Pub Date : 2024-10-16DOI: 10.1016/j.ecss.2024.108988
Martine Røysted Solås , Anne Gro Vea Salvanes , Dag L. Aksnes
Previous studies have shown that climate change makes Norwegian fjords prone to deoxygenation and water darkening (reduced light penetration) with ecological implications across the food web from phytoplankton to fish. While deoxygenation occurs in deep fjord basins due to reduced water renewal, water darkening has primarily been linked to increased loads of colored dissolved organic matter (CDOM) of terrestrial origin in rivers draining to the Baltic Sea, the North Sea and ultimately to the Norwegian Coastal Current and associated coastal waters. Here, we investigate the hypothesis that water darkening is also linked to deoxygenation of fjord basins. We measure the downwelling irradiance in a water column with hypoxic and anoxic water and compare it with a nearby, well-oxygenated water column. Our data show increased darkening in the hypoxic and anoxic layers, likely due to elevated concentrations of CDOM that is produced locally in these layers. We discuss the ecological implication of this result, which we believe is particularly relevant for the mesopelagic habitat.
{"title":"Association between water darkening and hypoxia in a Norwegian fjord","authors":"Martine Røysted Solås , Anne Gro Vea Salvanes , Dag L. Aksnes","doi":"10.1016/j.ecss.2024.108988","DOIUrl":"10.1016/j.ecss.2024.108988","url":null,"abstract":"<div><div>Previous studies have shown that climate change makes Norwegian fjords prone to deoxygenation and water darkening (reduced light penetration) with ecological implications across the food web from phytoplankton to fish. While deoxygenation occurs in deep fjord basins due to reduced water renewal, water darkening has primarily been linked to increased loads of colored dissolved organic matter (CDOM) of terrestrial origin in rivers draining to the Baltic Sea, the North Sea and ultimately to the Norwegian Coastal Current and associated coastal waters. Here, we investigate the hypothesis that water darkening is also linked to deoxygenation of fjord basins. We measure the downwelling irradiance in a water column with hypoxic and anoxic water and compare it with a nearby, well-oxygenated water column. Our data show increased darkening in the hypoxic and anoxic layers, likely due to elevated concentrations of CDOM that is produced locally in these layers. We discuss the ecological implication of this result, which we believe is particularly relevant for the mesopelagic habitat.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108988"},"PeriodicalIF":2.6,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142528536","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 : 2024-10-15DOI: 10.1016/j.ecss.2024.108989
Loyiso Dunga , Melanie Lück-Vogel , Laura K. Blamey , John Bolton , Mark Rothman , Phil Desmet , Kerry Sink
Globally, kelp forests play a vital role in providing ecological, social and economic services. They contribute to the livelihoods and resilience of many coastal communities. To date, a gap exists in contemporary, comprehensive and consistent maps of South African kelp forests, since they were last mapped partially in 2006 by covering 900 km of South Africa's coastline. This study addresses this gap by producing a comprehensive remotely sensed high-resolution 2016 map of canopy forming coastal kelp forests. Using the 10m resolution Sentinel-2 A and B spectral bands 4 (RED) and 8 (NIR), an expert derived Normalized Difference Vegetation Index (NDVI) threshold was used to detect surface protruding kelp forests along 1300 km coastline. The results were validated with expert verification and using Google Earth, data from historic maps, remote sensing and biomass estimation of South African kelp resources. Our study demonstrates the aptitude of Sentinel-2 for detecting canopy-forming kelps at low cost along South Africa's west and south coast. We report the encountered drawbacks in mapping an expansive coastline with varied sea conditions including wave activity, tides and turbidity. Comprehensive ground validation, long-term monitoring sites and the use of time series datasets remain a gap towards improving the calibration of remote sensing methods and long-term monitoring of South African kelp forests. Our results provide a foundation for continuous monitoring of South African kelp forests as well as exploring other unmapped kelp/similar habitats to inform research and environmental management.
