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Hall LA, Woo I, Marvin-DiPasquale M, Takekawa JY, Krabbenhoft DP, Yee D, Grenier L, De La Cruz SEW. Linking Mesoscale Spatial Variation in Methylmercury Production to Bioaccumulation in Tidal Marsh Food Webs. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:19263-19273. [PMID: 37956992 DOI: 10.1021/acs.est.3c04907] [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: 11/21/2023]
Abstract
Differences in sediment biogeochemistry among tidal marsh features with different hydrological and geomorphological characteristics, including marsh interiors, marsh edges, first-order channels, and third-order channels, can result in spatial variation in MeHg production and availability. To better understand the link between MeHg production in sediments and bioaccumulation in primary and secondary consumer invertebrates and fish, we characterized mesoscale spatial variation in sediment biogeochemistry and MeHg concentrations of sediments, water, and consumer tissues among marsh features. Our results indicated that marsh interiors had biogeochemical conditions, including greater concentrations of organic matter and sulfate reduction rates, that resulted in greater MeHg concentrations in sediments and surface water particulates from marsh interiors compared to other features. Tissue MeHg concentrations of consumers also differed among features, with greater concentrations from marsh edges and interiors compared to channels. This spatial mismatch of MeHg concentrations in sediments and water compared to those in consumers may have resulted from differences in behavior and physiology among consumers that influenced the spatial scale over which MeHg was integrated into tissues. Our results highlight the importance of sampling across a suite of marsh features and considering the behavioral and physiological traits of sentinel taxa for contaminant monitoring studies.
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Affiliation(s)
- Laurie A Hall
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - Isa Woo
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - Mark Marvin-DiPasquale
- U.S. Geological Survey, Water Mission Area, Earth System Processes Division, 345 Middlefield Road, Menlo Park, California 94025, United States
| | - John Y Takekawa
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
| | - David P Krabbenhoft
- U.S. Geological Survey, Mercury Research Laboratory, 8505 Research Way, Middleton, Wisconsin 53562, United States
| | - Donald Yee
- San Francisco Estuary Institute, 4911 Central Avenue, Richmond, California 94804, United States
| | - Letitia Grenier
- San Francisco Estuary Institute, 4911 Central Avenue, Richmond, California 94804, United States
| | - Susan E W De La Cruz
- U.S. Geological Survey, Western Ecological Research Center, San Francisco Bay Estuary Field Station, NASA Research Park Bldg. 19, N. Akron Road, Moffett Field, California 94035, United States
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Wang F, Liu J, Qin G, Zhang J, Zhou J, Wu J, Zhang L, Thapa P, Sanders CJ, Santos IR, Li X, Lin G, Weng Q, Tang J, Jiao N, Ren H. Coastal blue carbon in China as a nature-based solution toward carbon neutrality. Innovation (N Y) 2023; 4:100481. [PMID: 37636281 PMCID: PMC10451025 DOI: 10.1016/j.xinn.2023.100481] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Accepted: 07/09/2023] [Indexed: 08/29/2023] Open
Abstract
To achieve the Paris Agreement, China pledged to become "Carbon Neutral" by the 2060s. In addition to massive decarbonization, this would require significant changes in ecosystems toward negative CO2 emissions. The ability of coastal blue carbon ecosystems (BCEs), including mangrove, salt marsh, and seagrass meadows, to sequester large amounts of CO2 makes their conservation and restoration an important "nature-based solution (NbS)" for climate adaptation and mitigation. In this review, we examine how BCEs in China can contribute to climate mitigation. On the national scale, the BCEs in China store up to 118 Tg C across a total area of 1,440,377 ha, including over 75% as unvegetated tidal flats. The annual sedimental C burial of these BCEs reaches up to 2.06 Tg C year-1, of which most occurs in salt marshes and tidal flats. The lateral C flux of mangroves and salt marshes contributes to 1.17 Tg C year-1 along the Chinese coastline. Conservation and restoration of BCEs benefit climate change mitigation and provide other ecological services with a value of $32,000 ha-1 year-1. The potential practices and technologies that can be implemented in China to improve BCE C sequestration, including their constraints and feasibility, are also outlined. Future directions are suggested to improve blue carbon estimates on aerial extent, carbon stocks, sequestration, and mitigation potential. Restoring and preserving BCEs would be a cost-effective step to achieve Carbon Neutral by 2060 in China despite various barriers that should be removed.
