Spatio-temporal variability in hydro-chemical characteristics of coastal waters of Salimpur, Chittagong along the Bay of Bengal

Diverse seasonal characteristics of hydro-chemical parameters in the coastal zone are significantly related to aquaculture development. In this paper, general water quality condition derived from laboratory analysis from the coastal waters of Salimpur, Chittagong is presented. Samples were collected from onshore and offshore site of two adjacent coastal locations named as North Salimpur (experimental location) and South Kattoli (control) during a monsoon and a dry season spanning 2013-14. The spatio-temporal variability of studied parameters were found as air temperature 26.5-32.5 ˚C, water temperature 23-33 °C, pH 7.1-7.9, DO 4.29-7.11 mg/L, BOD 1.10-3.25 mg/L, salinity 1.6-21 ppt, EC 3.40-35.68 mS/cm, TDS 2.02-21.99 g/L, TSS 0.62-2.76 g/L, transparency 4.5-14 cm, precipitation 64-1992 mm, NO2-N 1.94-2.58 µg/L, PO4-P 0.45-1.84 µg/L, SiO3-Si 130.46-956.31 µg/L during investigation period. Average values of physicochemical parameters were found to be in compliance with standard guidelines. The ship breaking activities near experimental location possess negative impacts on local geomorphology, freshwater inputs, precipitation and aquatic environment as well. Moreover, wind driven forces, tidal action, wave characteristics and changes in monsoon pattern regulate the coastal processes. This research suggests the importance of regular monitoring to assess present status of water quality and future prospect of aquaculture in the Chittagong coastal zone

Geographic Variation in Salt Marsh Structure and Function for Nekton: a Guide to Finding Commonality Across Multiple Scales

Coastal salt marshes are distributed widely across the globe and are considered essential habitat for many fish and crustacean species. Yet, the literature on fishery support by salt marshes has largely been based on a few geographically distinct model systems, and as a result, inadequately captures the hierarchical nature of salt marsh pattern, process, and variation across space and time. A better understanding of geographic variation and drivers of commonalities and differences across salt marsh systems is essential to informing future management practices. Here, we address the key drivers of geographic variation in salt marshes: hydroperiod, seascape configuration, geomorphology, climatic region, sediment supply and riverine input, salinity, vegetation composition, and human activities. Future efforts to manage, conserve, and restore these habitats will require consideration of how environmental drivers within marshes affect the overall structure and subsequent function for fisheries species. We propose a future research agenda that provides both the consistent collection and reporting of sources of variation in small-scale studies and collaborative networks running parallel studies across large scales and geographically distinct locations to provide analogous information for data poor locations. These comparisons are needed to identify and prioritize restoration or conservation efforts, identify sources of variation among regions, and best manage fisheries and food resources across the globe

Ecosystem services: Delivering decision-making for salt marshes

Tidal marshes are one of the world’s most economically valuable habitats, yet they have experienced large and persistent declines globally. Increased knowledge of the ecosystem services delivered by marshes has become a powerful tool to conserve and restore them. But hesitancies regarding valuations and their application in decision making remain. Here we draw on the literature and collective experience of participants in the “Concepts and controversies in tidal Marsh ecology revisited” workshop, November 2nd and 3rd 2019, Mobile, Alabama, to provide a concise snapshot of the current field of salt marsh ecosystem service valuation, discuss the possible risks in salt marsh valuation, and the importance of stakeholder engagement to mitigate them. We provide examples of the application of valuation in conservation related decision making, illustrating the growing operationalization of ecosystem services in incentivizing salt marsh conservation and restoration.Ecosystem service quantification and valuation is already playing an important role in decision making by coastal risk managers, insurers, engineers and policy makers. While there are legitimate criticisms of valuation techniques and remaining uncertainties in ecosystem service delivery that arise both through natural variability across space and time and through differing and shifting cultural values, our perspective is that the rise of big data, the development of valuation techniques, a growing understanding and application of environmental justice practices, and increasing interdisciplinarity to tackle these complex issues, are paving the way for valuation to play a critical role in decision making around salt marshes

Fisheries rely on threatened salt marshes

Salt marsh ecosystems and the seascapes in which they are embedded serve as critical habitats for species harvested by fisheries (1), which provide food and economic security for hundreds of millions of people (2). Historical marsh losses coupled with increasing pressures from coastal development and climate change place these intertidal ecosystems and surrounding uplands under growing threat (3). Preventing further losses of salt marshes and associated fisheries production will require greater public awareness and difficult choices in coastal policy and management, underpinned by greater understanding of marsh function