Dynamics of Dissolved Oxygen in Relation to Saturation and Health of an Aquatic Body: A Case for Chilka Lagoon, India

Abstract

Dissolved oxygen (DO) is essential for an aquatic ecosystem since it controls the biological productivity. Here, we propose a unidimensional dynamic model for DO by incorporating biological (photosynthesis, respiration, and mineralization), physical (atmospheric reaeration) and chemical (nitrification) processes so characteristic of shallow coastal water bodies. The analytical study of the proposed model is focussed on supersaturation and undersaturation of oxygen in the water body. The controllability of the ecosystem health has also been investigated. Model results indicate that, while undersaturation of oxygen is largely governed by nitrification and Net Ecosystem Metabolism (NEM), the supersaturation is controlled by photosynthetic activity. The model results are corroborated with observed data collected from Chilka lagoon, India. Subsequently, a biogeochemical model to study the DO variations in Chilka lagoon has been constructed. The model is properly calibrated and validated with observed data. Two independent sets of data (2004-2005 and 2005-2006) were used for model calibration and validation and Chi-square tests supported its robustness ( 2 = 0.982 and 0.987; < 0.05). The model was used to evaluate independently the influence of individual taxa (diatoms, microphytobenthos, and cyanophyceans) on DO variations. Simulations indicate the vital role of microphytobenthos in lagoon DO dynamics and the overall wellbeing.

Anomalous Fluctuation of Halogens in Relation to the Pollution Status along Lake Mariout, Egypt

“…e average content of DO in the lake is higher than those reported for the ocean seawater (3.2-4.8 mg/L) [71]. e levels of DO probably relate to the oxygen-producing processes of the photosynthesis processes of phytoplankton and macrophytes [72].…”

The effect of stocking density and the application of Nitrobacter as ammonia decomposer in aquaponics system of Clarias gariepinus with water spinach (Ipomoea aquatica)

“…Dissolved oxygen is an important parameter because it is needed for the ammonia oxidation process and is a limiting factor for fish survival (7). Low DO concentration could influence the condition of aquatic life (29). The high amount of fish stock in a limited space increased oxygen consumption and metabolic waste product (30).…”

Tingkat Difusi Oksigen Selama Periode Blind Feeding Budidaya Intensif Udang Vaname (Litopenaeus vannamei)

“…Selama periode blind feeding budidaya udang, proses produksi oksigen terlarut didapatkan melalui mekanisme fotosintesis, difusi udara, penggunaan kincir air dan agitasi penambahan air baru pada saat dilakukan pergantian air di tambak (Prasad et al, 2014;Sanjou et al, 2018). Tingkat produksi oksigen terlarut malalui mekanisme fotosintesis yang berlangsung selama periode blind feeding diestimasi sebesar 1.51 mgO2/L/Ha (Vinatea et al, 2010).…”

“…Rasio estimasi produksi oksigen terlarut melalui mekanisme fotosintesis dan penggunaan kincir air tidak terpaut begitu jauh, karena kedua proses tersebut dipengaruhi oleh faktor biotik dan abiotik lingkungan perairan (Prasad et al, 2014). Kemudian untuk produksi oksigen terlarut yang ditimbulkan oleh proses agitasi dan produksi oksigen baru dari air yang masuk kedalam tambak melalui aktifitas pergantian air selama satu siklus budidaya diperoleh sekitar 0.6-0.8 mgO2/L/Ha atau sangat minim sekali (Hopkins et al, 1993).…”