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Affiliation(s)
- Faming Wang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
| | - Jihua Liu
- Marine Research Institute, Shandong University, Qingdao 266237, China
| | - Guoming Qin
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingfan Zhang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jinge Zhou
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jingtao Wu
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
| | - Lulu Zhang
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
| | - Poonam Thapa
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
| | - Christian J. Sanders
- National Marine Science Centre, Faculty of Science and Engineering, Southern Cross University, Coffs Harbour, NSW 2450, Australia
| | - Isaac R. Santos
- Department of Marine Sciences, University of Gothenburg, 41319 Gothenburg, Sweden
| | - Xiuzhen Li
- State Key Laboratory of Estuarine and Coastal Research and Institute of Eco-Chongming, East China Normal University, Shanghai 201100, China
| | - Guanghui Lin
- Key Laboratory for Earth System Modeling, Ministry of Education, Department of Earth System Science, Tsinghua University, Beijing 100084, China
- Laboratory of Stable Isotope and Gulf Ecology, Institute of Ocean Engineering, Tsinghua’s Shenzhen International Graduate School, Shenzhen 518055, China
| | - Qihao Weng
- Department of Land Surveying and Geo-Informatics, The Hong Kong Polytechnic University, Hongkong 999077, China
| | - Jianwu Tang
- State Key Laboratory of Estuarine and Coastal Research and Institute of Eco-Chongming, East China Normal University, Shanghai 201100, China
| | - Nianzhi Jiao
- Innovative Research Center for Carbon Neutralization, Global ONCE Program, Xiamen 361005, China
| | - Hai Ren
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and the CAS Engineering Laboratory for Ecological Restoration of Island and Coastal Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, China
- Southern Marine Science and Engineering Guangdong Laboratory (Guangzhou), Guangzhou 510650, China
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Hingst MC, McQuiggan RW, Peters CN, He C, Andres AS, Michael HA. Surface Water-Groundwater Connections as Pathways for Inland Salinization of Coastal Aquifers. GROUND WATER 2023; 61:626-638. [PMID: 36397676 DOI: 10.1111/gwat.13274] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/09/2022] [Accepted: 11/14/2022] [Indexed: 06/16/2023]
Abstract
Coastal agricultural zones are experiencing salinization due to accelerating rates of sea-level rise, causing reduction in crop yields and abandonment of farmland. Understanding mechanisms and drivers of this seawater intrusion (SWI) is key to mitigating its effects and predicting future vulnerability of groundwater resources to salinization. We implemented a monitoring network of pressure and specific conductivity (SC) sensors in wells and surface waters to target marsh-adjacent agricultural areas in greater Dover, Delaware. Recorded water levels and SC over a period of three years show that the mechanisms and timescales of SWI are controlled by local hydrology, geomorphology, and geology. Monitored wells did not indicate widespread salinization of deep groundwater in the surficial aquifer. However, monitored surface water bodies and shallow (<4 m deep) wells did show SC fluctuations due to tides and storm events, in one case leading to salinization of deeper (18 m deep) groundwater. Seasonal peaks in SC occurred during late summer months. Seasonal and interannual variation of SC was also influenced by relative sea level. The data collected in this study data highlight the mechanisms by which surface water-groundwater connections lead to salinization of aquifers inland, before SWI is detected in deeper groundwater nearer the coastline. Sharing of our data with stakeholders has led to the implementation of SWI mitigation efforts, illustrating the importance of strategic monitoring and stakeholder engagement to support coastal resilience.
