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Rodil IF, Rodriguez VP, Bernal-Ibáñez A, Pardiello M, Soccio F, Gestoso I. High contribution of an invasive macroalgae species to beach wrack CO 2 emissions. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 367:122021. [PMID: 39079488 DOI: 10.1016/j.jenvman.2024.122021] [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: 05/30/2024] [Revised: 07/16/2024] [Accepted: 07/26/2024] [Indexed: 08/15/2024]
Abstract
Accumulations of macroalgal wrack are important for adequate functioning of the beach ecosystem. However, the sudden beaching of seaweed masses smothers the coastline and forms decomposing piles on the shore, harming tourism-based economies, but also affecting the beach ecosystem metabolism. The decomposition of sudden pulses of wrack can modify the biogeochemistry of beach sands and increase greenhouse gas (GHG) emissions. The presence of invasive species in the wrack deposits can superimpose harmful effects on the beach functioning. We quantified the wrack biomass of Rugulopteryx okamurae, an invasive species of extreme impact, on five sandy beaches from the Atlantic coast of the Strait of Gibraltar (Spain), and we tested the effects on in situ respiratory CO2 fluxes using an infrared gas analyser. All the beaches showed massive accumulations of Rugulopteryx wrack deposits. However, the biomass changed significantly between beaches, ranging (mean ± SE) from 968.3 ± 287.7 kg m-1 to 9210 ± 1279.4 kg m-1 of wet weight. Wrack supported high respiration rates, with CO2 fluxes averaging (±SE) 19.15 ± 5.5 μmol CO2 m-2 s-1 across beaches, reaching astounding maximum peaks of 291 μmol CO2 m-2 s-1. The within-beach variability was related to the distance of the wrack deposits from the shoreline, as the average metabolic rates tended to increase significantly from the swash to the drift line. Thicker wrack and a more degraded algae stage showed significantly higher CO2 fluxes. We estimated that the annual CO2 flux of R. okamurae in our study area ranged between 0.39 (±0.01) and 23.30 (±11.33) kg C m-2 y-1. We suggest that massive amounts of beach wrack can become a globally significant contributor to GHG emissions that can offset any potential carbon-sink capacity of macroalgal forests. However, the piles of wrack located several meters above the drift line showed non-measurable CO2 efflux. Transferring beach wrack from swash to drier upper-beach areas, a common practice in many coastal regions suffering from massive wrack accumulations, might help reduce GHG emissions while removing the wrack stockpiles from the intertidal. However, this practice is not necessarily suitable for all beaches and can create ecological and conservation problems in the dune system. There is an urgent need to implement practical and sustainable management practices for massive wrack deposits capable of presenting various solutions to achieve a balance between conservation and recreation actions, answering the consequences of a problem that links both, environmental and economic issues.
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Affiliation(s)
- Iván Franco Rodil
- Marine Research Institute (INMAR)-Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Cádiz, Spain.
| | - Valle Perez Rodriguez
- Marine Research Institute (INMAR)-Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Cádiz, Spain
| | - Alejandro Bernal-Ibáñez
- MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação (ARDITI). Funchal, Madeira, Portugal; Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal; Instituto Andaluz de Investigación y Formación Agraria, Pesquera, Alimentaria y de la Producción Ecológica (IFAPA), Centro El Toruño, Junta de Andalucía, El Puerto de Santa María, Cádiz, Spain
| | - Mauro Pardiello
- Department of Earth and Environmental Sciences, University of Pavia, Italy
| | - Federica Soccio
- Department of Earth and Environmental Sciences, University of Pavia, Italy
| | - Ignacio Gestoso
- Marine Research Institute (INMAR)-Department of Biology, Faculty of Marine and Environmental Sciences, University of Cádiz, Puerto Real, Cádiz, Spain; MARE - Marine and Environmental Sciences Centre / ARNET - Aquatic Research Network, Agência Regional para o Desenvolvimento da Investigação Tecnologia e Inovação (ARDITI). Funchal, Madeira, Portugal; Smithsonian Environmental Research Center (SERC), Edgewater, MD, United States
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Martins M, Sousa F, Soares C, Sousa B, Pereira R, Rubal M, Fidalgo F. Beach wrack: Discussing ecological roles, risks, and sustainable bioenergy and agricultural applications. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2024; 356:120526. [PMID: 38492423 DOI: 10.1016/j.jenvman.2024.120526] [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: 11/15/2023] [Revised: 02/25/2024] [Accepted: 02/28/2024] [Indexed: 03/18/2024]
Abstract
