Baum, Antje and Rixen, Tim ORCID: https://orcid.org/0000-0001-8376-891X (2014) Dissolved inorganic nitrogen and phosphate in the human affected blackwater river Siak, Central Sumatra, Indonesia. Asian Journal of Water, Environment and Pollution, 11 (1). pp. 13-24. DOI https://doi.org/10.3233/AJW-2014-11_1_04.

Text Baum.pdf - Published Version Restricted to Registered users only Download (2MB)

Abstract

Increases in domestic, industrial and agricultural effluents have nearly doubled global riverine N and P fluxes into the coastal ocean during the last few decades. Indonesian rivers were modelled to be one global "hot spot" with respect to N and P yields (kg km\(^{-2}\) yr\(^{-1}\)) as a consequence of large-scale deforestation, intensive agriculture, urbanization and wastewater disposal. The objectives of this field study were (i) to identify sources of dissolved nutrients and (ii) to investigate the impact of anthropogenic activities on nutrient levels in the peat-draining blackwater river Siak. During seven expeditions between 2004 and 2009 dissolved inorganic nutrients (NO\(_3^-\), NO\(_2^-\), NH\(_4^+\) and PO\(_4^{3-}\)), chlorophyll-a (chl a), particulate and dissolved organic matter (POM, DOM) and stable carbon isotopes (δ\(^{13}\)C\(_{org}\)) of POM were determined along the river continuum as well as in urban sewage channels. The results showed that the Siak is a classical blackwater river characterized by high levels of dissolved organic matter (DOM) and low nutrient concentrations. Nevertheless, compared to other tropical blackwater rivers, nutrient concentrations are enriched indicating that the Siak is eutrophied. Decomposition of DOM leached from the surrounding peat soils is one factor controlling the DIN and the PO\(_4^{3-}\) concentration in the Siak. Wastewater discharges increased especially the PO\(_4^{3-}\) concentrations, which exceed the background concentration locally by a factor >4. The washout of N-fertilizers from palm oil estates seems to be a main factor influencing the DIN concentration and could even double the riverine DIN concentration as seen in March, 2004.

Document Type:	Article
Programme Area:	PA Not Applicable
Research affiliation:	Biogeochemistry and Geology > Carbon and Nutrient Cycling
Refereed:	Yes
Open Access Journal?:	No
DOI:	https://doi.org/10.3233/AJW-2014-11_1_04
ISSN:	0972-9860
Date Deposited:	17 Mar 2026 14:00
Last Modified:	17 Mar 2026 14:00
URI:	https://cris.leibniz-zmt.de/id/eprint/742

Actions (login required)

View Item