This study was supported by the National Science Foundation (OIA-1655221, OCE-1655686) and Rhode Island Sea Grant (NA22-OAR4170123, RISG22-R/2223-95-5-U). We also would like to thank the Rhode Island School of Design for developing the Vis-A-Thon project and this visualization.

1. Applying the N-mass balance model
<ol>
	<li>Download the dissolved inorganic nitrogen (DIN) data from the US Environmental Protection Agency (USEPA) for 166 stations in Narragansett Bay from 1990 to 2015. 
	NOTE: In this study, the sum of ammonium (NH4+), nitrite (NO2-), and nitrate (NO3-) concentrations were considered as the DIN concentration.</li>
	<li>Split the Narragansett Bay into fifteen boxes along its axis modified from ...

Integrated Visualization of Biogeochemical Data for Nutrient Management

<ol>
	<li>Nixon, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Coastal+marine+eutrophication:+A+definition,+social+causes,+and+future+concerns.">Coastal marine eutrophication: A definition, social causes, and future concerns.</a> Ophelia. 41, 199-219 (1995).</li><li>Kim, J. S., Brush, M. J., Song, B., Anderson, I. C. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Reconstructing+primary+production+in+a+changing+estuary:+A+mass+balance+modeling+approach.">Reconstructing primary production in a changing estuary: A mass balance modeling approach.</a> Limnology and Oceanography. 66 (6), 2535-2546 (2021).</li><li>Kemp, W. M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eutrophication+of+Chesapeake+Bay:+historical+trends+and+ecological+interactions.">Eutrophication of Chesapeake Bay: historical trends and ecological interactions.</a> Marine Ecology Progress Series. 303, 1-29 (2005).</li><li>Brush, M. J., Malone, T. C., Malej, A., Faganeli, F., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=.">.</a> Coastal Ecosystems in Transition: A Comparative Analysis of the Northern Adriatic and Chesapeake Bay. Chapter 5, (2021).</li><li>Howarth, R. W., Marino, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Nitrogen+as+the+limiting+nutrient+for+eutrophication+in+coastal+marine+ecosystems:+Evolving+views+over+three+decades.">Nitrogen as the limiting nutrient for eutrophication in coastal marine ecosystems: Evolving views over three decades.</a> Limnology and Oceanography. 51 (1 part 2), 364-376 (2006).</li><li>Paerl, H. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Controlling+eutrophication+along+the+freshwater-marine+continuum:+Dual+nutrient+(N+and+P)+reductions+are+essential.">Controlling eutrophication along the freshwater-marine continuum: Dual nutrient (N and P) reductions are essential.</a> Estuaries and Coasts. 32, 593-601 (2009).</li><li>Kim, J. S., Chapman, P., Rowe, G., DiMarco, S. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Categorizing+zonal+productivity+on+the+continental+shelf+with+nutrient-salinity+ratios.">Categorizing zonal productivity on the continental shelf with nutrient-salinity ratios.</a> Journal of Marine Systems. 206, 103336 (2020).</li><li>Rowe, G. T., Chapman, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Continental+shelf+hypoxia:+Some+nagging+questions.">Continental shelf hypoxia: Some nagging questions.</a> Gulf of Mexico Science. 20 (2), 153-160 (2002).</li><li>Nixon, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Eutrophication+and+the+macroscope.">Eutrophication and the macroscope.</a> Hydrobiologia. 629, 5-19 (2009).</li><li>Barbier, E. B., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+value+of+estuarine+and+coastal+ecosystem+services.">The value of estuarine and coastal ecosystem services.</a> Ecological Monographs. 81 (2), 169-193 (2011).</li><li>Cloern, J. E., Foster, S. Q., Kleckner, A. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Phytoplankton+primary+production+in+the+world's+estuarinecoastal+ecosystem.">Phytoplankton primary production in the world's estuarinecoastal ecosystem.</a> Biogeosciences. 11 (9), 2477-2501 (2014).</li><li>Codiga, D. L., Stoffel, H. E., Oviatt, C. A., Schmidt, C. E. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Managed+nitrogen+load+decrease+reduces+chlorophyll+and+hypoxia+in+warming+temperate+urban+estuary.">Managed nitrogen load decrease reduces chlorophyll and hypoxia in warming temperate urban estuary.</a> Frontiers in Marine Science. 9, 930347 (2022).</li><li>Sigman, D. M., Hain, M. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biological+productivity+of+the+ocean.">The biological productivity of the ocean.</a> Nature Education Knowledge. 3 (10), 21 (2012).</li><li>Kremer, J. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Simulating+property+exchange+in+estuarine+ecosystem+models+at+ecologically+appropriate+scales.">Simulating property exchange in estuarine ecosystem models at ecologically appropriate scales.</a> Ecological Modelling. 221 (7), 1080-1088 (2010).</li><li>Kim, J. S., Chapman, P., Rowe, G., DiMarco, S. F., Thornton, D. C. O. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Implications+of+different+nitrogen+input+sources+for+potential+production+and+carbon+flux+estimates+in+the+coastal+Gulf+of+Mexico+(GOM)+and+Korean+Peninsula+coastal+waters.">Implications of different nitrogen input sources for potential production and carbon flux estimates in the coastal Gulf of Mexico (GOM) and Korean Peninsula coastal waters.</a> Ocean Science. 16, 45-63 (2020).</li><li>Lake, S. J., Brush, M. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+contribution+of+microphytobenthos+to+total+productivity+in+upper+Narragansett+Bay,+Rhode+Island.">The contribution of microphytobenthos to total productivity in upper Narragansett Bay, Rhode Island.</a> Estuarine, Coastal and Shelf Science. 95 (2-3), 289-297 (2011).</li><li>Brush, M. J., Nixon, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Modeling+the+role+of+macroalgae+in+a+shallow+sub-estuary+of+Narragansett+Bay,+RI+(USA).">Modeling the role of macroalgae in a shallow sub-estuary of Narragansett Bay, RI (USA).</a> Ecological Modelling. 221 (7), 1065-1079 (2010).</li><li>Deacutis, C. F., Murray, D., Prell, W., Saarman, E., Korhun, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypoxia+in+the+upper+half+of+Narragansett+Bay,+RI,+during+August+2001+and+2002.">Hypoxia in the upper half of Narragansett Bay, RI, during August 2001 and 2002.</a> Northeastern Naturalist. 13 (Special Issue 4), 173-198 (2006).</li><li>Oviatt, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Managed+nutrient+reduction+impacts+on+nutrient+concentrations,+water+clarity,+primary+production,+and+hypoxia+in+a+north+temperate+estuary.">Managed nutrient reduction impacts on nutrient concentrations, water clarity, primary production, and hypoxia in a north temperate estuary.</a> Estuarine, Coastal and Shelf Science. 199, 25-34 (2017).</li><li>Boesch, D. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Barriers+and+bridges+in+abating+coastal+eutrophication.">Barriers and bridges in abating coastal eutrophication.</a> Frontiers in Marine Science. 6, 123 (2019).</li><li>Oviatt, C. A., Keller, A. A., Reed, L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Annual+primary+production+in+Narragansett+Bay+with+no+bay-wide+winter-spring+phytoplankton+bloom.">Annual primary production in Narragansett Bay with no bay-wide winter-spring phytoplankton bloom.</a> Estuarine, Coastal and Shelf Science. 54, 1013-1026 (2002).</li></ol>

