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Zeng Y, Wang H, Hu J, Zhang J, Wang F, Wang T, Zhou Q, Dahlgren RA, Gao M, Gao H, Chen Z. Illuminated fulvic acid stimulates denitrification and As(III) immobilization in flooded paddy soils via an enhanced biophotoelectrochemical pathway. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169670. [PMID: 38160830 DOI: 10.1016/j.scitotenv.2023.169670] [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: 10/08/2023] [Revised: 12/03/2023] [Accepted: 12/23/2023] [Indexed: 01/03/2024]
Abstract
Fulvic acid (FA) is a representative photosensitive dissolved organic matter (DOM) compound that occurs naturally in paddy soils. In this study, the effect of a FA + nitrate treatment (0, 4 and 8 mg/L FA + 20 mmol/L nitrate) on denitrification and As(III) immobilization in flooded paddy soils was assessed under dark and intermittently illuminated conditions (12 h light+12 h dark). The FA input stimulated denitrification in illuminated soils (~100 % of nitrate removal within 6 days) compared to dark conditions (~92 % nitrate removal after 6 days). Meanwhile, As(III) (initial concentration of 0.1 mmol/L) was nearly completely immobilized (~100 %) under illuminated conditions after 4 days for the FA + nitrate treatment compared to 90- 93 % retention in the dark. Denitrification and As immobilization were positively related to the FA dosage in the illuminated assays. The stronger denitrification in illuminated soils was ascribed to denitrifiers harvesting photoelectrons from photosensitive substrates/semiconducting minerals. FA addition also increased the activities of denitrifying enzymes (e.g., NAR, NIR and NOR) and the denitrification electron transport system by nearly 0.6-0.7 and 1.5-1.8 times that of the nitrate-alone treatment under illuminated and dark conditions, thereby fostering stronger denitrification. Upon irradiation, As(III) immobilization was not only stimulated by the interactions with the denitrification pathway whereby As(III) acts as an electron donor for denitrifiers, but was also modulated by Fe(III)/oxidative reactive species-derived photooxidation of As(III). Moreover, the FA + nitrate treatment promoted the enrichment of metal-oxidizing bacteria (e.g., Stenotrophomonas and Acidovorax) that are responsible for nitrate-dependent As(III)/Fe(II) oxidation. The results of this study enhance our understanding of interactions among the biogeochemical cycles of As, Fe, N and C, which are intricately linked by a biophotoelectrochemical pathway in flooded paddy soils.
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Affiliation(s)
- Yanqiong Zeng
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Honghui Wang
- School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, PR China
| | - Jiehua Hu
- Department of Marine Biology, Xiamen Ocean Vocational College, Xiamen 361100, PR China
| | - Jing Zhang
- School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, PR China
| | - Feng Wang
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China
| | - Tongyu Wang
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China; The State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou 325027, PR China
| | - Qiqi Zhou
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China; The State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou 325027, PR China
| | - Randy A Dahlgren
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China; Department of Land, Air & Water Resources, University of California, Davis, CA 95616, USA
| | - Meiling Gao
- The State Key Laboratory of Ophthalmology, Optometry and Visual Science, Wenzhou Medical University, Wenzhou 325027, PR China.
| | - Hui Gao
- Key Laboratory of Fertility Preservation and Maintenance of Ministry of Education, Ningxia Medical University, Yinchuan 750004, PR China.
| | - Zheng Chen
- School of Public Health & Management, Wenzhou Medical University, Wenzhou 325035, PR China; School of Environmental Science & Engineering, Tan Kah Kee College, Xiamen University, Zhangzhou 363105, PR China.
