Articles | Volume 21, issue 12
https://doi.org/10.5194/bg-21-2955-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/bg-21-2955-2024
© Author(s) 2024. This work is distributed under
the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Research article
| 
18 Jun 2024
Research article |
| 18 Jun 2024
| 18 Jun 2024
Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary: the Johor River and the East Johor Strait
Amanda Y. L. Cheong
Asian School of the Environment, Nanyang Technological University, 639798, Singapore
present address: Aon Singapore Pte Ltd., 068804, Singapore
Kogila Vani Annammala
Department of Water and Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Disaster Preparedness and Prevention Centre (DPPC), Malaysia–Japan International Institute of Technology (MJIIT), Universiti Teknologi Malaysia, 54100 Kuala Lumpur, Malaysia
Ee Ling Yong
Department of Water and Environmental Engineering, Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Centre for Environmental Sustainability and Water Security, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
Yongli Zhou
Asian School of the Environment, Nanyang Technological University, 639798, Singapore
present address: Department of Geography, University of Hong Kong, Hong Kong SAR, China
Robert S. Nichols
Asian School of the Environment, Nanyang Technological University, 639798, Singapore
present address: DHI Water & Environment (S) Pte Ltd., 608526, Singapore
Asian School of the Environment, Nanyang Technological University, 639798, Singapore
Related authors
No articles found.
Christian Lønborg, Cátia Carreira, Gwenaël Abril, Susana Agustí, Valentina Amaral, Agneta Andersson, Javier Arístegui, Punyasloke Bhadury, Mariana B. Bif, Alberto V. Borges, Steven Bouillon, Maria Ll. Calleja, Luiz C. Cotovicz Jr., Stefano Cozzi, Maryló Doval, Carlos M. Duarte, Bradley Eyre, Cédric G. Fichot, E. Elena García-Martín, Alexandra Garzon-Garcia, Michele Giani, Rafael Gonçalves-Araujo, Renee Gruber, Dennis A. Hansell, Fuminori Hashihama, Ding He, Johnna M. Holding, William R. Hunter, J. Severino P. Ibánhez, Valeria Ibello, Shan Jiang, Guebuem Kim, Katja Klun, Piotr Kowalczuk, Atsushi Kubo, Choon-Weng Lee, Cláudia B. Lopes, Federica Maggioni, Paolo Magni, Celia Marrase, Patrick Martin, S. Leigh McCallister, Roisin McCallum, Patricia M. Medeiros, Xosé Anxelu G. Morán, Frank E. Muller-Karger, Allison Myers-Pigg, Marit Norli, Joanne M. Oakes, Helena Osterholz, Hyekyung Park, Maria Lund Paulsen, Judith A. Rosentreter, Jeff D. Ross, Digna Rueda-Roa, Chiara Santinelli, Yuan Shen, Eva Teira, Tinkara Tinta, Guenther Uher, Masahide Wakita, Nicholas Ward, Kenta Watanabe, Yu Xin, Youhei Yamashita, Liyang Yang, Jacob Yeo, Huamao Yuan, Qiang Zheng, and Xosé Antón Álvarez-Salgado
Earth Syst. Sci. Data, 16, 1107–1119, https://doi.org/10.5194/essd-16-1107-2024, https://doi.org/10.5194/essd-16-1107-2024, 2024
Short summary
Short summary
In this paper, we present the first edition of a global database compiling previously published and unpublished measurements of dissolved organic matter (DOM) collected in coastal waters (CoastDOM v1). Overall, the CoastDOM v1 dataset will be useful to identify global spatial and temporal patterns and to facilitate reuse in studies aimed at better characterizing local biogeochemical processes and identifying a baseline for modelling future changes in coastal waters.
Jenny Choo, Nagur Cherukuru, Eric Lehmann, Matt Paget, Aazani Mujahid, Patrick Martin, and Moritz Müller
Biogeosciences, 19, 5837–5857, https://doi.org/10.5194/bg-19-5837-2022, https://doi.org/10.5194/bg-19-5837-2022, 2022
Short summary
Short summary
This study presents the first observation of water quality changes over space and time in the coastal systems of Sarawak, Malaysian Borneo, using remote sensing technologies. While our findings demonstrate that the southwestern coast of Sarawak is within local water quality standards, historical patterns of water quality degradation that were detected can help to alert local authorities and enhance management and monitoring strategies of coastal waters in this region.
Yongli Zhou, Patrick Martin, and Moritz Müller
Biogeosciences, 16, 2733–2749, https://doi.org/10.5194/bg-16-2733-2019, https://doi.org/10.5194/bg-16-2733-2019, 2019
Short summary
Short summary
We found that peatlands in coastal Sarawak, Borneo, export extremely humified organic matter, which dominates the riverine organic matter pool and conservatively mixes with seawater, while the freshly produced fraction is low and stable in concentration at all salinities. We estimated that terrigenous fractions, which showed high photolability, still account for 20 % of the coastal dissolved organic carbon pool, implying the importance of peat-derived organic matter in the coastal carbon cycle.
Patrick Martin, Nagur Cherukuru, Ashleen S. Y. Tan, Nivedita Sanwlani, Aazani Mujahid, and Moritz Müller
Biogeosciences, 15, 6847–6865, https://doi.org/10.5194/bg-15-6847-2018, https://doi.org/10.5194/bg-15-6847-2018, 2018
Short summary
Short summary
The carbon cycle is a key control for the Earth's climate. Every year rivers deliver a lot of organic carbon to coastal seas, but we do not know what happens to this carbon, particularly in the tropics. We show that rivers in Borneo deliver carbon from peat swamps to the sea with at most minimal biological or chemical alteration in estuaries, but sunlight can rapidly oxidise this carbon to CO2. This means that south-east Asian seas are likely hotspots of terrestrial carbon decomposition.
Related subject area
Biogeochemistry: Coastal Ocean
Responses of microbial metabolic rates to non-equilibrated silicate- versus calcium-based ocean alkalinity enhancement
High metabolic zinc demand within native Amundsen and Ross sea phytoplankton communities determined by stable isotope uptake rate measurements
The influence of zooplankton and oxygen on the particulate organic carbon flux in the Benguela Upwelling System
Reviews and syntheses: Biological indicators of low-oxygen stress in marine water-breathing animals
Temperature-enhanced effects of iron on Southern Ocean phytoplankton
Riverine nutrient impact on global ocean nitrogen cycle feedbacks and marine primary production in an Earth system model
The Northeast Greenland Shelf as a potential late-summer CO2 source to the atmosphere
Technical note: Ocean Alkalinity Enhancement Pelagic Impact Intercomparison Project (OAEPIIP)
Estimates of carbon sequestration potential in an expanding Arctic fjord (Hornsund, Svalbard) affected by dark plumes of glacial meltwater
An assessment of ocean alkalinity enhancement using aqueous hydroxides: kinetics, efficiency, and precipitation thresholds
Dissolved nitric oxide in the lower Elbe Estuary and the Port of Hamburg area
Variable contribution of wastewater treatment plant effluents to downstream nitrous oxide concentrations and emissions
Long-term variations of pH in coastal waters along the Korean Peninsula
Investigating the effect of silicate- and calcium-based ocean alkalinity enhancement on diatom silicification
Ocean alkalinity enhancement using sodium carbonate salts does not lead to measurable changes in Fe dynamics in a mesocosm experiment
Quantification and mitigation of bottom-trawling impacts on sedimentary organic carbon stocks in the North Sea
Influence of ocean alkalinity enhancement with olivine or steel slag on a coastal plankton community in Tasmania
Multi-model comparison of trends and controls of near-bed oxygen concentration on the northwest European continental shelf under climate change
Picoplanktonic methane production in eutrophic surface waters
Vertical mixing alleviates autumnal oxygen deficiency in the central North Sea
Hypoxia also occurs in small highly turbid estuaries: the example of the Charente (Bay of Biscay)
Assessing the impacts of simulated Ocean Alkalinity Enhancement on viability and growth of near-shore species of phytoplankton
Seasonality and response of ocean acidification and hypoxia to major environmental anomalies in the southern Salish Sea, North America (2014–2018)
Countering the effect of ocean acidification in coastal sediments through carbonate mineral additions
Oceanographic processes driving low-oxygen conditions inside Patagonian fjords
Above- and belowground plant mercury dynamics in a salt marsh estuary in Massachusetts, USA
Variability and drivers of carbonate chemistry at shellfish aquaculture sites in the Salish Sea, British Columbia
Unusual Hemiaulus bloom influences ocean productivity in Northeastern US Shelf waters
Insights into carbonate environmental conditions in the Chukchi Sea
UAV approaches for improved mapping of vegetation cover and estimation of carbon storage of small saltmarshes: examples from Loch Fleet, northeast Scotland
Iron “ore” nothing: benthic iron fluxes from the oxygen-deficient Santa Barbara Basin enhance phytoplankton productivity in surface waters
Marine anoxia initiates giant sulfur-oxidizing bacterial mat proliferation and associated changes in benthic nitrogen, sulfur, and iron cycling in the Santa Barbara Basin, California Borderland
Uncertainty in the evolution of northwestern North Atlantic circulation leads to diverging biogeochemical projections
The additionality problem of ocean alkalinity enhancement
Short-term variation in pH in seawaters around coastal areas of Japan: characteristics and forcings
Revisiting the applicability and constraints of molybdenum- and uranium-based paleo redox proxies: comparing two contrasting sill fjords
Influence of a small submarine canyon on biogenic matter export flux in the lower St. Lawrence Estuary, eastern Canada
Single-celled bioturbators: benthic foraminifera mediate oxygen penetration and prokaryotic diversity in intertidal sediment
Assessing impacts of coastal warming, acidification, and deoxygenation on Pacific oyster (Crassostrea gigas) farming: a case study in the Hinase area, Okayama Prefecture, and Shizugawa Bay, Miyagi Prefecture, Japan
Multiple nitrogen sources for primary production inferred from δ13C and δ15N in the southern Sea of Japan
Influence of manganese cycling on alkalinity in the redox stratified water column of Chesapeake Bay
Estuarine flocculation dynamics of organic carbon and metals from boreal acid sulfate soils
Drivers of particle sinking velocities in the Peruvian upwelling system
Impacts and uncertainties of climate-induced changes in watershed inputs on estuarine hypoxia
Considerations for hypothetical carbon dioxide removal via alkalinity addition in the Amazon River watershed
High metabolism and periodic hypoxia associated with drifting macrophyte detritus in the shallow subtidal Baltic Sea
Production and accumulation of reef framework by calcifying corals and macroalgae on a remote Indian Ocean cay
Zooplankton community succession and trophic links during a mesocosm experiment in the coastal upwelling off Callao Bay (Peru)
Temporal and spatial evolution of bottom-water hypoxia in the St Lawrence estuarine system
Significant nutrient consumption in the dark subsurface layer during a diatom bloom: a case study on Funka Bay, Hokkaido, Japan
Laura Marín-Samper, Javier Arístegui, Nauzet Hernández-Hernández, and Ulf Riebesell
Biogeosciences, 21, 5707–5724, https://doi.org/10.5194/bg-21-5707-2024, https://doi.org/10.5194/bg-21-5707-2024, 2024
Short summary
Short summary
This study exposed a natural community to two non-CO2-equilibrated ocean alkalinity enhancement (OAE) deployments using different minerals. Adding alkalinity in this manner decreases dissolved CO2, essential for photosynthesis. While photosynthesis was not suppressed, bloom formation was mildly delayed, potentially impacting marine food webs. The study emphasizes the need for further research on OAE without prior equilibration and on its ecological implications.