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Affiliation(s)
- Mary C Hingst
- Department of Earth Sciences, University of Delaware, Newark, DE, USA
| | | | - Chelsea N Peters
- Department of Environmental Studies, Roanoke College, Salem, VA, USA
| | | | | | - Holly A Michael
- Department of Earth Sciences, University of Delaware, Newark, DE, USA
- Department of Civil and Environmental Engineering, University of Delaware, Newark, DE, USA
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4
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Carol E, Galliari MJ, Santucci L, Nuñez F, Faleschini M. Assessment of groundwater-driven dissolved nutrient inputs to coastal wetlands associated with marsh-coastal lagoons systems of the littoral of the outer Río de la Plata estuary. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 885:163942. [PMID: 37149199 DOI: 10.1016/j.scitotenv.2023.163942] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/21/2023] [Accepted: 04/30/2023] [Indexed: 05/08/2023]
Abstract
In coastal wetlands the hydrological dynamics and in particular the groundwater flows play a critical role in the establishment of wetlands and in the transport of salts and nutrients. The aim of the work is to analyze the role that groundwater discharge has in the dynamics of the dissolved nutrients of the wetland associated with the coastal lagoon and marshes of the Punta Rasa Natural Reserve, which is located on the coastal sector of the southern end of the Río de la Plata estuary. A monitoring network in the form of transects was generated in order to define groundwater flows and take samples of dissolved species of N and P. The presence of sandy sediments with similar granulometric profiles in all geomorphological environments determines that the underground flow occurs in a homogeneous aquifer. From the dunes and beach ridges the fresh to brackish groundwater flows with a very low hydraulic gradient towards the marsh and coastal lagoon. The contributions of N and P would derive from the degradation of the organic matter of the environment, in the case of the marsh and coastal lagoon also from the tidal flow and discharge of groundwater, and possibly from atmospheric sources in the case of N. Since in all environments oxidizing conditions dominate, nitrification is the main process which is why the most abundant species of N is the NO3-. Under oxidizing conditions, P has a greater affinity for the sediments in which it is mostly retained, registering it in low concentrations in water. The discharge of groundwater from the dunes and beach ridges provides dissolved nutrients to the marsh and coastal lagoon. However, the low hydraulic gradient and the dominant oxidizing conditions determine that the flow is scarce and that it only acquires relevance in the contribution of NO3-.
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Affiliation(s)
- E Carol
- Centro de Investigaciones Geológicas (CIG), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de La Plata (UNLP), Argentina; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP), Argentina.
| | - M J Galliari
- Centro de Investigaciones Geológicas (CIG), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de La Plata (UNLP), Argentina; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP), Argentina
| | - L Santucci
- Centro de Investigaciones Geológicas (CIG), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Universidad Nacional de La Plata (UNLP), Argentina; Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP), Argentina
| | - F Nuñez
- Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata (UNLP), Argentina
| | - M Faleschini
- Centro para el Estudio de Sistemas Marinos (CESIMAR), Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Argentina
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5
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Climate-driven tradeoffs between landscape connectivity and the maintenance of the coastal carbon sink. Nat Commun 2023; 14:1137. [PMID: 36914625 PMCID: PMC10011419 DOI: 10.1038/s41467-023-36803-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 02/15/2023] [Indexed: 03/16/2023] Open
Abstract
Ecosystem connectivity tends to increase the resilience and function of ecosystems responding to stressors. Coastal ecosystems sequester disproportionately large amounts of carbon, but rapid exchange of water, nutrients, and sediment makes them vulnerable to sea level rise and coastal erosion. Individual components of the coastal landscape (i.e., marsh, forest, bay) have contrasting responses to sea level rise, making it difficult to forecast the response of the integrated coastal carbon sink. Here we couple a spatially-explicit geomorphic model with a point-based carbon accumulation model, and show that landscape connectivity, in-situ carbon accumulation rates, and the size of the landscape-scale coastal carbon stock all peak at intermediate sea level rise rates despite divergent responses of individual components. Progressive loss of forest biomass under increasing sea level rise leads to a shift from a system dominated by forest biomass carbon towards one dominated by marsh soil carbon that is maintained by substantial recycling of organic carbon between marshes and bays. These results suggest that climate change strengthens connectivity between adjacent coastal ecosystems, but with tradeoffs that include a shift towards more labile carbon, smaller marsh and forest extents, and the accumulation of carbon in portions of the landscape more vulnerable to sea level rise and erosion.