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Wainwright BJ, Millar T, Bowen L, Semon L, Hickman KJE, Lee JN, Yeo ZY, Zahn G. The core mangrove microbiome reveals shared taxa potentially involved in nutrient cycling and promoting host survival. ENVIRONMENTAL MICROBIOME 2023; 18:47. [PMID: 37264467 DOI: 10.1186/s40793-023-00499-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 05/01/2023] [Indexed: 06/03/2023]
Abstract
BACKGROUND Microbes have fundamental roles underpinning the functioning of our planet, they are involved in global carbon and nutrient cycling, and support the existence of multicellular life. The mangrove ecosystem is nutrient limited and if not for microbial cycling of nutrients, life in this harsh environment would likely not exist. The mangroves of Southeast Asia are the oldest and most biodiverse on the planet, and serve vital roles helping to prevent shoreline erosion, act as nursery grounds for many marine species and sequester carbon. Despite these recognised benefits and the importance of microbes in these ecosystems, studies examining the mangrove microbiome in Southeast Asia are scarce.cxs RESULTS: Here we examine the microbiome of Avicenia alba and Sonneratia alba and identify a core microbiome of 81 taxa. A further eight taxa (Pleurocapsa, Tunicatimonas, Halomonas, Marinomonas, Rubrivirga, Altererythrobacte, Lewinella, and Erythrobacter) were found to be significantly enriched in mangrove tree compartments suggesting key roles in this microbiome. The majority of those identified are involved in nutrient cycling or have roles in the production of compounds that promote host survival. CONCLUSION The identification of a core microbiome furthers our understanding of mangrove microbial biodiversity, particularly in Southeast Asia where studies such as this are rare. The identification of significantly different microbial communities between sampling sites suggests environmental filtering is occurring, with hosts selecting for a microbial consortia most suitable for survival in their immediate environment. As climate change advances, many of these microbial communities are predicted to change, however, without knowing what is currently there, it is impossible to determine the magnitude of any deviations. This work provides an important baseline against which change in microbial community can be measured.
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Affiliation(s)
- Benjamin J Wainwright
- Department of Biological Sciences, National University of Singapore, 16 Science Drive 4, Singapore, 117558, Singapore.
- Yale-NUS College, National University of Singapore, 16 College Avenue West, Singapore, 138527, Singapore.
| | - Trevor Millar
- Biology Department, Utah Valley University, 800 W University Parkway, Orem, UT, 84058, USA
| | - Lacee Bowen
- Biology Department, Utah Valley University, 800 W University Parkway, Orem, UT, 84058, USA
| | - Lauren Semon
- Biology Department, Utah Valley University, 800 W University Parkway, Orem, UT, 84058, USA
| | - K J E Hickman
- Biology Department, Utah Valley University, 800 W University Parkway, Orem, UT, 84058, USA
| | - Jen Nie Lee
- Faculty of Science and Marine Environment, Universiti Malaysia Terengganu, 21030, Kuala Nerus, Malaysia
| | - Zhi Yi Yeo
- Yale-NUS College, National University of Singapore, 16 College Avenue West, Singapore, 138527, Singapore
| | - Geoffrey Zahn
- Biology Department, Utah Valley University, 800 W University Parkway, Orem, UT, 84058, USA
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Navarro-Mayoral S, Tuya F, Prado P, Marco-Méndez C, Fernandez-Gonzalez V, Fernández-Torquemada Y, Espino F, Antonio de la Ossa J, Vilella DM, Machado M, Martínez-Crego B. Drivers of variation in seagrass-associated amphipods across biogeographical areas. MARINE ENVIRONMENTAL RESEARCH 2023; 186:105918. [PMID: 36791539 DOI: 10.1016/j.marenvres.2023.105918] [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: 07/13/2022] [Revised: 02/06/2023] [Accepted: 02/09/2023] [Indexed: 06/18/2023]
Abstract
Amphipods are one of the dominant epifaunal groups in seagrass meadows. However, our understanding of the biogeographical patterns in the distribution of these small crustaceans is limited. In this study, we investigated such patterns and the potential drivers in twelve Cymodocea nodosa meadows within four distinctive biogeographical areas across 2000 Km and 13° of latitude in two ocean basins (Mediterranean Sea and Atlantic Ocean). We found that species abundances in the assemblage of seagrass-associated amphipods differed among areas following a pattern largely explained by seagrass leaf area and epiphyte biomass, while the variation pattern in species presence/absence was determined by seagrass density and epiphyte biomass. Seagrass leaf area was also the most important determinant of greater amphipod total density and species richness, while amphipod density also increased with algal cover. Overall, our results evidenced that biogeographical patterns of variation in amphipod assemblages are mainly influenced by components of the habitat structure, which covary with environmental conditions, finding that structurally more complex meadows harboring higher abundance and richness of amphipods associated.
