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Special Issue "Recent Progress in River Biogeochemistry Research"

A special issue of Water (ISSN 2073-4441). This special issue belongs to the section "Hydrology".

Deadline for manuscript submissions: 31 October 2018

Special Issue Editors

Guest Editor
Prof. Dr. Y. Jun Xu

School of Renewable Natural Resources, Louisiana State University, Baton Rouge, LA 70803, USA
Website | E-Mail
Phone: +1-225-578-4168
Fax: +1-225-578-4227
Interests: surface hydrology, water quality, hydrologic and biogeochemical processes and modeling, sediment and nutrient transport, land use and climate change effects on water resources and biogeochemical cycles, isotopic tracer techniques, and GIS/Remote Sensing applications in surface hydrology
Guest Editor
Prof. Dr. Laodong Guo

School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E Greenfield Ave., Milwaukee, WI 53204, USA
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Phone: 414-382-1742
Fax: 414-382-1705
Interests: dissolved organic matter; phosphorus cycling; aquatic colloids; CDOM; metal-DOM interactions; aquatic biogeochemistry
Guest Editor
Prof. Dr. Jerome Gaillardet

Institut de Physique du Globe de Paris, Paris, France
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Guest Editor
Prof. Dr. Houjie Wang

College of Marine Geosciences, Ocean University of China, 238 Songling Rd., Qingdao 266100, China
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Special Issue Information

Dear Colleagues,

We invite you to submit your latest research findings showing progress in River Biogeochemistry to a special issue in Water (ISSN 2073-4441) – an open access journal (http://www.mdpi.com/journal/water). The world rivers discharge tremendous amounts of freshwater and dissolved and suspended solids to the sea, affecting physical, chemical, and biological domains of coastal and marine systems. The quantity and quality of the riverine outflows can be greatly affected by a number of factors in the drainage basins, including natural (e.g. climate fluctuation, earth surface, geochemical and terrestrial ecosystems processes), anthropogenic (e.g. land use change and river engineering) and the interactions with floodplains and wetlands. Over the past decades, many river basins have experienced significant climate, environmental and ecological changes. Concurrently, population growth and economic development have seen large areas of rural land converted for urban and industrial development. It is pertinent to quantify how these changes may have modified flow, sediment transport, and metal, nutrient and carbon fluxes from small and large rivers at a global scale. This special issue aims at bringing together the latest endeavors of research on material transport and biogeochemical processes along the aquatic continuum from river to estuary/coastal waters. We encourage submissions reporting the recent findings in the biogeochemistry of carbon, nutrients and trace elements from field observations, laboratory characterization, modeling, and synthetic studies of river systems, and we especially encourage papers that address the world’s large river systems and stimulate critical thinking pertinent to riverine biogeochemistry and its influence to the coastal and marine systems.

Prof. Dr. Y. Jun Xu
Prof. Dr. Laodong Guo
Prof. Dr. Jerome Gaillardet
Prof. Dr. Houjie Wang
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Water is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1500 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • River geochemistry
  • Biogeochemical processes of rivers
  • Riverine fluxes of carbon, nutrients, metals, and suspended sediment
  • Sediment and chemical constituents transport
  • Colloid chemistry in rivers
  • Biogeochemical connectivity of rivers, floodplains and wetlands
  • Climate and land use change effects on river biogeochemistry
  • Element transformation in freshwater-saltwater mixing
  • River data and modeling infrastructure

Published Papers (6 papers)