Riss M. Kell, Rebecca J. Chmiel, Deepa Rao, Dawn M. Moran, Matthew R. McIlvin, Tristan J. Horner, Nicole L. Schanke, Ichiko Sugiyama, Robert B. Dunbar, Giacomo R. DiTullio, and Mak A. Saito
Biogeosciences, 21, 5685–5706, https://doi.org/10.5194/bg-21-5685-2024, https://doi.org/10.5194/bg-21-5685-2024, 2024
Short summary
Short summary
Despite interest in modeling the biogeochemical uptake and cycling of the trace metal zinc (Zn), measurements of Zn uptake in natural marine phytoplankton communities have not been conducted previously. To fill this gap, we employed a stable isotope uptake rate measurement method to quantify Zn uptake into natural phytoplankton assemblages within the Southern Ocean. Zn demand was high and rapid enough to depress the inventory of Zn available to phytoplankton on seasonal timescales.
Luisa Chiara Meiritz, Tim Rixen, Anja Karin van der Plas, Tarron Lamont, and Niko Lahajnar
Biogeosciences, 21, 5261–5276, https://doi.org/10.5194/bg-21-5261-2024, https://doi.org/10.5194/bg-21-5261-2024, 2024
Short summary
Short summary
Moored and drifting sediment trap experiments in the northern (nBUS) and southern (sBUS) Benguela Upwelling System showed that active carbon fluxes by vertically migrating zooplankton were about 3 times higher in the sBUS than in the nBUS. Despite these large variabilities, the mean passive particulate organic carbon (POC) fluxes were almost equal in the two subsystems. The more intense near-bottom oxygen minimum layer seems to lead to higher POC fluxes and accumulation rates in the nBUS.
Michael R. Roman, Andrew H. Altieri, Denise Breitburg, Erica M. Ferrer, Natalya D. Gallo, Shin-ichi Ito, Karin Limburg, Kenneth Rose, Moriaki Yasuhara, and Lisa A. Levin
Biogeosciences, 21, 4975–5004, https://doi.org/10.5194/bg-21-4975-2024, https://doi.org/10.5194/bg-21-4975-2024, 2024
Short summary
Short summary
Oxygen-depleted ocean waters have increased worldwide. In order to improve our understanding of the impacts of this oxygen loss on marine life it is essential that we develop reliable indicators that track the negative impacts of low oxygen. We review various indicators of low-oxygen stress for marine animals including their use, research needs, and application to confront the challenges of ocean oxygen loss.
Charlotte Eich, Mathijs van Manen, J. Scott P. McCain, Loay J. Jabre, Willem H. van de Poll, Jinyoung Jung, Sven B. E. H. Pont, Hung-An Tian, Indah Ardiningsih, Gert-Jan Reichart, Erin M. Bertrand, Corina P. D. Brussaard, and Rob Middag
Biogeosciences, 21, 4637–4663, https://doi.org/10.5194/bg-21-4637-2024, https://doi.org/10.5194/bg-21-4637-2024, 2024
Short summary
Short summary
Phytoplankton growth in the Southern Ocean (SO) is often limited by low iron (Fe) concentrations. Sea surface warming impacts Fe availability and can affect phytoplankton growth. We used shipboard Fe clean incubations to test how changes in Fe and temperature affect SO phytoplankton. Their abundances usually increased with Fe addition and temperature increase, with Fe being the major factor. These findings imply potential shifts in ecosystem structure, impacting food webs and elemental cycling.
Miriam Tivig, David P. Keller, and Andreas Oschlies
Biogeosciences, 21, 4469–4493, https://doi.org/10.5194/bg-21-4469-2024, https://doi.org/10.5194/bg-21-4469-2024, 2024
Short summary
Short summary
Marine biological production is highly dependent on the availability of nitrogen and phosphorus. Rivers are the main source of phosphorus to the oceans but poorly represented in global model oceans. We include dissolved nitrogen and phosphorus from river export in a global model ocean and find that the addition of riverine phosphorus affects marine biology on millennial timescales more than riverine nitrogen alone. Globally, riverine phosphorus input increases primary production rates.
Esdoorn Willcox, Marcos Lemes, Thomas Juul-Pedersen, Mikael Kristian Sejr, Johnna Marchiano Holding, and Søren Rysgaard
Biogeosciences, 21, 4037–4050, https://doi.org/10.5194/bg-21-4037-2024, https://doi.org/10.5194/bg-21-4037-2024, 2024
Short summary
Short summary
In this work, we measured the chemistry of seawater from samples obtained from different depths and locations off the east coast of the Northeast Greenland National Park to determine what is influencing concentrations of dissolved CO2. Historically, the region has always been thought to take up CO2 from the atmosphere, but we show that it is possible for the region to become a source in late summer. We discuss the variables that may be related to such changes.
Lennart Thomas Bach, Aaron James Ferderer, Julie LaRoche, and Kai Georg Schulz
Biogeosciences, 21, 3665–3676, https://doi.org/10.5194/bg-21-3665-2024, https://doi.org/10.5194/bg-21-3665-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is an emerging marine CO2 removal method, but its environmental effects are insufficiently understood. The OAE Pelagic Impact Intercomparison Project (OAEPIIP) provides funding for a standardized and globally replicated microcosm experiment to study the effects of OAE on plankton communities. Here, we provide a detailed manual for the OAEPIIP experiment. We expect OAEPIIP to help build scientific consensus on the effects of OAE on plankton.
Marlena Szeligowska, Déborah Benkort, Anna Przyborska, Mateusz Moskalik, Bernabé Moreno, Emilia Trudnowska, and Katarzyna Błachowiak-Samołyk
Biogeosciences, 21, 3617–3639, https://doi.org/10.5194/bg-21-3617-2024, https://doi.org/10.5194/bg-21-3617-2024, 2024
Short summary
Short summary
The European Arctic is experiencing rapid regional warming, causing glaciers that terminate in the sea to retreat onto land. Due to this process, the area of a well-studied fjord, Hornsund, has increased by around 100 km2 (40%) since 1976. Combining satellite and in situ data with a mathematical model, we estimated that, despite some negative consequences of glacial meltwater release, such emerging coastal waters could mitigate climate change by increasing carbon uptake and storage by sediments.
Mallory C. Ringham, Nathan Hirtle, Cody Shaw, Xi Lu, Julian Herndon, Brendan R. Carter, and Matthew D. Eisaman
Biogeosciences, 21, 3551–3570, https://doi.org/10.5194/bg-21-3551-2024, https://doi.org/10.5194/bg-21-3551-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement leverages the large surface area and carbon storage capacity of the oceans to store atmospheric CO2 as dissolved bicarbonate. We monitored CO2 uptake in seawater treated with NaOH to establish operational boundaries for carbon removal experiments. Results show that CO2 equilibration occurred on the order of weeks to months, was consistent with values expected from equilibration calculations, and was limited by mineral precipitation at high pH and CaCO3 saturation.
Riel Carlo O. Ingeniero, Gesa Schulz, and Hermann W. Bange
Biogeosciences, 21, 3425–3440, https://doi.org/10.5194/bg-21-3425-2024, https://doi.org/10.5194/bg-21-3425-2024, 2024
Short summary
Short summary
Our research is the first to measure dissolved NO concentrations in temperate estuarine waters, providing insights into its distribution under varying conditions and enhancing our understanding of its production processes. Dissolved NO was supersaturated in the Elbe Estuary, indicating that it is a source of atmospheric NO. The observed distribution of dissolved NO most likely resulted from nitrification.
Weiyi Tang, Jeff Talbott, Timothy Jones, and Bess B. Ward
Biogeosciences, 21, 3239–3250, https://doi.org/10.5194/bg-21-3239-2024, https://doi.org/10.5194/bg-21-3239-2024, 2024
Short summary
Short summary
Wastewater treatment plants (WWTPs) are known to be hotspots of greenhouse gas emissions. However, the impact of WWTPs on the emission of the greenhouse gas N2O in downstream aquatic environments is less constrained. We found spatially and temporally variable but overall higher N2O concentrations and fluxes in waters downstream of WWTPs, pointing to the need for efficient N2O removal in addition to the treatment of nitrogen in WWTPs.
