The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest
<p>Determining the sources of water provisioning streams, soils, and vegetation can provide important insights into the water that sustains critical ecosystem functions now and how those functions may be expected to respond given projected changes in the global hydrologic cycle. We developed m...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-11-01
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| Series: | Hydrology and Earth System Sciences |
| Online Access: | https://hess.copernicus.org/articles/27/4173/2023/hess-27-4173-2023.pdf |
| _version_ | 1797542509181665280 |
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| author | E. I. Burt E. I. Burt G. R. Goldsmith R. M. Cruz-de Hoyos A. J. Ccahuana Quispe A. J. West |
| author_facet | E. I. Burt E. I. Burt G. R. Goldsmith R. M. Cruz-de Hoyos A. J. Ccahuana Quispe A. J. West |
| author_sort | E. I. Burt |
| collection | DOAJ |
| description | <p>Determining the sources of water provisioning streams, soils, and vegetation can provide important insights into the water that sustains critical ecosystem functions now and how those functions may be expected to respond given projected changes in the global hydrologic cycle. We developed multi-year time series of water isotope ratios (<span class="inline-formula"><i>δ</i><sup>18</sup></span>O and <span class="inline-formula"><i>δ</i><sup>2</sup></span>H) based on twice-monthly collections of precipitation, lysimeter, and tree branch xylem waters from a seasonally dry tropical montane cloud forest in the southeastern Andes mountains of Peru. We then used this information to determine indices of the seasonal origins, the young water fractions (<span class="inline-formula"><i>F</i><sub>yw</sub></span>), and the new water fractions (<span class="inline-formula"><i>F</i><sub>new</sub></span>) of soil, stream, and tree water. There was no evidence for intra-annual variation in the seasonal origins of stream water and lysimeter water from 1 m depth, both of which were predominantly comprised of wet-season precipitation even during the dry seasons. However, branch xylem waters demonstrated an intra-annual shift in seasonal origin: xylem waters were comprised of wet-season precipitation during the wet season and dry-season precipitation during the dry season. The young water fractions of lysimeter (<span class="inline-formula"><</span> 15 %) and stream (5 %) waters were lower than the young water fraction (37 %) in branch xylem waters. The new water fraction (an indicator of water <span class="inline-formula">≤</span> 2 weeks old in this study) was estimated to be 12 % for branch xylem waters, while there was no significant evidence for new water in stream or lysimeter waters from 1 m depth. Our results indicate that the source of water for trees in this system varied seasonally, such that recent precipitation may be more immediately taken up by shallow tree roots. In comparison, the source of water for soils and streams did not vary seasonally, such that precipitation may mix and reside in soils and take longer to transit into the stream. Our insights into the seasonal origins and ages of water in soils, streams, and vegetation in this humid tropical montane cloud forest add to understanding of the mechanisms that govern the partitioning of water moving through different ecosystems.</p> |
| first_indexed | 2024-03-10T13:31:33Z |
| format | Article |
| id | doaj.art-0030e722b9444eb29afa708f91f42dce |
| institution | Directory Open Access Journal |
| issn | 1027-5606 1607-7938 |
| language | English |
| last_indexed | 2024-03-10T13:31:33Z |
| publishDate | 2023-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Hydrology and Earth System Sciences |
| spelling | doaj.art-0030e722b9444eb29afa708f91f42dce2023-11-21T07:54:17ZengCopernicus PublicationsHydrology and Earth System Sciences1027-56061607-79382023-11-01274173418610.5194/hess-27-4173-2023The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forestE. I. Burt0E. I. Burt1G. R. Goldsmith2R. M. Cruz-de Hoyos3A. J. Ccahuana Quispe4A. J. West5Schmid College of Science and Technology, Chapman University, Orange, California 92866, USADepartment of Earth Sciences, University of Southern California, Los Angeles, California 90089, USASchmid College of Science and Technology, Chapman University, Orange, California 92866, USADepartment of Environmental Science, Policy and Management, University of California at Berkeley, Berkeley, California 94720, USAFacultad de Ciencias Biologicas, Universidad Nacional San Antonio Abad del Cusco (UNSAAC), Cusco, PeruDepartment of Earth Sciences, University of Southern California, Los Angeles, California 90089, USA<p>Determining the sources of water provisioning streams, soils, and vegetation can provide important insights into the water that sustains critical ecosystem functions now and how those functions may be expected to respond given projected changes in the global hydrologic cycle. We developed multi-year time series of water isotope ratios (<span class="inline-formula"><i>δ</i><sup>18</sup></span>O and <span class="inline-formula"><i>δ</i><sup>2</sup></span>H) based on twice-monthly collections of precipitation, lysimeter, and tree branch xylem waters from a seasonally dry tropical montane cloud forest in the southeastern Andes mountains of Peru. We then used this information to determine indices of the seasonal origins, the young water fractions (<span class="inline-formula"><i>F</i><sub>yw</sub></span>), and the new water fractions (<span class="inline-formula"><i>F</i><sub>new</sub></span>) of soil, stream, and tree water. There was no evidence for intra-annual variation in the seasonal origins of stream water and lysimeter water from 1 m depth, both of which were predominantly comprised of wet-season precipitation even during the dry seasons. However, branch xylem waters demonstrated an intra-annual shift in seasonal origin: xylem waters were comprised of wet-season precipitation during the wet season and dry-season precipitation during the dry season. The young water fractions of lysimeter (<span class="inline-formula"><</span> 15 %) and stream (5 %) waters were lower than the young water fraction (37 %) in branch xylem waters. The new water fraction (an indicator of water <span class="inline-formula">≤</span> 2 weeks old in this study) was estimated to be 12 % for branch xylem waters, while there was no significant evidence for new water in stream or lysimeter waters from 1 m depth. Our results indicate that the source of water for trees in this system varied seasonally, such that recent precipitation may be more immediately taken up by shallow tree roots. In comparison, the source of water for soils and streams did not vary seasonally, such that precipitation may mix and reside in soils and take longer to transit into the stream. Our insights into the seasonal origins and ages of water in soils, streams, and vegetation in this humid tropical montane cloud forest add to understanding of the mechanisms that govern the partitioning of water moving through different ecosystems.</p>https://hess.copernicus.org/articles/27/4173/2023/hess-27-4173-2023.pdf |
| spellingShingle | E. I. Burt E. I. Burt G. R. Goldsmith R. M. Cruz-de Hoyos A. J. Ccahuana Quispe A. J. West The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest Hydrology and Earth System Sciences |
| title | The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| title_full | The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| title_fullStr | The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| title_full_unstemmed | The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| title_short | The seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| title_sort | seasonal origins and ages of water provisioning streams and trees in a tropical montane cloud forest |
| url | https://hess.copernicus.org/articles/27/4173/2023/hess-27-4173-2023.pdf |
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