Interannual and Seasonal Variations in Estuarine Water Quality

Abstract

Anthropic processes degrade quality of estuarine environments, resulting in a worrying form of water pollution. The objective of the study was to describe and discuss interannual and seasonal changes of water quality based on indicators monitored in Goiana River estuary, as well as identifying the main drivers of such changes. We considered three estuarine areas or habitats (upper estuary, middle estuary and lower estuary), and two seasons (dry and rainy) for anchoring sample design. The information collected for surface and bottom water include water temperature (• C), salinity, dissolved oxygen (mg L −1), saturation (%) and Secchi depth (cm) (n = 864). The monthly total rainfall (mm) was compiled from public database. Multivariate analyses highlight inter dependency among these parameters. Water quality was reduced in dry periods (including episodes of hypoxia), but generally increased toward the mouth of estuary. Rainfall is the most important factor in the renewal and maintenance waters of small tropical estuaries. Regions most sensitive to climate change where water resources are depleted and/or compromised should pay even more attention to upcoming changes in rainfall (seasonal) and climatic patterns in addition to better water management practices.

Investigation of water quality from Damanga estuary through the water quality indexing Gujarat

“…Temperature was identical at the both stations during the period of winter (20.00 ± 1.41) which is lower to reported value than other two seasons and it was higher during the period of summer (27.50 ± 2.12) at downstream station (Figure 3.1). This observation was identical with the observation from Weir Cum-Causeway, Tapi river [16] and Industrial division of Hazira, Tapi estuary [18]; Ennon estuary [19]. The shower of heat from sunlight or fluctuated solar radiation leads to seasonal fluctuation of water temperature; normally intensity of sunlight, freshwater run-off, cooling of riverine water and mix-up with ebb, evaporation affected the temperature of surface water [20].…”

“…An ecosystem of estuary is very dynamic and tremendously productive [1], and their operational activities occurred in different systematic manner consisting of temporal and spatial cycles as well as diurnal and semidiurnal kind of tidal cycle [2]. The various life phases of marine organisms containing feeding, breeding and conservation from predators attained through the estuarine environment, and they provide shelter to several species; in addition to inhabitant species which pass across the life cycle in this habitat, more or less they contribute to social and economic values [3]. Alternations in the terra and aqua zone sensitively affected the estuarine ecosystem due to its fragile and sensitive nature.…”

Investigation of water quality from Damanganga estuary the water quality indexing, Gujarat

“…which is lower to reported value than other two seasons and it was higher during the period of summer (27.50 ± 2.12) at downstream station (Figure 3.1). This observation was identical with the observation from Weir Cum-Causeway, Tapi river [16] and Industrial division of Hazira, Tapi estuary [18]; Ennon estuary [19]. The principal sources for presence of metals in riverine waters are atmospheric deposition, human actitivities like agricultural run-off, domestic sewage, industrial discharges, and geologic weathering [25].…”

“…3 phases of marine organisms containing feeding, breeding and conservation from predators attained through the estuarine environment, and they provide shelter to several species; in addition to inhabitant species which pass across the life cycle in this habitat, more or less they contribute to social and economic values [3]. Alternations in the terra and aqua zone sensitively affected the estuarine ecosystem due to its fragile and sensitive nature.…”

Trophic dynamics in two South American estuaries encompassing industrial development and a biodiversity hotspot

“…Ideally, sufficient baseline ecological information would be used as a reference point for managing anthropogenic activities in estuaries to guarantee ecosystem capacity to maintain associated services. But in many cases economic development exceeds any such capacity, especially for estuaries in developing countries (Costa, Costa, Dantas, & Barletta, 2018).…”