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Affiliation(s)
- Sandra Navarro-Mayoral
- Grupo en Biodiversidad y Conservación, IU-Ecoaqua, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain.
| | - Fernando Tuya
- Grupo en Biodiversidad y Conservación, IU-Ecoaqua, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain
| | - Patricia Prado
- IRTA-Institute of Research and Technology in Food and Agriculture, Ctra. Poble Nou Km 5.5, 43540, Sant Carles de la Ràpita, Spain
| | - Candela Marco-Méndez
- Center for Advanced Studies of Blanes (CEAB, CSIC), Carrer Accés Cala Sant Francesc, 14, 17300, Blanes, Girona, Spain
| | - Victoria Fernandez-Gonzalez
- Department of Marine Science and Applied Biology, University of Alicante, Carretera San Vicente del Raspeig s/n, 03690, Alicante, Spain
| | - Yolanda Fernández-Torquemada
- Department of Marine Science and Applied Biology, University of Alicante, Carretera San Vicente del Raspeig s/n, 03690, Alicante, Spain
| | - Fernando Espino
- Grupo en Biodiversidad y Conservación, IU-Ecoaqua, Universidad de Las Palmas de Gran Canaria, Canary Islands, Spain
| | - Jose Antonio de la Ossa
- Department of Marine Science and Applied Biology, University of Alicante, Carretera San Vicente del Raspeig s/n, 03690, Alicante, Spain
| | - David Mateu Vilella
- IRTA-Institute of Research and Technology in Food and Agriculture, Ctra. Poble Nou Km 5.5, 43540, Sant Carles de la Ràpita, Spain
| | - Margarida Machado
- Centre of Marine Sciences of University of Algarve (CCMAR-UAlg), Campus de Gambelas, Ed. 7, 8005-139, Faro, Portugal
| | - Begoña Martínez-Crego
- Centre of Marine Sciences of University of Algarve (CCMAR-UAlg), Campus de Gambelas, Ed. 7, 8005-139, Faro, Portugal
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Sivadas SK, Patil AJ. Moving beyond traditional macrofaunal community structure studies in the Indian Ocean continental shelf: a research synthesis based on research weaving. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:19536-19563. [PMID: 36640230 DOI: 10.1007/s11356-022-25030-0] [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: 05/05/2022] [Accepted: 12/24/2022] [Indexed: 06/17/2023]
Abstract
The Indian Ocean (IO) continental shelf characterized by unique oceanographic and meteorological features and extreme habitat is a biodiversity hotspot region. Marine biodiversity provides valuable resources and services, in terms of economy, cultural, science, and education. Unsustainable exploitation and habitat degradation represent the greatest threat to biodiversity. Understanding how these services will change in the future requires knowledge of marine biodiversity. Although macrofaunal biodiversity is critical for the functioning of shelf systems, it has received much less attention, particularly in the IO, mainly due to logistics reasons precluding our ability to predict future changes. Here, we discuss the state of knowledge of macrofaunal ecology, to identify the knowledge gaps, which will allow for setting research priorities. The new framework in research synthesis, research weaving, that combines systematic mapping with bibliometric analysis was applied. The research weaving approach helps illustrate the evolution of research over time and identifies areas of current research interests and the performance of institutions and collaboration patterns. Data retrieved from the Web of Science were analyzed in the R and VOS Viewer software. The results highlight how macrofaunal research in IO is constrained by spatial and temporal scales, with the majority of studies focused on structural patterns. Moreover, most studies were conducted in a few countries (India, Australia, Saudi Arabia, Iran, and South Africa) using different sampling techniques hindering comparison within the IO habitats. Future studies investigating the macrofaunal community using a multidisciplinary approach and scientific collaboration (regional and international) can advance our efforts to close the marine biodiversity knowledge gaps.
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Affiliation(s)
- Sanitha K Sivadas
- National Centre for Coastal Research (NCCR), Ministry of Earth Sciences (MoES), NIOT Campus, Pallikaranai, Chennai, Tamil Nadu, India.
