M. Juarez Rivera, T. J. Mackey, I. Hawes, D. Y. Sumner
{"title":"Morphology and Distribution of Bubble-Supported Microbial Mats From Ice-Covered Antarctic Lakes","authors":"M. Juarez Rivera, T. J. Mackey, I. Hawes, D. Y. Sumner","doi":"10.1029/2024JG008516","DOIUrl":"https://doi.org/10.1029/2024JG008516","url":null,"abstract":"<p>Gas bubbles directly influence the macromorphology of benthic microbial mats resulting in preservable biosedimentary structures. This study characterizes the morphology and distribution of microbial mats growing in gas-supersaturated, perennially ice-covered lakes Fryxell, Joyce, and Hoare of the McMurdo Dry Valleys of Antarctica. Photosynthetic benthic mats within the gas-supersaturated zone trap oxygen-rich bubbles and become buoyant, tearing off the bottom as “liftoff mats.” These liftoff mats form a succession of morphologies starting with bubble-induced deformation of flat mats into tent, ridge, and finger liftoff mat. With progressive deformation, mats tear, forming sheet liftoff, while multiple cycles of deformation and tearing transform sheet into strip liftoff. Some mats detach from the substrate and float to the underside of the ice. The depth range of the liftoff zone has varied over time at each lake. Downslope expansion of bubble formation brings previously bubble-free, deep-water pinnacle mats into the liftoff zone. When the liftoff zone shallows, liftoff mats at the deeper end deflate and can become scaffolding for additional mat growth. The superposition and relative orientation of liftoff and pinnacle mats can be used to track the maximum depth of the liftoff zone and changes in gas saturation state in these lakes through time. Our results demonstrate that gas bubbles, even when they are transitory, can exert a significant impact on the morphology of microbial mats at larger scales. This provides a way to identify similar structures and gas supersaturated environments in the biosedimentary record.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008516","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Huizhong Zhang-Turpeinen, Heidi Aaltonen, Jing Tang, Dan Kou, Minna Kivimäenpää, Riikka Rinnan, Jukka Pumpanen
{"title":"Changes in the Factors Influencing Forest Floor Terpenoid Emissions During Post-Fire Forest Succession","authors":"Huizhong Zhang-Turpeinen, Heidi Aaltonen, Jing Tang, Dan Kou, Minna Kivimäenpää, Riikka Rinnan, Jukka Pumpanen","doi":"10.1029/2024JG008113","DOIUrl":"https://doi.org/10.1029/2024JG008113","url":null,"abstract":"<p>The forest floor acts as a source of terpenoid emissions to the atmosphere. These emissions can further impact atmospheric particle formation and impact the atmospheric radiation balance. Climate change escalates wildfire frequency in boreal forests. Wildfires are major disturbances with long-term ecosystem impacts, particularly on the forest floor, significantly influencing terpenoid sources and emissions. This study quantified the post-fire terpenoid emissions from the forest floor and characterized micro-environmental conditions, including abiotic (e.g., air temperature, soil temperature, soil moisture, and light intensity) and biotic factors (ground vegetation characteristics, soil respiration (CO<sub>2</sub> fluxes), and soil microbial biomass). We aimed to understand how abiotic and biotic factors affect terpenoid emissions during post-fire succession. Path models revealed direct impacts of ground vegetation on isoprene and monoterpene emissions, while sesquiterpene emissions were mainly regulated by various abiotic factors. Isoprene and monoterpene emissions were influenced by both direct and indirect abiotic factors, mediated through biotic factors like vegetation and soil processes. Effect sizes of the influencing factors varied across forest age classes. Due to the post-fire regrowth of ground vegetation, the impact of temperature on emissions was more pronounced in earlier burned areas than recently burned areas. The influence of soil moisture on terpenoid emissions diminished with forest age. Our findings emphasize the need to identify factors influencing forest floor terpenoid emissions across post-fire succession stages to understand and predict their emission patterns and subsequent impacts on climate.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689530","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P. Regier, K. Son, X. Chen, Y. Fang, P. Jiang, M. Taylor, W. M. Wollheim, J. Stegen