The equilibrium of the marine ecosystem is currently threatened by several constraints, among which climate change and anthropogenic activities stand out. Indeed, these factors favour the growth of macroalgae, which sometimes end up stranded on the beaches at the end of their life cycle, forming what is known as beach wrack. Despite its undeniable important ecological role on beaches, as it is an important source of organic matter (OM), and provides food and habitat for several invertebrates, reptiles, small mammals, and shorebirds, the overaccumulation of beach wrack is often associated with the release of greenhouse gases, negatively impacting tourist activities, and generating economic expenses for its removal. Although currently beach wrack is mainly treated as a waste, it can be used for numerous potential applications in distinct areas. This review aimed at providing a solid point of view regarding the process of wrack formation, its spatiotemporal location, as well as its importance and risks. It also contains the current advances of the research regarding sustainable alternatives to valorise this organic biomass, that range from bioenergy production to the incorporation of wrack in agricultural soils, considering a circular economy concept. Although there are some concerns regarding wrack utilisation, from its variable availability to a possible soil contamination with salts and other contaminants, this review comprises the overall beneficial effects of the incorporation of this residue particularly in the organic agricultural model, strengthening the conversion of this wasted biomass into a valuable resource.
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Affiliation(s)
- Maria Martins
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal.
| | - Filipa Sousa
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Cristiano Soares
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Bruno Sousa
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Ruth Pereira
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
| | - Marcos Rubal
- Centre of Molecular and Environmental Biology (CBMA/ARNET), Department of Biology, University of Minho, 4710-057, Braga, Portugal
| | - Fernanda Fidalgo
- GreenUPorto - Sustainable Agrifood Production Research Centre and INOV4AGRO, Biology Department, Faculty of Sciences, University of Porto, Rua do Campo Alegre, s/n, 4169-007, Porto, Portugal
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Li Y, Gundersen H, Poulsen RN, Xie L, Ge Z, Hancke K. Quantifying seaweed and seagrass beach deposits using high-resolution UAV imagery. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 331:117171. [PMID: 36623360 DOI: 10.1016/j.jenvman.2022.117171] [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: 07/04/2022] [Revised: 12/12/2022] [Accepted: 12/27/2022] [Indexed: 06/17/2023]
Abstract
Macroalgae and seagrass wash ashore by tidal waters and episodic events and create an ocean-to-land transport of carbon and nutrients. On land, these deposits (beach wrack) are consumed by macrofauna, remineralized by microorganisms, or washed back to the sea, during which recycling of carbon and nitrogen affect the biochemical cycles in coastal zones. Manual quantification of beach wracks is time-consuming and often difficult due to complex topography and remote locations. Here, we present a novel method using Unoccupied Aerial Vehicle (UAV) photogrammetry combined with in situ measurements of carbon and nitrogen contents of wrack to quantify marine carbon and nutrient deposits in beach zones. The UAV method was tested against placed cubes ranging from 125 to 88,218 cm3 and demonstrated a high accuracy (R2 > 0.99) for volume acquisition when compared to manual measurements. Also, the UAV-based assessments of the cross-sectional area of beach deposits demonstrated a high accuracy when compared to manual and high-precision GNSS (Global Navigation Satellite System) measurements without significant differences between the methods. This demonstrated that UAVs can provide detailed spatial maps, three-dimensional (3D) surface models, and accurate volumetric assessments of beach wrack deposits. In three case studies, combined with carbon and nitrogen measures, total organic carbon and nitrogen deposits in beach wracks were quantified ranging from 4.3 to 9.7 and from 0.3 to 0.5 kg per meter coastline, respectively. In conclusion, this UAV method demonstrated an effective tool to quantify ecosystem carbon and nitrogen deposits relevant to ecosystem assessments and quantification of blue carbon stocks. The method is optimal when the terrain below beach wrack deposits is known, as in the case with before-and-after or repeated surveys. Further, UAVs display strong time- and cost-effective advantages over manual methods which is amplified with increasing project scale. We propose it as a valuable method for multiple scientific and commercial applications related to environmental monitoring and management, including marine resource exploration and exploitation.