| | - Amit Jagannath Patil
- Key Laboratory of Subsurface Hydrology and Ecological Effects in Arid Region, Ministry of Education, School of Water and Environment, Chang'an University, No.126, Yanta Road, Xi'an, Shaanxi, 710064, China
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5
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Pillai UPA, Pinardi N, Alessandri J, Federico I, Causio S, Unguendoli S, Valentini A, Staneva J. A Digital Twin modelling framework for the assessment of seagrass Nature Based Solutions against storm surges. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 847:157603. [PMID: 35901893 DOI: 10.1016/j.scitotenv.2022.157603] [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: 03/31/2022] [Revised: 06/22/2022] [Accepted: 07/20/2022] [Indexed: 06/15/2023]
Abstract
In this paper we demonstrate a novel framework for assessing nature-based solutions (NBSs) in coastal zones using a new suite of numerical models that provide a virtual "replica" of the natural environment. We design experiments that use a Digital Twin strategy to establish the wave, sea level and current attenuation due to seagrass NBSs. This Digital Twin modelling framework allows us to answer "what if" scenario questions such as: (i) are indigenous seagrass meadows able to reduce the energy of storm surges, and if so how? (ii) what are the best seagrass types and their landscaping for optimal wave and current attenuation? An important result of the study is to show that the landscaping of seagrasses is an important design choice and that seagrass does not directly attenuate the sea level but the current amplitudes. This framework reveals the link between seagrass NBS and the components of the disruptive potential of storm surges (waves and sea level) and opens up new avenues for future studies.
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Affiliation(s)
| | - Nadia Pinardi
- Department of Physics and Astronomy, University of Bologna, Bologna 40127, Italy
| | - Jacopo Alessandri
- Department of Physics and Astronomy, University of Bologna, Bologna 40127, Italy; Hydro-Meteo-Climate Service of the Agency for Prevention, Environment and Energy of Emilia-Romagna, Arpae-SIMC, Bologna 40122, Italy
| | - Ivan Federico
- Euro-Mediterranean Center on Climate Change, Lecce 73100, Italy
| | | | - Silvia Unguendoli
- Hydro-Meteo-Climate Service of the Agency for Prevention, Environment and Energy of Emilia-Romagna, Arpae-SIMC, Bologna 40122, Italy
| | - Andrea Valentini
- Hydro-Meteo-Climate Service of the Agency for Prevention, Environment and Energy of Emilia-Romagna, Arpae-SIMC, Bologna 40122, Italy
| | - Joanna Staneva
- Institute of Coastal Systems-Analysis and Modeling, Helmholtz-Zentrum Hereon, Geesthacht 21502, Germany
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Inter-annual variability patterns of reef cryptobiota in the central Red Sea across a shelf gradient. Sci Rep 2022; 12:16944. [PMID: 36210380 PMCID: PMC9548503 DOI: 10.1038/s41598-022-21304-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 09/26/2022] [Indexed: 12/29/2022] Open
Abstract
The combination of molecular tools, standard surveying techniques, and long-term monitoring programs are relevant to understanding environmental and ecological changes in coral reef communities. Here we studied temporal variability in cryptobenthic coral reef communities across the continental shelf in the central Red Sea spanning 6 years (three sampling periods: 2013-2019) and including the 2015 mass bleaching event. We used a combination of molecular tools (barcoding and metabarcoding) to assess communities on Autonomous Reef Monitoring Structures (ARMS) as a standardized sampling approach. Community composition associated with ARMS for both methodologies (barcoding and metabarcoding) was statistically different across reefs (shelf position) and time periods. The partition of beta diversity showed a higher turnover and lower nestedness between pre-bleaching and post-bleaching samples than between the two post-bleaching periods, revealing a community shift from the bleaching event. However, a slight return to the pre-bleaching community composition was observed in 2019 suggesting a recovery trajectory. Given the predictions of decreasing time between bleaching events, it is concerning that cryptobenthic communities may not fully recover and communities with new characteristics will emerge. We observed a high turnover among reefs for all time periods, implying a homogenization of the cryptobiome did not occur across the cross shelf following the 2015 bleaching event. It is possible that dispersal limitations and the distinct environmental and benthic structures present across the shelf maintained the heterogeneity in communities among reefs. This study has to the best of our knowledge presented for the first time a temporal aspect into the analysis of ARMS cryptobenthic coral reef communities and encompasses a bleaching event. We show that these structures can detect cryptic changes associated with reef degradation and provides support for these being used as long-term monitoring tools.
