Pub Date : 2024-10-10DOI: 10.1016/j.ecss.2024.108983
J. Sánchez-Rodríguez , S. Sirviente , A. Sierra , J.J. Gómiz-Pascual , M. Bolado-Penagos , M. Bruno , J. Forja , T. Ortega
The Guadalquivir Estuary (main source of continental waters to the Gulf of Cadiz) has a carbonate basin, which enables the transport of inorganic carbon to adjacent coastal areas. Therefore, in order to study the dynamic of the carbonate system and its buffer capacity, a total of 12 samplings were carried out from 2017 to 2022. Samplings included longitudinal transects and tidal cycles in different seasonal and tidal conditions. Total alkalinity (TA) and dissolved inorganic carbon (DIC) showed increased values upstream, while calcium (Ca2+) presented the highest values in most of the marine samples. The ranges values obtained for these three variables were of 2180–5140 μmol kg−1, 430–3950 μmol kg−1 and 1295–10,855 μmol kg−1 for TA, DIC and Ca2+, respectively. Two buffer factors (βDIC and βH) were also calculated to study the variability of the buffer capacity of the Guadalquivir Estuary. These indicate that the estuary is well buffered for salinities above 10, while the inner part is more vulnerable to acidification effects. Using a non-linear 1D hydrodynamic model, net inorganic carbon system transports were calculated, showing that the Guadalquivir Estuary is exporting TA, DIC and Ca2+ to the Gulf of Cadiz.
{"title":"Buffer properties in the Guadalquivir Estuary (SW Iberian Peninsula)","authors":"J. Sánchez-Rodríguez , S. Sirviente , A. Sierra , J.J. Gómiz-Pascual , M. Bolado-Penagos , M. Bruno , J. Forja , T. Ortega","doi":"10.1016/j.ecss.2024.108983","DOIUrl":"10.1016/j.ecss.2024.108983","url":null,"abstract":"<div><div>The Guadalquivir Estuary (main source of continental waters to the Gulf of Cadiz) has a carbonate basin, which enables the transport of inorganic carbon to adjacent coastal areas. Therefore, in order to study the dynamic of the carbonate system and its buffer capacity, a total of 12 samplings were carried out from 2017 to 2022. Samplings included longitudinal transects and tidal cycles in different seasonal and tidal conditions. Total alkalinity (TA) and dissolved inorganic carbon (DIC) showed increased values upstream, while calcium (Ca<sup>2+</sup>) presented the highest values in most of the marine samples. The ranges values obtained for these three variables were of 2180–5140 μmol kg<sup>−1</sup>, 430–3950 μmol kg<sup>−1</sup> and 1295–10,855 μmol kg<sup>−1</sup> for TA, DIC and Ca<sup>2+</sup>, respectively. Two buffer factors (β<sub>DIC</sub> and β<sub>H</sub>) were also calculated to study the variability of the buffer capacity of the Guadalquivir Estuary. These indicate that the estuary is well buffered for salinities above 10, while the inner part is more vulnerable to acidification effects. Using a non-linear 1D hydrodynamic model, net inorganic carbon system transports were calculated, showing that the Guadalquivir Estuary is exporting TA, DIC and Ca<sup>2+</sup> to the Gulf of Cadiz.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108983"},"PeriodicalIF":2.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1016/j.ecss.2024.108984
Ahmed M. Khalifa , Ehab A. Meselhe , Kelin Hu , Denise Reed , Rachel Rhode , Natalie L. Snider
Evaluating the real-world impacts of proposed restoration strategies is a complex process. Typically, restoration is pursued to achieve a number of primary and secondary objectives as most coastal and deltaic areas support a variety of functions and activities with substantial social and economic values. In this analysis, we demonstrate the importance of considering the broad implications of planning and implementing restoration projects. We use a recently developed simplified and computationally efficient biophysical numerical model. The Mid-Barataria Sediment Diversion, a restoration project approximately 60 km down the Mississippi River from New Orleans, Louisiana, USA, offers an opportunity to quantify the benefits and potential impacts of large-scale restoration. Operation plans of the diversion are employed in this analysis to reveal the delicate balance between its potential benefits and possible adverse effects. Evaluation metrics include net land change and landscape evolution, change in salinity and subsequent shift in the distribution of marsh types, long-term change in the hydroperiod and marsh inundation, and change in the flood risk for unique local coastal communities and culture. We also consider subaqueous basin infilling, spatial sediment deposition, and creation of shallow water areas that might be of ecological value. These metrics are evaluated collectively under a set of future scenarios capturing long-term impacts of sea level rise and subsidence. This analysis provides evidence in favor of using a multi-metric approach to holistically evaluate restoration during the planning and design phases, as well as to guide the process of adaptively managing restoration projects post construction.