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Research

Open AccessArticle Spatial Variations in the Abundance and Chemical Speciation of Phosphorus across the River–Sea Interface in the Northern Beibu Gulf
Water 2018, 10(8), 1103; https://doi.org/10.3390/w10081103
Received: 8 June 2018 / Revised: 2 August 2018 / Accepted: 12 August 2018 / Published: 18 August 2018
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Abstract
Water samples were collected to measure dissolved and particulate phosphorus species in order to examine the dynamics of phosphorus in the water column across the river–sea interface from the lower Dafengjiang River to the open Beibu Gulf. Dissolved inorganic phosphorus concentrations were as
[...] Read more.
Water samples were collected to measure dissolved and particulate phosphorus species in order to examine the dynamics of phosphorus in the water column across the river–sea interface from the lower Dafengjiang River to the open Beibu Gulf. Dissolved inorganic phosphorus concentrations were as high as 0.90 ± 0.42 μM in river water but decreased dramatically to as low as 0.02 ± 0.01 μM in open coastal waters. Total dissolved phosphorus was largely measured in the form of dissolved inorganic phosphorus in river waters (58% ± 18%), whereas dissolved organic phosphorus became the predominant species (>90% on average) in open coastal waters. Total dissolved phosphorus was the dominant species, comprising 76% ± 16% of the total phosphorus, while total particulate phosphorus only comprised 24% ± 16% of the total phosphorus pool. Riverine inputs, physical and biological processes, and particulate phosphorus regeneration were the dominant factors responsible for the dynamic variations of phosphorus species in the study area. Based on a two-end-member mixing model, the biological uptake resulted in a dissolved inorganic phosphorus depletion of 0.12 ± 0.08 μM in the coastal surface water, whereas the replenishment of dissolved inorganic phosphorus in the lower river from particle P regeneration and release resulted in an increase (0.19 ± 0.22 μM) of dissolved inorganic phosphorus in the estuarine mixing region. The molar ratios of dissolved inorganic nitrogen to dissolved inorganic phosphorus and dissolved silicate to dissolved inorganic phosphorus in the open surface waters were >22, suggesting that, although the lower Dafengjiang River contained elevated concentrations of dissolved inorganic phosphorus, the northern Beibu Gulf was an overall P-limited coastal ecosystem. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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Open AccessArticle The Influences of a Clay Lens on the Hyporheic Exchange in a Sand Dune
Water 2018, 10(7), 826; https://doi.org/10.3390/w10070826
Received: 4 April 2018 / Revised: 19 June 2018 / Accepted: 20 June 2018 / Published: 22 June 2018
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Abstract
A laboratory flume simulating a riverbed sand dune containing a low-permeability clay lens was constructed to investigate its influence on the quality and quantity of hyporheic exchange. By varying the depths and spatial locations of the clay lens, 24 scenarios and one blank
[...] Read more.
A laboratory flume simulating a riverbed sand dune containing a low-permeability clay lens was constructed to investigate its influence on the quality and quantity of hyporheic exchange. By varying the depths and spatial locations of the clay lens, 24 scenarios and one blank control experiment were created. Dye tracers were applied to visualize patterns of hyporheic exchange and the extent of the hyporheic zone, while NaCl tracers were used to calculate hyporheic fluxes. The results revealed that the clay lens reduces hyporheic exchange and that the reduction depends on its spatial location. In general, the effect was stronger when the lens was in the center of the sand dune. The effect weakened when the lens was moved near the boundary of the sand dune. A change in horizontal location had a stronger influence on the extent of the hyporheic zone compared with a change in depth. The size of the hyporheic zone changed with the depth and position of the clay lens. There was a maximum of hyporheic extent with the lens at a depth of 0.1 m caused by changes of water flow paths. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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Open AccessFeature PaperArticle Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico
Water 2018, 10(6), 816; https://doi.org/10.3390/w10060816
Received: 21 May 2018 / Revised: 3 June 2018 / Accepted: 16 June 2018 / Published: 20 June 2018
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Abstract
