1
|
Bulseco AN, Murphy AE, Giblin AE, Tucker J, Sanderman J, Bowen JL. Marsh sediments chronically exposed to nitrogen enrichment contain degraded organic matter that is less vulnerable to decomposition via nitrate reduction. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 915:169681. [PMID: 38163591 DOI: 10.1016/j.scitotenv.2023.169681] [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: 10/11/2023] [Revised: 12/23/2023] [Accepted: 12/23/2023] [Indexed: 01/03/2024]
Abstract
Blue carbon habitats, including salt marshes, can sequester carbon at rates that are an order of magnitude greater than terrestrial forests. This ecosystem service may be under threat from nitrate (NO3-) enrichment, which can shift the microbial community and stimulate decomposition of organic matter. Despite efforts to mitigate nitrogen loading, salt marshes continue to experience chronic NO3- enrichment, however, the long-term consequence of this enrichment on carbon storage remains unclear. To investigate the effect of chronic NO3- exposure on salt marsh organic matter decomposition, we collected sediments from three sites across a range of prior NO3- exposure: a relatively pristine marsh, a marsh enriched to ~70 μmol L-1 NO3- in the flooding seawater for 13 years, and a marsh enriched between 100 and 1000 μmol L-1 for 40 years from wastewater treatment effluent. We collected sediments from 20 to 25 cm depth and determined that sediments from the most chronically enriched site had less bioavailable organic matter and a distinct assemblage of active microbial taxa compared to the other two sites. We also performed a controlled anaerobic decomposition experiment to test whether the legacy of NO3- exposure influenced the functional response to additional NO3-. We found significant changes to microbial community composition resulting from experimental NO3- addition. Experimental NO3- addition also increased microbial respiration in sediments collected from all sites. However, sediments from the most chronically enriched site exhibited the smallest increase, the lowest rates of total NO3- reduction by dissimilatory nitrate reduction to ammonium (DNRA), and the highest DNF:DNRA ratios. Our results suggest that chronic exposure to elevated NO3- may lead to residual pools of organic matter that are less biologically available for decomposition. Thus, it is important to consider the legacy of nutrient exposure when examining the carbon cycle of salt marsh sediments.
Collapse
Affiliation(s)
- Ashley N Bulseco
- Marine Science Center, Northeastern University, Nahant, MA, USA; Department of Biological Sciences, University of New Hampshire, Durham, NH, USA
| | - Anna E Murphy
- Marine Science Center, Northeastern University, Nahant, MA, USA; INSPIRE Environmental, Newport, RI, USA
| | - Anne E Giblin
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA, USA
| | - Jane Tucker
- The Ecosystems Center, Marine Biological Laboratory, Woods Hole, MA, USA
| | | | - Jennifer L Bowen
- Marine Science Center, Northeastern University, Nahant, MA, USA.
| |
Collapse
|
2
|
Sierra A, Correia C, Ortega T, Forja J, Rodrigues M, Cravo A. Dynamics of CO 2, CH 4, and N 2O in Ria Formosa coastal lagoon (southwestern Iberia) and export to the Gulf of Cadiz. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167094. [PMID: 37734615 DOI: 10.1016/j.scitotenv.2023.167094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 08/16/2023] [Accepted: 09/13/2023] [Indexed: 09/23/2023]
Abstract
A first characterization of greenhouse gases had been carried out to study their role and impact in a productive transitional coastal system of the southern Portugal - Ria Formosa lagoon. To this purpose, the partial pressure of CO2 (pCO2) and the concentration of dissolved CH4 and N2O have been measured. Two surveys were carried out during 2020, at low tide under typical conditions of Spring (March) and end of Summer (October). The samplings sites were distributed along the costal lagoon covering: i) inner areas with strong human impact (influence of different flows of treated wastewater discharges); and ii) main channels in connection with the main inlets to study the exchanges with the ocean. In general, the highest values of the three greenhouse gases were found at the inner studied areas, especially affected by the disposal of treated effluents from wastewater treatment plans, in October. The mean water - atmosphere fluxes of the CO2, CH4 and N2O are positive, showing that the study area acts as a source of these gases to the atmosphere. On the other hand, it was calculated a rough estimation of the three gases globally exported from Ria Formosa to the ocean, through the main six inlets to evaluate the magnitude of the supply of these gases from Ria Formosa to the adjacent ocean. The mean CO2, CH4 and N2O horizontal water fluxes exported from all the inlets of Ria Formosa to the Gulf of Cadiz for both seasons, during low water, are 8.7 ± 3.9 mmol m-2 s-1, 8.0 ± 3.5 μmol m-2 s-1 and 3.2 ± 1.5 μmol m-2 s-1, which corresponds to a mass transport through the inlets section of 0.7 ± 0.7 kg s-1, 0.2 ± 0.2 g s-1 and 0.2 ± 0.3 g s-1 respectively. From these estimates, as expected, the higher mass transport was found at the larger and deeper inlets (Faro-Olhão and Armona).