Yong-Woo Lee, Mi-Ok Park, Seong-Gil Kim, Tae-Hoon Kim, Yong-Hwa Oh, Sang Heun Lee, and Dong Joo Joung
EGUsphere, https://doi.org/10.5194/egusphere-2024-1836, https://doi.org/10.5194/egusphere-2024-1836, 2024
Short summary
Short summary
A long-term pH variation in coastal waters along the Korean peninsula was assessed for the first time, and it exhibited no significant pH change over an 11-year period. This contrasts with the ongoing pH decline in open oceans and other coastal areas. Analysis of environmental data showed that pH is mainly controlled by dissolved oxygen in bottom waters. This suggests that ocean warming could cause a pH decline in Korean coastal waters, affecting many fish and seaweeds aquaculture operations.
Aaron Ferderer, Kai G. Schulz, Ulf Riebesell, Kirralee G. Baker, Zanna Chase, and Lennart T. Bach
Biogeosciences, 21, 2777–2794, https://doi.org/10.5194/bg-21-2777-2024, https://doi.org/10.5194/bg-21-2777-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal; however, its ecological impacts remain largely unknown. We assessed the effects of simulated silicate- and calcium-based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate-based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.
David González-Santana, María Segovia, Melchor González-Dávila, Librada Ramírez, Aridane G. González, Leonardo J. Pozzo-Pirotta, Veronica Arnone, Victor Vázquez, Ulf Riebesell, and J. Magdalena Santana-Casiano
Biogeosciences, 21, 2705–2715, https://doi.org/10.5194/bg-21-2705-2024, https://doi.org/10.5194/bg-21-2705-2024, 2024
Short summary
Short summary
In a recent experiment off the coast of Gran Canaria (Spain), scientists explored a method called ocean alkalinization enhancement (OAE), where carbonate minerals were added to seawater. This process changed the levels of certain ions in the water, affecting its pH and buffering capacity. The researchers were particularly interested in how this could impact the levels of essential trace metals in the water.
Lucas Porz, Wenyan Zhang, Nils Christiansen, Jan Kossack, Ute Daewel, and Corinna Schrum
Biogeosciences, 21, 2547–2570, https://doi.org/10.5194/bg-21-2547-2024, https://doi.org/10.5194/bg-21-2547-2024, 2024
Short summary
Short summary
Seafloor sediments store a large amount of carbon, helping to naturally regulate Earth's climate. If disturbed, some sediment particles can turn into CO2, but this effect is not well understood. Using computer simulations, we found that bottom-contacting fishing gears release about 1 million tons of CO2 per year in the North Sea, one of the most heavily fished regions globally. We show how protecting certain areas could reduce these emissions while also benefitting seafloor-living animals.
Jiaying A. Guo, Robert F. Strzepek, Kerrie M. Swadling, Ashley T. Townsend, and Lennart T. Bach
Biogeosciences, 21, 2335–2354, https://doi.org/10.5194/bg-21-2335-2024, https://doi.org/10.5194/bg-21-2335-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement aims to increase atmospheric CO2 sequestration by adding alkaline materials to the ocean. We assessed the environmental effects of olivine and steel slag powder on coastal plankton. Overall, slag is more efficient than olivine in releasing total alkalinity and, thus, in its ability to sequester CO2. Slag also had less environmental effect on the enclosed plankton communities when considering its higher CO2 removal potential based on this 3-week experiment.
Giovanni Galli, Sarah Wakelin, James Harle, Jason Holt, and Yuri Artioli
Biogeosciences, 21, 2143–2158, https://doi.org/10.5194/bg-21-2143-2024, https://doi.org/10.5194/bg-21-2143-2024, 2024
Short summary
Short summary
This work shows that, under a high-emission scenario, oxygen concentration in deep water of parts of the North Sea and Celtic Sea can become critically low (hypoxia) towards the end of this century. The extent and frequency of hypoxia depends on the intensity of climate change projected by different climate models. This is the result of a complex combination of factors like warming, increase in stratification, changes in the currents and changes in biological processes.
Sandy E. Tenorio and Laura Farías
Biogeosciences, 21, 2029–2050, https://doi.org/10.5194/bg-21-2029-2024, https://doi.org/10.5194/bg-21-2029-2024, 2024
Short summary
Short summary
Time series studies show that CH4 is highly dynamic on the coastal ocean surface and planktonic communities are linked to CH4 accumulation, as found in coastal upwelling off Chile. We have identified the crucial role of picoplankton (> 3 µm) in CH4 recycling, especially with the addition of methylated substrates (trimethylamine and methylphosphonic acid) during upwelling and non-upwelling periods. These insights improve understanding of surface ocean CH4 recycling, aiding CH4 emission estimates.
Charlotte A. J. Williams, Tom Hull, Jan Kaiser, Claire Mahaffey, Naomi Greenwood, Matthew Toberman, and Matthew R. Palmer
Biogeosciences, 21, 1961–1971, https://doi.org/10.5194/bg-21-1961-2024, https://doi.org/10.5194/bg-21-1961-2024, 2024
Short summary
Short summary
Oxygen (O2) is a key indicator of ocean health. The risk of O2 loss in the productive coastal/continental slope regions is increasing. Autonomous underwater vehicles equipped with O2 optodes provide lots of data but have problems resolving strong vertical O2 changes. Here we show how to overcome this and calculate how much O2 is supplied to the low-O2 bottom waters via mixing. Bursts in mixing supply nearly all of the O2 to bottom waters in autumn, stopping them reaching ecologically low levels.
Sabine Schmidt and Ibrahima Iris Diallo
Biogeosciences, 21, 1785–1800, https://doi.org/10.5194/bg-21-1785-2024, https://doi.org/10.5194/bg-21-1785-2024, 2024
Short summary
Short summary
Along the French coast facing the Bay of Biscay, the large Gironde and Loire estuaries suffer from hypoxia. This prompted a study of the small Charente estuary located between them. This work reveals a minimum oxygen zone in the Charente estuary, which extends for about 25 km. Temperature is the main factor controlling the hypoxia. This calls for the monitoring of small turbid macrotidal estuaries that are vulnerable to hypoxia, a risk expected to increase with global warming.
Jessica L. Oberlander, Mackenzie E. Burke, Cat A. London, and Hugh L. MacIntyre
EGUsphere, https://doi.org/10.5194/egusphere-2024-971, https://doi.org/10.5194/egusphere-2024-971, 2024
Short summary
Short summary
OAE is a promising negative emission technology that could restore the oceanic pH and carbonate system to a pre-industrial state. To our knowledge, this paper is the first to assess the potential impact of OAE on phytoplankton through an analysis of prior studies and the effects of simulated OAE on photosynthetic competence. Our findings suggest that there may be little if any significant impact on most phytoplankton studied to date if OAE is conducted in well-flushed, near-shore environments.
Simone R. Alin, Jan A. Newton, Richard A. Feely, Samantha Siedlecki, and Dana Greeley
Biogeosciences, 21, 1639–1673, https://doi.org/10.5194/bg-21-1639-2024, https://doi.org/10.5194/bg-21-1639-2024, 2024
Short summary
Short summary
We provide a new multi-stressor data product that allows us to characterize the seasonality of temperature, O2, and CO2 in the southern Salish Sea and delivers insights into the impacts of major marine heatwave and precipitation anomalies on regional ocean acidification and hypoxia. We also describe the present-day frequencies of temperature, O2, and ocean acidification conditions that cross thresholds of sensitive regional species that are economically or ecologically important.
Kadir Bice, Tristen Myers, George Waldbusser, and Christof Meile
EGUsphere, https://doi.org/10.5194/egusphere-2024-796, https://doi.org/10.5194/egusphere-2024-796, 2024
Short summary
Short summary
We studied the effect of addition of carbonate minerals on coastal sediments, We carried out laboratory experiments to quantify the dissolution kinetics and integrated these observations into a numerical model that describes biogeochemical cycling in surficial sediments. Using the model, we demonstrate the buffering effect of the mineral additions and its duration. We quantify the effect under different environmental conditions and assess the potential for increased atmospheric CO2 uptake.
Pamela Linford, Iván Pérez-Santos, Paulina Montero, Patricio A. Díaz, Claudia Aracena, Elías Pinilla, Facundo Barrera, Manuel Castillo, Aida Alvera-Azcárate, Mónica Alvarado, Gabriel Soto, Cécile Pujol, Camila Schwerter, Sara Arenas-Uribe, Pilar Navarro, Guido Mancilla-Gutiérrez, Robinson Altamirano, Javiera San Martín, and Camila Soto-Riquelme
Biogeosciences, 21, 1433–1459, https://doi.org/10.5194/bg-21-1433-2024, https://doi.org/10.5194/bg-21-1433-2024, 2024
Short summary
Short summary
The Patagonian fjords comprise a world region where low-oxygen water and hypoxia conditions are observed. An in situ dataset was used to quantify the mechanism involved in the presence of these conditions in northern Patagonian fjords. Water mass analysis confirmed the contribution of Equatorial Subsurface Water in the advection of the low-oxygen water, and hypoxic conditions occurred when the community respiration rate exceeded the gross primary production.
Ting Wang, Buyun Du, Inke Forbrich, Jun Zhou, Joshua Polen, Elsie M. Sunderland, Prentiss H. Balcom, Celia Chen, and Daniel Obrist
Biogeosciences, 21, 1461–1476, https://doi.org/10.5194/bg-21-1461-2024, https://doi.org/10.5194/bg-21-1461-2024, 2024
Short summary
Short summary
The strong seasonal increases of Hg in aboveground biomass during the growing season and the lack of changes observed after senescence in this salt marsh ecosystem suggest physiologically controlled Hg uptake pathways. The Hg sources found in marsh aboveground tissues originate from a mix of sources, unlike terrestrial ecosystems, where atmospheric GEM is the main source. Belowground plant tissues mostly take up Hg from soils. Overall, the salt marsh currently serves as a small net Hg sink.
