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Mos B, Erler D, Lawson C, Dworjanyn SA. Crown-of-thorns starfish complete their larval phase eating only nitrogen-fixing Trichodesmium cyanobacteria. SCIENCE ADVANCES 2024; 10:eado2682. [PMID: 39018391 PMCID: PMC466945 DOI: 10.1126/sciadv.ado2682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 06/13/2024] [Indexed: 07/19/2024]
Abstract
Cyanobacteria of the genus Trichodesmium form extensive blooms that supply new N to nutrient-poor marine ecosystems. Yet little is known about what eats Trichodesmium. In this laboratory study, we show that one of the greatest threats to coral reefs, predatory crown-of-thorns starfish (CoTS), Acanthaster sp., completes their larval phase feeding solely on Trichodesmium. We observed Trichodesmium erythraeum CMP1985 in the stomachs of larvae using florescence microscopy and traced the assimilation of nitrogen from labeled trichomes into larval tissues using stable isotopes. Some larvae fed T. erythraeum were morphologically ready to become benthic juveniles after 19 days. Given that Trichodesmium can be food for CoTS, reported increases in Trichodesmium could be a driving factor in the heightened frequency of CoTS population irruptions that have devastated coral reefs in past decades. Future studies could test this through investigating the diets of wild larvae and incorporating Trichodesmium abundance into models of CoTS population dynamics.
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Affiliation(s)
- Benjamin Mos
- Moreton Bay Research Station (MBRS), School of the Environment, The University of Queensland, Dunwich 4183, Australia
- Centre for Marine Science (CMS), The University of Queensland, Brisbane 4072, Australia
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour 2450, Australia
| | - Dirk Erler
- Faculty of Science and Engineering, Southern Cross University, Lismore 2480, Australia
| | - Corinne Lawson
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour 2450, Australia
| | - Symon A. Dworjanyn
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour 2450, Australia
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2
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Rico-Esenaro SD, de Jesús Adolfo Tortolero-Langarica J, Iglesias-Prieto R, Carricart-Ganivet JP. The δ 15N in Orbicella faveolata organic matter reveals anthropogenic impact by sewage inputs in a Mexican Caribbean coral reef lagoon. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:118872-118880. [PMID: 37919495 DOI: 10.1007/s11356-023-30476-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 10/10/2023] [Indexed: 11/04/2023]
Abstract
Coral-reef ecosystems provide essentials services to human societies, representing the most important source of income (e.g., tourism and artisanal fishing) for many coastal developing countries. In the Caribbean region, most touristic and coastal developments are in the vicinity of coral reefs where they may contribute to reef degradation. Here we evaluated the influence of sewage inputs in the coral reef lagoon of Puerto Morelos during a period of 40 years (1970-2012). Annual δ15N values were determined in the organic matter (OM) extracted from coral skeletons of Orbicella faveolata. Average protein content in the OM was 0.33 mg of protein g-1 CaCO3 (±0.10 SD) and a 0.03% of OM relative to the sample weight (n =100). The average of N g-1 CaCO3 was 0.002% (± 0.001 SD). The results showed an increase (p < 0.001) in δ15N over the time, positively correlated with population growth derived from touristic development. These findings emphasize the need to generate urban-planning remediation strategies that consider the impact on natural environments, reduce sewage pollution, and mitigate local stressors that threaten the status of coral-reef communities in the Caribbean region.