{"title":"Allometric Scaling of Hyporheic Respiration Across Basins in the Pacific Northwest United States","authors":"P. Regier, K. Son, X. Chen, Y. Fang, P. Jiang, M. Taylor, W. M. Wollheim, J. Stegen","doi":"10.1029/2024JG008344","DOIUrl":"https://doi.org/10.1029/2024JG008344","url":null,"abstract":"<p>Hyporheic zones regulate biogeochemical processes in streams and rivers, but high spatiotemporal heterogeneity makes it difficult to predict how these processes scale from individual reaches to river basins. Recent work applying allometric scaling (i.e., power-law relationships between size and function) to river networks provides a new paradigm for understanding cumulative hyporheic biogeochemical processes. We used previously published model predictions of reach-scale hyporheic aerobic respiration to explore patterns in allometric scaling across two climatically divergent basins with differing characteristics in the Pacific Northwest, United States. In the model, hydrologic exchange fluxes (HEFs) regulate hyporheic respiration, so we examined how HEFs might influence allometric scaling of respiration. We found consistent scaling behaviors where HEFs were either very low or very high, but differences between basins when HEFs were moderate. Our findings provide initial model-generated hypotheses for factors influencing allometric scaling of hyporheic respiration. These hypotheses can be used to optimize new data generation efforts aimed at developing predictive understanding of allometries that can, in turn, be used to scale biogeochemical dynamics across watersheds.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008344","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammed Fatih Sert, Hans C. Bernstein, Knut Ola Dølven, Sebastian Petters, Timo Kekäläinen, Janne Jänis, Jorge Corrales-Guerrero, Bénédicte Ferré
{"title":"Cold Seeps and Coral Reefs in Northern Norway: Carbon Cycling in Marine Ecosystems With Coexisting Features","authors":"Muhammed Fatih Sert, Hans C. Bernstein, Knut Ola Dølven, Sebastian Petters, Timo Kekäläinen, Janne Jänis, Jorge Corrales-Guerrero, Bénédicte Ferré","doi":"10.1029/2024JG008475","DOIUrl":"https://doi.org/10.1029/2024JG008475","url":null,"abstract":"<p>Cold seeps and cold-water corals (CWCs) coexist on Northern Norway's continental shelf at the Hola trough between Lofoten and Vesterålen. Here, cold seeps release methane from the seabed, yet none reaches the sea surface. Instead, the methane dissolves and disperses in the ocean where it is ultimately consumed by methane-oxidizing microorganisms. These microorganisms metabolize methane and release carbon dioxide and dissolved organic matter (DOM), which may impact the biogeochemical habitat of CWCs in close vicinity of cold seeps. We investigated the biogeochemistry of carbon, carbon isotopes, nutrients, DOM compositions, and microbial diversity in the water column. Our results indicated that dissolved inorganic carbon concentrations were 29% higher near cold seeps with modified carbon's isotopic compositions. The hydrophysical parameters and surface-to-bottom control of sinking particles mainly govern water column productivity and nutrient cycle. DOM compositions implied that the seep-associated microbiomes modify DOM's chemical diversity and isotopic composition at CWCs and the entire water column near cold seeps. Cold seeps and CWCs coexist in Northern Norway's continental shelves; however, enhanced water temperatures and consequent increase in methane release at cold seeps may modify the carbon cycling in the area, which could mitigate the ecological role and functioning of CWC reefs in the future.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143688934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Songhan Wang, Kees Jan van Groenigen, Christoph Müller, Xuhui Wang, Lian Song, Yunlong Liu, Yu Jiang, Josep Peñuelas, Yanfeng Ding
{"title":"Improved Estimates of Regional Rice Yield Responses to Elevated CO2 by Considering Sub-Species Discrepancies","authors":"Songhan Wang, Kees Jan van Groenigen, Christoph Müller, Xuhui Wang, Lian Song, Yunlong Liu, Yu Jiang, Josep Peñuelas, Yanfeng Ding","doi":"10.1029/2024JG008438","DOIUrl":"https://doi.org/10.1029/2024JG008438","url":null,"abstract":"<p>Increased rice yields due to rising atmospheric carbon dioxide (CO<sub>2</sub>), known as the CO<sub>2</sub> fertilization effect (CFE), is one of several important factors sustaining global food security. However, model projections on future rice yields are still largely uncertain, partly owing to the lack of how CFE varies between rice species. Here, through synthesis of hundreds of field observations, we found the experimental evidence of a 12.8 ± 0.8% yield increase per 100 ppm CO<sub>2</sub> increase for Indica, but only about a half for Japonica (6.3 ± 0.5 %). After accounting for differences in sub-species, crop model projections showed substantial regional discrepancies of CFE, which are not captured by original models. More importantly, the spatial and temporal variations of rice yield were projected more accurately after considering this sub-species difference. Together, these results suggest strong influences of genotype on rice yield responses to CO<sub>2</sub> and highlight the need for crop models to consider genotypes for improving projections of global crop yield.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143689041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mina Rahmani, Jamal Asgari, Milad Asgarimehr, Jens Wickert