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6
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Krask JL, Buck TL, Dunn RP, Smith EM. Increasing tidal inundation corresponds to rising porewater nutrient concentrations in a southeastern U.S. salt marsh. PLoS One 2022; 17:e0278215. [PMID: 36441803 PMCID: PMC9704656 DOI: 10.1371/journal.pone.0278215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Accepted: 11/11/2022] [Indexed: 11/29/2022] Open
Abstract
Salt marshes are ecologically and economically important features of coastal environments that are vulnerable to sea level rise, the rate of which has accelerated in recent decades along the southeastern US Atlantic coast. Increased flooding frequency and duration across the marsh platform is predicted to impact vegetation community structure and overall marsh persistence, but the effect of changing inundation patterns on biogeochemical processes in marsh sediments remains largely unexplored. As part of a long-term monitoring effort to assess how marshes are responding to sea level rise in North Inlet estuary (South Carolina, USA), we collected data on porewater nutrient concentrations from a series of permanent monitoring plots across multiple transects spanning the marsh elevation gradient during the growing season from 2009 to 2019. Additionally, we calculated time inundated for each plot using local water level data and high-resolution elevation measurements to assess the change in time flooded at each plot. Our results indicate that both NH4 and PO4 nutrient concentrations have increased in most permanent plots over the 11-year study period and that nutrient concentrations are higher with increasing proximity to the creek. Spatial patterns in nutrient increases through time are coincident with considerable increases in tidal inundation observed over the marsh platform. Across plots located in the low marsh, porewater NH4 and PO4 concentrations have risen at average rates of 8.96 μM/year and 0.86 μM/year, respectively, and have reached rates as high as 27.25 μM/year and 3.13 μM/year. We suggest that increased inundation time due to rising sea level has altered biogeochemical conditions influencing nutrient availability in marsh porewater, resulting in increases that likely have relevance for larger scale nutrient cycles as well as marsh ecosystem stability and function.
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Affiliation(s)
- Julie L. Krask
- North Inlet-Winyah Bay National Estuarine Research Reserve, Baruch Institute for Coastal and Marine Sciences, University of South Carolina, Georgetown, SC, United States of America
- * E-mail:
| | - Tracy L. Buck
- North Inlet-Winyah Bay National Estuarine Research Reserve, Baruch Institute for Coastal and Marine Sciences, University of South Carolina, Georgetown, SC, United States of America
| | - Robert P. Dunn
- North Inlet-Winyah Bay National Estuarine Research Reserve, Baruch Institute for Coastal and Marine Sciences, University of South Carolina, Georgetown, SC, United States of America
| | - Erik M. Smith
- North Inlet-Winyah Bay National Estuarine Research Reserve, Baruch Institute for Coastal and Marine Sciences, University of South Carolina, Georgetown, SC, United States of America
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7
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Advances in the Study and Understanding of Groundwater Discharge to Surface Water. WATER 2022. [DOI: 10.3390/w14111698] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Groundwater discharge is vitally important for maintaining or restoring valuable ecosystems in surface water and at the underlying groundwater-surface-water ecotone [...]
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Sturbois A, Riera P, Desroy N, Brébant T, Carpentier A, Ponsero A, Schaal G. Spatio-temporal patterns in stable isotope composition of a benthic intertidal food web reveal limited influence from salt marsh vegetation and green tide. MARINE ENVIRONMENTAL RESEARCH 2022; 175:105572. [PMID: 35134641 DOI: 10.1016/j.marenvres.2022.105572] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2021] [Revised: 01/28/2022] [Accepted: 01/30/2022] [Indexed: 06/14/2023]
Abstract
Assessing fluxes of matter and energy in food webs within and across benthic habitats is important to understand the ecological functioning in bays and estuaries, where the productivity is favoured by a wide diversity of primary producers. The temporal variability (March vs September 2019) in the carbon and nitrogen stable isotope composition of primary food sources and benthic invertebrates consumers was investigated in a large intertidal area (Western English-Channel, France). The study area is influenced by megatidal conditions and characterised by salt marshes in the sheltered part, and seasonal Ulva spp. blooms. The spatio-temporal variability in the structure of the benthic food web was analysed at the scales of both the whole bay and the different assemblages, which constitute the mosaic of habitats. Inferences on potential sources fuelling the food web were supported by spatio-temporal patterns based on covariations and stable isotope trajectory analysis. Results highlighted that phytoplankton, microphytobenthos and SOM were, most likely, the main food sources. The trophic connectivity between salt marsh and benthic habitats within the bay was limited to some macrofauna species inhabiting muddy creeks within the salt marsh. Unexpectedly, the influence of Ulva spp. blooms appeared also limited. Spatial patterns illustrates the constancy of the spatial variability in the benthic pelagic coupling, with a higher influence of microphytobenthos in the upper shore compared to low shore assemblages. This first attempt to characterize intertidal benthic food web constitutes a relevant baseline for the conservation of the bay of Saint-Brieuc where a national Nature Reserve has been created in 1998 for the conservation of overwintering birds. The spatial and temporal patterns of the benthic food web observed in this study (1) confirm the importance to consider food web variability at spatial and temporal scales from sampling designs to data analysis, and (2) demonstrate the ability of the stable isotope trajectory analysis framework to highlight food web dynamics.