Collapse
Affiliation(s)
- A Sierra
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - C Correia
- FCT, CIMA, Centre of Marine and Environmental Research\ARNET - Infrastructure Network in Aquatic Research, University of Algarve, Campus de Gambelas, 8000-139 Faro, Portugal.
| | - T Ortega
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - J Forja
- Dpto. Química-Física, INMAR, Facultad de Ciencias del Mar y Ambientales, Universidad de Cádiz, Campus Universitario Río San Pedro, 11510 Puerto Real, Cádiz, Andalucía, Spain.
| | - M Rodrigues
- Laboratório Nacional de Engenharia Civil, Avenida do Brasil, 101, 1700-066 Lisboa, Portugal.
| | - A Cravo
- FCT, CIMA, Centre of Marine and Environmental Research\ARNET - Infrastructure Network in Aquatic Research, University of Algarve, Campus de Gambelas, 8000-139 Faro, Portugal.
| |
Collapse
|
3
|
Mason VG, Burden A, Epstein G, Jupe LL, Wood KA, Skov MW. Blue carbon benefits from global saltmarsh restoration. GLOBAL CHANGE BIOLOGY 2023; 29:6517-6545. [PMID: 37746862 DOI: 10.1111/gcb.16943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2023] [Revised: 08/30/2023] [Accepted: 08/31/2023] [Indexed: 09/26/2023]
Abstract
Coastal saltmarshes are found globally, yet are 25%-50% reduced compared with their historical cover. Restoration is incentivised by the promise that marshes are efficient storers of 'blue' carbon, although the claim lacks substantiation across global contexts. We synthesised data from 431 studies to quantify the benefits of saltmarsh restoration to carbon accumulation and greenhouse gas uptake. The results showed global marshes store approximately 1.41-2.44 Pg carbon. Restored marshes had very low greenhouse gas (GHG) fluxes and rapid carbon accumulation, resulting in a mean net accumulation rate of 64.70 t CO2 e ha-1 year-1 . Using this estimate and potential restoration rates, we find saltmarsh regeneration could result in 12.93-207.03 Mt CO2 e accumulation per year, offsetting the equivalent of up to 0.51% global energy-related CO2 emissions-a substantial amount, considering marshes represent <1% of Earth's surface. Carbon accumulation rates and GHG fluxes varied contextually with temperature, rainfall and dominant vegetation, with the eastern coasts of the USA and Australia particular hotspots for carbon storage. While the study reveals paucity of data for some variables and continents, suggesting need for further research, the potential for saltmarsh restoration to offset carbon emissions is clear. The ability to facilitate natural carbon accumulation by saltmarshes now rests principally on the action of the management-policy community and on financial opportunities for supporting restoration.