{"title":"Toward understanding the hydrologic, ecologic and community flooding implications of coastal restoration strategies: Sediment diversions","authors":"Ahmed M. Khalifa , Ehab A. Meselhe , Kelin Hu , Denise Reed , Rachel Rhode , Natalie L. Snider","doi":"10.1016/j.ecss.2024.108984","DOIUrl":"10.1016/j.ecss.2024.108984","url":null,"abstract":"<div><div>Evaluating the real-world impacts of proposed restoration strategies is a complex process. Typically, restoration is pursued to achieve a number of primary and secondary objectives as most coastal and deltaic areas support a variety of functions and activities with substantial social and economic values. In this analysis, we demonstrate the importance of considering the broad implications of planning and implementing restoration projects. We use a recently developed simplified and computationally efficient biophysical numerical model. The Mid-Barataria Sediment Diversion, a restoration project approximately 60 km down the Mississippi River from New Orleans, Louisiana, USA, offers an opportunity to quantify the benefits and potential impacts of large-scale restoration. Operation plans of the diversion are employed in this analysis to reveal the delicate balance between its potential benefits and possible adverse effects. Evaluation metrics include net land change and landscape evolution, change in salinity and subsequent shift in the distribution of marsh types, long-term change in the hydroperiod and marsh inundation, and change in the flood risk for unique local coastal communities and culture. We also consider subaqueous basin infilling, spatial sediment deposition, and creation of shallow water areas that might be of ecological value. These metrics are evaluated collectively under a set of future scenarios capturing long-term impacts of sea level rise and subsidence. This analysis provides evidence in favor of using a multi-metric approach to holistically evaluate restoration during the planning and design phases, as well as to guide the process of adaptively managing restoration projects post construction.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108984"},"PeriodicalIF":2.6,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coastal wetlands, crucial in the global carbon cycle, face increasing challenges brought by extreme climate events, particularly high temperatures above plant tolerance thresholds. These conditions often exert great impact on plant, thereby potentially reducing overall ecosystem productivity. However, it has been observed that alien species, typically exhibiting higher productivity compared to native plant. Would plant invasion offset the loss of productivity caused by high-temperature events at ecosystem scale? In this study, we utilized data from 2020 to 2023 in China's Yangtze Estuary to investigate the responses of Spartina alterniflora (alien) and Phragmites australis (native) to high-temperature stress. Our results demonstrate that though the alien vegetation exhibits higher productivity before high temperature events, it experiences significant declines during high temperatures. In average, net ecosystem productivity (NEP) and gross primary productivity (GPP) of alien plant drops by 21.03% overall, with a notable 29.59% reduction during Neap tide. In contrast, native vegetation maintains a more stable productivity profile under the same conditions. Spring tide alleviate the negative impact of high temperatures on the alien vegetation, exhibiting a distinct environmental buffering effect. Photosynthetic photon flux density emerged as a crucial factor driving productivity, yet its effectiveness was moderated by aerodynamic conductance for heat transfer (Ga_h). Through the application of the Michaelis-Menten model, we confirmed that both species maintain similar maximum light utilization efficiencies, yet native vegetation demonstrates greater resilience to thermal stress. Additionally, we observed a 33.82% overestimation in productivity by the vegetation photosynthesis model (VPM) under high temperatures, emphasizing the need to refine how Ga_h impacts are integrated, particularly when comparing the resilience of native and alien species. We emphasize necessity of incorporating canopy structure factors into ecological models and underscore the importance of maintaining tidal dynamics for coastal wetland management.
{"title":"Long-term alien marsh grass in China brings high carbon uptake capacity but cannot sustain high-temperature weather","authors":"Qi Yuan, Hai-Qiang Guo, Dong-Fan Xu, Si-Qi Zhou, Bing Tan, Bin Zhao","doi":"10.1016/j.ecss.2024.108979","DOIUrl":"10.1016/j.ecss.2024.108979","url":null,"abstract":"<div><div>Coastal wetlands, crucial in the global carbon cycle, face increasing challenges brought by extreme climate events, particularly high temperatures above plant tolerance thresholds. These conditions often exert great impact on plant, thereby potentially reducing overall ecosystem productivity. However, it has been observed that alien species, typically exhibiting higher productivity compared to native plant. Would plant invasion offset the loss of productivity caused by high-temperature events at ecosystem scale? In this study, we utilized data from 2020 to 2023 in China's Yangtze Estuary to investigate the responses of <em>Spartina alterniflora</em> (alien) and <em>Phragmites australis</em> (native) to high-temperature stress. Our results demonstrate that though the alien vegetation exhibits higher productivity before high temperature events, it experiences significant declines during high temperatures. In average, net ecosystem productivity (NEP) and gross primary productivity (GPP) of alien plant drops by 21.03% overall, with a notable 29.59% reduction during Neap tide. In contrast, native vegetation maintains a more stable productivity profile under the same conditions. Spring tide alleviate the negative impact of high temperatures