Spatial variation of nutrients and primary productivity in the Rufiji Delta mangroves, Tanzania

Abstract

Determinations of spatial and temporal variations in organic matter and nutrient dynamics in water and sediments are crucial for understanding changes in aquatic bodies. In this study, we (i) determine the spatial dynamics of dissolved inorganic nutrients, during the transition from the dry to the rainy season, and (ii) provide future productivity predictions for the Rufiji Delta mangroves, Tanzania, based on the input of various nutrients. Water samples were collected from six locations, three times per year between April 2012 and January 2014, and analysed for dissolved nutrients, total organic and inorganic carbon, chlorophyll a, chlorophyll b and total carotenoids. The prediction of future net primary productivity in the Rufiji mangroves was undertaken using the software STELLA. The mean nutrient concentrations were of the order: nitrate > phosphate > ammonium > silica > dissolved organic carbon. The study revealed that high nutrient concentrations occurred in the northern part of the Rufiji Delta as a result of anthropogenic influence in the watershed. Modelling of nutrient inputs into the delta indicated enhanced primary productivity, which is expected to increase the vulnerability of water quality in the near future due to eutrophication.

Bioprospecting of Selected Mangrove Fruits Based-Nutritional, Antioxidant, and Element Properties to Support Functional Food Materials for Pulau Sembilan Coastal Communities, Indonesia

“…Among them, A. officinalis, R. mucronata, and X. granatum were promising nutritional and antioxidant materials sources.This study's nutritional values were almost similar values with those previous studies [19]- [21], even much higher value than reported in Rawn Park [12]. Mangroves are known as source of some secondary metabolites and utilized for antibacterial and antifungal [22], antifeedant [23], and property [24].…”

Effects of Temperature and Salinity on Incubation Time, Hatching Success, and Larvae Survival of the Giant Tiger Prawn Penaeus monodon under Experimental Conditions

“…The present study was conducted to determine the effects of the combinations of three different temperature levels (27 °C, 31 °C and 35 °C) and three salinity levels (30 ppt, 35 ppt and 40 ppt) on incubation time, hatching success, larvae and postlarvae survival of Penaeus monodon. The highest temperature and salinity chosen for this study were relatively higher than those found in the Rufiji Delta (8.2-31.2 °C and 2-32 ppt) (Minu et al 2020), where the P. monodon broodstock were taken. The results of the study indicate reduced incubation time for P. monodon eggs at high temperature and high salinity combinations which could be linked to increased egg development rate due to increased metabolic rates (Bett and Vinatea 2009).…”

“…The average temperature and salinity in the Rufiji Delta where the broodstock (spawners) were collected are 28.2-31.2 °C and 2-32 ppt, respectively (Minu et al 2020). The experiments were conducted at three different temperature groups of 27 °C, 31 °C and 35 °C.…”

Assessment of Riparian Ecosystem Health in the Tamiang River, Aceh, Indonesia as Remains Habitat of Batagur borneoensis (Schlegel & Muller, 1844)

“…The value of DO in all locations did not meet the Indonesian government standard, i.e.> 5 mg/L. Some human activities can increase the level of pollutants and sediment in the water, further reducing the DO concentration in the water for the degradation process [30] [31].…”