在全球范围内,海藻林在提供生态、社会和经济服务方面发挥着至关重要的作用。它们为许多沿海社区的生计和恢复能力做出了贡献。迄今为止,南非海藻林的当代、全面和一致的地图还存在空白,因为上一次绘制南非海藻林的部分地图是在 2006 年,覆盖了南非 900 公里的海岸线。本研究针对这一空白,绘制了一幅全面的遥感高分辨率 2016 年沿海海藻林冠层地图。利用 10 米分辨率的哨兵-2 A 波段和 B 波段 4(红光)和 8(近红外),使用专家得出的归一化差异植被指数(NDVI)阈值来检测 1300 公里海岸线上的地表突出海藻林。专家通过谷歌地球、历史地图数据、南非海藻资源遥感和生物量估算对结果进行了验证。我们的研究表明,哨兵-2 能够以较低的成本探测南非西海岸和南海岸的冠状海带。我们报告了在绘制波浪活动、潮汐和浊度等不同海况的广阔海岸线地图时遇到的缺点。在改进遥感方法的校准和南非海藻森林的长期监测方面,全面的地面验证、长期监测点和时间序列数据集的使用仍然存在差距。我们的研究成果为持续监测南非海藻林以及探索其他未绘制地图的海藻/类似栖息地奠定了基础,为研究和环境管理提供了信息。
{"title":"Mapping South Africa's canopy-forming kelp forests using low-cost, high-resolution Sentinel-2 imagery","authors":"Loyiso Dunga , Melanie Lück-Vogel , Laura K. Blamey , John Bolton , Mark Rothman , Phil Desmet , Kerry Sink","doi":"10.1016/j.ecss.2024.108989","DOIUrl":"10.1016/j.ecss.2024.108989","url":null,"abstract":"<div><div>Globally, kelp forests play a vital role in providing ecological, social and economic services. They contribute to the livelihoods and resilience of many coastal communities. To date, a gap exists in contemporary, comprehensive and consistent maps of South African kelp forests, since they were last mapped partially in 2006 by covering 900 km of South Africa's coastline. This study addresses this gap by producing a comprehensive remotely sensed high-resolution 2016 map of canopy forming coastal kelp forests. Using the 10m resolution Sentinel-2 A and B spectral bands 4 (RED) and 8 (NIR), an expert derived Normalized Difference Vegetation Index (NDVI) threshold was used to detect surface protruding kelp forests along 1300 km coastline. The results were validated with expert verification and using Google Earth, data from historic maps, remote sensing and biomass estimation of South African kelp resources. Our study demonstrates the aptitude of Sentinel-2 for detecting canopy-forming kelps at low cost along South Africa's west and south coast. We report the encountered drawbacks in mapping an expansive coastline with varied sea conditions including wave activity, tides and turbidity. Comprehensive ground validation, long-term monitoring sites and the use of time series datasets remain a gap towards improving the calibration of remote sensing methods and long-term monitoring of South African kelp forests. Our results provide a foundation for continuous monitoring of South African kelp forests as well as exploring other unmapped kelp/similar habitats to inform research and environmental management.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108989"},"PeriodicalIF":2.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554843","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 : 2024-10-15DOI: 10.1016/j.ecss.2024.108986
Cécile Vulliet , Jack Koci , Marcus Sheaves , Nathan Waltham
A key value of saltmarshes is their role in providing trophic subsidies, notably in the form of prey pulses of crab zoeae (CZ). No studies to date, however, have investigated quantitatively the patterns between crab zoeae pulses and saltmarsh tidal connectivity in tropical estuaries. In this study, CZ densities were examined over successive tides and months using a zooplankton sampling pump to examine links between tidal fluctuations and pulses of CZ in a tropical Australian estuary with a complex of tidal saltmarshes, mangroves, and unvegetated flats. CZ densities were linked to spatially explicit information on tidal wetland inundation that was derived from Unattended-Aerial-Vehicle (UAV) Structure from motion (SfM) photogrammetry and two-dimensional hydrodynamic modelling. The study found that: (1) tidal connectivity is a key trigger to prey pulse export; (2) while tidal connectivity was critical in the export of CZ, not all tidal connections resulted in meaningful ecological connectivity; and (3) succulent saltmarsh was one of the tidal wetland types contributing to the export of CZ. Surprisingly, we reveal that not all succulent saltmarshes were uniformly participating in CZ export. These findings highlight the significance of quantitative eco-hydrological approaches to assess saltmarsh and tidal connectivity values. This study supports the need for management and restoration approaches to integrate a contextual understanding of the synergies between hydrology, ecology, and habitat heterogeneity. These data emphasise the need to move beyond generalisations that “similar” habitat type share similar ecological functions and should be managed equally.