Collapse
Affiliation(s)
- Victoria G Mason
- School of Ocean Sciences, Bangor University, Anglesey, UK
- Department of Estuarine and Delta Systems, Royal Netherlands Institute for Sea Research (NIOZ) and Utrecht University, Yerseke, The Netherlands
- Department of Physical Geography, Faculty of Geosciences, Utrecht University, Utrecht, The Netherlands
| | - Annette Burden
- UK Centre for Ecology & Hydrology, Environment Centre Wales, Bangor, UK
| | - Graham Epstein
- Centre for Ecology and Conservation, University of Exeter, Cornwall, UK
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Lucy L Jupe
- Wildfowl & Wetlands Trust, Slimbridge Wetland Centre, Slimbridge, UK
| | - Kevin A Wood
- Wildfowl & Wetlands Trust, Slimbridge Wetland Centre, Slimbridge, UK
| | - Martin W Skov
- School of Ocean Sciences, Bangor University, Anglesey, UK
| |
Collapse
|
4
|
Watson EB, Rahman FI, Woolfolk A, Meyer R, Maher N, Wigand C, Gray AB. High nutrient loads amplify carbon cycling across California and New York coastal wetlands but with ambiguous effects on marsh integrity and sustainability. PLoS One 2022; 17:e0273260. [PMID: 36084085 PMCID: PMC9462672 DOI: 10.1371/journal.pone.0273260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2022] [Accepted: 08/04/2022] [Indexed: 11/18/2022] Open
Abstract
Eutrophic conditions in estuaries are a globally important stressor to coastal ecosystems and have been suggested as a driver of coastal salt marsh loss. Potential mechanisms in marshes include disturbance caused by macroalgae accumulations, enhanced soil sulfide levels linked to high labile carbon inputs, accelerated decomposition, and declines in belowground biomass that contribute to edge instability, erosion, and slumping. However, results of fertilization studies have been mixed, and it is unclear the extent to which local environmental conditions, such as soil composition and nutrient profiles, help shape the response of salt marshes to nutrient exposure. In this study, we characterized belowground productivity and decomposition, organic matter mineralization rates, soil respiration, microbial biomass, soil humification, carbon and nitrogen inventories, nitrogen isotope ratios, and porewater profiles at high and low marsh elevations across eight marshes in four estuaries in California and New York that have strong contrasts in nutrient inputs. The higher nutrient load marshes were characterized by faster carbon turnover, with higher belowground production and decomposition and greater carbon dioxide efflux than lower nutrient load marshes. These patterns were robust across marshes of the Atlantic and Pacific coasts that varied in plant species composition, soil flooding patterns, and soil texture. Although impacts of eutrophic conditions on carbon cycling appeared clear, it was ambiguous whether high nutrient loads are causing negative effects on long-term marsh sustainability in terms of studied metrics. While high nutrient exposure marshes had high rates of decomposition and soil respiration rates, high nutrient exposure was also associated with increased belowground production, and reduced levels of sulfides, which should lead to greater marsh sustainability. While this study does not resolve the extent to which nutrient loads are negatively affecting these salt marshes, we do highlight functional differences between Atlantic and Pacific wetlands which may be useful for understanding coastal marsh health and integrity.