{"title":"Investigation of the Global Influence of Surface Roughness on Space-Borne GNSS-R Observations","authors":"Mina Rahmani, Jamal Asgari, Milad Asgarimehr, Jens Wickert","doi":"10.1029/2024JG008243","DOIUrl":"https://doi.org/10.1029/2024JG008243","url":null,"abstract":"<p>Accurately characterizing the impact of vegetation and roughness on CYGNSS observations, which are two main sources of disturbance, is essential for achieving high-quality estimates of soil moisture through this mission. While there are several ancillary data sets that can be employed to address vegetation influence, the lack of a global data set for soil surface roughness motivates us to globally map the contribution of soil roughness to CYGNSS observations. To accomplish this, since separating the contribution of surface roughness and vegetation on reflected signals is often challenging, we initially integrate the vegetation and roughness contributions into a unique variable, denoted as VR. Next, the impacts of vegetation integrated into the CYGNSS-derived VR were separated using Leaf Area Index to map the roughness parameter Hr. The mean value of Hr obtained in this research through CYGNSS observations ranges from 3.2 to 4.6. We observed that the spatial distribution of Hr values is influenced by the predominant vegetation types, with forests exhibiting higher roughness values (Hr = 4.47–4.67), while deserts, shrubs, crops, and bare soils exhibit the smallest Hr values (Hr = 3.25–3.36). Furthermore, we inferred vegetation optical depth (VOD) through CYGNSS observations in conjunction with estimated Hr values. The good agreement observed between the estimated VOD in this study and other vegetation indices, including Vegetation Water Content and tree height, highlights the effectiveness of the introduced Hr global data set in our research and its promising potential in the future GNSS-R studies.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143645727","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Daehyuk Kim, So-Young Kang, Jae-Hong Moon, Hyun-Chae Jung, Subin Kim
{"title":"Impacts of Physical Mixing Combined With Biological Activity on Spatiotemporal Evolution of CO2 Uptake Within the Plume Discharged From the Changjiang River in the Summer of 2016","authors":"Daehyuk Kim, So-Young Kang, Jae-Hong Moon, Hyun-Chae Jung, Subin Kim","doi":"10.1029/2024JG008545","DOIUrl":"https://doi.org/10.1029/2024JG008545","url":null,"abstract":"<p>Understanding carbon dynamics in the river-dominated marginal seas remains challenging due to limited temporal and spatial in situ measurements and complexities of coupled physical-biogeochemical systems. In this study, a coupled physical-biogeochemistry regional ocean model was used to investigate the underlying drivers of the spatiotemporal evolution of oceanic CO<sub>2</sub> uptake within the Changjiang River Plume (CRP) during the summer of 2016. Three comparative experiments were conducted to quantify the contribution of physical and biological processes and air–sea gas exchange within the CRP. In the estuary, strong turbulent mixing due to tides largely inhibited biological production despite being supplied with a high concentration of riverine nutrients, making this area a vigorous source of atmospheric CO<sub>2</sub>. On the other hand, phytoplankton growth was rapidly promoted by weakened turbulent mixing on the nearshore slope, leading to the strongest drawdown in the partial pressure of CO<sub>2</sub> (<i>p</i>CO<sub>2</sub>) due to biological processes. In the offshore region, the air–sea CO<sub>2</sub> exchange contributed to increasing <i>p</i>CO<sub>2</sub> (approximately 10%), which finally altered the offshore water to a weak CO<sub>2</sub> source into the atmosphere. An additional experiment without tides further demonstrated that strong fluctuations in turbulent mixing in the nearshore slope modulate surface flows with a spring-neap cycle of stratification and destratification, resulting in the formation of an elongated chlorophyll front and its periodically undulating behavior of extending seaward or retreating shoreward. Our findings highlight the deep impacts of tidal modulation combined with biological activities on spatiotemporally evolving biogeochemical responses in river-dominated marginal seas.