{"title":"Intertidal crab prey pulse export quantifies the importance of tidal wetland connectivity","authors":"Cécile Vulliet , Jack Koci , Marcus Sheaves , Nathan Waltham","doi":"10.1016/j.ecss.2024.108986","DOIUrl":"10.1016/j.ecss.2024.108986","url":null,"abstract":"<div><div>A key value of saltmarshes is their role in providing trophic subsidies, notably in the form of prey pulses of crab zoeae (CZ). No studies to date, however, have investigated quantitatively the patterns between crab zoeae pulses and saltmarsh tidal connectivity in tropical estuaries. In this study, CZ densities were examined over successive tides and months using a zooplankton sampling pump to examine links between tidal fluctuations and pulses of CZ in a tropical Australian estuary with a complex of tidal saltmarshes, mangroves, and unvegetated flats. CZ densities were linked to spatially explicit information on tidal wetland inundation that was derived from Unattended-Aerial-Vehicle (UAV) Structure from motion (SfM) photogrammetry and two-dimensional hydrodynamic modelling. The study found that: (1) tidal connectivity is a key trigger to prey pulse export; (2) while tidal connectivity was critical in the export of CZ, not all tidal connections resulted in meaningful ecological connectivity; and (3) succulent saltmarsh was one of the tidal wetland types contributing to the export of CZ. Surprisingly, we reveal that not all succulent saltmarshes were uniformly participating in CZ export. These findings highlight the significance of quantitative eco-hydrological approaches to assess saltmarsh and tidal connectivity values. This study supports the need for management and restoration approaches to integrate a contextual understanding of the synergies between hydrology, ecology, and habitat heterogeneity. These data emphasise the need to move beyond generalisations that “similar” habitat type share similar ecological functions and should be managed equally.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108986"},"PeriodicalIF":2.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527420","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 : 2024-10-15DOI: 10.1016/j.ecss.2024.108985
T.R. Athira , Aymen Nefla , K.A. Rubeena , Sabir Bin Muzaffar , Omer R. Reshi , T. Jobiraj , P. Thejass , K.M. Aarif
The near-threatened Bar-tailed Godwit (Limosa lapponica) makes the longest non-stop endurance flights among shorebirds. They are regular winter visitors to the Kadalundi-Vallikkunnu Community Reserve and adjoining sand beaches along the west coast of India. The research investigates their foraging strategies within sand beaches, observed over six years (2016–2022). Extensive field observations across major sand beaches documented two distinct modes of continuous stitching behaviour; a straight-line mode and a zigzag mode. Despite predation pressure and human disturbances, Bar-tailed Godwits achieved high prey capture rates, likely due to the abundance of benthic invertebrates. The study also revealed the prevalence of this behaviour and its association with rate of prey consumption, particularly focusing on the availability of Cosmonotus crabs, the dominant prey species. The zigzag pattern, was associated with higher prey capture rates, suggesting an adaptive response to prey distribution. Our findings suggest that, this unique foraging strategy allows Bar-tailed Godwits to optimize prey capture while conserving time and energy, especially in resource-scarce environments. Furthermore, the implications of these behaviours are discussed in the context of prey availability, nutrient content, and the energetic demands of long-distance migration, shedding light on to the adaptive mechanisms employed by shorebirds in challenging habitats.