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Affiliation(s)
- Serguei Damián Rico-Esenaro
- Laboratorio de Esclerocronología de Corales Arrecifales, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Prol. Av. Niños Héroes S/N, Domicilio conocido, Puerto Morelos, Q. Roo, 77580, México
- Departamento El Hombre y su Ambiente, Universidad Autónoma Metropolitana Unidad Xochimilco, Calzada del Hueso 1100, Col. Villa Quietud, Coyoacán, Cd. de México, 04960, México
| | - José de Jesús Adolfo Tortolero-Langarica
- Laboratorio de Esclerocronología de Corales Arrecifales, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Prol. Av. Niños Héroes S/N, Domicilio conocido, Puerto Morelos, Q. Roo, 77580, México
- Tecnológico Nacional de México/IT Bahía de Banderas, Crucero a Punta de Mita S/N, Bahía de Banderas, 63734, Nayarit, México
| | - Roberto Iglesias-Prieto
- Department of Biology, The Pennsylvania State University, 208 Mueller Lab, University Park, PA, 16802, USA
| | - Juan P Carricart-Ganivet
- Laboratorio de Esclerocronología de Corales Arrecifales, Unidad Académica de Sistemas Arrecifales, Instituto de Ciencias del Mar y Limnología, Universidad Nacional Autónoma de México, Prol. Av. Niños Héroes S/N, Domicilio conocido, Puerto Morelos, Q. Roo, 77580, México.
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3
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Cybulski JD, Duprey NN, Thibodeau B, Yasuhara M, Geeraert N, Leonard N, Vonhof HB, Martínez-García A, Baker DM. Coral carbonate-bound isotopes reveal monsoonal influence on nitrogen sources in Southeastern China's Greater Bay Area from the mid-Holocene until the Anthropocene. MARINE POLLUTION BULLETIN 2023; 197:115757. [PMID: 37988964 DOI: 10.1016/j.marpolbul.2023.115757] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/30/2023] [Accepted: 11/03/2023] [Indexed: 11/23/2023]
Abstract
Most anthropogenic nitrogen (N) reaches coastal waters via rivers carrying increasing loads of sewage, fertilizer, and sediments. To understand anthropogenic N impacts, we need to understand historical N-dynamics before human influence. Stable isotope ratios of N preserved in carbonates are one way to create temporal N records. However, records that span periods of human occupation are scarce, limiting our ability to contextualize modern N dynamics. Here, we produce a fossil-bound N-record using coral subfossils, spanning 6700 years in China's Greater Bay Area (GBA). We found that during the mid-to-late Holocene, the GBA's coastal N was dominated by fluvial sources. The weakening of the Asia monsoon throughout the late-Holocene decreased river outflow, leading to a relative increase of marine nitrate. This source shift from riverine-to-ocean dominance was overprinted by anthropogenic N. During the late 1980s to early 1990s, human development and associated effluent inundated the coastal system, contributing to the decline of coral communities.
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Affiliation(s)
- Jonathan D Cybulski
- The Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong; School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong; Smithsonian Tropical Research Institute, Balboa, Panama; Max Planck Institute for Chemistry (Otto Hahn Institute), Climate Geochemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany.
| | - Nicolas N Duprey
- Max Planck Institute for Chemistry (Otto Hahn Institute), Climate Geochemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany
| | - Benoit Thibodeau
- Earth and Environmental Sciences Programme, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong; School of Life Sciences, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Moriaki Yasuhara
- School of Biological Sciences, Area of Ecology and Biodiversity, Swire Institute of Marine Science, Institute for Climate and Carbon Neutrality, Musketeers Foundation Institute of Data Science, The University of Hong Kong, Kadoorie Biological Sciences Building, Pokfulam Road, Hong Kong; State Key Laboratory of Marine Pollution, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong
| | - Naomi Geeraert
- The Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong; School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong
| | - Nicole Leonard
- Radiogenic Isotope Facility, School of Earth and Environmental Sciences, The University of Queensland, Australia
| | - Hubert B Vonhof
- Max Planck Institute for Chemistry (Otto Hahn Institute), Climate Geochemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany
| | - Alfredo Martínez-García
- Max Planck Institute for Chemistry (Otto Hahn Institute), Climate Geochemistry Department, Hahn-Meitner-Weg 1, 55128 Mainz, Germany
| | - David M Baker
- The Swire Institute of Marine Science, The University of Hong Kong, Cape D'Aguilar Road, Shek O, Hong Kong; School of Biological Sciences, The University of Hong Kong, Pok Fu Lam, Hong Kong.
