{"title":"Synchrony dynamics of dissolved organic carbon in high-mountain streams: Insights into scale-dependent processes","authors":"Lluís Gómez-Gener, Nicola Deluigi, Tom J. Battin","doi":"10.1002/lno.12768","DOIUrl":null,"url":null,"abstract":"<p>In high-mountain landscapes, organic carbon (OC) is often limited and heterogeneously stored in poorly developed soils, snow, ground ice, and glaciers. Climate change influences the dynamics of OC mobilization to—and processing into—the recipient streams. Dynamics vary from seasonal (e.g., snow melt in spring) to daily (e.g., ice melt in summer) depending on the location of the streams within the catchment. Capturing the temporal richness of stream biogeochemical signals has become a reality with the advent of high-resolution sensors. In this study, we applied wavelet analysis to high-frequency discharge (<i>Q</i>) and dissolved organic carbon (DOC) measurements from nine streams in the Swiss Alps to investigate the persistence of synchrony in <i>Q</i> (<i>S</i><sub><i>Q</i></sub>) and DOC (<i>S</i><sub>DOC</sub>) among streams, and their response to drainage network position, climate, and land cover gradients across different time scales. Our findings revealed that <i>S</i><sub><i>Q</i></sub> and S<sub>DOC</sub> decayed non-linearly over the first ~ 5 km and stabilized from this point onwards, indicating that localized controls influenced synchrony within single basins, but drivers operating at regional scale acted as synchrony stabilizers. We also showed that short-term (0–10 d) <i>S</i><sub><i>Q</i></sub> and <i>S</i><sub>DOC</sub> were strongly influenced by the distance between streams and network connectivity. In contrast, catchment-related properties (i.e., altitude or land cover) were more important drivers of <i>S</i><sub><i>Q</i></sub> and <i>S</i><sub>DOC</sub> dynamics at longer time scales (> 50 d). However, the degree to which local catchment properties controlled synchrony patterns at the longest timescales depended both on response variables (i.e., <i>Q</i> vs. DOC) and land cover (i.e., vegetation vs. glacier). Elucidating the most prominent timescales of <i>S</i><sub>DOC</sub> is relevant given the hydrological alterations projected for high-mountain regions. We show that glaciers impose a unique seasonal regime on DOC concentration, potentially overriding the effects of other local hydrological or biogeochemical processes during downstream transport. Consequently, <i>S</i><sub>DOC</sub> dynamics in high-mountain streams may change as glaciers shrink, thereby altering downstream opportunities for biogeochemical transformations.</p>","PeriodicalId":18143,"journal":{"name":"Limnology and Oceanography","volume":"70 2","pages":"411-425"},"PeriodicalIF":3.8000,"publicationDate":"2025-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/lno.12768","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Limnology and Oceanography","FirstCategoryId":"89","ListUrlMain":"https://onlinelibrary.wiley.com/doi/10.1002/lno.12768","RegionNum":1,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"LIMNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
In high-mountain landscapes, organic carbon (OC) is often limited and heterogeneously stored in poorly developed soils, snow, ground ice, and glaciers. Climate change influences the dynamics of OC mobilization to—and processing into—the recipient streams. Dynamics vary from seasonal (e.g., snow melt in spring) to daily (e.g., ice melt in summer) depending on the location of the streams within the catchment. Capturing the temporal richness of stream biogeochemical signals has become a reality with the advent of high-resolution sensors. In this study, we applied wavelet analysis to high-frequency discharge (Q) and dissolved organic carbon (DOC) measurements from nine streams in the Swiss Alps to investigate the persistence of synchrony in Q (SQ) and DOC (SDOC) among streams, and their response to drainage network position, climate, and land cover gradients across different time scales. Our findings revealed that SQ and SDOC decayed non-linearly over the first ~ 5 km and stabilized from this point onwards, indicating that localized controls influenced synchrony within single basins, but drivers operating at regional scale acted as synchrony stabilizers. We also showed that short-term (0–10 d) SQ and SDOC were strongly influenced by the distance between streams and network connectivity. In contrast, catchment-related properties (i.e., altitude or land cover) were more important drivers of SQ and SDOC dynamics at longer time scales (> 50 d). However, the degree to which local catchment properties controlled synchrony patterns at the longest timescales depended both on response variables (i.e., Q vs. DOC) and land cover (i.e., vegetation vs. glacier). Elucidating the most prominent timescales of SDOC is relevant given the hydrological alterations projected for high-mountain regions. We show that glaciers impose a unique seasonal regime on DOC concentration, potentially overriding the effects of other local hydrological or biogeochemical processes during downstream transport. Consequently, SDOC dynamics in high-mountain streams may change as glaciers shrink, thereby altering downstream opportunities for biogeochemical transformations.
期刊介绍:
Limnology and Oceanography (L&O; print ISSN 0024-3590, online ISSN 1939-5590) publishes original articles, including scholarly reviews, about all aspects of limnology and oceanography. The journal''s unifying theme is the understanding of aquatic systems. Submissions are judged on the originality of their data, interpretations, and ideas, and on the degree to which they can be generalized beyond the particular aquatic system examined. Laboratory and modeling studies must demonstrate relevance to field environments; typically this means that they are bolstered by substantial "real-world" data. Few purely theoretical or purely empirical papers are accepted for review.