{"title":"Survival strategies of Bar-tailed Godwit in tropical sand beaches: Straight-line and zigzag foraging techniques","authors":"T.R. Athira , Aymen Nefla , K.A. Rubeena , Sabir Bin Muzaffar , Omer R. Reshi , T. Jobiraj , P. Thejass , K.M. Aarif","doi":"10.1016/j.ecss.2024.108985","DOIUrl":"10.1016/j.ecss.2024.108985","url":null,"abstract":"<div><div>The near-threatened Bar-tailed Godwit (<em>Limosa lapponica</em>) makes the longest non-stop endurance flights among shorebirds. They are regular winter visitors to the Kadalundi-Vallikkunnu Community Reserve and adjoining sand beaches along the west coast of India. The research investigates their foraging strategies within sand beaches, observed over six years (2016–2022). Extensive field observations across major sand beaches documented two distinct modes of continuous stitching behaviour; a straight-line mode and a zigzag mode. Despite predation pressure and human disturbances, Bar-tailed Godwits achieved high prey capture rates, likely due to the abundance of benthic invertebrates. The study also revealed the prevalence of this behaviour and its association with rate of prey consumption, particularly focusing on the availability of Cosmonotus crabs, the dominant prey species. The zigzag pattern, was associated with higher prey capture rates, suggesting an adaptive response to prey distribution. Our findings suggest that, this unique foraging strategy allows Bar-tailed Godwits to optimize prey capture while conserving time and energy, especially in resource-scarce environments. Furthermore, the implications of these behaviours are discussed in the context of prey availability, nutrient content, and the energetic demands of long-distance migration, shedding light on to the adaptive mechanisms employed by shorebirds in challenging habitats.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108985"},"PeriodicalIF":2.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527419","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 : 2024-10-15DOI: 10.1016/j.ecss.2024.108987
Alexandra Cravo, José Jacob, Alexandra Rosa , Cátia Correia
Coastal lagoons are highly productive systems and the quantification of mass fluxes, which is of paramount importance for the sustainable management of these systems, remains poorly studied. In this context, a detailed study was conducted to better understand the exchanges between the productive coastal lagoon Ria Formosa (South-West Europe) and the ocean. The exchanges of water, nutrients, chlorophyll-a and suspended solids between the main inlets (Faro-Olhão inlet - BFO; Armona inlet - BAR; and Ancão inlet - BAN) and adjacent channels (Faro - CF and Olhão - CO) and the adjacent ocean were estimated along complete semidiurnal tidal cycles, under extreme fortnightly tidal ranges and different seasonal and environmental/oceanographic conditions. The net tidal prism was highest during spring tides. Among the three inlets, BFO was the most important in terms of exchange, followed by BAR and BAN. Net transport at BFO was lowest during the Summer campaign, although it exported material that fertilised the adjacent coast. The persistent net export of suspended solids and ammonium suggests the higher biological productivity of Ria Formosa compared to that found in coastal waters. In the Winter campaign, after a period of rainfall and increased land runoff, there was a remarkable export of matter, on which, ammonium and suspended particles exported can exceed 0.3 times and almost 0.9 times, respectively, those imported from coastal water. However, the import of phosphate and nitrate can be attributed to a weak coastal upwelling event, as well to low consumption and nitrification at this period of low temperature. During the Spring and Autumn campaigns, the Ria Formosa was fertilised either by upwelling events or due to rapid consumption of nutrients by phytoplankton in this shallow system. BFO and the other two inlets of the western sector of Ria Formosa are interconnected by CF and CO. The higher nutrient transport was recorded at CF, despite the highest nutrients concentrations was recorded at CO. The data show the strong link between physical and biogeochemical processes with meteorological/oceanographic factors. The study showed that associated biological processes are superimposed on the tidal effect in this system. Data from this study could be used as a reference, particularly important for management of Ria Formosa, a productive system where bivalves production depends deeply on water quality. In addition, the nutrient concentrations and mass exchanges resulting from the different processes can be used as a reference for other lagoon systems where shellfish production is practised.