on the alien vegetation, exhibiting a distinct environmental buffering effect. Photosynthetic photon flux density emerged as a crucial factor driving productivity, yet its effectiveness was moderated by aerodynamic conductance for heat transfer (Ga_h). Through the application of the Michaelis-Menten model, we confirmed that both species maintain similar maximum light utilization efficiencies, yet native vegetation demonstrates greater resilience to thermal stress. Additionally, we observed a 33.82% overestimation in productivity by the vegetation photosynthesis model (VPM) under high temperatures, emphasizing the need to refine how Ga_h impacts are integrated, particularly when comparing the resilience of native and alien species. We emphasize necessity of incorporating canopy structure factors into ecological models and underscore the importance of maintaining tidal dynamics for coastal wetland management.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108979"},"PeriodicalIF":2.6,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432991","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ecss.2024.108977
Pedro Augusto dos Santos Longo , Marianne Azevedo-Silva , Karine Ferreira Ribeiro Mansur , Thais Aparecida Marinho , André Guilherme Madeira , Anete Pereira de Souza , Shun K. Hirota , Yoshihisa Suyama , Gustavo Maruyama Mori , Fosca Pedini Pereira Leite
Unraveling the patterns of genetic structure and demographic history of marine species, as well as the factors that shape their genetic variations, is fundamental for informing conservation strategies for species and their environments. In this work, we investigate the current population structure and historical demographic patterns of the conspicuous seaweed-associated amphipod Hyale niger at a fine spatial scale in the subtropical SW Atlantic coast, in Brazil, by using both genome-wide and mitochondrial DNA markers. We also investigate how geographic distance, current oceanographic conditions, and variations in a key morphological trait contribute to the genetic variability of the amphipod. We observed an evident population genetic structure, even at a fine spatial scale, although genetic differentiation was lower than our expectations for a benthic direct brooder. Demographic history inferences were consistent across populations and showed two major demographic expansions on interglacial periods during the late Pleiostocene, before and after the last glacial maximum. We also demonstrated that isolation-by-environment (IBE) was the main driver of genetic differentiation, although we could not separate it from the effects of isolation-by-distance (IBD). Among environmental factors, nutrient concentrations in seawater were most relevant for explaining genetic structure. In addition, our data suggest that morphological variation in gnathopod 2 structure of males were not genetic-related and were probably plastic as a response to variations in macroalgae frond size. Our study reinforces the importance of using multiple molecular markers and analytical approaches to unveil patterns and processes generating genetic variation in natural populations.
揭示海洋物种的遗传结构和人口历史模式，以及形成其遗传变异的因素，是为物种及其环境的保护策略提供信息的基础。在这项研究中，我们利用全基因组和线粒体 DNA 标记，在精细的空间尺度上研究了巴西亚热带西南大西洋沿岸与海藻相关的显性片脚类动物黑潮（Hyale niger）的当前种群结构和历史人口模式。我们还研究了地理距离、当前海洋学条件和一个关键形态特征的变化是如何导致片脚类动物遗传变异的。尽管遗传分化程度低于我们对底栖直接育雏动物的预期，但我们观察到了明显的种群遗传结构，甚至在精细的空间尺度上也是如此。不同种群的人口史推断是一致的，并表明在更新世晚期的间冰期，即最后一次冰川最大值之前和之后，出现了两次主要的人口扩张。我们还证明，环境隔离（IBE）是遗传分化的主要驱动因素，尽管我们无法将其与距离隔离（IBD）的影响区分开来。在环境因素中，海水中的营养浓度与解释遗传结构最为相关。此外，我们的数据还表明，雄性尾足2结构的形态变化与遗传无关，可能是对大型藻类叶片大小变化的可塑性反应。我们的研究强调了使用多种分子标记和分析方法揭示自然种群遗传变异的模式和过程的重要性。
{"title":"Towards the understanding of genetic and morphological variations of a highly abundant seaweed-associated marine invertebrate","authors":"Pedro Augusto dos Santos Longo , Marianne Azevedo-Silva , Karine Ferreira Ribeiro Mansur , Thais Aparecida Marinho , André Guilherme Madeira , Anete Pereira de Souza , Shun K. Hirota , Yoshihisa Suyama , Gustavo Maruyama Mori , Fosca Pedini Pereira Leite","doi":"10.1016/j.ecss.2024.108977","DOIUrl":"10.1016/j.ecss.2024.108977","url":null,"abstract":"<div><div>Unraveling the patterns of genetic structure and demographic history of marine species, as well as the factors that shape their genetic variations, is fundamental for informing conservation strategies for species and their environments. In this work, we investigate the current population structure and historical demographic patterns of the conspicuous seaweed-associated amphipod <em>Hyale niger</em> at a fine spatial scale in the subtropical SW Atlantic coast, in Brazil, by using both genome-wide and mitochondrial DNA markers. We also investigate how geographic distance, current oceanographic conditions, and variations in a key morphological trait contribute to the genetic variability of the amphipod. We observed an evident population genetic structure, even at a fine spatial scale, although genetic differentiation was lower than our expectations for a benthic direct brooder. Demographic history inferences were consistent across populations and showed two major demographic expansions on interglacial periods during the late Pleiostocene, before and after the last glacial maximum. We also demonstrated that isolation-by-environment (IBE) was the main driver of genetic differentiation, although we could not separate it from the effects of isolation-by-distance (IBD). Among environmental factors, nutrient concentrations in seawater were most relevant for explaining genetic structure. In addition, our data suggest that morphological variation in gnathopod 2 structure of males were not genetic-related and were probably plastic as a response to variations in macroalgae frond size. Our study reinforces the importance of using multiple molecular markers and analytical approaches to unveil patterns and processes generating genetic variation in natural populations.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108977"},"PeriodicalIF":2.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417073","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ecss.2024.108973
