Application of Salish Sea model: water quality improvement through anthropogenic nutrient reductions

Salish Sea includes a network of coastal waterways spanning the southwest British Columbia (Canada) and northwest Washington State (USA) and includes the major waterbodies, the Strait of Georgia, the Strait of Juan de Fuca and Puget Sound. The Salish Sea Model was developed by PNNL in cooperation with Ecology based on the unstructured FVCOM model for hydrodynamics and the CE-QUAL-ICM model for water quality. The model is forced by river and wastewater inflows, tides, wind and solar radiation. The land based freshwater inputs include almost 100 wastewater plants (municipal and industrial) as well as another 100 or so watershed inflows that have direct discharge into the Salish Sea. These sources contribute anthropogenic loadings of nutrients to the Salish Sea. An assessment of the model’s response to reference conditions as well as current conditions gives us a sense of the extent of water quality impacts due to anthropogenic nutrient loads alone. An overview will be presented that will include model response from our latest model scenarios with various reductions of anthropogenic nutrient loads and how the model responds to these reductions. This will set the stage on how we may approach a “nutrient management strategy” to reduce/eliminate the impact of anthropogenic nutrient loads on dissolved oxygen

River and wastewater effluent nutrient inputs into the Salish Sea model

The Salish Sea Model was developed by Pacific Northwest National Laboratories in collaboration with the Washington State Department of Ecology. The model is being used to evaluate the relative effects of human nutrient inputs and climate influences on the occurrence of low dissolved oxygen (DO) levels throughout the Salish Sea, with a focus on evaluating water quality in Puget Sound. Developing an inventory of point and nonpoint source nutrient inputs entering the Salish Sea is essential to the model’s development. This presentation will present some significant updates to nutrient inputs developed for the Salish Sea Model from wastewater treatment plants (WWTPs) and rivers. Using a combination of monitoring data and statistical methods, we now have a daily time-series of river and wastewater treatment plant effluent flow and nutrient inputs throughout the Salish Sea from 1999 through mid-2017. These nutrient loading estimates are some of most comprehensive estimates developed for the region to date, allowing us to: identify the relative contributions of nutrient loads from WWTPs and rivers, recognize spatial patterns in loads being delivered to different basins of Puget Sound, and describe the seasonal nature of these loads. We have also developed estimates of 1) reference conditions, and 2) future conditions. The reference conditions are aimed at representing, as close as is feasible, what nutrient inputs would be in the absence of local human activities within the Puget Sound region. Future conditions represent nutrient inputs in 2040 while taking into population growth and climate change. These nutrient inputs are essential in the application of the Salish Sea Model to simulate existing, reference, and future conditions in the Salish Sea and to help guide the Puget Sound Nutrient Reduction Strategy

South Puget Sound dissolved oxygen study: water quality model calibration and scenarios

Portions of South and Central Puget Sound are on the Clean Water Act Section 303(d) list of impaired waters because observed dissolved oxygen measurements do not meet the Washington State water quality standards. Human sources of nutrients can increase algae growth, which can decrease oxygen as the additional organic matter decays. Low oxygen can impair fish and other marine life. Computer modeling tools are needed to isolate the impacts of human contributions. The purpose of this study is to identify how much human contributions are contributing to low dissolved oxygen (DO) in South Puget Sound. Previous reports summarize data collection, nutrient load estimates for marine point sources and watershed inflows that include point and nonpoint sources, and the circulation model. This report summarizes the calibration and application of the water quality model to isolate the impacts from groups of sources. The model predicts the regional and seasonal patterns of chlorophyll, DO, and nitrogen throughout South and Central Puget Sound. The model predicts that internal (inside the model domain) current human nutrient loads from marine point sources and watersheds as well as external (north of model domain) current anthropogenic loads are causing DO to decline by as much as 0.4 mg/L in portions of Totten, Eld, Budd, Carr, and Case inlets, and East Passage, which violates the standards. There are not violations across the entire South or Central Puget Sound. While keeping the external anthropogenic load constant, internal marine point sources exert a greater impact than human sources within watershed inflows. Reducing the internal human nutrient load would decrease the magnitude and extent of DO depletion. Additional scenarios are needed to isolate the effects of individual sources

Predicting Puget Sound\u27s organic carbon—and why we need enhanced monitoring

How much has the total organic carbon deposited into the water column and sediments of Puget Sound increased due to human activity? How has that increase impacted sediment flux rates, hypoxia and the carbonate system balance? These are two important questions with answers that are still elusive. To date, both marine and freshwater organic carbon measurements in Puget Sound are relatively sparse. In the long-term, inadequate temporal and spatial organic carbon data may lead to an incomplete and incoherent understanding of carbon cycling in the Puget Sound. The Salish Sea Model, developed by PNNL in collaboration with Department of Ecology, provides insights into the extent of organic carbon loading and concentrations in the Puget Sound. Model scenario runs indicate that autochtonous organic detritus derived from increased productivity related to human nitrogen loading, combined with allochthonous carbon from direct loading due to human activity, has resulted in an increased loading of non-algal organic carbon ranging from 20 and 25% in a significant portion of the Puget Sound’s main basin, as well as in multiple inlets. This increase in organic carbon is expected to have an impact in heterotrophic respiration rates and eutrophication. This presentation will focus on loading rates and predicted organic carbon concentrations throughout the Puget Sound using the Salish Sea Model. It will point to the need for enhanced dissolved and particulate organic carbon measurements in our region, as well as basin-scale measurements of respiration rates, to optimize the alignment of on-going, long term monitoring and modeling efforts