沿海泻湖是高产系统,而质量通量的量化对这些系统的可持续管理至关重要,但这方面的研究仍然很少。为此,我们进行了一项详细研究,以更好地了解富饶的沿海泻湖 Ria Formosa(欧洲西南部)与海洋之间的交换情况。在每两周一次的极端潮差以及不同的季节和环境/海洋条件下,对主要入海口(法罗-奥尔 良入海口-BFO;阿尔莫纳入海口-BAR;安康入海口-BAN)和邻近水道(法罗-CF 和奥尔 良-CO)与邻近海洋之间的水、营养物、叶绿素-a 和悬浮固体的交换进行了估算。净潮汐棱镜在春潮期间最大。在三个入海口中,BFO 的交换量最大,其次是 BAR 和 BAN。在夏季活动期间,BFO 的净输送量最低,尽管它输出的物质为邻近海岸提供了肥料。悬浮固体和铵的持续净输出表明,与沿岸水域相比,福尔摩沙河的生物生产力较高。在冬季活动中,经过一段时间的降雨和陆地径流的增加,物质输出量显著增加,其中氨和悬浮颗粒的输出量可分别超过从沿岸水域输入量的 0.3 倍和近 0.9 倍。然而,磷酸盐和硝酸盐的输入可归因于微弱的沿岸上升流活动,以及低温时期的低消耗和硝化作用。在春季和秋季活动期间,福莫萨湾因上升流活动或该浅水系统中浮游植物快速消耗养分而肥沃起来。BFO 和福尔摩沙岛西区的其他两个入海口通过 CF 和 CO 相互连接。尽管 CO 处的营养物浓度最高,但 CF 处的营养物迁移量更大。这些数据表明,物理和生物地球化学过程与气象/海洋因素密切相关。研究表明,在该系统中,相关的生物过程与潮汐效应叠加在一起。这项研究的数据可作为参考,对福尔摩沙河的管理尤为重要,因为福尔摩沙河是一个富饶的系统,双壳贝类的产量在很大程度上取决于水质。此外,不同过程产生的营养物浓度和质量交换也可作为其他生产贝类的环礁湖系统的参考。
{"title":"Integrating physical and biogeochemical processes and oceanic exchanges at a coastal lagoon in Southern West Europe","authors":"Alexandra Cravo, José Jacob, Alexandra Rosa , Cátia Correia","doi":"10.1016/j.ecss.2024.108987","DOIUrl":"10.1016/j.ecss.2024.108987","url":null,"abstract":"<div><div>Coastal lagoons are highly productive systems and the quantification of mass fluxes, which is of paramount importance for the sustainable management of these systems, remains poorly studied. In this context, a detailed study was conducted to better understand the exchanges between the productive coastal lagoon Ria Formosa (South-West Europe) and the ocean. The exchanges of water, nutrients, chlorophyll-a and suspended solids between the main inlets (Faro-Olhão inlet - BFO; Armona inlet - BAR; and Ancão inlet - BAN) and adjacent channels (Faro - CF and Olhão - CO) and the adjacent ocean were estimated along complete semidiurnal tidal cycles, under extreme fortnightly tidal ranges and different seasonal and environmental/oceanographic conditions. The net tidal prism was highest during spring tides. Among the three inlets, BFO was the most important in terms of exchange, followed by BAR and BAN. Net transport at BFO was lowest during the Summer campaign, although it exported material that fertilised the adjacent coast. The persistent net export of suspended solids and ammonium suggests the higher biological productivity of Ria Formosa compared to that found in coastal waters. In the Winter campaign, after a period of rainfall and increased land runoff, there was a remarkable export of matter, on which, ammonium and suspended particles exported can exceed 0.3 times and almost 0.9 times, respectively, those imported from coastal water. However, the import of phosphate and nitrate can be attributed to a weak coastal upwelling event, as well to low consumption and nitrification at this period of low temperature. During the Spring and Autumn campaigns, the Ria Formosa was fertilised either by upwelling events or due to rapid consumption of nutrients by phytoplankton in this shallow system. BFO and the other two inlets of the western sector of Ria Formosa are interconnected by CF and CO. The higher nutrient transport was recorded at CF, despite the highest nutrients concentrations was recorded at CO. The data show the strong link between physical and biogeochemical processes with meteorological/oceanographic factors. The study showed that associated biological processes are superimposed on the tidal effect in this system. Data from this study could be used as a reference, particularly important for management of Ria Formosa, a productive system where bivalves production depends deeply on water quality. In addition, the nutrient concentrations and mass exchanges resulting from the different processes can be used as a reference for other lagoon systems where shellfish production is practised.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108987"},"PeriodicalIF":2.6,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527417","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 : 2024-10-11DOI: 10.1016/j.ecss.2024.108981