Masuma Chowdhury , Isabel Caballero , Ignacio de la Calle , Irene Laiz
Analyzing the variability of chlorophyll-a (Chl-a) and total suspended matter (TSM) in estuarine and coastal environments is crucial for understanding ecosystem health, guiding environmental management decisions, and evaluating climate change impacts. Satellite remote sensing offers a powerful tool for this analysis due to its extensive spatial and temporal coverage. Although several algorithms exist for complex coastal and estuarine waters, long-term datasets such as GlobColor's Ocean Color (OC5) and neural network (NN) algorithms are frequently used for robust variability analysis. This study uses the GlobColor NN algorithm to investigate the seasonal and inter-annual variability of Chl-a and TSM in a data-scare region, namely the Meghna estuary in Bangladesh and its adjacent coastal fringe. The other algorithm (i.e. OC5), while offers the longest time series, cannot be used in this region due to the high number of invalid pixels. Therefore, this study examines different environmental factors (i.e. sea surface temperature (SST), photosynthetically active radiation (PAR), rainfall, zonal (ZWC) and meridional (MWC) wind components, and ocean currents) and climatic indices (i.e., El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD)) to understand their influence on the seasonal and inter-annual variability of Chl-a and TSM derived from the GlobColor NN algorithm. Empirical orthogonal function analysis identifies the seasonal signal as dominant in the study region. The seasonal cycle of Chl-a is influenced by factors including MWC, TSM, SST, and rainfall. In contrast, TSM seasonal variations are primarily driven by rainfall and MWC. Post-monsoon Chl-a inter-annual fluctuations are mainly linked to TSM inter-annual variability, with secondary influences from monsoon rainfall and the winter ENSO index. Inter-annual changes in TSM are primarily associated with the winter ENSO index and monsoon rainfall. This research elucidates the primary mechanisms influencing Chl-a and TSM variability in the Meghna estuary and its adjacent coast, thus advancing the understanding of the dynamics in the study region. The information obtained through this study is valuable for scientists, policymakers, and stakeholders involved in the sustainable management of the Meghna estuary and its coastal resources, particularly in the context of climate change.
{"title":"Chlorophyll-a and suspended matter variability in a data-scarce coastal-estuarine ecosystem","authors":"Masuma Chowdhury , Isabel Caballero , Ignacio de la Calle , Irene Laiz","doi":"10.1016/j.ecss.2024.108973","DOIUrl":"10.1016/j.ecss.2024.108973","url":null,"abstract":"<div><div>Analyzing the variability of chlorophyll-<em>a</em> (Chl-<em>a</em>) and total suspended matter (TSM) in estuarine and coastal environments is crucial for understanding ecosystem health, guiding environmental management decisions, and evaluating climate change impacts. Satellite remote sensing offers a powerful tool for this analysis due to its extensive spatial and temporal coverage. Although several algorithms exist for complex coastal and estuarine waters, long-term datasets such as GlobColor's Ocean Color (OC5) and neural network (NN) algorithms are frequently used for robust variability analysis. This study uses the GlobColor NN algorithm to investigate the seasonal and inter-annual variability of Chl-<em>a</em> and TSM in a data-scare region, namely the Meghna estuary in Bangladesh and its adjacent coastal fringe. The other algorithm (i.e. OC5), while offers the longest time series, cannot be used in this region due to the high number of invalid pixels. Therefore, this study examines different environmental factors (i.e. sea surface temperature (SST), photosynthetically active radiation (PAR), rainfall, zonal (ZWC) and meridional (MWC) wind components, and ocean currents) and climatic indices (i.e., El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD)) to understand their influence on the seasonal and inter-annual variability of Chl-<em>a</em> and TSM derived from the GlobColor NN algorithm. Empirical orthogonal function analysis identifies the seasonal signal as dominant in the study region. The seasonal cycle of Chl-<em>a</em> is influenced by factors including MWC, TSM, SST, and rainfall. In contrast, TSM seasonal variations are primarily driven by rainfall and MWC. Post-monsoon Chl-<em>a</em> inter-annual fluctuations are mainly linked to TSM inter-annual variability, with secondary influences from monsoon rainfall and the winter ENSO index. Inter-annual changes in TSM are primarily associated with the winter ENSO index and monsoon rainfall. This research elucidates the primary mechanisms influencing Chl-<em>a</em> and TSM variability in the Meghna estuary and its adjacent coast, thus advancing the understanding of the dynamics in the study region. The information obtained through this study is valuable for scientists, policymakers, and stakeholders involved in the sustainable management of the Meghna estuary and its coastal resources, particularly in the context of climate change.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108973"},"PeriodicalIF":2.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-05DOI: 10.1016/j.ecss.2024.108980
Kristen K. Beck , Mark Schuerch , Daniel Magnone , Marco A. Aquino-Lopez , Katie Gunning , Josephine Westlake , Sophie Beckerton
