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Abstract Estuarine exchange flow regulates aspects of estuarine biogeochemical processes; however, other tracer‐specific factors can also play an important role. Here, we analyze realistic simulations from a coupled physical‐biological model to quantify volume‐integrated budgets of heat, total nitrogen (TN), and dissolved oxygen (DO) in the Salish Sea and its sub‐basins. Our goal is to evaluate the role of exchange flow in shaping tracer budgets, extending beyond the traditionally emphasized salt budget in estuaries. The three budgets reveal that exchange flow is a consistently important term with a clear annual cycle, but its relative role differs across tracers. For heat, exchange flow‐driven cooling is primarily offset by atmospheric heating, with the two reaching opposing seasonal extremes in summer. For TN, seasonal variability is dominated by exchange flow, whereas the annual mean is dominated by inputs from rivers and wastewater outfalls, and a loss due to benthic denitrification. The DO budget is the most complex: sinks from exchange flow export and respiration are balanced by sources from photosynthesis and air‐sea transfer. Across all three budgets, the sign of the inflow‐outflow tracer concentration differences determines whether exchange flow imports or exports tracers. These concentration differences, which are strongly influenced by coastal wind conditions, set the distinct seasonality of the exchange flow budget terms, while variations in the exchange flow volume transport play a minor role. Our budget quantification approach, based on archived model output, can be extended to other tracers such as carbon and other estuaries for long‐term budget studies.
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Critical evaluation of heat extraction temperature on soluble microbial products (SMP) and extracellular polymeric substances (EPS) quantification in wastewater processes
Abstract While soluble microbial products (SMP) and extracellular polymeric substances (EPS) in wastewater bioprocesses have been widely studied, a lack of standard quantification procedures make it difficult to compare results between studies. This study investigated the effect of temperature on SMP and EPS profiles for biological nutrient removal (BNR) sludges and aerobic membrane bioreactor sludge by adapting the commonly used heat extraction and centrifugation scheme, followed by colorimetric quantification of the carbohydrate and protein fractions using the phenol-sulfuric acid (PS) and the bicinchoninic acid (BCA) methods, respectively. To overcome known inconsistencies in colorimetry, total carbon (TC), total nitrogen (TN), and fluorometry analyses were performed in tandem. SMP samples marginally benefitted from heat extraction, owing to their mostly soluble nature, while EPS profiles were greatly influenced by temperature. 60 °C appears to be a suitable general-purpose extraction temperature near the lysis threshold for the sludges tested. The PS method's misestimation due to lack of specificity was observed and contrasted by TC analyses, while the TN analyses corroborated the BCA assays. Fluorometry proved to be a sensitive and rapid analytical method that provided semi-quantitative information on SMP and EPS constituents, particularly its proteinaceous components, with positive implications for robust wastewater process control.
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- Award ID(s):
- 1805631
- PAR ID:
- 10366575
- Publisher / Repository:
- DOI PREFIX: 10.2166
- Date Published:
- Journal Name:
- Water Science and Technology
- Volume:
- 85
- Issue:
- 8
- ISSN:
- 0273-1223
- Page Range / eLocation ID:
- p. 2318-2331
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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