Eleanor Simpson, Debby Ianson, Karen E. Kohfeld, Ana C. Franco, Paul A. Covert, Marty Davelaar, and Yves Perreault
Biogeosciences, 21, 1323–1353, https://doi.org/10.5194/bg-21-1323-2024, https://doi.org/10.5194/bg-21-1323-2024, 2024
Short summary
Short summary
Shellfish aquaculture operates in nearshore areas where data on ocean acidification parameters are limited. We show daily and seasonal variability in pH and saturation states of calcium carbonate at nearshore aquaculture sites in British Columbia, Canada, and determine the contributing drivers of this variability. We find that nearshore locations have greater variability than open waters and that the uptake of carbon by phytoplankton is the major driver of pH and saturation state variability.
S. Alejandra Castillo Cieza, Rachel H. R. Stanley, Pierre Marrec, Diana N. Fontaine, E. Taylor Crockford, Dennis J. McGillicuddy Jr., Arshia Mehta, Susanne Menden-Deuer, Emily E. Peacock, Tatiana A. Rynearson, Zoe O. Sandwith, Weifeng Zhang, and Heidi M. Sosik
Biogeosciences, 21, 1235–1257, https://doi.org/10.5194/bg-21-1235-2024, https://doi.org/10.5194/bg-21-1235-2024, 2024
Short summary
Short summary
The coastal ocean in the northeastern USA provides many services, including fisheries and habitats for threatened species. In summer 2019, a bloom occurred of a large unusual phytoplankton, the diatom Hemiaulus, with nitrogen-fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes may become more prevalent as the ocean warms due to climate change.
Claudine Hauri, Brita Irving, Sam Dupont, Rémi Pagés, Donna D. W. Hauser, and Seth L. Danielson
Biogeosciences, 21, 1135–1159, https://doi.org/10.5194/bg-21-1135-2024, https://doi.org/10.5194/bg-21-1135-2024, 2024
Short summary
Short summary
Arctic marine ecosystems are highly susceptible to impacts of climate change and ocean acidification. We present pH and pCO2 time series (2016–2020) from the Chukchi Ecosystem Observatory and analyze the drivers of the current conditions to get a better understanding of how climate change and ocean acidification could affect the ecological niches of organisms.
William Hiles, Lucy C. Miller, Craig Smeaton, and William E. N. Austin
Biogeosciences, 21, 929–948, https://doi.org/10.5194/bg-21-929-2024, https://doi.org/10.5194/bg-21-929-2024, 2024
Short summary
Short summary
Saltmarsh soils may help to limit the rate of climate change by storing carbon. To understand their impacts, they must be accurately mapped. We use drone data to estimate the size of three saltmarshes in NE Scotland. We find that drone imagery, combined with tidal data, can reliably inform our understanding of saltmarsh size. When compared with previous work using vegetation communities, we find that our most reliable new estimates of stored carbon are 15–20 % smaller than previously estimated.
De'Marcus Robinson, Anh L. D. Pham, David J. Yousavich, Felix Janssen, Frank Wenzhöfer, Eleanor C. Arrington, Kelsey M. Gosselin, Marco Sandoval-Belmar, Matthew Mar, David L. Valentine, Daniele Bianchi, and Tina Treude
Biogeosciences, 21, 773–788, https://doi.org/10.5194/bg-21-773-2024, https://doi.org/10.5194/bg-21-773-2024, 2024
Short summary
Short summary
The present study suggests that high release of ferrous iron from the seafloor of the oxygen-deficient Santa Barabara Basin (California) supports surface primary productivity, creating positive feedback on seafloor iron release by enhancing low-oxygen conditions in the basin.
David J. Yousavich, De'Marcus Robinson, Xuefeng Peng, Sebastian J. E. Krause, Frank Wenzhöfer, Felix Janssen, Na Liu, Jonathan Tarn, Franklin Kinnaman, David L. Valentine, and Tina Treude
Biogeosciences, 21, 789–809, https://doi.org/10.5194/bg-21-789-2024, https://doi.org/10.5194/bg-21-789-2024, 2024
Short summary
Short summary
Declining oxygen (O2) concentrations in coastal oceans can threaten people’s ways of life and food supplies. Here, we investigate how mats of bacteria that proliferate on the seafloor of the Santa Barbara Basin sustain and potentially worsen these O2 depletion events through their unique chemoautotrophic metabolism. Our study shows how changes in seafloor microbiology and geochemistry brought on by declining O2 concentrations can help these mats grow as well as how that growth affects the basin.
Krysten Rutherford, Katja Fennel, Lina Garcia Suarez, and Jasmin G. John
Biogeosciences, 21, 301–314, https://doi.org/10.5194/bg-21-301-2024, https://doi.org/10.5194/bg-21-301-2024, 2024
Short summary
Short summary
We downscaled two mid-century (~2075) ocean model projections to a high-resolution regional ocean model of the northwest North Atlantic (NA) shelf. In one projection, the NA shelf break current practically disappears; in the other it remains almost unchanged. This leads to a wide range of possible future shelf properties. More accurate projections of coastal circulation features would narrow the range of possible outcomes of biogeochemical projections for shelf regions.
Lennart Thomas Bach
Biogeosciences, 21, 261–277, https://doi.org/10.5194/bg-21-261-2024, https://doi.org/10.5194/bg-21-261-2024, 2024
Short summary
Short summary
Ocean alkalinity enhancement (OAE) is a widely considered marine carbon dioxide removal method. OAE aims to accelerate chemical rock weathering, which is a natural process that slowly sequesters atmospheric carbon dioxide. This study shows that the addition of anthropogenic alkalinity via OAE can reduce the natural release of alkalinity and, therefore, reduce the efficiency of OAE for climate mitigation. However, the additionality problem could be mitigated via a variety of activities.
Tsuneo Ono, Daisuke Muraoka, Masahiro Hayashi, Makiko Yorifuji, Akihiro Dazai, Shigeyuki Omoto, Takehiro Tanaka, Tomohiro Okamura, Goh Onitsuka, Kenji Sudo, Masahiko Fujii, Ryuji Hamanoue, and Masahide Wakita
Biogeosciences, 21, 177–199, https://doi.org/10.5194/bg-21-177-2024, https://doi.org/10.5194/bg-21-177-2024, 2024
Short summary
Short summary
We carried out parallel year-round observations of pH and related parameters in five stations around the Japan coast. It was found that short-term acidified situations with Omega_ar less than 1.5 occurred at four of five stations. Most of such short-term acidified events were related to the short-term low salinity event, and the extent of short-term pH drawdown at high freshwater input was positively correlated with the nutrient concentration of the main rivers that flow into the coastal area.
K. Mareike Paul, Martijn Hermans, Sami A. Jokinen, Inda Brinkmann, Helena L. Filipsson, and Tom Jilbert
Biogeosciences, 20, 5003–5028, https://doi.org/10.5194/bg-20-5003-2023, https://doi.org/10.5194/bg-20-5003-2023, 2023
Short summary
Short summary
Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.
Hannah Sharpe, Michel Gosselin, Catherine Lalande, Alexandre Normandeau, Jean-Carlos Montero-Serrano, Khouloud Baccara, Daniel Bourgault, Owen Sherwood, and Audrey Limoges
Biogeosciences, 20, 4981–5001, https://doi.org/10.5194/bg-20-4981-2023, https://doi.org/10.5194/bg-20-4981-2023, 2023
Short summary
Short summary
We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.
Dewi Langlet, Florian Mermillod-Blondin, Noémie Deldicq, Arthur Bauville, Gwendoline Duong, Lara Konecny, Mylène Hugoni, Lionel Denis, and Vincent M. P. Bouchet
Biogeosciences, 20, 4875–4891, https://doi.org/10.5194/bg-20-4875-2023, https://doi.org/10.5194/bg-20-4875-2023, 2023
Short summary
Short summary
Benthic foraminifera are single-cell marine organisms which can move in the sediment column. They were previously reported to horizontally and vertically transport sediment particles, yet the impact of their motion on the dissolved fluxes remains unknown. Using microprofiling, we show here that foraminiferal burrow formation increases the oxygen penetration depth in the sediment, leading to a change in the structure of the prokaryotic community.
Masahiko Fujii, Ryuji Hamanoue, Lawrence Patrick Cases Bernardo, Tsuneo Ono, Akihiro Dazai, Shigeyuki Oomoto, Masahide Wakita, and Takehiro Tanaka
Biogeosciences, 20, 4527–4549, https://doi.org/10.5194/bg-20-4527-2023, https://doi.org/10.5194/bg-20-4527-2023, 2023
Short summary
Short summary
This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae as a result of longer exposure to lower-pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.
Taketoshi Kodama, Atsushi Nishimoto, Ken-ichi Nakamura, Misato Nakae, Naoki Iguchi, Yosuke Igeta, and Yoichi Kogure
Biogeosciences, 20, 3667–3682, https://doi.org/10.5194/bg-20-3667-2023, https://doi.org/10.5194/bg-20-3667-2023, 2023
Short summary
Short summary
Carbon and nitrogen are essential elements for organisms; their stable isotope ratios (13C : 12C, 15N : 14N) are useful tools for understanding turnover and movement in the ocean. In the Sea of Japan, the environment is rapidly being altered by human activities. The 13C : 12C of small organic particles is increased by active carbon fixation, and phytoplankton growth increases the values. The 15N : 14N variations suggest that nitrates from many sources contribute to organic production.
Aubin Thibault de Chanvalon, George W. Luther, Emily R. Estes, Jennifer Necker, Bradley M. Tebo, Jianzhong Su, and Wei-Jun Cai
Biogeosciences, 20, 3053–3071, https://doi.org/10.5194/bg-20-3053-2023, https://doi.org/10.5194/bg-20-3053-2023, 2023
Short summary
Short summary
The intensity of the oceanic trap of CO2 released by anthropogenic activities depends on the alkalinity brought by continental weathering. Between ocean and continent, coastal water and estuaries can limit or favour the alkalinity transfer. This study investigate new interactions between dissolved metals and alkalinity in the oxygen-depleted zone of estuaries.