The authors have no conflicts of interest to declare.

This study estimated the extent of nutrient impacts from riverine inputs in Narraganset Bay (NB) based on the N-mass balance model by defining the three theoretical zones. Historically, hypoxic zones appeared near the Providence River, the western side of Greenwich Bay, and Mount Hope Bay during the summer period18, which were defined as brown zones in this study. Moreover, the zonation of NB is comparable to the results of a previous study19, which examined nutrient concen...

Primary productivity, the production of organic compounds by phytoplankton, fuels ecosystem food webs, and is important for understanding the system&#39;s function in response to environmental changes1,2. Estuarine primary productivity is also closely linked to eutrophication which is defined as excessive nutrients in the ecosystem1, causing several harmful consequences in the coastal regions, such as an overgrowth of phytoplankton leading to large algal blooms and subsequent hypoxia3,4. Importantly, primary productivity in estuaries is highly dependent on the riverine nutrient loading, particularly nitrogen concentrations, which are the typical limiting nutrient in most temperate ocean ecosystems5,6. However, an estimation of the extent of riverine nitrogen impacts in coastal areas remains challenging.
To estimate the estuarine primary productivity, a nitrogen (N) mass balance model is a useful tool to calculate nitrogen fluxes2. The N-mass balance model also provides an understanding of biological mechanisms beyond data observations, revealing information at the edges of different primary productivity zones7. Three different zones8, defined as brown, green, and blue zones, are particularly useful for predicting the impact of nutrient loading in hypoxic regions. The brown zone, defined as the nearest region of a river mouth, represents a high physical process, the green zone has high biological productivity, and the blue zone represents low biological process. The boundary of each zone depends on river flow, nutrient concentrations, and mixing rates8.
Narragansett Bay (NB) is a coastal, temperate estuary in Rhode Island, USA, supporting economic and ecological services and goods9,10,11, in which hypoxia has been consistently occurring. These hypoxic events, defined as the period of low dissolved oxygen (i.e., less than 2-3 mg of oxygen per liter), are particularly prevalent in July and August and are heavily impacted by riverine nitrogen loading during these months12. With an increase in primary production and hypoxia due to anthropogenic emissions of nutrients13, understanding the nitrogen inputs into NB is critical to managing and addressing coastal issues such as eutrophication and hypoxia. Thus, in this study, the rate of primary production in NB is calculated from the N-mass balance model using historically observed nutrient data, especially dissolved inorganic nitrogen (DIN). Based on the results of the N-mass balance model by converting to carbon units using the Redfield ratio, three different primary productivity zones were identified to visualize the extent of nitrogen influence from the river in NB. The model was then recreated into a 3D representation to better visualize the different zones. The products produced from this study can better inform nutrient management in NB in response to hypoxia and eutrophication. Further, results from this study are applicable to other coastal regions to visualize the effects of riverine transport on nutrients and primary productivity.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Adobe Illustrator&#160;</td>
			<td>Adobe</td>
			<td>version 27.6.1</td>
			<td>https://www.adobe.com/products/illustrator.html</td>
		</tr>
		<tr>
			<td>Ampersand Gessobord Uncradled 1/8&#34; Profile 8&#34; x 8&#34;</td>
			<td>Risdstore</td>
			<td>70731053088</td>
			<td>https://www.risdstore.com/ampersand-gessobord-8x8-flat-1-8-profile.html</td>
		</tr>
		<tr>
			<td>Ocean Data View software</td>
			<td></td>
			<td></td>
			<td>https://odv.awi.de/en/software/download/</td>
		</tr>
		<tr>
			<td>W-Series (Wide) Flexible LED Strip Light - Ultra Bright (18 LEDs/foot)</td>
			<td>aspectLED</td>
			<td>SKU AL-SL-W-U</td>
			<td>https://www.aspectled.com/products/w-wide-5050-ultra-bright?gclid=CjwKCAjwm4ukBhAuEiwA0z 
			QxkyqisRPqBcHvXEW8KcJE-bK0d2cvGtqlOxXWJI_ 
			E2rd6DzttPR0FLRoCgfkQAvD_BwE</td>
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visualization of productivity zones based on nitrogen mass balance model in narragansett bay, rhode island

Primary productivity in the coastal regions, linked to eutrophication and hypoxia, provides a critical understanding of ecosystem function. Although primary productivity largely depends on riverine nutrient inputs, estimation of the extent of riverine nutrient influences in the coastal regions is challenging. A nitrogen mass balance model is a practical tool to evaluate coastal ocean productivity to understand biological mechanisms beyond data observations. This study visualizes the biological production zones in Narragansett Bay, Rhode Island, USA, where hypoxia frequently occurs, by applying a nitrogen mass balance model. The Bay is divided into three zones - brown, green, and blue zones - based on primary productivity, which are defined by the mass balance model results. Brown, green, and blue zones represent a high physical process, a high biological process, and a low biological process zone, depending on river flow, nutrient concentrations, and mixing rates. The results of this study can better inform nutrient management in the coastal ocean in response to hypoxia and eutrophication.