Coastal marshes, encompassing saltmarshes and freshwater marshes, are important environments for carbon sequestration and coastal protection; however, they are at risk due to climate change, sea level rise and human activity. Freshwater wetlands sit inland of saltmarshes and are often characterised by high biodiversity and productivity. Increasingly, conservation efforts are focussed on freshwater habitats, sometimes even at the expense of saltmarshes, through the construction of defences and embankments. However, these sea defences have unintended consequences on both coastal freshwater marshes and saltmarshes. In this study we investigate the implications of an embankment on a freshwater marsh and saltmarsh from Gibraltar Point, UK using a palaeoecological approach. A multiproxy approach was used on sediment archives from the freshwater marsh and saltmarsh to reconstruct the marsh geomorphological characteristics before and after the embankment was built. In the Freshwater marsh our results show the development of a transitional marsh over the past 200 years with ecological and morphological changes mainly dictated by storm surges with some influence from the embankment installation (ca. 1880 CE). The Old Saltmarsh shows the succession of a mature saltmarsh including rising elevation and vegetation development with negligible impact from the embankment construction. Whilst sea defences contribute to potential future coastal squeeze, by truncating areas of valuable freshwater marsh and cutting them off from their external sediment supply, they create risk to future inundation by sea-level rise. Natural development into freshwater marshes habitats have a greater potential for more biodiverse and multifunctional ecosystems and improved carbon storage capacity whilst enhancing coastal protection.
{"title":"Long-term impacts of embankments on coastal marsh vegetation and carbon sequestration","authors":"Kristen K. Beck , Mark Schuerch , Daniel Magnone , Marco A. Aquino-Lopez , Katie Gunning , Josephine Westlake , Sophie Beckerton","doi":"10.1016/j.ecss.2024.108980","DOIUrl":"10.1016/j.ecss.2024.108980","url":null,"abstract":"<div><div>Coastal marshes, encompassing saltmarshes and freshwater marshes, are important environments for carbon sequestration and coastal protection; however, they are at risk due to climate change, sea level rise and human activity. Freshwater wetlands sit inland of saltmarshes and are often characterised by high biodiversity and productivity. Increasingly, conservation efforts are focussed on freshwater habitats, sometimes even at the expense of saltmarshes, through the construction of defences and embankments. However, these sea defences have unintended consequences on both coastal freshwater marshes and saltmarshes. In this study we investigate the implications of an embankment on a freshwater marsh and saltmarsh from Gibraltar Point, UK using a palaeoecological approach. A multiproxy approach was used on sediment archives from the freshwater marsh and saltmarsh to reconstruct the marsh geomorphological characteristics before and after the embankment was built. In the Freshwater marsh our results show the development of a transitional marsh over the past 200 years with ecological and morphological changes mainly dictated by storm surges with some influence from the embankment installation (ca. 1880 CE). The Old Saltmarsh shows the succession of a mature saltmarsh including rising elevation and vegetation development with negligible impact from the embankment construction. Whilst sea defences contribute to potential future coastal squeeze, by truncating areas of valuable freshwater marsh and cutting them off from their external sediment supply, they create risk to future inundation by sea-level rise. Natural development into freshwater marshes habitats have a greater potential for more biodiverse and multifunctional ecosystems and improved carbon storage capacity whilst enhancing coastal protection.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108980"},"PeriodicalIF":2.6,"publicationDate":"2024-10-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142432992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-04DOI: 10.1016/j.ecss.2024.108978
Haisheng Yu , Weiming Xie , Zhong Peng , Fan Xu , Jianwei Sun , Qing He
Strong hydrodynamic forces generated by storms are key in shaping coastal tidal flats. Most tidal flats achieve equilibrium by adapting to hydrodynamic conditions and sediment inputs. However, high-energy wave activity during storms disrupts this equilibrium, causing rapid and significant changes, particularly in tidal flats, especially in microtidal flats, which are characterized by low tidal ranges. In this study, we conducted an 11-d field campaign on a microtidal flat in the Yellow River Delta (YRD), capturing data during both stormy and calm weather conditions. We measured tidal currents, wave activity, suspended sediment concentrations and sediment grain sizes. The results demonstrated that the tidal flat maintained equilibrium under calm conditions, with minimal fluctuations in bed level (within ±2 mm). Contrastingly, severe erosion and sediment removal during the storm significantly altered the equilibrium of the area. The storm-induced high shear stresses, ranging from 1.02 to 1.48 , along with alongshore sediment transport, resulted in an elevation change of −10 mm. Furthermore, the subsequent bed level recovery was minimal and insufficient to offset the erosion. Compared to that of the mesotidal and macrotidal flats, post-storm recovery on microtidal flats was limited due to shorter inundation periods and weaker hydrodynamic forces. Therefore, frequent storms may lead to continuous shoreline retreat on microtidal coasts. Conclusively, the present findings underscore the significant impact of storm-induced erosion on the evolutionary processes of microtidal flats and suggest that greater attention should be given to protecting these areas during storms in the Yellow River Delta. The insights can guide the development of more effective coastal protection strategies, highlighting the need for enhanced measures to mitigate erosion and promote resilience in microtidal regions.