Joonas J. Virtasalo, Peter Österholm, and Eero Asmala
Biogeosciences, 20, 2883–2901, https://doi.org/10.5194/bg-20-2883-2023, https://doi.org/10.5194/bg-20-2883-2023, 2023
Short summary
Short summary
We mixed acidic metal-rich river water from acid sulfate soils and seawater in the laboratory to study the flocculation of dissolved metals and organic matter in estuaries. Al and Fe flocculated already at a salinity of 0–2 to large organic flocs (>80 µm size). Precipitation of Al and Fe hydroxide flocculi (median size 11 µm) began when pH exceeded ca. 5.5. Mn transferred weakly to Mn hydroxides and Co to the flocs. Up to 50 % of Cu was associated with the flocs, irrespective of seawater mixing.
Moritz Baumann, Allanah Joy Paul, Jan Taucher, Lennart Thomas Bach, Silvan Goldenberg, Paul Stange, Fabrizio Minutolo, and Ulf Riebesell
Biogeosciences, 20, 2595–2612, https://doi.org/10.5194/bg-20-2595-2023, https://doi.org/10.5194/bg-20-2595-2023, 2023
Short summary
Short summary
The sinking velocity of marine particles affects how much atmospheric CO2 is stored inside our oceans. We measured particle sinking velocities in the Peruvian upwelling system and assessed their physical and biochemical drivers. We found that sinking velocity was mainly influenced by particle size and porosity, while ballasting minerals played only a minor role. Our findings help us to better understand the particle sinking dynamics in this highly productive marine system.
Kyle E. Hinson, Marjorie A. M. Friedrichs, Raymond G. Najjar, Maria Herrmann, Zihao Bian, Gopal Bhatt, Pierre St-Laurent, Hanqin Tian, and Gary Shenk
Biogeosciences, 20, 1937–1961, https://doi.org/10.5194/bg-20-1937-2023, https://doi.org/10.5194/bg-20-1937-2023, 2023
Short summary
Short summary
Climate impacts are essential for environmental managers to consider when implementing nutrient reduction plans designed to reduce hypoxia. This work highlights relative sources of uncertainty in modeling regional climate impacts on the Chesapeake Bay watershed and consequent declines in bay oxygen levels. The results demonstrate that planned water quality improvement goals are capable of reducing hypoxia levels by half, offsetting climate-driven impacts on terrestrial runoff.
Linquan Mu, Jaime B. Palter, and Hongjie Wang
Biogeosciences, 20, 1963–1977, https://doi.org/10.5194/bg-20-1963-2023, https://doi.org/10.5194/bg-20-1963-2023, 2023
Short summary
Short summary
Enhancing ocean alkalinity accelerates carbon dioxide removal from the atmosphere. We hypothetically added alkalinity to the Amazon River and examined the increment of the carbon uptake by the Amazon plume. We also investigated the minimum alkalinity addition in which this perturbation at the river mouth could be detected above the natural variability.
Karl M. Attard, Anna Lyssenko, and Iván F. Rodil
Biogeosciences, 20, 1713–1724, https://doi.org/10.5194/bg-20-1713-2023, https://doi.org/10.5194/bg-20-1713-2023, 2023
Short summary
Short summary
Aquatic plants produce a large amount of organic matter through photosynthesis that, following erosion, is deposited on the seafloor. In this study, we show that plant detritus can trigger low-oxygen conditions (hypoxia) in shallow coastal waters, making conditions challenging for most marine animals. We propose that the occurrence of hypoxia may be underestimated because measurements typically do not consider the region closest to the seafloor, where detritus accumulates.
M. James McLaughlin, Cindy Bessey, Gary A. Kendrick, John Keesing, and Ylva S. Olsen
Biogeosciences, 20, 1011–1026, https://doi.org/10.5194/bg-20-1011-2023, https://doi.org/10.5194/bg-20-1011-2023, 2023
Short summary
Short summary
Coral reefs face increasing pressures from environmental change at present. The coral reef framework is produced by corals and calcifying algae. The Kimberley region of Western Australia has escaped land-based anthropogenic impacts. Specimens of the dominant coral and algae were collected from Browse Island's reef platform and incubated in mesocosms to measure calcification and production patterns of oxygen. This study provides important data on reef building and climate-driven effects.
Patricia Ayón Dejo, Elda Luz Pinedo Arteaga, Anna Schukat, Jan Taucher, Rainer Kiko, Helena Hauss, Sabrina Dorschner, Wilhelm Hagen, Mariona Segura-Noguera, and Silke Lischka
Biogeosciences, 20, 945–969, https://doi.org/10.5194/bg-20-945-2023, https://doi.org/10.5194/bg-20-945-2023, 2023
Short summary
Short summary
Ocean upwelling regions are highly productive. With ocean warming, severe changes in upwelling frequency and/or intensity and expansion of accompanying oxygen minimum zones are projected. In a field experiment off Peru, we investigated how different upwelling intensities affect the pelagic food web and found failed reproduction of dominant zooplankton. The changes projected could severely impact the reproductive success of zooplankton communities and the pelagic food web in upwelling regions.
Mathilde Jutras, Alfonso Mucci, Gwenaëlle Chaillou, William A. Nesbitt, and Douglas W. R. Wallace
Biogeosciences, 20, 839–849, https://doi.org/10.5194/bg-20-839-2023, https://doi.org/10.5194/bg-20-839-2023, 2023
Short summary
Short summary
The deep waters of the lower St Lawrence Estuary and gulf have, in the last decades, experienced a strong decline in their oxygen concentration. Below 65 µmol L-1, the waters are said to be hypoxic, with dire consequences for marine life. We show that the extent of the hypoxic zone shows a seven-fold increase in the last 20 years, reaching 9400 km2 in 2021. After a stable period at ~ 65 µmol L⁻¹ from 1984 to 2019, the oxygen level also suddenly decreased to ~ 35 µmol L-1 in 2020.
Sachi Umezawa, Manami Tozawa, Yuichi Nosaka, Daiki Nomura, Hiroji Onishi, Hiroto Abe, Tetsuya Takatsu, and Atsushi Ooki
Biogeosciences, 20, 421–438, https://doi.org/10.5194/bg-20-421-2023, https://doi.org/10.5194/bg-20-421-2023, 2023
Short summary
Short summary
We conducted repetitive observations in Funka Bay, Japan, during the spring bloom 2019. We found nutrient concentration decreases in the dark subsurface layer during the bloom. Incubation experiments confirmed that diatoms could consume nutrients at a substantial rate, even in darkness. We concluded that the nutrient reduction was mainly caused by nutrient consumption by diatoms in the dark.
Cited articles
Alkhatib, M., Jennerjahn, T. C., and Samiaji, J.: Biogeochemistry of the Dumai River estuary, Sumatra, Indonesia, a tropical black-water river, Limnol. Oceanogr., 52, 2410–2417, https://doi.org/10.4319/lo.2007.52.6.2410, 2007.
Altieri, A. H., Harrison, S. B., Seemann, J., Collin, R., Diaz, R. J., and Knowlton, N.: Tropical dead zones and mass mortalities on coral reefs, P. Natl. Acad. Sci. USA, 114, 3660–3665, https://doi.org/10.1073/pnas.1621517114, 2017.
Asmala, E., Kaartokallio, H., Carstensen, J., and Thomas, D. N.: Variation in Riverine Inputs Affect Dissolved Organic Matter Characteristics throughout the Estuarine Gradient, Front. Mar. Sci., 2, 125, https://doi.org/10.3389/fmars.2015.00125, 2016.
Ballagh, F. E. A., Rabouille, C., Andrieux-Loyer, F., Soetaert, K., Elkalay, K., and Khalil, K.: Spatio-temporal dynamics of sedimentary phosphorus along two temperate eutrophic estuaries: A data-modelling approach, Cont. Shelf Res., 193, 104037, https://doi.org/10.1016/j.csr.2019.104037, 2020.
Baum, A., Rixen, T., and Samiaji, J.: Relevance of peat draining rivers in central Sumatra for the riverine input of dissolved organic carbon into the ocean, Estuar. Coast. Shelf S., 73, 563–570, https://doi.org/10.1016/j.ecss.2007.02.012, 2007.
Battin, T. J.: Dissolved organic matter and its optical properties in a blackwater tributary of the upper Orinoco River, Venezuela, Org. Geochem., 28, 561–569, 1998.
Bernard, R. J., Mortazavi, B., and Kleinhuizen, A. A.: Dissimilatory nitrate reduction to ammonium (DNRA) seasonally dominates NO
Beusen, A. H. W., Bouwman, A. F., Van Beek, L. P. H., Mogollón, J. M., and Middelburg, J. J.: Global riverine N and P transport to ocean increased during the 20th century despite increased retention along the aquatic continuum, Biogeosciences, 13, 2441–2451, https://doi.org/10.5194/bg-13-2441-2016, 2016.
Bianchi, T. S. and Morrison, E. S.: Estuarine Chemistry, in: Estuarine Ecology, edited by: Crump, B. C., Testa, J. M., and Dunton, K. H., 3rd Edn., John Wiley & Sons, Hoboken, NJ, 36–77, 2023.
Burford, M. A., Webster, I. T., Revill, A. T., Kenyon, R. A., Whittle, M., and Curwen, G.: Controls on phytoplankton productivity in a wet–dry tropical estuary, Estuar. Coast. Shelf S., 113, 141–151, https://doi.org/10.1016/j.ecss.2012.07.017, 2012.
Cai, P., Shi, X., Hong, Q., Li, Q., Liu, L., Guo, X., and Dai, M.: Using
Carr, N., Davis, C. E., Blackbird, S., Daniels, L. R., Preece, C., Woodward, M., and Mahaffey, C.: Seasonal and spatial variability in the optical characteristics of DOM in a temperate shelf sea, Prog. Oceanogr., 177, 101929, https://doi.org/10.1016/j.pocean.2018.02.025, 2019.