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Affiliation(s)
- A Sturbois
- Vivarmor Nature, 18 C rue du Sabot, 22440, Ploufragan, France; Réserve naturelle nationale de la Baie de Saint-Brieuc, site de l'étoile, 22120, Hillion, France; Ifremer, Laboratoire Environnement et Ressources Bretagne nord, 38 rue du Port Blanc, 35800, Dinard, France; Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 CNRS/UBO/IRD/IFREMER, BP 70, 29280, Plouzané, France.
| | - P Riera
- Sorbonne Université, CNRS, Station Biologique de Roscoff, UMR7144, Place Georges Teissier, CS90074, 29688, Roscoff Cedex, France
| | - N Desroy
- Ifremer, Laboratoire Environnement et Ressources Bretagne nord, 38 rue du Port Blanc, 35800, Dinard, France
| | - T Brébant
- Ifremer, Laboratoire Environnement et Ressources Bretagne nord, 38 rue du Port Blanc, 35800, Dinard, France
| | - A Carpentier
- Université de Rennes 1, BOREA, Muséum National d'Histoire Naturelle, Sorbonne Université, Université de Caen Normandie, Université des Antilles), Campus de Beaulieu, 35000, Rennes, France
| | - A Ponsero
- Réserve naturelle nationale de la Baie de Saint-Brieuc, site de l'étoile, 22120, Hillion, France; Saint-Brieuc Agglomération Baie d'Armor, 5 rue du 71ème RI, 22000, Saint-Brieuc, France
| | - G Schaal
- Laboratoire des Sciences de l'Environnement Marin (LEMAR), UMR 6539 CNRS/UBO/IRD/IFREMER, BP 70, 29280, Plouzané, France
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Salehi Hikouei I, Kim SS, Mishra DR. Machine-Learning Classification of Soil Bulk Density in Salt Marsh Environments. SENSORS 2021; 21:s21134408. [PMID: 34199102 PMCID: PMC8271383 DOI: 10.3390/s21134408] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 06/22/2021] [Accepted: 06/23/2021] [Indexed: 11/24/2022]
Abstract
Remotely sensed data from both in situ and satellite platforms in visible, near-infrared, and shortwave infrared (VNIR–SWIR, 400–2500 nm) regions have been widely used to characterize and model soil properties in a direct, cost-effective, and rapid manner at different scales. In this study, we assess the performance of machine-learning algorithms including random forest (RF), extreme gradient boosting machines (XGBoost), and support vector machines (SVM) to model salt marsh soil bulk density using multispectral remote-sensing data from the Landsat-7 Enhanced Thematic Mapper Plus (ETM+) platform. To our knowledge, use of remote-sensing data for estimating salt marsh soil bulk density at the vegetation rooting zone has not been investigated before. Our study reveals that blue (band 1; 450–520 nm) and NIR (band 4; 770–900 nm) bands of Landsat-7 ETM+ ranked as the most important spectral features for bulk density prediction by XGBoost and RF, respectively. According to XGBoost, band 1 and band 4 had relative importance of around 41% and 39%, respectively. We tested two soil bulk density classes in order to differentiate salt marshes in terms of their capability to support vegetation that grows in either low (0.032 to 0.752 g/cm3) or high (0.752 g/cm3 to 1.893 g/cm3) bulk density areas. XGBoost produced a higher classification accuracy (88%) compared to RF (87%) and SVM (86%), although discrepancies in accuracy between these models were small (<2%). XGBoost correctly classified 178 out of 186 soil samples labeled as low bulk density and 37 out of 62 soil samples labeled as high bulk density. We conclude that remote-sensing-based machine-learning models can be a valuable tool for ecologists and engineers to map the soil bulk density in wetlands to select suitable sites for effective restoration and successful re-establishment practices.
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Affiliation(s)
- Iman Salehi Hikouei
- Appalachian Laboratory, University of Maryland Center for Environmental Science, Frostburg, MD 21532, USA;
| | - S. Sonny Kim
- College of Engineering, University of Georgia, Athens, GA 30602, USA
- Correspondence: ; Tel.: +1-70-6542-9804
| | - Deepak R. Mishra
- Department of Geography, University of Georgia, Athens, GA 30602, USA;
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