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Affiliation(s)
- Yalei Li
- Section for Marine Biology, Norwegian Institute for Water Research (NIVA), Oslo, Norway; State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, China.
| | - Hege Gundersen
- Section for Marine Biology, Norwegian Institute for Water Research (NIVA), Oslo, Norway.
| | | | - Lina Xie
- Section for Marine Biology, Norwegian Institute for Water Research (NIVA), Oslo, Norway; State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, China.
| | - Zhenming Ge
- State Key Laboratory of Estuarine and Coastal Research, Institute of Eco-Chongming, East China Normal University, Shanghai, China.
| | - Kasper Hancke
- Section for Marine Biology, Norwegian Institute for Water Research (NIVA), Oslo, Norway.
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Hyndes GA, Berdan EL, Duarte C, Dugan JE, Emery KA, Hambäck PA, Henderson CJ, Hubbard DM, Lastra M, Mateo MA, Olds A, Schlacher TA. The role of inputs of marine wrack and carrion in sandy-beach ecosystems: a global review. Biol Rev Camb Philos Soc 2022; 97:2127-2161. [PMID: 35950352 PMCID: PMC9804821 DOI: 10.1111/brv.12886] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 06/26/2022] [Accepted: 06/29/2022] [Indexed: 01/09/2023]
Abstract
Sandy beaches are iconic interfaces that functionally link the ocean with the land via the flow of organic matter from the sea. These cross-ecosystem fluxes often comprise uprooted seagrass and dislodged macroalgae that can form substantial accumulations of detritus, termed 'wrack', on sandy beaches. In addition, the tissue of the carcasses of marine animals that regularly wash up on beaches form a rich food source ('carrion') for a diversity of scavenging animals. Here, we provide a global review of how wrack and carrion provide spatial subsidies that shape the structure and functioning of sandy-beach ecosystems (sandy beaches and adjacent surf zones), which typically have little in situ primary production. We also examine the spatial scaling of the influence of these processes across the broader land- and seascape, and identify key gaps in our knowledge to guide future research directions and priorities. Large quantities of detrital kelp and seagrass can flow into sandy-beach ecosystems, where microbial decomposers and animals process it. The rates of wrack supply and its retention are influenced by the oceanographic processes that transport it, the geomorphology and landscape context of the recipient beaches, and the condition, life history and morphological characteristics of the macrophyte taxa that are the ultimate source of wrack. When retained in beach ecosystems, wrack often creates hotspots of microbial metabolism, secondary productivity, biodiversity, and nutrient remineralization. Nutrients are produced during wrack breakdown, and these can return to coastal waters in surface flows (swash) and aquifers discharging into the subtidal surf. Beach-cast kelp often plays a key trophic role, being an abundant and preferred food source for mobile, semi-aquatic invertebrates that channel imported algal matter to predatory invertebrates, fish, and birds. The role of beach-cast marine carrion is likely to be underestimated, as it can be consumed rapidly by highly mobile scavengers (e.g. foxes, coyotes, raptors, vultures). These consumers become important vectors in transferring marine productivity inland, thereby linking marine and terrestrial ecosystems. Whilst deposits of organic matter on sandy-beach ecosystems underpin a range of ecosystem functions and services, they can be at variance with aesthetic perceptions resulting in widespread activities, such as 'beach cleaning and grooming'. This practice diminishes the energetic base of food webs, intertidal fauna, and biodiversity. Global declines in seagrass beds and kelp forests (linked to global warming) are predicted to cause substantial reductions in the amounts of marine organic matter reaching many beach ecosystems, likely causing flow-on effects for food webs and biodiversity. Similarly, future sea-level rise and increased storm frequency are likely to alter profoundly the physical attributes of beaches, which in turn can change the rates at which beaches retain and process the influxes of wrack and animal carcasses. Conservation of the multi-faceted ecosystem services that sandy beaches provide will increasingly need to encompass a greater societal appreciation and the safeguarding of ecological functions reliant on beach-cast organic matter on innumerable ocean shores worldwide.