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143646261","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Mudflat Biostabilization Alters Coastal Landscape Sediment Connectivity","authors":"K. Valentine, M. L. Kirwan","doi":"10.1029/2024JG008500","DOIUrl":"https://doi.org/10.1029/2024JG008500","url":null,"abstract":"<p>Connectivity between adjacent ecosystems is thought to increase ecosystem resilience and function. In coastal ecosystems, the exchange of sediment and nutrients between mudflats and marshes is important for the long-term dynamics of both systems. Mudflat morphodynamics are driven by the interaction of waves and sediment erodibility, which is a function of sediment type and the presence of biostabilizers such as microphytobenthos. However, there is a poor understanding about how the evolution of mudflats may impact the morphodynamics and function of adjacent salt marshes. Here, we use a Coastal Landscape Transect model connecting mudflats and marshes to investigate how microphytobenthos influence the coupled behavior of mudflats and marshes, and how that coupled behavior influences carbon storage. We find that biofilms reduce the connectivity between mudflats and marshes by reducing erodibility and sediment exchange. Reduced connectivity associated with microphytobenthos leads to a shallower mudflat and more carbon stored in the mudflat sediments, which in turn cascades to a higher combined marsh and mudflat carbon stock. Furthermore, our results highlight the role of connectivity across the coastal landscape and suggest that biostabilization leads to relatively small changes in morphodynamics but relatively large changes in ecosystem function.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143632687","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Nitrogen Cycling Through Secondary Succession in a Northwestern Virginia Chronosequence","authors":"A. M. Parisien, H. E. Epstein","doi":"10.1029/2024JG008584","DOIUrl":"https://doi.org/10.1029/2024JG008584","url":null,"abstract":"<p>Forest clearing for agricultural use followed by cropland or pasture abandonment is a leading cause of forest disturbance. While theoretical models broadly predict the biogeochemical and structural dynamics of secondary forest succession following disturbances, much remains unknown regarding how specific components of biogeochemical cycling vary through secondary succession. Here we investigate two post-agricultural disturbance chronosequences at Blandy Experimental Farm in Boyce, VA, each consisting of an early, mid, and late successional field (∼20, ∼35, and ∼100 years old, respectively). We collected data observing a wide range of ecosystem N pools, transformations, and fluxes, including soil, litter, and foliar N; net N mineralization and nitrification; soil N leaching potential; and soil and foliar <sup>15</sup>N natural abundance. We found that total soil N increased throughout secondary succession; while litter N concentration decreased in late succession, total litter mass increased, so total litter N increased as well. Foliar N concentration increased from early to late succession, among and within species. While soil ammonium concentration decreased through succession, soil nitrate concentration increased. Net N mineralization and nitrification both increased throughout succession, and a greater proportion of mineralized N was nitrified later in succession. Isotopic analysis suggested high N-fixation in mid-succession, and these observations taken together indicated high N availability and a relatively open N cycle later in succession in this system. Comprehensive field observations such as these are essential for honing a mechanistic understanding of successional systems and making predictions about the biogeochemical cycling and ecosystem function of current and future successional forests.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2024JG008584","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143632689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xiaojuan Feng, Deborah Huntzinger, Ben Bond-Lamberty, Gil Bohrer, Marguerite A. Xenopoulos
{"title":"Honoring Our 2024 Reviewers: Advancing Excellence and Equity in JGR Biogeosciences","authors":"Xiaojuan Feng, Deborah Huntzinger, Ben Bond-Lamberty, Gil Bohrer, Marguerite A. Xenopoulos","doi":"10.1029/2025JG008871","DOIUrl":"https://doi.org/10.1029/2025JG008871","url":null,"abstract":"<p>Peer review is a critical evaluation process, one that is time-consuming but needed to maintain quality and credibility in science. At <i>JGR Biogeosciences</i> we are honoring the many 2024 reviewers who donated their time and expertise to ensure rigor, novelty, inclusiveness, and open practices for improving and advancing biogeosciences research.</p>","PeriodicalId":16003,"journal":{"name":"Journal of Geophysical Research: Biogeosciences","volume":"130 3","pages":""},"PeriodicalIF":3.7,"publicationDate":"2025-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1029/2025JG008871","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143622521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}