『Abstract
　Stream water from a stream network of 15 small boreal catchments (0.03-67 km²) in northern Sweden was analyzed for infiltered (total) and filtered (＜0.4μm) concentrations of iron (Fetot and Fe＜0.4) and manganese (Mntot and Mn＜0.4). The purpose was to investigate the temporal and spatial dynamics of Fe, Mn and dissolved organic carbon (DOC) as influenced by snow melt driven spring floods and landscape properties, in particular the proportion of wetland area. During spring flood, concentrations of Fetot, Fe＜0.4, Mntot, Mn＜0.4 and DOC increased in streams with forested catchments (＜2％ wetland area). In catchments with high coverage of wetlands (＞30％ wetland area) the opposite behavior was observed. The hydrogeochemistry of Fe was highly dependent on wetlands as shown by the strong positive correlation of the Fetot/Altot ratio with wetland coverage (r²=0.89, p＜0.001). Furthermore, PCA analysis showed that at base flow Fetot and Fe＜0.4 were positively associated with wetlands and DOC, whereas they were not associated during peak flow at spring flood. The temporal variation of Fe was likely related to varying hydrological pathways. At peak discharge Fetot was associated with variables like silt coverage, which highlights the importance of particulates during high discharge events. For Mn there was no significant correlation with wetlands, instead, PCA analysis showed that during spring flood Mn was apparently more dependent on the supply of minerogenic particulates from silt deposits on the stream banks of some of the streams. The influence of minerogenic particulates on the concentration of, in particular, Mn was greatest in the larger, lower gradient streams, characterized by silt deposits in the near-stream zone. In the small forested streams underlain by till, DOC was of greater importance for the observed concentrations, as indicated by the positive correlation of both Fetot and Fe＜0.4 with DOC (r²=0.77 and r²=0.76, p＜0.001) at the smallest headwater forest site. In conclusion, wetland area and DOC were important for Fe concentrations in this boreal stream network, whereas silt deposits strongly influenced Mn concentrations. This study highlights the importance of studying stream water chemistry from a landscape perspective in order to address future environmental issues concerning mobility of Fe, Mn and associated trace metals.』

1. Introduction
2. Site description
　2.1. Geology, quaternary deposits and topography
　2.2. Climate and hydrology
　2.3. Vegetation and land use
3. Methods
　3.1. Water discharge
　3.2. Sample collection
　3.3. Sample treatment and chemical analyses
　3.4. Suspended material
　3.5. Data analyses
　　3.5.1. Principal component analysis (PCA)
　　3.5.2. Weighted discharge
4. Results
　4.1. Discharge and water chemistry
　4.2. Temporal variation of Fe,Mn, DOC and pH in contrasting catchments
　　4.2.1. Forested catchment
　　4.2.2. Wetland catchment
　　4.2.3. Mixed catchment: catchment outlet (C16)
　4.3. Principal component analysis
　　4.3.1. Winter base flow
　　4.3.2. spring peak flow
　4.4. Influence of particulates and landscape properties
　　4.4.1. Particulates
　　4.4.2. Landscape properties
5. Discussion
　5.1. Flow-related variations of Fe and Mn in forested vs. wetland catchments
　5.2. Fe and Mn hydrogeochemistry: influence of landscape properties
　5.3. Fe and Mn hydrogeochemistry: influence of particulates
6. Conclusions
Acknowledgments
References