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Affiliation(s)
- Glenn A. Hyndes
- Centre for Marine Ecosystems Research, School of ScienceEdith Cowan UniversityJoondalupWestern AustraliaAustralia
| | - Emma L. Berdan
- Department of Marine SciencesUniversity of GothenburgGöteborgSweden
| | - Cristian Duarte
- Departamento de Ecología y Biodiversidad, Facultad de Ciencias de la VidaUniversidad Andres BelloSantiagoChile
| | - Jenifer E. Dugan
- Marine Science InstituteUniversity of CaliforniaSanta BarbaraCA93106USA
| | - Kyle A. Emery
- Marine Science InstituteUniversity of CaliforniaSanta BarbaraCA93106USA
| | - Peter A. Hambäck
- Department of Ecology, Environment and Plant SciencesStockholm UniversityStockholmSweden
| | - Christopher J. Henderson
- School of Science, Technology, and EngineeringUniversity of the Sunshine CoastMaroochydoreQueenslandAustralia
| | - David M. Hubbard
- Marine Science InstituteUniversity of CaliforniaSanta BarbaraCA93106USA
| | - Mariano Lastra
- Centro de Investigación Mariña, Edificio CC ExperimentaisUniversidade de Vigo, Campus de Vigo36310VigoSpain
| | - Miguel A. Mateo
- Centre for Marine Ecosystems Research, School of ScienceEdith Cowan UniversityJoondalupWestern AustraliaAustralia,Centro de Estudios Avanzados de Blanes, Consejo Superior de Investigaciones CientíficasBlanesSpain
| | - Andrew Olds
- School of Science, Technology, and EngineeringUniversity of the Sunshine CoastMaroochydoreQueenslandAustralia
| | - Thomas A. Schlacher
- School of Science, Technology, and EngineeringUniversity of the Sunshine CoastMaroochydoreQueenslandAustralia
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Dolliver J, O’Connor N. Whole System Analysis Is Required To Determine The Fate Of Macroalgal Carbon: A Systematic Review. JOURNAL OF PHYCOLOGY 2022; 58:364-376. [PMID: 35397178 PMCID: PMC9325415 DOI: 10.1111/jpy.13251] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/20/2021] [Accepted: 03/09/2022] [Indexed: 06/14/2023]
Abstract
The role of marine primary producers in capturing atmospheric CO2 has received increased attention in the global mission to mitigate climate change. Yet, our understanding of carbon sequestration performed by macroalgae has been limited to a relatively small number of studies that have estimated the ultimate fate of macroalgal-derived carbon. This systematic review was conducted to provide a timely synthesis of the methods used to determine the fate of macroalgal carbon in this rapidly expanding research area. It also aimed to provide suggestions for more effective future research. We found that the most common methods to estimate the fate of macroalgal carbon can be categorized into groups based on those that quantify: (i) export of macroalgal carbon to other environments-known as horizontal transport; (ii) sequestration of macroalgal carbon into deep-sea sediments-known as vertical transport; (iii) burial of macroalgal carbon directly beneath a benthic community; (iv) the loss of macroalgal carbon as particulate carbon or dissolved carbon to the water column; (v) the loss of macroalgal carbon to primary consumers; and finally (vi) those studies that combined multiple methods in one location. Based on this review, several recommendations for future research were formulated, which require the combination of multiple methods in a whole system analysis approach.