{"title":"The impact of a storm on the microtidal flat in the Yellow River Delta","authors":"Haisheng Yu , Weiming Xie , Zhong Peng , Fan Xu , Jianwei Sun , Qing He","doi":"10.1016/j.ecss.2024.108978","DOIUrl":"10.1016/j.ecss.2024.108978","url":null,"abstract":"<div><div>Strong hydrodynamic forces generated by storms are key in shaping coastal tidal flats. Most tidal flats achieve equilibrium by adapting to hydrodynamic conditions and sediment inputs. However, high-energy wave activity during storms disrupts this equilibrium, causing rapid and significant changes, particularly in tidal flats, especially in microtidal flats, which are characterized by low tidal ranges. In this study, we conducted an 11-d field campaign on a microtidal flat in the Yellow River Delta (YRD), capturing data during both stormy and calm weather conditions. We measured tidal currents, wave activity, suspended sediment concentrations and sediment grain sizes. The results demonstrated that the tidal flat maintained equilibrium under calm conditions, with minimal fluctuations in bed level (within ±2 mm). Contrastingly, severe erosion and sediment removal during the storm significantly altered the equilibrium of the area. The storm-induced high shear stresses, ranging from 1.02 to 1.48 <span><math><mrow><mi>N</mi><mo>/</mo><msup><mi>m</mi><mn>2</mn></msup></mrow></math></span>, along with alongshore sediment transport, resulted in an elevation change of −10 mm. Furthermore, the subsequent bed level recovery was minimal and insufficient to offset the erosion. Compared to that of the mesotidal and macrotidal flats, post-storm recovery on microtidal flats was limited due to shorter inundation periods and weaker hydrodynamic forces. Therefore, frequent storms may lead to continuous shoreline retreat on microtidal coasts. Conclusively, the present findings underscore the significant impact of storm-induced erosion on the evolutionary processes of microtidal flats and suggest that greater attention should be given to protecting these areas during storms in the Yellow River Delta. The insights can guide the development of more effective coastal protection strategies, highlighting the need for enhanced measures to mitigate erosion and promote resilience in microtidal regions.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"311 ","pages":"Article 108978"},"PeriodicalIF":2.6,"publicationDate":"2024-10-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142657153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecss.2024.108972
Iván Cano, Aitor Ugena, Estefanía González-González, José Carlos Hernández
The sea urchin Diadema africanum is an herbivore that has a significant influence on subtidal rocky reef communities on the Canary Islands, facilitating transitions between macroalgal beds and barren grounds. Barren grounds in the archipelago are characterized by a dominance of crustose coralline algae and a lack of invertebrates and fishes compared to macroalgal beds, which are mainly dominated by brown algae. To assess the impact of these benthic community states on the early life success of D. africanum, a manipulative study was conducted in September 2021 at four sites on the eastern coast of Tenerife Island, characterized by the availability of historical settlement rates and adult data for this species. For this purpose, experimental larval collectors modified with a hollow algae-container were employed to examine sea urchin settlement rates in response to two dominant algal species, Lobophora schneideri, in macroalgal beds and crustose coralline algae (CCA) in barren grounds. Statistical analysis revealed significant spatial differences in sea urchin settlement and the interaction between site and treatment response. Specifically, the site with higher sea urchin settlement exhibited lower numbers of D. africanum settlers in treatments containing L. schneideri than in the Control and CCA treatments. Three decapod species (the pistol shrimp Alpheus macrocheles, and the crabs Lophozozimus incisus, and Pachygrapsus marmoratus) negatively correlated with D. africanum settlers. These results suggest that larval supply, L. schneideri beds, and micropredator abundance play a role in the early life success of this species. This may imply a community stability mechanism that helps to prevent shifts between alternative stable states.