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Bahadori M, Chen C, Lewis S, Wang J, Shen J, Hou E, Rashti MR, Huang Q, Bainbridge Z, Stevens T. The origin of suspended particulate matter in the Great Barrier Reef. Nat Commun 2023; 14:5629. [PMID: 37699913 PMCID: PMC10497579 DOI: 10.1038/s41467-023-41183-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2022] [Accepted: 08/24/2023] [Indexed: 09/14/2023] Open
Abstract
River run-off has long been regarded as the largest source of organic-rich suspended particulate matter (SPM) in the Great Barrier Reef (GBR), contributing to high turbidity, pollutant exposure and increasing vulnerability of coral reef to climate change. However, the terrestrial versus marine origin of the SPM in the GBR is uncertain. Here we provide multiple lines of evidence (13C NMR, isotopic and genetic fingerprints) to unravel that a considerable proportion of the terrestrially-derived SPM is degraded in the riverine and estuarine mixing zones before it is transported further offshore. The fingerprints of SPM in the marine environment were completely different from those of terrestrial origin but more consistent with that formed by marine phytoplankton. This result indicates that the SPM in the GBR may not have terrestrial origin but produced locally in the marine environment, which has significant implications on developing better-targeted management practices for improving water quality in the GBR.
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Affiliation(s)
- Mohammad Bahadori
- Australian Rivers Institute, Griffith University, Nathan, QLD, 4111, Australia
- School of Environment and Science, Griffith University, Nathan, QLD, 4111, Australia
| | - Chengrong Chen
- Australian Rivers Institute, Griffith University, Nathan, QLD, 4111, Australia.
- School of Environment and Science, Griffith University, Nathan, QLD, 4111, Australia.
| | - Stephen Lewis
- Catchment to Reef Research Group, Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD, Australia
| | - Juntao Wang
- Hawkesbury Institute for the Environment, Western Sydney University, Penrith, NSW, Australia
- Global Centre for Land-Based Innovation, Western Sydney University, Penrith, NSW, Australia
| | - Jupei Shen
- School of Geographical Sciences, Fujian Normal University, Fuzhou, PR China
| | - Enqing Hou
- Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, China
| | - Mehran Rezaei Rashti
- Australian Rivers Institute, Griffith University, Nathan, QLD, 4111, Australia
- School of Environment and Science, Griffith University, Nathan, QLD, 4111, Australia
| | - Qiaoyun Huang
- State Key Laboratory of Agricultural Microbiology, Huazhong Agricultural University, Wuhan, China
| | - Zoe Bainbridge
- Catchment to Reef Research Group, Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD, Australia
| | - Tom Stevens
- Catchment to Reef Research Group, Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD, Australia
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5
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Robinson RS, Smart SM, Cybulski JD, McMahon KW, Marcks B, Nowakowski C. Insights from Fossil-Bound Nitrogen Isotopes in Diatoms, Foraminifera, and Corals. ANNUAL REVIEW OF MARINE SCIENCE 2023; 15:407-430. [PMID: 35977410 DOI: 10.1146/annurev-marine-032122-104001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Nitrogen is a major limiting element for biological productivity, and thus understanding past variations in nitrogen cycling is central to understanding past and future ocean biogeochemical cycling, global climate cycles, and biodiversity. Organic nitrogen encapsulated in fossil biominerals is generally protected from alteration, making it an important archive of the marine nitrogen cycle on seasonal to million-year timescales. The isotopic composition of fossil-bound nitrogen reflects variations in the large-scale nitrogen inventory, local sources and processing, and ecological and physiological traits of organisms. The ability to measure trace amounts of fossil-bound nitrogen has expanded with recent method developments. In this article, we review the foundations and ground truthing for three important fossil-bound proxy types: diatoms, foraminifera, and corals. We highlight their utility with examples of high-resolution evidence for anthropogenic inputs of nitrogen to the oceans, glacial-interglacial-scale assessments of nitrogen inventory change, and evidence for enhanced CO2 drawdown in the high-latitude ocean. Future directions include expanded method development, characterization of ecological and physiological variation, and exploration of extended timescales to push reconstructions further back in Earth's history.