Salish Sea model: ocean acidification module and the response to regional anthropogenic nutrient sources

Several monitoring programs indicate the presence of lower pH and related changes in carbonate system variables in the Salish Sea. This project expands the existing Salish Sea Model to evaluate carbonate system variables. This project quantifies the influences of regional nutrient sources on acidification. The model accounts for Pacific Ocean upwelled water, regional human nutrient contributions, and air emissions around the Salish Sea. This effort also identifies geographical areas and seasons experiencing greater influence from regional sources of nutrients to Salish Sea waters. Results from this effort indicate that increased dissolved inorganic nitrogen, phytoplankton biomass, and non-algal organic carbon caused by regional anthropogenic nutrient sources can constitute significant contributors to acidification in the Salish Sea

Sensitivity of the regional ocean acidification and carbonate system in Puget Sound to ocean and freshwater inputs

While ocean acidification was first investigated as a global phenomenon, coastal acidification has received significant attention in recent years, as its impacts have been felt by different socio-economic sectors (e.g., high mortality of shellfish larvae in aquaculture farms). As a region that connects land and ocean, the Salish Sea (consisting of Puget Sound and the Straits of Juan de Fuca and Georgia) receives inputs from many different sources (rivers, wastewater treatment plants, industrial waste treatment facilities, etc.), making these coastal waters vulnerable to acidification. Moreover, the lowering of pH in the Northeast Pacific Ocean also affects the Salish Sea, as more acidic waters get transported into the bottom waters of the straits and estuaries. Here, we use a numerical ocean model of the Salish Sea to improve our understanding of the carbonate system in Puget Sound; in particular, we studied the sensitivity of carbonate variables (e.g., dissolved inorganic carbon, total alkalinity, pH, saturation state of aragonite) to ocean and freshwater inputs. The model is the updated version of our FVCOM-ICM framework (Finite Volume Community Ocean Model coupled to the water-quality model CE-QUAL-ICM), now with carbonate-system and sediment modules. Sensitivity experiments altering concentrations at the open boundaries and freshwater sources indicate that not only ocean conditions entering the Strait of Juan de Fuca, but also the dilution of carbonate variables by freshwater sources, are key drivers of the carbonate system in Puget Sound. This work is an update from our presentation in the Salish Sea Conference 2016, showing the final results from our model experiments

An overview of the Salish Sea model: existence of reflux mixing and recurring hypoxia

An improved version of a diagnostic hydrodynamic and biogeochemical model (nutrients, phytoplankton, carbon, dissolved oxygen, pH) of the Salish Sea has been developed with the ability to simulate characteristic circulation and water quality features. Notable improvements include expansion of the model domain beyond the Salish Sea, encompassing Vancouver Island and out to the continental shelf boundary. In this talk we present an overview of the model setup describing the model domain coverage, modeling framework, development of boundary conditions, and tidal, riverine, wastewater, and meteorological inputs. Ability of the model to reproduce known circulation features within the Salish Sea is highlighted. The existence of a strong circulation cell between Admiralty Inlet and Tacoma Narrows sills is discussed reflecting on the implications of reflux flow back into Central Puget Sound. Simulation of sediment diagenesis processes and coupling to the water column provides improved model performance that is responsive to land based and oceanic nutrient loads. This coupling is also credited with the improvements in simulation of hypoxia in selected sub-basins within the Salish Sea such as Hood Canal, Penn Cove, and East Sound. Using tidally averaged velocity profiles from the Salish Sea Model, we demonstrate that Hood Canal sub-basin, with a sill near the mouth, a deep channel configuration, and a freshwater source at its landward end, behaves like a classic-fjord. The dominant and notable feature is that circulation and exchange in the inner basin of Hood Canal occurs in the upper 40% of the water column while the lower 60% remains poorly mixed and relatively isolated from the exchange. This results in conditions well suited for the settling of organic matter and long residence times \u3e230 days, and causes recurring hypoxia in the inner regions of Hood Canal in late fall

Urgent need for a non-discriminatory and non-stigmatizing nomenclature for monkeypox virus

Free PMC article: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9451062/We propose a novel, non-discriminatory classification of monkeypox virus diversity. Together with the World Health Organization, we named three clades (I, IIa and IIb) in order of detection. Within IIb, the cause of the current global outbreak, we identified multiple lineages (A.1, A.2, A.1.1 and B.1) to support real-time genomic surveillance.info:eu-repo/semantics/publishedVersio

A year of genomic surveillance reveals how the SARS-CoV-2 pandemic unfolded in Africa

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Emergence and spread of two SARS-CoV-2 variants of interest in Nigeria.

Identifying the dissemination patterns and impacts of a virus of economic or health importance during a pandemic is crucial, as it informs the public on policies for containment in order to reduce the spread of the virus. In this study, we integrated genomic and travel data to investigate the emergence and spread of the SARS-CoV-2 B.1.1.318 and B.1.525 (Eta) variants of interest in Nigeria and the wider Africa region. By integrating travel data and phylogeographic reconstructions, we find that these two variants that arose during the second wave in Nigeria emerged from within Africa, with the B.1.525 from Nigeria, and then spread to other parts of the world. Data from this study show how regional connectivity of Nigeria drove the spread of these variants of interest to surrounding countries and those connected by air-traffic. Our findings demonstrate the power of genomic analysis when combined with mobility and epidemiological data to identify the drivers of transmission, as bidirectional transmission within and between African nations are grossly underestimated as seen in our import risk index estimates