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Mohapatra M, Manu S, Dash SP, Rastogi G. Seagrasses and local environment control the bacterial community structure and carbon substrate utilization in brackish sediments. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 314:115013. [PMID: 35447445 DOI: 10.1016/j.jenvman.2022.115013] [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: 12/13/2021] [Revised: 03/16/2022] [Accepted: 04/02/2022] [Indexed: 06/14/2023]
Abstract
Seagrasses are complex benthic coastal ecosystems that play a crucial role in organic matter cycling and carbon sequestration. However, little is known about how seagrasses influence the structure and carbon utilization potential of benthic bacterial communities. This study examined the bacterial communities in monospecific and mixed meadows of seagrasses and compared with bulk (unvegetated) sediments from Chilika, a brackish water coastal lagoon of India. High-throughput sequencing of 16S rRNA genes revealed a vegetation effect in terms of differences in benthic bacterial community diversity, composition, and abundances in comparison with bulk sediments. Desulfobacterales, Chromatiales, Enterobacteriales, Clostridiales, Vibrionales, and Acidimicrobiales were major taxa that contributed to differences between seagrass and bulk sediments. Seagrasses supported ∼5.94 fold higher bacterial abundances than the bulk due to rich organic carbon stock in their sediments. Co-occurrence network demonstrated much stronger potential interactions and connectedness in seagrass bacterial communities compared to bulk. Chromatiales and Acidimicrobiales were identified as the top two keystone taxa in seagrass bacterial communities, whereas, Dehalococcoidales and Rhizobiales were in bulk communities. Seagrasses and local environmental factors, namely, water depth, water pH, sediment salinity, redox potential, total organic carbon, available nitrogen, sediment texture, sediment pH, and sediment core depth were the major drivers of benthic bacterial community composition. Carbon metabolic profiling revealed that heterotrophic bacteria in seagrass sediments were much more metabolically diverse and active than bulk. The utilization of carbon substrate guilds, namely, amino acids, amines, carboxylic acids, carbohydrates, polymers, and phenolic compounds was enhanced in seagrass sediments. Metabolic mapping predicted higher prevalence of sulfate-reducer and N2 fixation metabolic functions in seagrass sediments. Overall, this study showed that seagrasses control benthic bacterial community composition and diversity, enhance heterotrophic carbon substrate utilization, and play crucial roles in organic matter cycling including degradation of hydrocarbon and xenobiotics in coastal sediments.
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Affiliation(s)
- Madhusmita Mohapatra
- Wetland Research and Training Centre, Chilika Development Authority, Balugaon, 752030, Odisha, India
| | - Shivakumara Manu
- CSIR-Centre for Cellular and Molecular Biology, Hyderabad, 500048, India
| | - Stiti Prangya Dash
- Wetland Research and Training Centre, Chilika Development Authority, Balugaon, 752030, Odisha, India
| | - Gurdeep Rastogi
- Wetland Research and Training Centre, Chilika Development Authority, Balugaon, 752030, Odisha, India.
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Monitoring of benthic eukaryotic communities in two tropical coastal lagoons through eDNA metabarcoding: a spatial and temporal approximation. Sci Rep 2022; 12:10089. [PMID: 35710829 PMCID: PMC9203746 DOI: 10.1038/s41598-022-13653-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Accepted: 05/09/2022] [Indexed: 11/14/2022] Open
Abstract
Tropical coastal lagoons are important ecosystems that support high levels of biodiversity and provide several goods and services. Monitoring of benthic biodiversity and detection of harmful or invasive species is crucial, particularly in relation to seasonal and spatial variation of environmental conditions. In this study, eDNA metabarcoding was used in two tropical coastal lagoons, Chacahua (CH) and Corralero (C) (Southern Mexican Pacific), to describe the benthic biodiversity and its spatial–temporal dynamics. The distribution of benthic diversity within the lagoons showed a very particular pattern evidencing a transition from freshwater to seawater. Although the two lagoon systems are similar in terms of the species composition of metazoans and microeukaryotes, our findings indicate that they are different in taxa richness and structure, resulting in regional partitioning of the diversity with salinity as the driving factor of community composition in CH. Harmful, invasive, non-indigenous species, bioindicators and species of commercial importance were detected, demonstrating the reach of this technique for biodiversity monitoring along with the continued efforts of building species reference libraries.