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Affiliation(s)
- Rebecca S Robinson
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA; , , , ,
| | - Sandi M Smart
- Department of Geological Sciences, University of Alabama, Tuscaloosa, Alabama, USA;
| | - Jonathan D Cybulski
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA; , , , ,
- Smithsonian Tropical Research Institute, Balboa, Republic of Panama
| | - Kelton W McMahon
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA; , , , ,
| | - Basia Marcks
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA; , , , ,
| | - Catherine Nowakowski
- Graduate School of Oceanography, University of Rhode Island, Narragansett, Rhode Island, USA; , , , ,
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6
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Pan K, Zheng X, Liu X, Jiang H. Nitrogen cycling in a tropical coral reef ecosystem under severe anthropogenic disturbance in summer: Insights from isotopic compositions. WATER RESEARCH 2021; 207:117824. [PMID: 34758438 DOI: 10.1016/j.watres.2021.117824] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Revised: 10/18/2021] [Accepted: 10/30/2021] [Indexed: 06/13/2023]
Abstract
Coral reefs, one of the most productive ecosystems, have been dramatically declining in recent decades. While studies contend a prominent correlation between coral reef degradation and increased anthropogenic nitrogen (N) loads, a quantitative description of the N sources and cycling processes in these ecologically important ecosystems is lacking. Through a comprehensive depiction of the δ15N compositions of seawaters and sediments, we systematically accessed the N cycling processes in the Weizhou coral reef ecosystem. The correlations between the nitrate (NO3-) concentrations and isotopic compositions (δ15N/δ18O-NO3-) indicated the pelagic NO3- loads were largely regulated by mixing between precipitation and sewage. Biological NO3- turnover processes appeared to be weak. In the sediments, N2 fixation contributed about one-third of the sedimentary organic N, with the rest coming from the settlement of pelagic organic N. We also uncovered significant sedimentary mineralization-nitrification-denitrification processes in which the N loss was greater than the input. While pelagic N significantly contributed to the sedimentary N, the N export from the sediments to surface seawater was potentially short-circuited by the high N retention and recycling efficiencies of the organisms in the coral reef ecosystem. Overall, this study shows that the complex N cycling processes in the ecosystem are effectively reflected in the isotopic compositions of seawater and sediment, thus adding an important dimension to understanding the N cycling in coral reef ecosystems.
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Affiliation(s)
- Ke Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Xinqing Zheng
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005, China
| | - Xinming Liu
- Institute of Marine Drugs, Guangxi University of Chinese Medicine, Nanning, 530200, China
| | - Hao Jiang
- Key Laboratory of Aquatic Botany and Watershed Ecology, Wuhan Botanical Garden, Chinese Academy of Sciences, Wuhan, 430074, China.
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7
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Marion GS, Jupiter SD, Radice VZ, Albert S, Hoegh-Guldberg O. Linking isotopic signatures of nitrogen in nearshore coral skeletons with sources in catchment runoff. MARINE POLLUTION BULLETIN 2021; 173:113054. [PMID: 34744009 DOI: 10.1016/j.marpolbul.2021.113054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 09/20/2021] [Accepted: 10/10/2021] [Indexed: 06/13/2023]
Abstract
We use a multi-tracer approach to identify catchment sources of nitrogen (N) in the skeletons of nearshore Porites corals within the Great Barrier Reef. We measured δ15N, δ13C and C:N ratios of particulate organic matter (POM) sampled from the Pioneer River catchment and identified five distinct end-members: (1) marine planktonic and algal-dominated matter with higher δ15N values from the river mouth and coastal waters; (2) estuarine planktonic and algal matter with lower δ15N values associated with estuarine mixing; (3) lower river freshwater phytoplankton and algal-dominated matter in stratified reservoirs adjacent to catchment weirs, with the 15N-enriched source likely caused by microbial remineralization and denitrification; (4) upper river low δ15N terrigenous soil matter eroded from cane fields bordering waterways; and (5) terrestrial plant detrital matter in forest streams, representing a low δ15N fixed atmospheric nitrogen source. The δ15N values of adjacent, nearshore Porites coral skeletons is reflective of POM composition in coastal waters, with 15N-enriched values reflective of transformed N during flood pulses from the Pioneer River.