Chai, X., Li, X., Hii, K. S., Zhang, Q., Deng, Q., Wan, L., Zheng, L., Lim, P. T., Tan, S. N., Mohd-Din, M., Song, C., Song, L., Zhou, Y., and Cao, X.: Blooms of diatom and dinoflagellate associated with nutrient imbalance driven by cycling of nitrogen and phosphorus in anaerobic sediments in Johor Strait (Malaysia), Mar. Environ. Res., 169, 105398, https://doi.org/10.1016/j.marenvres.2021.105398, 2021.
Chen, B., Liu, H., Landry, M., Chen, M., Sun, J., Shek, L., Chen, X., and Harrison, P.: Estuarine nutrient loading affects phytoplankton growth and microzooplankton grazing at two contrasting sites in Hong Kong coastal waters, Mar. Ecol.-Prog. Ser., 379, 77–90, https://doi.org/10.3354/meps07888, 2009.
Chénard, C., Wijaya, W., Vaulot, D., Lopes Dos Santos, A., Martin, P., Kaur, A., and Lauro, F. M.: Temporal and spatial dynamics of Bacteria, Archaea and protists in equatorial coastal waters, Sci. Rep., 9, 16390, https://doi.org/10.1038/s41598-019-52648-x, 2019.
Clark, J. B. and Mannino, A.: Preferential loss of Yukon River delta colored dissolved organic matter under nutrient replete conditions, Limnol. Oceanogr., 66, 1613–1626, https://doi.org/10.1002/lno.11706, 2021.
Clark, J. M., Lane, S. N., Chapman, P. J., and Adamson, J. K.: Export of dissolved organic carbon from an upland peatland during storm events: Implications for flux estimates, J. Hydrol., 347, 438–447, https://doi.org/10.1016/j.jhydrol.2007.09.030, 2007.
Coble, P. G.: Marine Optical Biogeochemistry: The Chemistry of Ocean Color, Chem. Rev., 107, 402–418, https://doi.org/10.1021/cr050350+, 2007.
Dai, M., Yin, Z., Meng, F., Liu, Q., and Cai, W.-J.: Spatial distribution of riverine DOC inputs to the ocean: an updated global synthesis, Curr. Opin. Env. Sust., 4, 170–178, https://doi.org/10.1016/j.cosust.2012.03.003, 2012.
Damar, A., Colijn, F., Hesse, K.-J., Adrianto, L., Yonvitner, Fahrudin, A., Kurniawan, F., Prismayanti, A. D., Rahayu, S. M., Rudianto, B. Y., and Ramli, A.: Phytoplankton biomass dynamics in tropical coastal waters of Jakarta Bay, Indonesia in the period between 2001 and 2019, J. Mar. Sci. Eng., 8, 674, https://doi.org/10.3390/jmse8090674, 2020.
Davidson, K., Gowen, R. J., Harrison, P. J., Fleming, L. E., Hoagland, P., and Moschonas, G.: Anthropogenic nutrients and harmful algae in coastal waters, J. Environ. Manage., 146, 206–216, https://doi.org/10.1016/j.jenvman.2014.07.002, 2014.
Dittmar, T., Hertkorn, N., Kattner, G., and Lara, R. J.: Mangroves, a major source of dissolved organic carbon to the oceans, Global Biogeochem. Cy., 20, GB1012, https://doi.org/10.1029/2005GB002570, 2006.
Dong, L. F., Sobey, M. N., Smith, C. J., Rusmana, I., Phillips, W., Stott, A., Osborn, A. M., and Nedwell, D. B.: Dissimilatory reduction of nitrate to ammonium, not denitrification or anammox, dominates benthic nitrate reduction in tropical estuaries, Limnol. Oceanogr., 56, 279–291, https://doi.org/10.4319/lo.2011.56.1.0279, 2011.
Drake, T. W., Barthel, M., Mbongo, C. E., Mpambi, D. M., Baumgartner, S., Botefa, C. I., Bauters, M., Kurek, M. R., Spencer, R. G. M., McKenna, A.M., Haghipour, N., Ekamba, G. L., Wabakanghanzi, J. N., Eglinton, T. I., Oost, K. V., and Six, J.: Hydrology drives export and composition of carbon in a pristine tropical river, Limnol. Oceanogr., 68, 2476–2491, https://doi.org/10.1002/lno.12436, 2023.
Eyre, B. and Balls, P.: A Comparative Study of Nutrient Behavior along the Salinity Gradient of Tropical and Temperate Estuaries, Estuaries, 22, 313–326, https://doi.org/10.2307/1352987, 1999.
Fichot, C. G. and Benner, R.: A novel method to estimate DOC concentrations from CDOM absorption coefficients in coastal waters, Geophys. Res. Lett., 38, L03610, https://doi.org/10.1029/2010GL046152, 2011.
Gin, K. Y.-H., Lin, X., and Zhang, S.: Dynamics and size structure of phytoplankton in the coastal waters of Singapore, J. Plankton Res., 22, 1465–1484, https://doi.org/10.1093/plankt/22.8.1465, 2000.
Green, S. A. and Blough, N. V.: Optical absorption and fluorescence properties of chromophoric dissolved organic matter in natural waters, Limnol. Oceanogr., 39, 1903–1916, https://doi.org/10.4319/lo.1994.39.8.1903, 1994.
Han, H., Hwang, J., and Kim, G.: Characterizing the origins of dissolved organic carbon in coastal seawater using stable carbon isotope and light absorption characteristics, Biogeosciences, 18, 1793–1801, https://doi.org/10.5194/bg-18-1793-2021, 2021.
Hansen, A. M., Kraus, T. E. C., Pellerin, B. A., Fleck, J. A., Downing, B. D., and Bergamaschi, B. A.: Optical properties of dissolved organic matter (DOM): Effects of biological and photolytic degradation, Limnol. Oceanogr., 61, 1015–1032, https://doi.org/10.1002/lno.10270, 2016.
Hansen, M. C., Potapov, P. V., Moore, R., Hancher, M., Turubanova, S. A., Tyukavina, A., Thau, D., Stehman, S. V., Goetz, S. J., Loveland, T. R., Kommareddy, A., Egorov, A., Chini, L., Justice, C. O., and Townshend, J. R. G.: High-Resolution Global Maps of 21st-Century Forest Cover Change, Science, 342, 850–853, https://doi.org/10.1126/science.1244693, 2013.
Helms, J. R., Stubbins, A., Ritchie, J. D., Minor, E. C., Kieber, D. J., and Mopper, K.: Absorption spectral slopes and slope ratios as indicators of molecular weight, source, and photobleaching of chromophoric dissolved organic matter, Limnol. Oceanogr., 53, 955–969, https://doi.org/10.4319/lo.2008.53.3.0955, 2008.
Helms, J. R., Mao, J., Stubbins, A., Schmidt-Rohr, K., Spencer, R. G. M., Hernes, P. J., and Mopper, K.: Loss of optical and molecular indicators of terrigenous dissolved organic matter during long-term photobleaching, Aquat. Sci., 76, 353–373, https://doi.org/10.1007/s00027-014-0340-0, 2014.
Huang, T. H., Chen, C. T. A., Tseng, H. C., Lou, J. Y., Wang, S. L., Yang, L., Kandasamy, S., Gao, X., Wang, J. T., Aldrian, E., Jacinto, G. S., Anshari, G. Z., Sompongchaiyakul, P., and Wang, B. J.: Riverine carbon fluxes to the South China Sea, J. Geophys. Res.-Biogeo., 122, 1239–1259, https://doi.org/10.1002/2016JG003701, 2017.
Huffman, G., Bolvin, D., Braithwaite, D., Hsu, R., Joyce, R., and Xie, P.: Integrated Multi-Satellite Retrievals for GPM (IMERG), version 4.4, NASA's Precipitation Processing Center, https://gpm.nasa.gov/data/imerg (last access: January 2023), 2014.
Jennerjahn, T. C.: Biogeochemical response of tropical coastal systems to present and past environmental change, Earth Sci. Rev., 114, 19–41, https://doi.org/10.1016/j.earscirev.2012.04.005, 2012.
Jennerjahn, T. C. and Ittekkot, V.: Relevance of mangroves for the production and deposition of organic matter along tropical continental margins, Naturwissenschaften, 89, 23–30, https://doi.org/10.1007/s00114-001-0283-x, 2002.
Jennerjahn, T. C., Ittekkot, V., Klöpper, S., Adi, S., Purwo Nugroho, S., Sudiana, N., Yusmal, A., Prihartanto, and Gaye-Haake, B.: Biogeochemistry of a tropical river affected by human activities in its catchment: Brantas River estuary and coastal waters of Madura Strait, Java, Indonesia, Estuar. Coast. Shelf S., 60, 503–514, https://doi.org/10.1016/j.ecss.2004.02.008, 2004.
Jennerjahn, T. C., Knoppers, B. A., Souza, W. F. L., Brunskill, G. J., and Silva, E. I. L.: Factors controlling dissolved silica in tropical rivers, in: The Silicon Cycle: Human Perturbations and Impacts on Aquatic Systems, edited by: Ittekkot, V., Unger, D., Humborg, C., and Tac An, N., 29–51, Island Press, ISBN 9781597261159, 2006.
Jiang, S., Müller, M., Jin, J., Wu, Y., Zhu, K., Zhang, G., Mujahid, A., Rixen, T., Muhamad, M. F., Sia, E. S. A., Jang, F. H. A., and Zhang, J.: Dissolved inorganic nitrogen in a tropical estuary in Malaysia: transport and transformation, Biogeosciences, 16, 2821–2836, https://doi.org/10.5194/bg-16-2821-2019, 2019.