非洲海胆（Diadema africanum）是一种食草动物，对加那利群岛潮下岩礁群落有重大影响，促进大型藻床和贫瘠地之间的过渡。加那利群岛荒地的特点是甲壳珊瑚藻占主导地位，与主要由褐藻占主导地位的大型藻床相比，缺少无脊椎动物和鱼类。为了评估这些底栖生物群落状态对非洲鳕早期生活成功率的影响，2021 年 9 月在特内里费岛东部海岸的四个地点开展了一项操纵性研究。为此，研究人员使用了改装过的中空海藻容器实验性幼体采集器，以检测海胆沉降率对两种主要藻类（大型藻床中的石花菜和荒地中的甲壳珊瑚藻）的反应。统计分析显示，海胆沉降的空间差异以及地点与处理反应之间的交互作用非常明显。具体而言，在海胆沉降量较高的地点，在含有 L. schneideri 的处理中，D. africanum 的沉降数量低于对照组和 CCA 处理。三种十足目动物（活塞虾 Alpheus macrocheles、螃蟹 Lophozozimus incisus 和 Pachygrapsus marmoratus）与 D. africanum 的定居者数量呈负相关。这些结果表明，幼虫供应、L. schneideri床和微小食肉动物的丰度对该物种早期生活的成功起着一定的作用。这可能意味着一种群落稳定机制，有助于防止替代稳定状态之间的转变。
{"title":"Assessing the influence of macroalgae and micropredators on the early life success of the echinoid Diadema africanum","authors":"Iván Cano, Aitor Ugena, Estefanía González-González, José Carlos Hernández","doi":"10.1016/j.ecss.2024.108972","DOIUrl":"10.1016/j.ecss.2024.108972","url":null,"abstract":"<div><div>The sea urchin <em>Diadema africanum</em> is an herbivore that has a significant influence on subtidal rocky reef communities on the Canary Islands, facilitating transitions between macroalgal beds and barren grounds. Barren grounds in the archipelago are characterized by a dominance of crustose coralline algae and a lack of invertebrates and fishes compared to macroalgal beds, which are mainly dominated by brown algae. To assess the impact of these benthic community states on the early life success of <em>D. africanum</em>, a manipulative study was conducted in September 2021 at four sites on the eastern coast of Tenerife Island, characterized by the availability of historical settlement rates and adult data for this species. For this purpose, experimental larval collectors modified with a hollow algae-container were employed to examine sea urchin settlement rates in response to two dominant algal species, <em>Lobophora schneideri</em>, in macroalgal beds and crustose coralline algae (CCA) in barren grounds. Statistical analysis revealed significant spatial differences in sea urchin settlement and the interaction between site and treatment response. Specifically, the site with higher sea urchin settlement exhibited lower numbers of <em>D. africanum</em> settlers in treatments containing <em>L. schneideri</em> than in the Control and CCA treatments. Three decapod species (the pistol shrimp <em>Alpheus macrocheles,</em> and the crabs <em>Lophozozimus incisus</em>, and <em>Pachygrapsus marmoratus</em>) negatively correlated with <em>D. africanum</em> settlers. These results suggest that larval supply, <em>L. schneideri</em> beds, and micropredator abundance play a role in the early life success of this species. This may imply a community stability mechanism that helps to prevent shifts between alternative stable states.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108972"},"PeriodicalIF":2.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecss.2024.108975
Aladin Andrisoa , Thomas C. Stieglitz , Marenjaka Masimana , Brillant Sambo , Patrick Raimbault , Jamal Mahafina
Whilst the impact of continental and marine nutrient sources on the ecological functioning of coastal food webs is well investigated in temperate regions, tropical ecosystems remain less well understood, in particular coastal lagoons. In this study, the sources of carbon and nitrogen in a coastal lagoon system in the southeast of Madagascar are traced using stable isotopes of carbon (δ13C) and nitrogen (δ15N). Three interconnected coastal lagoons with different degree of river influence and eutrophication are investigated. Their food webs are assessed with respect to spatial and seasonal (wet and dry seasons) variations in lagoon water conditions, as well as with respect to the sources of nutrients and organic matters. Results show that river input is the main source of NO3−, and that NO3− supply is significantly higher during the wet season. In contrast, NH4+ is produced internally in the lagoon, and concentrations are higher during the dry season. A lower δ13C value observed in particulate organic matter (POM; proxy of phytoplankton) indicates terrestrial-riverine carbon inputs, which generally have low δ13C values. During the dry season, exceptionally high δ15N values of lagoon POM suggest the uptake of newly produced lagoon water NH4+ and/or the 15N enrichment of lagoon POM pool due to mineralization, resulting in 15N enrichment in consumers. Moreover, δ13C and δ15N values of consumers (fishes and invertebrates) reflect predominantly those of lagoon POM and sediment organic matter (SOM), suggesting that consumers primarily depend on lagoon POM and SOM as sources of carbon and nitrogen. The δ15N values in consumers further indicate that some species feed on more than one trophic level, suggesting flexible foraging strategy of consumers as a function of food source availability. This study demonstrates the roles of both river inflow and sediment in supplying carbon and nitrogen to a coastal lagoon food web, documenting the ecological implications of seasonal variations in lagoon hydrological conditions.