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Affiliation(s)
- Jessie Dolliver
- Department of ZoologyTrinity College DublinDublinD02 F6N2Ireland
- Department of Plant SciencesUniversity of OxfordOxfordOX1 3RBUK
| | - Nessa O’Connor
- Department of ZoologyTrinity College DublinDublinD02 F6N2Ireland
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Aromokeye DA, Willis-Poratti G, Wunder LC, Yin X, Wendt J, Richter-Heitmann T, Henkel S, Vázquez S, Elvert M, Mac Cormack W, Friedrich MW. Macroalgae degradation promotes microbial iron reduction via electron shuttling in coastal Antarctic sediments. ENVIRONMENT INTERNATIONAL 2021; 156:106602. [PMID: 34051435 DOI: 10.1016/j.envint.2021.106602] [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: 02/04/2021] [Revised: 04/21/2021] [Accepted: 04/23/2021] [Indexed: 06/12/2023]
Abstract
Colonization of newly ice-free areas by marine benthic organisms intensifies burial of macroalgae detritus in Potter Cove coastal surface sediments (Western Antarctic Peninsula). Thus, fresh and labile macroalgal detritus serves as primary organic matter (OM) source for microbial degradation. Here, we investigated the effects on post-depositional microbial iron reduction in Potter Cove using sediment incubations amended with pulverized macroalgal detritus as OM source, acetate as primary product of OM degradation and lepidocrocite as reactive iron oxide to mimic in situ conditions. Humic substances analogue anthraquinone-2,6-disulfonic acid (AQDS) was also added to some treatments to simulate potential for electron shuttling. Microbial iron reduction was promoted by macroalgae and further enhanced by up to 30-folds with AQDS. Notably, while acetate amendment alone did not stimulate iron reduction, adding macroalgae alone did. Acetate, formate, lactate, butyrate and propionate were detected as fermentation products from macroalgae degradation. By combining 16S rRNA gene sequencing and RNA stable isotope probing, we reconstructed the potential microbial food chain from macroalgae degraders to iron reducers. Psychromonas, Marinifilum, Moritella, and Colwellia were detected as potential fermenters of macroalgae and fermentation products such as lactate. Members of class deltaproteobacteria including Sva1033, Desulfuromonas, and Desulfuromusa together with Arcobacter (former phylum Epsilonbacteraeota, now Campylobacterota) acted as dissimilatory iron reducers. Our findings demonstrate that increasing burial of macroalgal detritus in an Antarctic fjord affected by glacier retreat intensifies early diagenetic processes such as iron reduction. Under scenarios of global warming, the active microbial populations identified above will expand their environmental function, facilitate OM remineralisation, and contribute to an increased release of iron and CO2 from sediments. Such indirect consequences of glacial retreat are often overlooked but might, on a regional scale, be relevant for the assessment of future nutrient and carbon fluxes.
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Affiliation(s)
- David A Aromokeye
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
| | - Graciana Willis-Poratti
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; Instituto Antártico Argentino, San Martín, Buenos Aires, Argentina; Facultad de Ciencias Exactas, Universidad Nacional de La Plata, La Plata, Buenos Aires, Argentina.
| | - Lea C Wunder
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; Max Planck Institute for Marine Microbiology, Bremen, Germany.
| | - Xiuran Yin
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
| | - Jenny Wendt
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
| | - Tim Richter-Heitmann
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
| | - Susann Henkel
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Alfred Wegener Institute Helmholtz Centre for Polar and Marine Research, Bremerhaven, Germany.
| | - Susana Vázquez
- CONICET - Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Nanobiotecnología (NANOBIOTEC), Buenos Aires, Argentina.
| | - Marcus Elvert
- MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany; Faculty of Geosciences, University of Bremen, Bremen, Germany.
| | - Walter Mac Cormack
- Instituto Antártico Argentino, San Martín, Buenos Aires, Argentina; CONICET - Universidad de Buenos Aires, Facultad de Farmacia y Bioquímica, Instituto de Nanobiotecnología (NANOBIOTEC), Buenos Aires, Argentina.
| | - Michael W Friedrich
- Microbial Ecophysiology Group, Faculty of Biology/Chemistry, University of Bremen, Bremen, Germany; MARUM - Center for Marine Environmental Sciences, University of Bremen, Bremen, Germany.