This study aims to evaluate recent total phosphorus (TP) and dissolved inorganic phosphorus (DIP) transport from three coastal rivers—the Calcasieu, Mermentau, and Vermilion Rivers—that drain watersheds with varied agriculture intensities (21%, 67%, and 61%, respectively) into the northern Gulf of Mexico, one of
[...] Read more.
This study aims to evaluate recent total phosphorus (TP) and dissolved inorganic phosphorus (DIP) transport from three coastal rivers—the Calcasieu, Mermentau, and Vermilion Rivers—that drain watersheds with varied agriculture intensities (21%, 67%, and 61%, respectively) into the northern Gulf of Mexico, one of the world’s largest summer hypoxic zones. The study also examined the spatial trends of TP and DIP from freshwater to saltwater along an 88-km estuarine reach with salinity increasing from 0.02 to 29.50. The results showed that from 1990–2009 to 2010–2017, the TP fluxes for one of the agriculture-intensive rivers increased while no significant change was found for the other two rivers. Change in river discharge was the main reason for this TP flux trend. The two more agriculture-intensive river basins showed consistently higher TP and DIP concentrations and fluxes, as well as higher DIP:TP ratios than the river draining less agriculture-intensive land, confirming the strong effect of land uses on phosphorus input and speciation. Longitudinal profiles of DIP along the salinity gradient of the estuarine reach displayed characteristic input behavior. Desorption of DIP from suspended solids and river bed sediments, urban inputs, as well as stronger calcium carbonate and phosphorus co-precipitation at the marine endmember could be the reasons for such mixing dynamics. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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Open AccessArticle Spatial and Seasonal Patterns of Nutrients and Heavy Metals in Twenty-Seven Rivers Draining into the South China Sea
Water 2018, 10(1), 50; https://doi.org/10.3390/w10010050
Received: 10 November 2017 / Revised: 5 January 2018 / Accepted: 7 January 2018 / Published: 10 January 2018
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Abstract
Due to the acceleration of industrialization and urbanization in recent decades, the majority of coastal rivers and estuaries in China have been moderately or severely contaminated by a variety of pollutants. We investigated the spatial and seasonal variations of water nutrients (permanganate index,
[...] Read more.
Due to the acceleration of industrialization and urbanization in recent decades, the majority of coastal rivers and estuaries in China have been moderately or severely contaminated by a variety of pollutants. We investigated the spatial and seasonal variations of water nutrients (permanganate index, chemical oxygen demand, biochemical oxygen demand, ammonium, nitrate, total nitrogen, and total phosphorus) and heavy metals (Hg, Pb, Cu, Zn, Se, As, Cd, Cr, Fe, and Mn) in 27 subtropical rivers draining into the South China Sea. Our results indicated that the average concentrations of all water quality parameters except ammonium, total nitrogen, and total phosphorus satisfied the requirements for grade III of the surface water quality standard of China. The concentrations of both nutrients and heavy metals showed a strong spatial variation. Cluster analysis classified the 27 rivers into three spatial clusters corresponding to low, moderate, and high pollution levels. In terms of seasonal variation, the values of chemical oxygen demand and biochemical oxygen demand in wet seasons were significantly lower than those in dry seasons. Multivariate statistical analyses demonstrated that river nutrients might mainly originate from domestic, industrial, and agricultural wastewaters, while heavy metals likely came from industrial activities and natural weathering processes. The findings of this study suggest that for reducing the pollution of subtropical rivers draining into the South China Sea, further efforts should be made to control nitrogen and phosphorus export from catchments. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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Open AccessArticle Permafrost Boundary Shift in Western Siberia May Not Modify Dissolved Nutrient Concentrations in Rivers
Water 2017, 9(12), 985; https://doi.org/10.3390/w9120985
Received: 10 November 2017 / Revised: 11 December 2017 / Accepted: 13 December 2017 / Published: 17 December 2017
Cited by 1 | PDF Full-text (1659 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Identifying the landscape and climate factors that control nutrient export by rivers in high latitude regions is one of the main challenges for understanding the Arctic Ocean response to ongoing climate change. This is especially true for Western Siberian rivers, which are responsible
