,7]. Physiological stress in Avicennia marina within short time period [8, 9] Variables such as agricultural activities at the catchment of mangroves, urban development, effluent containing sewage, flooding, and sand storms, presumably can lead to an influx of high concentration of nutrients in mangroves, which contributes to nutrient enrichment [10, 11]. The mangroves of the Caribbean and islands in Southeast Asia and the Red Sea with limited nutrients have been reported to have a dwarf stature [18, 19]

Objectives

Methods

Results

Conclusion