Christian Lønborg , Stiig Markager , Simon David Herzog , Catia Carreira , Signe Høgslund
Globally coastal sediments are frequently disturbed by a wide range of physical anthropogenic processes (e.g. bottom trawling) which causes resuspension of sediment organic matter (OM) into the overlaying water column. In this study we present experimental results showing that anthropogenic sediment resuspension decreases the organic carbon (14x) and nitrogen (3x) content in the sediment material resuspended to the water column, while no measurable response was found for organic phosphorus. Our findings furthermore show that the OM bioavailability decreased and the Carbon:Nitrogen:Phosphorus stoichiometry was changed suggesting that anthropogenic resuspension changes the chemical composition, and/or production and degradation pathways of the OM pool. The detected changes in OM biogeochemistry could affect nutrient release, fuel oxygen consumption and at the same time increase CO2 production in coastal waters.
全球沿海沉积物经常受到各种物理人为过程(如底拖网捕捞)的扰动,导致沉积物 有机物(OM)重新悬浮到上覆水体中。在这项研究中,我们的实验结果表明,人为的沉积物再悬浮会使再悬浮到水体中的沉积物中的有机碳(14 倍)和氮(3 倍)含量降低,而对有机磷则没有发现可测量的反应。我们的研究结果还表明,有机物的生物利用率降低,碳:氮:磷的化学计量发生了变化,这表明人为的再悬浮改变了有机物池的化学组成和/或生成和降解途径。检测到的 OM 生物地球化学变化可能会影响沿岸水域的营养物质释放、氧气消耗,同时增加二氧化碳的产生。
{"title":"Impacts of anthropogenic resuspension on sediment organic matter: An experimental approach","authors":"Christian Lønborg , Stiig Markager , Simon David Herzog , Catia Carreira , Signe Høgslund","doi":"10.1016/j.ecss.2024.108981","DOIUrl":"10.1016/j.ecss.2024.108981","url":null,"abstract":"<div><div>Globally coastal sediments are frequently disturbed by a wide range of physical anthropogenic processes (e.g. bottom trawling) which causes resuspension of sediment organic matter (OM) into the overlaying water column. In this study we present experimental results showing that anthropogenic sediment resuspension decreases the organic carbon (14x) and nitrogen (3x) content in the sediment material resuspended to the water column, while no measurable response was found for organic phosphorus. Our findings furthermore show that the OM bioavailability decreased and the Carbon:Nitrogen:Phosphorus stoichiometry was changed suggesting that anthropogenic resuspension changes the chemical composition, and/or production and degradation pathways of the OM pool. The detected changes in OM biogeochemistry could affect nutrient release, fuel oxygen consumption and at the same time increase CO<sub>2</sub> production in coastal waters.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108981"},"PeriodicalIF":2.6,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142527421","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 : 2024-10-11DOI: 10.1016/j.ecss.2024.108982
Guillaume Bridier , Frédéric Olivier , Laurent Chauvaud , Vincent Le Garrec , Gabin Droual , Jacques Grall
Arctic and sub-Arctic marine ecosystems are experiencing some of the highest sea surface warming in the world, which has intensified water column stratification and subsequently reduced phytoplankton production and particulate organic matter quality. However, the effects of these changes on benthic food webs and the transfer of organic matter to higher trophic levels are still poorly understood. This study examines the spatial and temporal variability of food web structure in a sub-Arctic benthic community exposed to contrasting thermal stratification conditions. The study hypothesizes that during stratified periods, oceanographic conditions would have a limited effect on benthic invertebrates located above/at the thermocline due to their direct access to surface/subsurface primary production. On the other hand, organisms below the thermocline may be more sensitive to increased stratification because they do not have direct access to these food resources. To test this hypothesis, we sampled benthic invertebrates