Author Spotlight: Understanding Riverine Nitrogen Impacts and Primary Productivity for Effective Nutrient Management

Visualization of Productivity Zones Based on Nitrogen Mass Balance Model in Narragansett Bay, Rhode Island

This study estimate the extension of the riverine nitrogen impacts and the primary productivity for better nutrient management in Narragansett Bay, the coastal area in the Rhode Island, USA. With increased primary production and hypoxia due to anthropogenic emissions of nutrients, understanding the nitrogen inputs into the bay is critical to managing and addressing coastal issues such as eutrophication and hypoxia. However, estimating the extent of nutrient inputs in coastal areas remains challenging.In this study, three different primary productivity zones were identified to visualize the extent of nitrogen influence from the river in the bay using the N mass balance model. This study also produced the results into a 3D representation for better visualization and nutrient management in the bay. As explained in the manuscript, the three theoretical zone can change over time depending on the nutrient concentration of the freshwater, mixing rate, and the river flow.As a result, the future work are the required to quantify these factors attributed to the flexibility of these regions better.

Three theoretical zones of Narragansett Bay based on the N-mass balance model 
The three theoretical zones in Narragansett Bay (NB) were defined based on the N-mass balance model results, in which the DIN data were applied to fifteen boxes of NB, and then the mean DIN in each box was converted to the PPP rates for the summer period. As shown in Figure 2, based on the mean summer (June to September) PPP rates of each box, three (brown, green, and blue) zones in NB were i...

Watch this Scientific Journal Video about Visualization of Productivity Zones Based on Nitrogen Mass Balance Model in Narragansett Bay, Rhode Island at JoVE.com

Here, we aim to visualize the zonation of biological productivity in Narragansett Bay, Rhode Island, based on the nitrogen mass balance model. The results will inform nutrient management in the coastal regions to reduce hypoxia and eutrophication.

Primary productivity in the coastal regions, linked to eutrophication and hypoxia, provides a critical understanding of ecosystem function. Although ...

visualization-productivity-zones-based-on-nitrogen-mass-balance-model

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Applying the N-Mass Balance Model for Visualizing Biological Productivity Zones in Narragansett Bay, Rhode Island

To begin, after downloading the DIN data from the US Environmental Protection Agency, use Adobe Illustrator to divide Narraganset Bay into 15 boxes along its axis modified from the previous study. Using the given formula, calculate the mean concentration of DIN at each box. Calculate the potential primary production, or PPP rate, based on the N-Mass balance model by converting the net DIN removal to carbon units using the Redfield ratio.Save the PPP rate data of each box as a txt file. Then open the Ocean Data View software and load the PPP rate data by clicking the file menu and selecting open. In the metadata variable association window, click the associate variables box, latitude, longitude with station, latitude degrees north, and longitude degrees east.From the import window, click the OK button. Next, Right Click on the map and click zoom. Then drag the red box to zoom into the data area of the map, and click on Enter.From the view menu, click the one scatter window of the layout templates. Then Right Click In the sample panel and select derived variables. From the list of choices panel, under metadata, select latitude and click the add button.Repeat the same step for longitude and click OK.Next, by Right Clicking on the scatter window, select x variable as DRVD longitude degrees east. Similarly select y variable as DRVD latitude degrees north, and z variable as PPP in gram carbon per square meter per day. Select properties by Right Clicking on the scatter window and go to the display style option.Select the gridded field. Then move to the contours option and click the left Shift Button to make 0, 0.1 and two values only remain in the already defined panes of the left. Finally, click the OK button.Based on the contour plot from the software, define the edge of the brown, green, and blue zones in Narraganset Bay. Then using Adobe Illustrator, visualize these zones in the map. The N-Mass balance model identified three theoretical zones in Narraganset Bay for the summer.Brown zones had PPP rates greater than two gram carbon per square meter per day, indicating strong physical and biological processes, with high turbidity and limitation. Green zones had PPP rates between 0.1 to two gram carbon per square meter per day, displaying nutrient limitation and high primary production. Blue zones had PPP rates less than 0.1 to two gram carbon per square meter per day, representing low biological productivity.Physical frameworks were created using acrylic panels with LED lights to show overlaps of zone boundaries and sediment turbidity levels in each zone.

215 Views.  University of Texas - Rio Grande Valley.  Here, we aim to visualize the zonation of biological productivity in Narragansett Bay, Rhode Island, based on the nitrogen mass balance model. The results will inform nutrient management in the coastal regions to reduce hypoxia and eutrophication.

Integrated Visualization of Biogeochemical Data for Nutrient Management

Summary