Collapse
Affiliation(s)
- Elizabeth Burke Watson
- Department of Biodiversity, Earth and Environmental Sciences and The Academy of Natural Sciences, Drexel University, Philadelphia, PA, United States of America
- * E-mail:
| | - Farzana I. Rahman
- Department of Biodiversity, Earth and Environmental Sciences and The Academy of Natural Sciences, Drexel University, Philadelphia, PA, United States of America
| | - Andrea Woolfolk
- Elkhorn Slough National Estuarine Research Reserve, Watsonville, California, United States of America
| | - Robert Meyer
- Elkhorn Slough National Estuarine Research Reserve, Watsonville, California, United States of America
| | - Nicole Maher
- The Nature Conservancy in New York, Uplands Farm Sanctuary, Cold Spring Harbor, New York, United States of America
| | - Cathleen Wigand
- Atlantic Coastal Environmental Sciences Division, United States Environmental Protection Agency, Narragansett, Rhode Island, United States of America
| | - Andrew B. Gray
- Department of Environmental Sciences, University of California, Riverside, California, United States of America
| |
Collapse
|
5
|
Peng X, Ji Q, Angell JH, Kearns PJ, Bowen JL, Ward BB. Long-Term Fertilization Alters Nitrous Oxide Cycling Dynamics in Salt Marsh Sediments. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:10832-10842. [PMID: 34291904 DOI: 10.1021/acs.est.1c01542] [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: 06/13/2023]
Abstract
Salt marsh sediments are known hotspots for nitrogen cycling, including the production and consumption of nitrous oxide (N2O), a potent greenhouse gas and ozone-depleting agent. Coastal eutrophication, particularly elevated nitrogen loading from the application of fertilizers, is accelerating nitrogen cycling processes in salt marsh sediments. Here, we examine the impact of long-term fertilization on nitrogen cycling processes with a focus on N2O dynamics in a New England salt marsh. By combining 15N-tracer experiments with numerical modeling, we found that both nitrification and denitrification contribute to net N2O production in fertilized sediments. Long-term fertilization increased the relative importance of nitrification to N2O production, likely a result of increased oxygen penetration from nutrient-induced increases in marsh elevation. Substrate utilization rates of key nitrogen cycling processes revealed links between functions and the corresponding microbial communities. Higher specific substrate utilization rates leading to N2O production from nitrification in fertilized sediments indicate a shift in the community composition of ammonia oxidizers, whereas the lack of change in specific substrate utilization of N2O production from denitrification under long-term fertilization suggests resilience of the denitrifying communities. Both are consistent with previous studies on the functional gene community composition in these experimental plots.
Collapse
Affiliation(s)
- Xuefeng Peng
- Department of Geosciences, Princeton University, Princeton 08544, New Jersey, United States
| | - Qixing Ji
- Department of Geosciences, Princeton University, Princeton 08544, New Jersey, United States
| | - John H Angell
- Department of Biology, University of Massachusetts, Boston 02125-3300, Massachusetts, United States
| | - Patrick J Kearns
- Department of Biology, University of Massachusetts, Boston 02125-3300, Massachusetts, United States
| | - Jennifer L Bowen
- Department of Biology, University of Massachusetts, Boston 02125-3300, Massachusetts, United States
| | - Bess B Ward
- Department of Geosciences, Princeton University, Princeton 08544, New Jersey, United States
| |
Collapse
|
6
|
Wu D, Zhao C, Bai H, Feng F, Sui X, Sun G. Characteristics and metabolic patterns of soil methanogenic archaea communities in the high-latitude natural forested wetlands of China. Ecol Evol 2021; 11:10396-10408. [PMID: 34367583 PMCID: PMC8328403 DOI: 10.1002/ece3.7842] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 04/07/2021] [Accepted: 06/10/2021] [Indexed: 01/12/2023] Open
Abstract
Soil methanogenic microorganisms are one of the primary methane-producing microbes in wetlands. However, we still poorly understand the community characteristic and metabolic patterns of these microorganisms according to vegetation type and seasonal changes. Therefore, to better elucidate the effects of the vegetation type and seasonal factors on the methanogenic community structure and metabolic patterns, we detected the characteristics of the soil methanogenic mcrA gene from three types of natural wetlands in different seasons in the Xiaoxing'an Mountain region, China. The results indicated that the distribution of Methanobacteriaceae (hydrogenotrophic methanogens) was higher in winter, while Methanosarcinaceae and Methanosaetaceae accounted for a higher proportion in summer. Hydrogenotrophic methanogenesis was the dominant trophic pattern in each wetland. The results of principal coordinate analysis and cluster analysis showed that the vegetation type considerably influenced the methanogenic community composition. The methanogenic community structure in the Betula platyphylla-Larix gmelinii wetland was relatively different from the structure of the other two wetland types. Indicator species analysis further demonstrated that the corresponding species of indicator operational taxonomic units from the Alnus sibirica wetland and the Betula ovalifolia wetland were similar. Network analysis showed that cooperative and competitive relationships exist both within and between the same or different trophic methanogens. The core methanogens with higher abundance in each wetland were conducive to the adaptation to environmental disturbances. This information is crucial for the assessment of metabolic patterns of soil methanogenic archaea and future fluxes in the wetlands of the Xiaoxing'an Mountain region given their vulnerability.
