06 Sep 2023
 | 06 Sep 2023
Status: this preprint is open for discussion.

Seasonal and interannual Dissolved Organic Carbon transport process dynamics in a subarctic headwater catchment revealed by high-resolution measurements

Danny Croghan, Pertti Ala-Aho, Jeffrey Welker, Kaisa-Riikka Mustonen, Kieran Khamis, David M. Hannah, Jussi Vuorenmaa, Bjørn Kløve, and Hannu Marttila

Abstract. Dissolved organic carbon (DOC) dynamics are evolving in the rapidly changing Arctic and a comprehensive understanding of the controlling processes is urgently required. For example, the transport processes governing DOC dynamics are prone to climate driven alteration given their strong seasonal nature. Hence, high-resolution and long-term studies are required to assess potential seasonal and inter-annual changes in DOC transport processes. In this study, we monitored DOC at a 30-minute resolution from September 2018 to December 2022 in a headwater peatland-influenced stream in Northern Finland (Pallas catchment, 68° N). To assess transport processes multiple methods were used: concentration – discharge (C-Q) slope for seasonal analysis, a modified hysteresis index for event analysis, yield analysis, and random forest regression models to determine the hydroclimatic controls on transport. The findings reveal the following distinct patterns: (a) the slope of the C-Q relationship displays a strong seasonal trend, indicating increasing transport limitation each month after snowmelt begins; (b) the hysteresis index decreases post-snowmelt, signifying the influence of distal sources and DOC mobilization through slower pathways; and (c) interannual variations in these metrics are generally low, often smaller than month-to-month fluctuations. These results highlight the importance of long-term and detailed monitoring to enable separation of inter and intra annual variability to better understand the complexities of DOC transport. This study contributes to a broader comprehension of DOC transport dynamics in the Arctic because knowledge gained regarding the dominant transport mechanisms and their seasonal variations is vital for evaluating how the carbon cycle will change in the future in Arctic ecosystems.

Danny Croghan et al.

Status: open (until 01 Nov 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1986', Sean Carey, 25 Sep 2023 reply

Danny Croghan et al.


Total article views: 195 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
135 49 11 195 13 4 4
  • HTML: 135
  • PDF: 49
  • XML: 11
  • Total: 195
  • Supplement: 13
  • BibTeX: 4
  • EndNote: 4
Views and downloads (calculated since 06 Sep 2023)
Cumulative views and downloads (calculated since 06 Sep 2023)

Viewed (geographical distribution)

Total article views: 185 (including HTML, PDF, and XML) Thereof 185 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
Latest update: 03 Oct 2023
Short summary
The transport of Dissolved Organic Carbon (DOC) from the land into streams is changing due to climate change. We used a multi-year dataset of DOC and predictors of DOC in a subarctic stream to find to how transport of DOC varied between seasons and between years. We found that the way DOC is transported varied strongly seasonally, but year to year differences were less apparent. We conclude the mechanisms of transport show a higher degree of inter-annual consistency than thought.