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Lafi Al Solami, Sathianeson Satheesh. Spatio-Temporal Variations in Macrobenthic Community Distribution on the Central Red Sea Coast: Role of Heavy Metal Content of the Sediment. CONTEMP PROBL ECOL+ 2022. [DOI: 10.1134/s1995425522030027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Cloud Processing for Simultaneous Mapping of Seagrass Meadows in Optically Complex and Varied Water. REMOTE SENSING 2022. [DOI: 10.3390/rs14030609] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Improved development of remote sensing approaches to deliver timely and accurate measurements for environmental monitoring, particularly with respect to marine and estuarine environments is a priority. We describe a machine learning, cloud processing protocol for simultaneous mapping seagrass meadows in waters of variable quality across Moreton Bay, Australia. This method was adapted from a protocol developed for mapping coral reef areas. Georeferenced spot check field-survey data were obtained across Moreton Bay, covering areas of differing water quality, and categorized into either substrate or ≥25% seagrass cover. These point data with coincident Landsat 8 OLI satellite imagery (30 m resolution; pulled directly from Google Earth Engine’s public archive) and a bathymetric layer (30 m resolution) were incorporated to train a random forest classifier. The semiautomated machine learning algorithm was applied to map seagrass in shallow areas of variable water quality simultaneously, and a bay-wide map was created for Moreton Bay. The output benthic habitat map representing seagrass presence/absence was accurate (63%) as determined by validation with an independent data set.
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Kanhai A. Spatial and seasonal variation in polychaete communities according to their trophic categories in Southwest Tobago, West Indies. NEOTROPICAL BIODIVERSITY 2022. [DOI: 10.1080/23766808.2021.2021051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
Affiliation(s)
- Attish Kanhai
- Biodiversity and Ecology Research Programme, Institute of Marine Affairs, Chaguaramas, Trinidad and Tobago
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12
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Barnes RSK. What does measuring species diversity in estuarine seagrass systems actually assess? MARINE ENVIRONMENTAL RESEARCH 2021; 172:105500. [PMID: 34653926 DOI: 10.1016/j.marenvres.2021.105500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 10/01/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023]
Abstract
Relationships between species diversity and other species-density and species-richness metrics were investigated in the seagrass macrobenthos of Knysna estuarine bay, South Africa. Although a wide range of species density occurred across sites, neither Hill-Shannon nor Hill-Simpson diversity showed any significant relationship with it, although they did with species richness. Instead species diversity was very closely related to relative evenness, and (negatively) to overall assemblage abundance. No significant relationship was found between species density and evenness. Whilst there was a clear and marked decrease in species density upstream along the main estuarine channel, only one of the species-diversity indices (the Hill-Shannon) showed a significant equivalent decrease. Relationships depended on how 'species richness' was assessed, and were very strongly influenced by the superabundant local occurrence of a few individual faunal components (three gastropod and one tanaid species). Species-diversity analysis contributes nothing new in such estuarine seagrass meadows and seems best avoided.
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Affiliation(s)
- R S K Barnes
- Department of Zoology and Entomology, Rhodes University, Makhanda, Eastern Cape, 6140, South Africa; Department of Zoology & Conservation Research Institute, University of Cambridge, Cambridge, UK.
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Salt Marshes Buffer El Niño Effects on Benthic Secondary Production. Ecosystems 2021. [DOI: 10.1007/s10021-021-00707-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Nondestructive Monitoring of Soft Bottom Fish and Habitats Using a Standardized, Remote and Unbaited 360° Video Sampling Method. FISHES 2021. [DOI: 10.3390/fishes6040050] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Lagoon soft-bottoms are key habitats within coral reef seascapes. Coral reef fish use these habitats as nurseries, feeding grounds and transit areas. At present, most soft-bottom sampling methods are destructive (trawling, longlining, hook and line). We developed a remote, unbaited 360° video sampling method (RUV360) to monitor fish species assemblages in soft bottoms. A low-cost, high-definition camera enclosed in a waterproof housing and fixed on a tripod was set on the sea floor in New Caledonia from a boat. Then, 534 videos were recorded to assess the efficiency of the RUV360. The technique was successful in sampling bare soft-bottoms, seagrass beds, macroalgae meadows and mixed soft-bottoms. It is easy to use and particularly efficient, i.e., 88% of the stations were sampled successfully. We observed 10,007 fish belonging to 172 species, including 45 species targeted by fishermen in New Caledonia, as well as many key species. The results are consistent with the known characteristics of the lagoon soft bottom fish assemblages of New Caledonia. We provide future users with general recommendations and reference plots to estimate the proportion of the theoretical total species richness sampled, according to the number of stations or the duration of the footage.