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Affiliation(s)
- Guy S Marion
- ARC Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Stacy D Jupiter
- ARC Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, QLD 4072, Australia; ARC Centre of Excellence for Coral Reef Studies, Research School of Earth Sciences, The Australian National University, Canberra, ACT 0200, Australia; Wildlife Conservation Society, Melanesia Program, 11 Ma'afu St, Suva, Fiji.
| | - Veronica Z Radice
- ARC Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, QLD 4072, Australia; Old Dominion University, Norfolk, VA, USA
| | - Simon Albert
- School of Civil Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Ove Hoegh-Guldberg
- ARC Centre of Excellence for Coral Reef Studies, The University of Queensland, Brisbane, QLD 4072, Australia; School of Biological Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; Global Change Institute, The University of Queensland, Brisbane, QLD 4072, Australia
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8
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Killam D, Al-Najjar T, Clapham M. Giant clam growth in the Gulf of Aqaba is accelerated compared to fossil populations. Proc Biol Sci 2021; 288:20210991. [PMID: 34428968 PMCID: PMC8385342 DOI: 10.1098/rspb.2021.0991] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2021] [Accepted: 08/05/2021] [Indexed: 11/12/2022] Open
Abstract
The health of reef-building corals has declined due to climate change and pollution. However, less is known about whether giant clams, reef-dwelling bivalves with a photosymbiotic partnership similar to that found in reef-building corals, are also threatened by environmental degradation. To compare giant clam health against a prehistoric baseline, we collected fossil and modern Tridacna shells from the Gulf of Aqaba, Northern Red Sea. After calibrating daily/twice-daily growth lines from the outer shell layer, we determined that modern individuals of all three species (Tridacna maxima, T. squamosa and T. squamosina) grew faster than Holocene and Pleistocene specimens. Modern specimens also show median shell organic δ15N values 4.2‰ lower than fossil specimens, which we propose is most likely due to increased deposition of isotopically light nitrate aerosols in the modern era. Nitrate fertilization accelerates growth in cultured Tridacna, so nitrate aerosol deposition may contribute to faster growth in modern wild populations. Furthermore, colder winter temperatures and past summer monsoons may have depressed fossil giant clam growth. Giant clams can serve as sentinels of reef environmental change, both to determine their individual health and the health of the reefs they inhabit.
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Affiliation(s)
- Daniel Killam
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
| | - Tariq Al-Najjar
- Department of Marine Biology, University of Jordan, Aqaba Branch, Jordan
| | - Matthew Clapham
- Department of Earth and Planetary Sciences, University of California, Santa Cruz, CA, USA
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Bell PRF. Analysis of satellite imagery using a simple algorithm supports evidence that Trichodesmium supplies a significant new nitrogen load to the GBR lagoon. AMBIO 2021; 50:1200-1210. [PMID: 33454915 PMCID: PMC8068736 DOI: 10.1007/s13280-020-01460-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 10/21/2020] [Accepted: 11/30/2020] [Indexed: 06/12/2023]
Abstract
This work supports previous studies in the Great Barrier Reef lagoon that show the new nitrogen (N) load introduced by Trichodesmium is similar to or greater than that from riverine discharges. However, the current management programs aimed at improving the chronic eutrophic state of the GBR ignore the N load from Trichodesmium. These programs also ignore the evidence that Trichodesmium blooms could promote the bioavailability of heavy metals and be a source of toxins in the ciguatera food chain. Further work is urgently required to better quantify the potential impacts of Trichodesmium and develop management plans to reduce those impacts. A simple algorithm that uses MODIS imagery is developed for not only monitoring the spatial extent of Trichodesmium blooms but also for quantifying the concentration of those blooms. The algorithm is based on the readily available MODIS L2 data. A management plan that includes the harvesting of Trichodesmium is outlined.
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Affiliation(s)
- Peter R F Bell
- School of Chemical Engineering, University of Queensland, St Lucia, 4072, Australia.
