UZH-Logo

Maintenance Infos

Spatial heterogeneity of the spring flood acid pulse in a boreal stream network


Buffam, Ishi; Laudon, Hjalmar; Seibert, Jan; Mörth, Carl-Magnus; Bishop, Kevin H (2008). Spatial heterogeneity of the spring flood acid pulse in a boreal stream network. Science of the Total Environment, 407(1):708-722.

Abstract

Spatial and temporal patterns in streamwater acidity are ecologically important, but difficult to measure in parallel. Here we present the spatial distribution of streamwater chemistry relevant to acidity from 60 stream sites distributed throughout a 67 km2 boreal catchment, sampled during a period of winter baseflow (high pH) and during a spring flood episode (low pH). Sites were grouped based on pH level and pH change from winter baseflow to spring flood. The site attributes of each pH group were then assessed in terms of both stream chemistry and subcatchment landscape characteristics. Winter baseflow pH was high throughout most of the stream network (median pH 6.4), but during the spring flood episode stream sites experienced declines in pH ranging from 0–1.6 pH units, resulting in pH ranging from 4.3–6.3. Spring flood pH was highest in larger, lower altitude catchments underlain by fine sorted sediments, and lowest in small, higher altitude catchments with a mixture of peat wetlands and forested till. Wetland-dominated headwater catchments had low but stable pH, while the spring flood pH drop was largest in a group of catchments of intermediate size which contained well-developed coniferous forest and a moderate proportion of peat wetlands. There was a trend with distance downstream of higher pH, acid neutralizing capacity (ANC) and base cation concentrations together with lower dissolved organic carbon (DOC, strongly negatively correlated with pH). This apparent scale- dependence of stream chemistry could be explained by a number of environmental factors which vary predictably with altitude, catchment area and distance downstream— most notably, a shift in surficial sediment type from unsorted till and peat wetlands to fine sorted sediments at lower altitudes in this catchment. As a result of the combination of spatial heterogeneity in landscape characteristics and scale-related processes, boreal catchments like this one can be expected to experience high spatial variability both in terms of chemistry at any given point in time, and in the change experienced during high discharge episodes. Although chemistry patterns showed associations with landscape characteristics, considerable additional variability remained, suggesting that the modeling of dynamic stream chemistry from map parameters will continue to present a challenge.

Abstract

Spatial and temporal patterns in streamwater acidity are ecologically important, but difficult to measure in parallel. Here we present the spatial distribution of streamwater chemistry relevant to acidity from 60 stream sites distributed throughout a 67 km2 boreal catchment, sampled during a period of winter baseflow (high pH) and during a spring flood episode (low pH). Sites were grouped based on pH level and pH change from winter baseflow to spring flood. The site attributes of each pH group were then assessed in terms of both stream chemistry and subcatchment landscape characteristics. Winter baseflow pH was high throughout most of the stream network (median pH 6.4), but during the spring flood episode stream sites experienced declines in pH ranging from 0–1.6 pH units, resulting in pH ranging from 4.3–6.3. Spring flood pH was highest in larger, lower altitude catchments underlain by fine sorted sediments, and lowest in small, higher altitude catchments with a mixture of peat wetlands and forested till. Wetland-dominated headwater catchments had low but stable pH, while the spring flood pH drop was largest in a group of catchments of intermediate size which contained well-developed coniferous forest and a moderate proportion of peat wetlands. There was a trend with distance downstream of higher pH, acid neutralizing capacity (ANC) and base cation concentrations together with lower dissolved organic carbon (DOC, strongly negatively correlated with pH). This apparent scale- dependence of stream chemistry could be explained by a number of environmental factors which vary predictably with altitude, catchment area and distance downstream— most notably, a shift in surficial sediment type from unsorted till and peat wetlands to fine sorted sediments at lower altitudes in this catchment. As a result of the combination of spatial heterogeneity in landscape characteristics and scale-related processes, boreal catchments like this one can be expected to experience high spatial variability both in terms of chemistry at any given point in time, and in the change experienced during high discharge episodes. Although chemistry patterns showed associations with landscape characteristics, considerable additional variability remained, suggesting that the modeling of dynamic stream chemistry from map parameters will continue to present a challenge.

Citations

32 citations in Web of Science®
32 citations in Scopus®
Google Scholar™

Altmetrics

Downloads

1 download since deposited on 31 Jan 2013
0 downloads since 12 months
Detailed statistics

Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Institute of Geography
Dewey Decimal Classification:910 Geography & travel
Language:English
Date:2008
Deposited On:31 Jan 2013 17:38
Last Modified:05 Apr 2016 16:26
Publisher:Elsevier
ISSN:0048-9697
Publisher DOI:https://doi.org/10.1016/j.scitotenv.2008.10.006

Download

[img]
Content: Published Version
Language: English
Filetype: PDF - Registered users only
Size: 1MB
View at publisher

TrendTerms

TrendTerms displays relevant terms of the abstract of this publication and related documents on a map. The terms and their relations were extracted from ZORA using word statistics. Their timelines are taken from ZORA as well. The bubble size of a term is proportional to the number of documents where the term occurs. Red, orange, yellow and green colors are used for terms that occur in the current document; red indicates high interlinkedness of a term with other terms, orange, yellow and green decreasing interlinkedness. Blue is used for terms that have a relation with the terms in this document, but occur in other documents.
You can navigate and zoom the map. Mouse-hovering a term displays its timeline, clicking it yields the associated documents.

Author Collaborations