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Warming and Wrack Supply Will Accelerate CO2 Emission and Nutrients Release on Antarctic Sedimentary Shores: A Case Study on a Volcanic Island. Ecosystems 2020. [DOI: 10.1007/s10021-020-00553-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Braeckman U, Pasotti F, Vázquez S, Zacher K, Hoffmann R, Elvert M, Marchant H, Buckner C, Quartino ML, Mác Cormack W, Soetaert K, Wenzhöfer F, Vanreusel A. Degradation of macroalgal detritus in shallow coastal Antarctic sediments. LIMNOLOGY AND OCEANOGRAPHY 2019; 64:1423-1441. [PMID: 31598006 PMCID: PMC6774326 DOI: 10.1002/lno.11125] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/31/2018] [Accepted: 12/21/2018] [Indexed: 05/22/2023]
Abstract
Glaciers along the western Antarctic Peninsula are retreating at unprecedented rates, opening up sublittoral rocky substrate for colonization by marine organisms such as macroalgae. When macroalgae are physically detached due to storms or erosion, their fragments can accumulate in seabed hollows, where they can be grazed upon by herbivores or be degraded microbially or be sequestered. To understand the fate of the increasing amount of macroalgal detritus in Antarctic shallow subtidal sediments, a mesocosm experiment was conducted to track 13C- and 15N-labeled macroalgal detritus into the benthic bacterial, meiofaunal, and macrofaunal biomass and respiration of sediments from Potter Cove (King George Island). We compared the degradation pathways of two macroalgae species: one considered palatable for herbivores (the red algae Palmaria decipiens) and other considered nonpalatable for herbivores (the brown algae Desmarestia anceps). The carbon from Palmaria was recycled at a higher rate than that of Desmarestia, with herbivores such as amphipods playing a stronger role in the early degradation process of the Palmaria fragments and the microbial community taking over at a later stage. In contrast, Desmarestia was more buried in the subsurface sediments, stimulating subsurface bacterial degradation. Macrofauna probably relied indirectly on Desmarestia carbon, recycled by bacteria and microphytobenthos. The efficient cycling of the nutrients and carbon from the macroalgae supports a positive feedback loop among bacteria, microphytobenthos, and meiofaunal and macrofaunal grazers, resulting in longer term retention of macroalgal nutrients in the sediment, hence creating a food bank for the benthos.
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Affiliation(s)
- U. Braeckman
- Marine Biology Research GroupGhent UniversityGhentBelgium
- HGF‐MPG Group for Deep Sea Ecology and Technology, Alfred Wegener InstituteHelmholtz Center for Polar and Marine Research, Bremerhaven and Max Planck Institute for Marine MicrobiologyBremenGermany
| | - F. Pasotti
- Marine Biology Research GroupGhent UniversityGhentBelgium
| | - S. Vázquez
- Cátedra de Biotecnología, Facultad de Farmacia y BioquímicaUniversidad de Buenos Aires, NANOBIOTEC UBA‐CONICETBuenos AiresArgentina
| | - K. Zacher
- Functional Ecology, Alfred Wegener InstituteHelmholtz Center for Polar and Marine ResearchBremerhavenGermany
| | - R. Hoffmann
- HGF‐MPG Group for Deep Sea Ecology and Technology, Alfred Wegener InstituteHelmholtz Center for Polar and Marine Research, Bremerhaven and Max Planck Institute for Marine MicrobiologyBremenGermany
| | - M. Elvert
- MARUM Center for Marine Environmental Sciences and Department of GeosciencesUniversity of BremenBremenGermany
| | - H. Marchant
- Biogeochemistry GroupMax Planck Institute for Marine MicrobiologyBremenGermany
| | - C. Buckner
- Biogeochemistry GroupMax Planck Institute for Marine MicrobiologyBremenGermany
| | - M. L. Quartino
- Instituto Antártico Argentino, Coastal Biology DepartmentBuenos AiresArgentina
- Museo Argentino de Ciencias Naturales Bernardino RivadaviaBuenos AiresArgentina
| | - W. Mác Cormack
- Cátedra de Biotecnología, Facultad de Farmacia y BioquímicaUniversidad de Buenos Aires, NANOBIOTEC UBA‐CONICETBuenos AiresArgentina
- Instituto Antártico Argentino, Coastal Biology DepartmentBuenos AiresArgentina
| | - K. Soetaert
- NIOZ Yerseke, Estuarine and Delta Studies and Utrecht UniversityThe Netherlands
| | - F. Wenzhöfer
- HGF‐MPG Group for Deep Sea Ecology and Technology, Alfred Wegener InstituteHelmholtz Center for Polar and Marine Research, Bremerhaven and Max Planck Institute for Marine MicrobiologyBremenGermany
| | - A. Vanreusel
- Marine Biology Research GroupGhent UniversityGhentBelgium
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