Kang, C. S. and Kanniah, K. D.: Land use and land cover change and its impact on river morphology in Johor River Basin, Malaysia, J. Hydrol. Reg. Stud., 41, 101072, https://doi.org/10.1016/j.ejrh.2022.101072, 2022.
Kérouel, R. and Aminot, A.: Fluorometric determination of ammonia in sea and estuarine waters by direct segmented flow analysis, Mar. Chem., 57, 265–275, https://doi.org/10.1016/S0304-4203(97)00040-6, 1997.
Kok, J. W. K. and Leong, S. C. Y.: Nutrient conditions and the occurrence of a Karenia mikimotoi (Kareniaceae) bloom within East Johor Straits, Singapore, Reg. Stud. Mar. Sci., 27, 100514, https://doi.org/10.1016/j.rsma.2019.100514, 2019.
Kuo, N.-W., Jien, S.-H., Hong, N.-M., Chen, Y.-T., and Lee, T.-Y.: Contribution of urban runoff in Taipei metropolitan area to dissolved inorganic nitrogen export in the Danshui River, Taiwan, Environ. Sci. Pollut. R., 24, 578–590, https://doi.org/10.1007/s11356-016-7825-4, 2017.
Kurek, M. R., Stubbins, A., Drake, T. W., Dittmar, T., Moura, J. M. S., Holmes, R. M., Osterholz, H., Six, J., Wabakanghanzi, J. N., Dinga, B., Mitsuya, M., and Spencer, R. G. M.: Organic molecular signatures of the Congo River and comparison to the Amazon, Global Biogeochem. Cy., 36, e2022GB007301, https://doi.org/10.1029/2022GB007301, 2022.
Le Moal, M., Gascuel-Odoux, C., Ménesguen, A., Souchon, Y., Étrillard, C., Levain, A., Moatar, F., Pannard, A., Souchu, P., Lefebvre, A., and Pinay, G.: Eutrophication: A new wine in an old bottle?, Sci. Total Environ., 651, 1–11, https://doi.org/10.1016/j.scitotenv.2018.09.139, 2019.
Lee, M.-H., Osburn, C. L., Shin, K.-H., and Hur, J.: New insight into the applicability of spectroscopic indices for dissolved organic matter (DOM) source discrimination in aquatic systems affected by biogeochemical processes, Water Res., 147, 164–176, https://doi.org/10.1016/j.watres.2018.09.048, 2018.
Lee, C. W., Lim, J. H., Heng, P. L., Marican, N. F., Narayanan, K., Sim, E. U. H., and Bong, C. W.: Influence of elevated river flow on hypoxia occurrence, nutrient concentration and microbial dynamics in a tropical estuary, Environ. Monit. Assess., 192, 660, https://doi.org/10.1007/s10661-020-08625-3, 2020.
Li, X., Sardans, J., Hou, L., Gao, D., Liu, M., and Peñuelas, J.: Dissimilatory Nitrate/Nitrite Reduction Processes in River Sediments Across Climatic Gradient: Influences of Biogeochemical Controls and Climatic Temperature Regime, J. Geophys. Res.-Biogeo., 124, 2305–2320, https://doi.org/10.1029/2019JG005045, 2019.
Liang, Y. Q., Annammala, K. V., Martín, P., Yong, E. L., Mazilamani, L. S., and Najib, M. Z. M.: Assessment of Physical-Chemical Water Quality Characteristics and Heavy Metals Content of Lower Johor River, Malaysia, J. Environ. Treat. Tech., 8, 961–966, 2020.
Lim, J. H., Wong, Y. Y., Lee, C. W., Bong, C. W., and Kudo, I.: Long-term comparison of dissolved nitrogen species in tropical estuarine and coastal water systems, Estuar. Coast. Shelf S., 222, 103–111, https://doi.org/10.1016/j.ecss.2019.04.008, 2019.
Lønborg, C., McKinna, L. I. W., Slivkoff, M. M., and Carreira, C.: Coloured dissolved organic matter dynamics in the Great Barrier Reef, Cont. Shelf Res., 219, 104395, https://doi.org/10.1016/j.csr.2021.104395, 2021a.
Lønborg, C., Müller, M., Butler, E. C. V., Jiang, S., Ooi, S. K., Trinh, D. H., Wong, P. Y., Ali, S. M., Cui, C., Siong, W. B., Yando, E. S., Friess, D. A., Rosentreter, J. A., Eyre, B. D., and Martin, P.: Nutrient cycling in tropical and temperate coastal waters: Is latitude making a difference?, Estuar. Coast. Shelf S., 262, 107571, https://doi.org/10.1016/j.ecss.2021.107571, 2021b.
Lu, C.-J., Benner, R., Fichot, C. G., Fukuda, H., Yamashita, Y., and Ogawa, H.: Sources and Transformations of Dissolved Lignin Phenols and Chromophoric Dissolved Organic Matter in Otsuchi Bay, Japan, Front. Mar. Sci., 3, 85, https://doi.org/10.3389/fmars.2016.00085, 2016.
MacDonald, R. W. and McLaughlin, F. A.: The effect of storage by freezing on dissolved inorganic phosphate, nitrate and reactive silicate for samples from coastal and estuarine waters, Water Res., 16, 95–104, https://doi.org/10.1016/0043-1354(82)90058-6, 1982.
Martin, P.: Replication data for: Distribution of nutrients and dissolved organic matter in a eutrophic equatorial estuary, the Johor River and East Johor Strait, V3, DR-NTU [code, data set], https://doi.org/10.21979/N9/XJWPHI, 2023.
Martin, P. and Bianchi, T. S.: Organic Carbon Cycling and Transformation, in: Treatise on Estuarine and Coastal Science, 2nd Edn., edited by: Baird, D. and Elliott, M., 164–224, Academic Press, Oxford, https://doi.org/10.1016/B978-0-323-90798-9.00061-5, 2024.
Martin, P., Cherukuru, N., Tan, A. S. Y., Sanwlani, N., Mujahid, A., and Müller, M.: Distribution and cycling of terrigenous dissolved organic carbon in peatland-draining rivers and coastal waters of Sarawak, Borneo, Biogeosciences, 15, 6847–6865, https://doi.org/10.5194/bg-15-6847-2018, 2018.
Martin, P., Moynihan, M. A., Chen, S., Woo, O. Y., Zhou, Y., Nichols, R. S., Chang, K. Y. W., Tan, A. S. Y., Chen, Y.-H., Ren, H., and Chen, M.: Monsoon-driven biogeochemical dynamics in an equatorial shelf sea: Time-series observations in the Singapore Strait, Estuar. Coast. Shelf S., 270, 107855, https://doi.org/10.1016/j.ecss.2022.107855, 2022.
Massicotte, P., Asmala, E., Stedmon, C., and Markager, S.: Global distribution of dissolved organic matter along the aquatic continuum: Across rivers, lakes and oceans, Sci. Total Environ., 609, 180–191, https://doi.org/10.1016/j.scitotenv.2017.07.076, 2017.
Mohd-Din, M., Abdul-Wahab, M. F., Mohamad, S. E., Jamaluddin, H., Shahir, S., Ibrahim, Z., Hii, K. S., Tan, S. N., Leaw, C. P., Gu, H., and Lim, P. T.: Prolonged high biomass diatom blooms induced formation of hypoxic-anoxic zones in the inner part of Johor Strait, Environ. Sci. Pollut. R., 27, 42948–42959, https://doi.org/10.1007/s11356-020-10184-6, 2020.
Moore, S., Gauci, V., Evans, C. D., and Page, S. E.: Fluvial organic carbon losses from a Bornean blackwater river, Biogeosciences, 8, 901–909, https://doi.org/10.5194/bg-8-901-2011, 2011.
Neumann, B., Vafeidis, A. T., Zimmermann, J., and Nicholls, R. J.: Future Coastal Population Growth and Exposure to Sea-Level Rise and Coastal Flooding – A Global Assessment, PLoS ONE, 10, e0118571, https://doi.org/10.1371/journal.pone.0118571, 2015.
Pak, H. Y., Chuah, C. J., Yong, E. L., and Snyder, S. A.: Effects of land use configuration, seasonality and point source on water quality in a tropical watershed: A case study of the Johor River Basin, Sci. Total Environ., 780, 146661, https://doi.org/10.1016/j.scitotenv.2021.146661, 2021.
Pratihary, A. K., Naqvi, S. W. A., Naik, H., Thorat, B. R., Narvenkar, G., Manjunatha, B. R., and Rao, V. P.: Benthic fluxes in a tropical estuary and their role in the ecosystem, Estuar. Coast. Shelf S., 85, 387–398, https://doi.org/10.1016/j.ecss.2009.08.012, 2009.
Osburn, C. L., Kinsey, J. D., Bianchi, T. S., and Shields, M. R.: Formation of planktonic chromophoric dissolved organic matter in the ocean, Mar. Chem., 209, 1–13, https://doi.org/10.1016/j.marchem.2018.11.010, 2019.
Raymond, P. A. and Saiers, J. E.: Event controlled DOC export from forested watersheds, Biogeochemistry, 100, 197–209, https://doi.org/10.1007/s10533-010-9416-7, 2010.
Regnier, P., Resplandy, L., Najjar, R. G., and Ciais, P.: The land-to-ocean loops of the global carbon cycle, Nature, 603, 401–410, https://doi.org/10.1038/s41586-021-04339-9, 2022.
Rixen, T., Baum, A., Wit, F., and Samiaji, J.: Carbon Leaching from Tropical Peat Soils and Consequences for Carbon Balances, Front. Earth Sci., 4, 74, https://doi.org/10.3389/feart.2016.00074, 2016.
Rixen, T., Wit, F., Hutahaean, A. A., Schlüter, A., Baum, A., Klemme, A., Müller, M., Pranowo, W. S., Samiaji, J., and Warneke, T.: 4 – Carbon cycle in tropical peatlands and coastal seas, in: Science for the protection of Indonesian coastal ecosystems (SPICE), edited by: Jennerjahn, T. C., Rixen, T., Irianto, H. E., and Samiaji, J., 83–142, Elsevier, https://doi.org/10.1016/B978-0-12-815050-4.00011-0, 2022.