and several fish species on the Newfoundland Shelf along a cross-shore transect (2 shallow stations versus 2 deep stations above and below the thermocline, respectively) over two seasons. We used isotopic analyses (δ13C and δ15N) to study the structure of the food web and the transfer of organic matter. No temporal variation and little spatial variability in food web structure was observed, resulting in a 73.2% overlap between isotopic niches of shallow and deep stations. At all stations, most primary consumers were characterized by high trophic plasticity, feeding on both phytoplankton and benthic organic matter (mean dependence on benthic sources = 46.7%). In the context of global warming and increased thermal stratification, we hypothesize that benthic primary production may be less vulnerable to nutrient depletion than phytoplankton. We suggest that an increased contribution of benthic primary producers to organic matter fluxes in shallow coastal food webs could significantly enhance the resilience of the benthic food web to stratification intensification.
{"title":"Benthic food web structure of a highly stratified sub-Arctic archipelago on the Newfoundland Shelf (Northwest Atlantic Ocean)","authors":"Guillaume Bridier , Frédéric Olivier , Laurent Chauvaud , Vincent Le Garrec , Gabin Droual , Jacques Grall","doi":"10.1016/j.ecss.2024.108982","DOIUrl":"10.1016/j.ecss.2024.108982","url":null,"abstract":"<div><div>Arctic and sub-Arctic marine ecosystems are experiencing some of the highest sea surface warming in the world, which has intensified water column stratification and subsequently reduced phytoplankton production and particulate organic matter quality. However, the effects of these changes on benthic food webs and the transfer of organic matter to higher trophic levels are still poorly understood. This study examines the spatial and temporal variability of food web structure in a sub-Arctic benthic community exposed to contrasting thermal stratification conditions. The study hypothesizes that during stratified periods, oceanographic conditions would have a limited effect on benthic invertebrates located above/at the thermocline due to their direct access to surface/subsurface primary production. On the other hand, organisms below the thermocline may be more sensitive to increased stratification because they do not have direct access to these food resources. To test this hypothesis, we sampled benthic invertebrates and several fish species on the Newfoundland Shelf along a cross-shore transect (2 shallow stations versus 2 deep stations above and below the thermocline, respectively) over two seasons. We used isotopic analyses (δ<sup>13</sup>C and δ<sup>15</sup>N) to study the structure of the food web and the transfer of organic matter. No temporal variation and little spatial variability in food web structure was observed, resulting in a 73.2% overlap between isotopic niches of shallow and deep stations. At all stations, most primary consumers were characterized by high trophic plasticity, feeding on both phytoplankton and benthic organic matter (mean dependence on benthic sources = 46.7%). In the context of global warming and increased thermal stratification, we hypothesize that benthic primary production may be less vulnerable to nutrient depletion than phytoplankton. We suggest that an increased contribution of benthic primary producers to organic matter fluxes in shallow coastal food webs could significantly enhance the resilience of the benthic food web to stratification intensification.</div></div>","PeriodicalId":50497,"journal":{"name":"Estuarine Coastal and Shelf Science","volume":"310 ","pages":"Article 108982"},"PeriodicalIF":2.6,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142444563","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.2024.108983
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}