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10
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Jiang H, Ma J, Xu H, Xu Z, Liu W, Pan K. Multiple isotopic compositions reveal complex nitrogen cycling in a subtropical estuary. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2021; 272:116410. [PMID: 33433349 DOI: 10.1016/j.envpol.2020.116410] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/09/2020] [Accepted: 12/28/2020] [Indexed: 06/12/2023]
Abstract
Nitrogen (N) pollution and the resulting eutrophication can have deleterious consequences on estuaries, such as hypoxia, fish kills, and loss of biotic diversity. An understanding of N sources and cycling in estuaries is fundamental to determining how to effectively manage these ecologically and commercially important areas. We applied a multiple-isotopic approach to examine the transformations and sources of the N pools in the Pearl River Estuary (PRE) during winter. The surface water in the West PRE was characterized by low salinity and high NO3-, while that in the east had high salinity and low NO3-. The NO3- in the West PRE was largely regulated by a conservative mixing process. In contrast, assimilation and nitrification dominated in the East PRE, which was attributed to the long water-residence time. For the first time, the source contributions of NO3- and NH4+ were estimated by isotope mixing models. Our results suggest that river discharge and nitrification contributed 81% and 12% to the NO3- pool, respectively. A major portion (68%) of the NH4+ was from river discharge, with the remainder likely from sewage and the aquitard-aquifer system. Our study demonstrates that internal nitrification can potentially be of pivotal importance in determining the NO3- level in an estuary and its export to coastal waters.
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Affiliation(s)
- Hao Jiang
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China; College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China
| | - Jie Ma
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Huo Xu
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China
| | - Zhifang Xu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Wenjing Liu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, 100029, China
| | - Ke Pan
- Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, 518060, China.
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11
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Bahadori M, Chen C, Lewis S, Rashti MR, Cook F, Parnell A, Esfandbod M, Stevens T. Tracing the sources of sediment and associated particulate nitrogen from different land uses in the Johnstone River catchment, Wet Tropics, north-eastern Australia. MARINE POLLUTION BULLETIN 2020; 157:111344. [PMID: 32658700 DOI: 10.1016/j.marpolbul.2020.111344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 06/02/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
While the ecosystem of the Great Barrier Reef (GBR), north-eastern Australia, is being threatened by the elevated levels of sediments and nutrients discharged from adjacent coastal river systems, the source of these detrimental pollutants are not well understood. Here we used a combined isotopic (δ13C, δ15N) and geochemical (Zn, Pt and S) signatures and stable isotope analysis in R (SIAR) mixing model to estimate the contribution of different land uses to the sediment and associated particulate nitrogen delivered to the Johnstone River. Results showed that rainforest was the largest contributor of suspended and bed sediments in the river estuary (both 33.1%), followed by banana (26.7%, 20.4%), sugarcane (21.5%, 21.4%) and grazing (18.7%, 25.1%). However, bananas and sugarcane land uses had the highest contribution to sediments delivered to the coast per unit of area. This will help land managers to prioritise on-ground activities to improve water quality in the GBR lagoon.
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Affiliation(s)
- Mohammad Bahadori
- Australian Rivers Institute, Griffith University, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, Brisbane, Queensland 4111, Australia
| | - Chengrong Chen
- Australian Rivers Institute, Griffith University, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, Brisbane, Queensland 4111, Australia.
| | - Stephen Lewis
- Catchment to Reef Research Group, Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia
| | - Mehran Rezaei Rashti
- Australian Rivers Institute, Griffith University, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, Brisbane, Queensland 4111, Australia
| | - Freeman Cook
- Australian Rivers Institute, Griffith University, Brisbane, QLD 4111, Australia; Freeman Cook & Associates Pty Ltd, Australia
| | | | - Maryam Esfandbod
- Australian Rivers Institute, Griffith University, Brisbane, QLD 4111, Australia; School of Environment and Science, Griffith University, Brisbane, Queensland 4111, Australia
| | - Thomas Stevens
- Catchment to Reef Research Group, Centre for Tropical Water and Aquatic Ecosystem Research, James Cook University, Townsville, QLD 4811, Australia
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