[...] Read more.
Identifying the landscape and climate factors that control nutrient export by rivers in high latitude regions is one of the main challenges for understanding the Arctic Ocean response to ongoing climate change. This is especially true for Western Siberian rivers, which are responsible for a significant part of freshwater and solutes delivery to the Arctic Ocean and are draining vast permafrost-affected areas most vulnerable to thaw. Forty-nine small- and medium-sized rivers (10–100,000 km2) were sampled along a 1700 km long N–S transect including both permafrost-affected and permafrost-free zones of the Western Siberian Lowland (WSL) in June and August 2015. The N, P, dissolved organic and inorganic carbon (DOC and DIC, respectively), particular organic carbon (POC), Si, Ca, K, Fe, and Mn were analyzed to assess the role of environmental parameters, such as temperature, runoff, latitude, permafrost, bogs, lake, and forest coverage on nutrient concentration. The size of the watershed had no influence on nutrient concentrations in the rivers. Bogs and lakes retained nutrients whereas forests supplied P, Si, K, Ca, DIC, and Mn to rivers. The river water temperature was negatively correlated with Si and positively correlated with Fe in permafrost-free rivers. In permafrost-bearing rivers, the decrease in T northward was coupled with significant increases in PO4, Ptot, NH4, pH, DIC, Si, Ca, and Mn. North of the permafrost boundary (61° N), there was no difference in nutrient concentrations among permafrost zones (isolated, sporadic, discontinuous, and continuous). The climate warming in Western Siberia may lead to a permafrost boundary shift northward. Using a substituting space for time scenario, this may decrease or maintain the current levels of N, P, Si, K, Ca, DIC, and DOC concentrations in rivers of continuous permafrost zones compared to the present state. As a result, the export flux of nutrients by the small- and medium-sized rivers of the Western Siberian subarctic to the Arctic Ocean coastal zone may remain constant, or even decrease. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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Open AccessFeature PaperArticle Unravelling the Relative Contribution of Dissolved Carbon by the Red River to the Atchafalaya River
Water 2017, 9(11), 871; https://doi.org/10.3390/w9110871
Received: 15 August 2017 / Revised: 27 October 2017 / Accepted: 4 November 2017 / Published: 8 November 2017
Cited by 1 | PDF Full-text (3196 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The Atchafalaya River (AR), North America’s largest swamp river, annually discharges a large volume of freshwater (nearly 200 km3), delivering ~25% of the Mississippi River’s (MR) flow and the entire Red River’s (RR) flow into the Gulf of Mexico. Studies have reported higher
[...] Read more.
The Atchafalaya River (AR), North America’s largest swamp river, annually discharges a large volume of freshwater (nearly 200 km3), delivering ~25% of the Mississippi River’s (MR) flow and the entire Red River’s (RR) flow into the Gulf of Mexico. Studies have reported higher levels of organic carbon in the AR’s outlets compared to the MR’s outlet, raising questions about local carbon sources. In this study, we investigated dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) inputs into the AR from the RR and MR using DOC and DIC concentrations, mass loading, and isotopic signature (δ13C) analyses. Monthly river water sampling was conducted in the MR and RR near their confluence where the AR is formed from May 2015–May 2016. DIC concentrations in the RR were found to be only half of those found in the MR, while the RR’s DOC concentrations were on average 1.8 times higher than those found in the MR. Based on the models developed for this study period, the RR’s contribution to DIC mass loading in the AR represented 1.41 teragrams (Tg) (or, 29.7%) of the total 4.76 Tg DIC transported by both tributaries, while its contribution to DOC mass loading was disproportionately high, accounting for 1.74 Tg of the 2.75 Tg DOC (or, 63.2% of total DOC) entering the AR. Both δ13CDIC and δ13CDOC showed significantly more negative values in the RR than those found in the MR. Significant correlation between δ13CDIC and δ13CDOC isotope values in the RR indicated interrelation of dissolved carbon processing, which was not observable in the MR. These results strongly suggest that the RR is an extremely significant source of DOC to the AR, and thus the Gulf of Mexico, and additionally plays an important role in diluting the anthropogenically enhanced DIC fluxes of the MR. Full article
(This article belongs to the Special Issue Recent Progress in River Biogeochemistry Research)
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