Roubeix, V., Rousseau, V., and Lancelot, C.: Diatom succession and silicon removal from freshwater in estuarine mixing zones: From experiment to modelling, Estuar. Coast. Shelf S., 78, 14–26, https://doi.org/10.1016/j.ecss.2007.11.007, 2008a.
Roubeix, V., Becquevort, S., and Lancelot, C.: Influence of bacteria and salinity on diatom biogenic silica dissolution in estuarine systems, Biogeochemistry, 88, 47–62, https://doi.org/10.1007/s10533-008-9193-8, 2008b.
Samsudin, M. S., Azid, A., Khalit, S. I., Saudi, A. S. M., and Zaudi, M. A.: River water quality assessment using APCS-MLR and statistical process control in Johor River Basin, Malaysia, Int. J. Adv. Appl. Sci., 4, 84–97, https://doi.org/10.21833/ijaas.2017.08.013, 2017.
Sanwlani, N., Evans, C. D., Müller, M., Cherukuru, N., and Martin, P.: Rising dissolved organic carbon concentrations in coastal waters of northwestern Borneo related to tropical peatland conversion, Sci. Adv., 8, eabi5688, https://doi.org/10.1126/sciadv.abi5688, 2022.
Schaefer, S. C. and Hollibaugh, J. T.: Temperature Decouples Ammonium and Nitrite Oxidation in Coastal Waters, Environ. Sci. Technol., 51, 3157–3164, https://doi.org/10.1021/acs.est.6b03483, 2017.
Siegel, H., Gerth, M., Stottmeister, I., Baum, A., and Samiaji, J.: Remote Sensing of Coastal Discharge of SE Sumatra (Indonesia), in: Remote Sensing of the Asian Seas, edited by: Barale, V. and Gade, M., Springer International Publishing, Cham, 359–376, https://doi.org/10.1007/978-3-319-94067-0_20, 2019.
Sinha, E., Michalak, A. M., Calvin, K. V., and Lawrence, P. J.: Societal decisions about climate mitigation will have dramatic impacts on eutrophication in the 21st century, Nat. Commun., 10, 939, https://doi.org/10.1038/s41467-019-08884-w, 2019.
Spencer, R. G. M., Stubbins, A., Hernes, P. J., Baker, A., Mopper, K., Aufdenkampe, A. K., Dyda, R. Y., Mwamba, V. L., Mangangu, A. M., Wabakanghanzi, J. N., and Six, J.: Photochemical degradation of dissolved organic matter and dissolved lignin phenols from the Congo River, J. Geophys. Res., 114, G03010, https://doi.org/10.1029/2009JG000968, 2009.
Stedmon, C. A. and Markager, S.: Behaviour of the optical properties of coloured dissolved organic matter under conservative mixing, Estuar. Coast. Shelf S., 57, 973–979, https://doi.org/10.1016/S0272-7714(03)00003-9, 2003.
Stedmon, C. A. and Nelson, N. B.: The Optical Properties of DOM in the Ocean, in: Biogeochemistry of Marine Dissolved Organic Matter, 2nd Edn., edited by: Carlson, C. A., Academic Press, Boston, 481–508, https://doi.org/10.1016/B978-0-12-405940-5.00010-8, 2015.
Stibig, H.-J., Achard, F., Carboni, S., Raši, R., and Miettinen, J.: Change in tropical forest cover of Southeast Asia from 1990 to 2010, Biogeosciences, 11, 247–258, https://doi.org/10.5194/bg-11-247-2014, 2014.
Sulu-Gambari, F., Hagens, M., Behrends, T., Seitaj, D., Meysman, F. J. R., Middelburg, J., and Slomp, C. P.: Phosphorus Cycling and Burial in Sediments of a Seasonally Hypoxic Marine Basin, Estuar. Coast., 41, 921–939, https://doi.org/10.1007/s12237-017-0324-0, 2018.
Suratman, S., Abdul Aziz, A., Mohd Tahir, N., and Lee, L. H.: Distribution and Behaviour of Nitrogen Compounds in the Surface Water of the Sungai Terengganu Estuary, Southern Waters of South China Sea, Malaysia, Sains Malays., 47, 651–659, https://doi.org/10.17576/jsm-2018-4704-02, 2018.
Tanaka, Y., Minggat, E., and Roseli, W.: The impact of tropical land-use change on downstream riverine and estuarine water properties and biogeochemical cycles: a review, Ecol. Process., 10, 40, https://doi.org/10.1186/s13717-021-00315-3, 2021.
Taillardat, P., Marchand, C., Friess, D. A., Widory, D., David, F., Ohte, N., Nakamura, T., Vinh, T. V., Thanh-Nho, N., and Ziegler, A. D.: Respective contribution of urban wastewater and mangroves on nutrient dynamics in a tropical estuary during the monsoon season, Mar. Pollut. Bull., 160, 111652, https://doi.org/10.1016/j.marpolbul.2020.111652, 2020.
Teixeira, C., Magalhães, C., Joye, S. B., and Bordalo, A. A.: Response of anaerobic ammonium oxidation to inorganic nitrogen fluctuations in temperate estuarine sediments, J. Geophys. Res.-Biogeo., 121, 1829–1839, https://doi.org/10.1002/2015JG003287, 2016.
Traina, S. J., Novak, J., and Smeck, N. E.: An Ultraviolet Absorbance Method of Estimating the Percent Aromatic Carbon Content of Humic Acids, J. Environ. Qual., 19, 151–153, https://doi.org/10.2134/jeq1990.00472425001900010023x, 1990.
van der Wulp, S. A., Damar, A., Ladwig, N., and Hesse, K.-J.: Numerical simulations of river discharges, nutrient flux and nutrient dispersal in Jakarta Bay, Indonesia, Mar. Pollut. Bull., 110, 675–685, https://doi.org/10.1016/j.marpolbul.2016.05.015, 2016.
van Maren, D. S., Liew, S. C., and Hasan, G. M. J.: The role of terrestrial sediment on turbidity near Singapore's coral reefs, Cont. Shelf Res., 76, 75–88, https://doi.org/10.1016/j.csr.2013.12.001, 2014.
Vieillard, A. M., Newell, S. E., and Thrush, S. F.: Recovering From Bias: A Call for Further Study of Underrepresented Tropical and Low-Nutrient Estuaries, J. Geophys. Res.-Biogeo., 125, e2020JG005766, https://doi.org/10.1029/2020JG005766, 2020.
Voss, M., Wannicke, N., Deutsch, B., Bronk, D., Sipler, R., Purvaja, R., Ramesh, R., and Rixen, T.: Internal Cycling of Nitrogen and Nitrogen Transformations, in: Treatise on Estuarine and Coastal Science, edited by: Wolanski, E. and McLusky, D., Elsevier, 231–259, https://doi.org/10.1016/B978-0-12-374711-2.00508-8, 2011.
Weishaar, J. L., Aiken, G. R., Bergamaschi, B. A., Fram, M. S., Fujii, R., and Mopper, K.: Evaluation of Specific Ultraviolet Absorbance as an Indicator of the Chemical Composition and Reactivity of Dissolved Organic Carbon, Environ. Sci. Technol., 37, 4702–4708, https://doi.org/10.1021/es030360x, 2003.
Wijaya, W., Suhaimi, Z., Chua, C. X., Sunil, R. S., Kolundžija, S., Rohaizat, A. M. B., Azmi, N. B. Md., Hazrin-Chong, N. H., and Lauro, F. M.: Frequent pulse disturbances shape resistance and resilience in tropical marine microbial communities, ISME Commun., 3, 55, https://doi.org/10.1038/s43705-023-00260-6, 2023.
Wit, F., Müller, D., Baum, A., Warneke, T., Pranowo, W. S., Müller, M., and Rixen, T.: The impact of disturbed peatlands on river outgassing in Southeast Asia, Nat. Commun., 6, 10155, https://doi.org/10.1038/ncomms10155, 2015.
Xiao, H.-M., Lo, M.-H., and Yu, J.-Y.: The increased frequency of combined El Niño and positive IOD events since 1965s and its impacts on maritime continent hydroclimates, Sci. Rep., 12, 7532, https://doi.org/10.1038/s41598-022-11663-1, 2022.
Xu, Z. X., Takeuchi, K., and Ishidaira, H.: Correlation between El Niño–Southern Oscillation (ENSO) and precipitation in South-east Asia and the Pacific region, Hydrol. Process., 18, 107–123, https://doi.org/10.1002/hyp.1315, 2004.
Zhou, Y., Evans, C. D., Chen, Y., Chang, K. Y. W., and Martin, P.: Extensive Remineralization of Peatland-Derived Dissolved Organic Carbon and Ocean Acidification in the Sunda Shelf Sea, Southeast Asia, J. Geophys. Res.-Oceans, 126, e2021JC017292, https://doi.org/10.1029/2021JC017292, 2021.
Zhu, G., Wang, S., Wang, W., Wang, Y., Zhou, L., Jiang, B., Op Den Camp, H. J. M., Risgaard-Petersen, N., Schwark, L., Peng, Y., Hefting, M. M., Jetten, M. S. M., and Yin, C.: Hotspots of anaerobic ammonium oxidation at land–freshwater interfaces, Nat. Geosci., 6, 103–107, https://doi.org/10.1038/ngeo1683, 2013.
Short summary
We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to understand their sources and cycling. Our data show that the dissolved organic matter originates partly from land and partly from microbial processes in the water. Internal recycling is likely important for maintaining high nutrient concentrations, and we found that there is often excess nitrogen compared to silicon and phosphorus. Our data help to explain how eutrophication persists in this system.
We measured nutrients and dissolved organic matter for 1 year in a eutrophic tropical estuary to...
Altmetrics
Final-revised paper
Preprint