Advanced

Photo-reactivity (apparent quantum yield) of dissolved organic carbon during the freshwater transit from land to sea

Panneer Selvam, Balathandayuthabani LU ; Lapierre, Jean-François ; Soares, Ana LU and Berggren, Martin LU (2016) ASLO Summer meeting, 2016
Abstract
In spite of substantial greenhouse gas emissions from photo-degradation of dissolved organic carbon (DOC), little is known about the variability in DOC photo-reactivity. It has been suggested that photo-reactivity depends on the degree of DOC pigmentation. However, recent evidence suggests that also non-colored fractions can be photo-reactive. Furthermore photo-degradation processes interact with extrinsic factors such as pH and Fe concentrations. Thus, the overall changes in photo-reactivity in the aquatic network are poorly known. We measured apparent quantum yield for CO2 production normalized to 350 nm (AQY350) in water from streams, lakes and rivers in boreal Sweden. Additionally, samples were incubated for 365 days to follow AQY350... (More)
In spite of substantial greenhouse gas emissions from photo-degradation of dissolved organic carbon (DOC), little is known about the variability in DOC photo-reactivity. It has been suggested that photo-reactivity depends on the degree of DOC pigmentation. However, recent evidence suggests that also non-colored fractions can be photo-reactive. Furthermore photo-degradation processes interact with extrinsic factors such as pH and Fe concentrations. Thus, the overall changes in photo-reactivity in the aquatic network are poorly known. We measured apparent quantum yield for CO2 production normalized to 350 nm (AQY350) in water from streams, lakes and rivers in boreal Sweden. Additionally, samples were incubated for 365 days to follow AQY350 over the long-term course of microbial degradation. We found no trends of decreasing AQY350 with overall losses in DOC color across space and time. Interestingly, there was a quadratic (U-shaped) relationship between AQY and pH. Overall, in situ AQY350 increased with reductions in specific DOC absorbance and with rising autochthonous DOC contributions. We suggest that partly due to extrinsic factors, photo-reactivity of DOC is sustained during the DOC residence time in the aquatic network. (Less)
Please use this url to cite or link to this publication:
author
; ; and
organization
publishing date
type
Contribution to conference
publication status
published
subject
pages
1 pages
conference name
ASLO Summer meeting, 2016
conference location
Santa Fé, United States
conference dates
2016-06-05 - 2016-06-10
language
English
LU publication?
yes
id
68e89848-c8a0-4c43-b46c-45fb225ca4c0
date added to LUP
2018-07-05 16:13:21
date last changed
2019-03-25 16:09:57
@misc{68e89848-c8a0-4c43-b46c-45fb225ca4c0,
  abstract     = {In spite of substantial greenhouse gas emissions from photo-degradation of dissolved organic carbon (DOC), little is known about the variability in DOC photo-reactivity. It has been suggested that photo-reactivity depends on the degree of DOC pigmentation. However, recent evidence suggests that also non-colored fractions can be photo-reactive. Furthermore photo-degradation processes interact with extrinsic factors such as pH and Fe concentrations. Thus, the overall changes in photo-reactivity in the aquatic network are poorly known. We measured apparent quantum yield for CO2 production normalized to 350 nm (AQY350) in water from streams, lakes and rivers in boreal Sweden. Additionally, samples were incubated for 365 days to follow AQY350 over the long-term course of microbial degradation. We found no trends of decreasing AQY350 with overall losses in DOC color across space and time. Interestingly, there was a quadratic (U-shaped) relationship between AQY and pH. Overall, in situ AQY350 increased with reductions in specific DOC absorbance and with rising autochthonous DOC contributions. We suggest that partly due to extrinsic factors, photo-reactivity of DOC is sustained during the DOC residence time in the aquatic network.},
  author       = {Panneer Selvam, Balathandayuthabani and Lapierre, Jean-François and Soares, Ana and Berggren, Martin},
  language     = {eng},
  title        = {Photo-reactivity (apparent quantum yield) of dissolved organic carbon during the freshwater transit from land to sea},
  year         = {2016},
}