Collapse
Affiliation(s)
- Di Wu
- Key Laboratory of Saline‐Alkali Vegetation Ecology Restoration (Northeast Forestry University)Ministry of EducationHarbinChina
- College of Life ScienceNortheast Forestry UniversityHarbinChina
| | - Caihong Zhao
- College of Life ScienceNortheast Forestry UniversityHarbinChina
| | - Hui Bai
- Key Laboratory of Fast‐Growing Tree Cultivating of Heilongjiang ProvinceForestry Science Research Institute of Heilongjiang ProvinceHarbinChina
| | - Fujuan Feng
- College of Life ScienceNortheast Forestry UniversityHarbinChina
| | - Xin Sui
- Heilongjiang Provincial Key Laboratory of Ecological Restoration and Resource Utilization for Cold RegionSchool of Life SciencesHeilongjiang UniversityHarbinChina
| | - Guangyu Sun
- Key Laboratory of Saline‐Alkali Vegetation Ecology Restoration (Northeast Forestry University)Ministry of EducationHarbinChina
- College of Life ScienceNortheast Forestry UniversityHarbinChina
| |
Collapse
|
7
|
Mozdzer TJ, Drew SE, Caplan JS, Weber PE, Deegan LA. Rapid recovery of carbon cycle processes after the cessation of chronic nutrient enrichment. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 750:140927. [PMID: 32853928 DOI: 10.1016/j.scitotenv.2020.140927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Revised: 07/09/2020] [Accepted: 07/10/2020] [Indexed: 06/11/2023]
Abstract
Salt marshes provide critical ecosystem services including some of the highest rates of carbon storage on Earth. However, many salt marshes receive very high nutrient loads and there is a growing body of evidence indicating that this nutrient enrichment alters carbon cycle processes. While many restoration plans prioritize nutrient management in their efforts to conserve salt marsh ecosystems, there has been little empirical investigation of the capacity for carbon cycle processes to recover once nutrient loading is reduced. To address this, we compared rates of greenhouse gas fluxes (i.e., CO2 and methane) measured using static chambers, and soil organic matter decomposition, using both litter bags and the Tea Bag Index (TBI), during the last two years of a long-term, ecosystem-scale nutrient enrichment experiment (2015-2016) as well as in the first two years of recovery post-enrichment (2017-2018). We found that both ecosystem respiration (Reco) and decomposition processes (i.e., rhizome decomposition and soil organic matter stabilization) were enhanced by nutrient enrichment, but returned to reference ecosystem levels within the first year following the cessation of nutrient enrichment and remained at reference levels in the second year. These results suggest that management practices intended to reduce nutrient loads in coastal systems may, in fact, allow for rapid recovery of carbon cycle processes, potentially restoring the high carbon sequestration rates of these blue carbon ecosystems.
Collapse
Affiliation(s)
- Thomas J Mozdzer
- Bryn Mawr College, Department of Biology, 101 N Merion Ave, Bryn Mawr, PA, 19010, United States of America.
| | - Sophie E Drew
- Bryn Mawr College, Department of Biology, 101 N Merion Ave, Bryn Mawr, PA, 19010, United States of America
| | - Joshua S Caplan
- Department of Architecture and Environmental Design, Temple University, 580 Meetinghouse Rd., Ambler, PA 19002, United States of America
| | - Paige E Weber
- Bryn Mawr College, Department of Biology, 101 N Merion Ave, Bryn Mawr, PA, 19010, United States of America
| | - Linda A Deegan
- Woods Hole Research Center, 149 Woods Hole Rd., Woods Hole, MA 02540, United States of America
| |
Collapse
|