{"title":"Carbon and nitrogen sources in tropical coastal lagoon food webs under variable hydrological conditions","authors":"Aladin Andrisoa , Thomas C. Stieglitz , Marenjaka Masimana , Brillant Sambo , Patrick Raimbault , Jamal Mahafina","doi":"10.1016/j.ecss.2024.108975","DOIUrl":"10.1016/j.ecss.2024.108975","url":null,"abstract":"<div><div>Whilst the impact of continental and marine nutrient sources on the ecological functioning of coastal food webs is well investigated in temperate regions, tropical ecosystems remain less well understood, in particular coastal lagoons. In this study, the sources of carbon and nitrogen in a coastal lagoon system in the southeast of Madagascar are traced using stable isotopes of carbon (δ<sup>13</sup>C) and nitrogen (δ<sup>15</sup>N). Three interconnected coastal lagoons with different degree of river influence and eutrophication are investigated. Their food webs are assessed with respect to spatial and seasonal (wet and dry seasons) variations in lagoon water conditions, as well as with respect to the sources of nutrients and organic matters. Results show that river input is the main source of NO<sub>3</sub><sup>−</sup>, and that NO<sub>3</sub><sup>−</sup> supply is significantly higher during the wet season. In contrast, NH<sub>4</sub><sup>+</sup> is produced internally in the lagoon, and concentrations are higher during the dry season. A lower δ<sup>13</sup>C value observed in particulate organic matter (POM; proxy of phytoplankton) indicates terrestrial-riverine carbon inputs, which generally have low δ<sup>13</sup>C values. During the dry season, exceptionally high δ<sup>15</sup>N values of lagoon POM suggest the uptake of newly produced lagoon water NH<sub>4</sub><sup>+</sup> and/or the <sup>15</sup>N enrichment of lagoon POM pool due to mineralization, resulting in <sup>15</sup>N enrichment in consumers. Moreover, δ<sup>13</sup>C and δ<sup>15</sup>N values of consumers (fishes and invertebrates) reflect predominantly those of lagoon POM and sediment organic matter (SOM), suggesting that consumers primarily depend on lagoon POM and SOM as sources of carbon and nitrogen. The δ<sup>15</sup>N values in consumers further indicate that some species feed on more than one trophic level, suggesting flexible foraging strategy of consumers as a function of food source availability. This study demonstrates the roles of both river inflow and sediment in supplying carbon and nitrogen to a coastal lagoon food web, documenting the ecological implications of seasonal variations in lagoon hydrological conditions.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108975"},"PeriodicalIF":2.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-01DOI: 10.1016/j.ecss.2024.108976
Eric Wolanski , Miguel De Le Court , Jonathan Lambrechts , Michael Kingfsord
This paper evaluates the conditions experienced by water-born passive larvae of broadcast spawning coral and crown-of-thorn starfish and how they self-recruit to their natal reefs in the Great Barrier Reef. The hypothesis that passive larvae are trapped for extended periods around specific areas of their natal reef (100s of metres) was found to be generally invalid. However, at some sites long-term trapping may occur when flow separation at headlands and in reef passages creates recirculating flows in embayments and behind concave-shaped reefs. Linear reefs do not trap passive larvae. This was demonstrated using satellite images and oceanographic modeling. The degree of self-recruitment at locations depended on the details of the incident flow speed, the shape of the headlands and the reef passages, the orientation of the reef compared to that of the tidal currents, the aspect ratio of the embayment, the curvature of the reef, and the time that the developing mushroom tidal jets takes to pass in front of the embayment. Self-recruitment of passive larvae depends on the spatial scale; at scales of 100s of metres, it is a rare process in the Great Barrier Reef. An exception was in a high-density reef matrix where the sticky water effect prevailed and self-recruitment was higher. Further, at scales of whole reefs (kilometres) and clusters of reefs (kms to 10s of kilometres) the likelihood of self-recruitment was higher. The probability of self-recruitment for reef fish larvae swimming directionally to their natal reefs following auditory and chemical cues is predicted to be much higher.
{"title":"Mechanisms enabling the self-recruitment of passive larvae in the Great Barrier Reef","authors":"Eric Wolanski , Miguel De Le Court , Jonathan Lambrechts , Michael Kingfsord","doi":"10.1016/j.ecss.2024.108976","DOIUrl":"10.1016/j.ecss.2024.108976","url":null,"abstract":"<div><div>This paper evaluates the conditions experienced by water-born passive larvae of broadcast spawning coral and crown-of-thorn starfish and how they self-recruit to their natal reefs in the Great Barrier Reef. The hypothesis that passive larvae are trapped for extended periods around specific areas of their natal reef (100s of metres) was found to be generally invalid. However, at some sites long-term trapping may occur when flow separation at headlands and in reef passages creates recirculating flows in embayments and behind concave-shaped reefs. Linear reefs do not trap passive larvae. This was demonstrated using satellite images and oceanographic modeling. The degree of self-recruitment at locations depended on the details of the incident flow speed, the shape of the headlands and the reef passages, the orientation of the reef compared to that of the tidal currents, the aspect ratio of the embayment, the curvature of the reef, and the time that the developing mushroom tidal jets takes to pass in front of the embayment. Self-recruitment of passive larvae depends on the spatial scale; at scales of 100s of metres, it is a rare process in the Great Barrier Reef. An exception was in a high-density reef matrix where the sticky water effect prevailed and self-recruitment was higher. Further, at scales of whole reefs (kilometres) and clusters of reefs (kms to 10s of kilometres) the likelihood of self-recruitment was higher. The probability of self-recruitment for reef fish larvae swimming directionally to their natal reefs following auditory and chemical cues is predicted to be much higher.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"309 ","pages":"Article 108976"},"PeriodicalIF":2.6,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142417165","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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