Sphagnum-dominated bog systems are highly effective yet variable sources of bio-available iron to marine waters

Author(s)

Regina Krachler, Rudolf Krachler, Gabriele Wallner, Peter Steier, Yasin El Abiead, Hubert Wiesinger, Franz Jirsa, Bernhard Keppler

Abstract

Iron is a micronutrient of particular interest as low levels of iron limit primary production of phytoplankton and carbon fluxes in extended regions of the world's oceans. Sphagnum-peatland runoff is extraordinarily rich in dissolved humic-bound iron. Given that several of the world's largest wetlands are Sphagnum-dominated peatlands, this ecosystem type may serve as one of the major sources of iron to the ocean. Here, we studied five near-coastal creeks in North Scotland using freshwater/seawater mixing experiments of natural creek water and synthetic seawater based on a Fe-59 radiotracer technique combined with isotopic characterization of dissolved organic carbon by Accelerator Mass Spectrometry. Three of the creeks meander through healthy Sphagnum-dominated peat bogs and the two others through modified peatlands which have been subject to artificial drainage for centuries. The results revealed that, at the time of sampling (August 16-24, 2014), the creeks that run through modified peatlands delivered 11-15 mu g iron per liter creek water to seawater, whereas the creeks that run through intact peatlands delivered 350-470 mu g iron per liter creek water to seawater. To find out whether this humic-bound iron is bio-available to marine algae, we performed algal growth tests using the unicellular flagellated marine prymnesiophyte Diacronema lutheri and the unicellular marine green alga Chlorella salina, respectively. In both cases, the riverine humic material provided a highly bio-available source of iron to the marine algae. These results add a new item to the list of ecosystem services of Sphagnum-peatlands. (C) 2016 The Authors. Published by Elsevier B.V.

Organisation(s)

Department of Inorganic Chemistry, Isotope Physics, Functional and Evolutionary Ecology, Department of Analytical Chemistry

External organisation(s)

University of Johannesburg (UJ)

Journal

Science of the Total Environment

Volume

556

Pages

53-62

No. of pages

10

ISSN

0048-9697

DOI

https://doi.org/10.1016/j.scitotenv.2016.03.012

Publication date

06-2016

Peer reviewed

Yes

Austrian Fields of Science 2012

104003 Inorganic chemistry, 104023 Environmental chemistry, 105306 Oceanography

Keywords

ASJC Scopus subject areas

Pollution, Waste Management and Disposal, Environmental Engineering, Environmental Chemistry

Sustainable Development Goals

SDG 14 - Life Below Water, SDG 15 - Life on Land

Portal url

https://ucris.univie.ac.at/portal/en/publications/sphagnumdominated-bog-systems-are-highly-effective-yet-variable-sources-of-bioavailable-iron-to-marine-waters(06284b4e-d54d-4c67-b05d-93803e2ee029).html