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The Seagrass Holobiont: What We Know and What We Still Need to Disclose for Its Possible Use as an Ecological Indicator. WATER 2021. [DOI: 10.3390/w13040406] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Microbes and seagrass establish symbiotic relationships constituting a functional unit called the holobiont that reacts as a whole to environmental changes. Recent studies have shown that the seagrass microbial associated community varies according to host species, environmental conditions and the host’s health status, suggesting that the microbial communities respond rapidly to environmental disturbances and changes. These changes, dynamics of which are still far from being clear, could represent a sensitive monitoring tool and ecological indicator to detect early stages of seagrass stress. In this review, the state of art on seagrass holobiont is discussed in this perspective, with the aim of disentangling the influence of different factors in shaping it. As an example, we expand on the widely studied Halophila stipulacea’s associated microbial community, highlighting the changing and the constant components of the associated microbes, in different environmental conditions. These studies represent a pivotal contribution to understanding the holobiont’s dynamics and variability pattern, and to the potential development of ecological/ecotoxicological indices. The influences of the host’s physiological and environmental status in changing the seagrass holobiont, alongside the bioinformatic tools for data analysis, are key topics that need to be deepened, in order to use the seagrass-microbial interactions as a source of ecological information.
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Alsaffar Z, Cúrdia J, Irigoien X, Carvalho S. Composition, uniqueness and connectivity across tropical coastal lagoon habitats in the Red Sea. BMC Ecol 2020; 20:61. [PMID: 33228627 PMCID: PMC7686702 DOI: 10.1186/s12898-020-00329-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2020] [Accepted: 11/11/2020] [Indexed: 11/15/2022] Open
Abstract
Background Tropical habitats and their associated environmental characteristics play a critical role in shaping macroinvertebrate communities. Assessing patterns of diversity over space and time and investigating the factors that control and generate those patterns is critical for conservation efforts. However, these factors are still poorly understood in sub-tropical and tropical regions. The present study applied a combination of uni- and multivariate techniques to test whether patterns of biodiversity, composition, and structure of macrobenthic assemblages change across different lagoon habitats (two mangrove sites; two seagrass meadows with varying levels of vegetation cover; and an unvegetated subtidal area) and between seasons and years. Results In total, 4771 invertebrates were identified belonging to 272 operational taxonomic units (OTUs). We observed that macrobenthic lagoon assemblages are diverse, heterogeneous and that the most evident biological pattern was spatial rather than temporal. To investigate whether macrofaunal patterns within the lagoon habitats (mangrove, seagrass, unvegetated area) changed through the time, we analysed each habitat separately. The results showed high seasonal and inter-annual variability in the macrofaunal patterns. However, the seagrass beds that are characterized by variable vegetation cover, through time, showed comparatively higher stability (with the lowest values of inter-annual variability and a high number of resident taxa). These results support the theory that seagrass habitat complexity promotes diversity and density of macrobenthic assemblages. Despite the structural and functional importance of seagrass beds documented in this study, the results also highlighted the small-scale heterogeneity of tropical habitats that may serve as biodiversity repositories. Conclusions Comprehensive approaches at the “seascape” level are required for improved ecosystem management and to maintain connectivity patterns amongst habitats. This is particularly true along the Saudi Arabian coast of the Red Sea, which is currently experiencing rapid coastal development. Also, considering the high temporal variability (seasonal and inter-annual) of tropical shallow-water habitats, monitoring and management plans must include temporal scales.
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Affiliation(s)
- Zahra Alsaffar
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.,Chemistry Department, College of Science, King Saud University (KSU), Riyadh, P.O. Box 2455, 11451, Saudi Arabia
| | - João Cúrdia
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia
| | - Xabier Irigoien
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.,AZTI - Marine Research, Herrera Kaia, Pasaia, 20100, Spain.,IKERBASQUE, Basque Foundation for Science, Bilbao, 48013, Spain
| | - Susana Carvalho
- Red Sea Research Centre, King Abdullah University of Science and Technology (KAUST), Thuwal, 23955-6900, Saudi Arabia.
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