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Rojas-Castillo OA, Kepfer-Rojas S, Vargas N, Jacobsen D. Forest buffer-strips mitigate the negative impact of oil palm plantations on stream communities. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 873:162259. [PMID: 36801315 DOI: 10.1016/j.scitotenv.2023.162259] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 02/07/2023] [Accepted: 02/11/2023] [Indexed: 06/18/2023]
Abstract
The global area cultivated with oil palm has doubled in the past two decades, causing deforestation, land-use change, freshwater pollution, and species loss in tropical ecosystems worldwide. Despite the palm-oil industry been linked to severe deterioration of freshwater ecosystems, most studies have focused on terrestrial environments, while freshwaters have been significantly less studied. We evaluated these impacts by contrasting freshwater macroinvertebrate communities and habitat conditions in 19 streams from primary forests (7), grazing lands (6), and oil palm plantations (6). In each stream, we measured environmental characteristics, e.g., habitat composition, canopy cover, substrate, water temperature, and water quality; and we identified and quantified the assemblage of macroinvertebrates. Streams in oil palm plantations lacking riparian forest strips showed warmer and more variable temperatures, higher turbidity, lower silica content, and poorer macroinvertebrate taxon richness than primary forests. Grazing lands showed higher conductivity and temperature, and lower dissolved oxygen and macroinvertebrate taxon richness than primary forests. In contrast, streams in oil palm plantations that conserved a riparian forest, showed a substrate composition, temperature, and canopy cover more similar to the ones in primary forests. These habitat improvements by riparian forests in the plantations increased macroinvertebrate taxon richness and maintained a community resembling more the one in primary forests. Therefore, the conversion of grazing lands (instead of primary forests) to oil palm plantations can increase freshwater taxon richness only if riparian native forests are safeguarded.
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Affiliation(s)
- O A Rojas-Castillo
- Freshwater Biology Section, Department of Biology, University of Copenhagen, Universitetsparken 4, third floor, 2100 Ø, CPH, Denmark; Escuela de Biología, Universidad de San Carlos, Ciudad Universitaria zona 12, Edificios T-10 y T-12, Guatemala.
| | - S Kepfer-Rojas
- Forest, Nature and Biomass Section, Department of Geosciences and Natural Resource Management, University of Copenhagen, Rolighedsvej, 23 1958 Frederiksberg C, Denmark
| | - N Vargas
- Centro de Estudios del Mar y Acuicultura, Universidad de San Carlos, Ciudad Universitaria zona 12, Edificio T-14, Guatemala; Escuela de Biología, Universidad de San Carlos, Ciudad Universitaria zona 12, Edificios T-10 y T-12, Guatemala
| | - D Jacobsen
- Freshwater Biology Section, Department of Biology, University of Copenhagen, Universitetsparken 4, third floor, 2100 Ø, CPH, Denmark
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Nitzsche KN, Wakaki S, Yamashita K, Shin K, Kato Y, Kamauchi H, Tayasu I. Calcium and strontium stable isotopes reveal similar behaviors of essential Ca and nonessential Sr in stream food webs. Ecosphere 2022. [DOI: 10.1002/ecs2.3921] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Affiliation(s)
- Kai Nils Nitzsche
- RIHN Center Research Institute for Humanity and Nature (RIHN) Kyoto Japan
| | - Shigeyuki Wakaki
- Kochi Institute for Core Sample Research Japan Agency for Marine‐Earth Science and Technology (JAMSTEC) Kochi Japan
| | - Katsuyuki Yamashita
- Department of Earth Sciences, Faculty of Science Okayama University Okayama Japan
| | - Ki‐Cheol Shin
- RIHN Center Research Institute for Humanity and Nature (RIHN) Kyoto Japan
| | - Yoshikazu Kato
- RIHN Center Research Institute for Humanity and Nature (RIHN) Kyoto Japan
| | - Hiromitsu Kamauchi
- RIHN Center Research Institute for Humanity and Nature (RIHN) Kyoto Japan
| | - Ichiro Tayasu
- RIHN Center Research Institute for Humanity and Nature (RIHN) Kyoto Japan
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Elevated Allochthony in Stream Food Webs as a Result of Longitudinal Cumulative Effects of Forest Management. Ecosystems 2021; 25:1311-1327. [PMID: 36187364 PMCID: PMC9519712 DOI: 10.1007/s10021-021-00717-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022]
Abstract
The river continuum concept (RCC) predicts a downstream shift in the reliance of aquatic consumers from terrestrial to aquatic carbon sources, but this concept has rarely been assessed with longitudinal studies. Similarly, there are no studies addressing how forestry related disturbances to the structure of headwater food webs manifest (accumulate/dissipate) downstream and/or whether forest management alters natural longitudinal trends predicted by the RCC. Using stable isotopes of carbon, nitrogen and hydrogen, we investigated how: 1) autochthony in macroinvertebrates and fish change from small streams to larger downstream sites within a basin with minimal forest management (New Brunswick, Canada); 2) longitudinal trends in autochthony and food web length compare among three basins with different forest management intensity [intensive (harvest and replanting), extensive (harvest only), minimal] to detect potential cumulative/dissipative effects; and 3) forest management intensity and other catchment variables are influencing food web dynamics. We showed that, as predicted, the reliance of some macroinvertebrate taxa (especially collector feeders) on algae increased from small streams to downstream waters in the minimally managed basin, but that autochthony in the smallest shaded stream was higher than expected based on the RCC (as high as 90% for some taxa). However, this longitudinal increase in autochthony was not observed within the extensively managed basin and was weaker within the intensively managed one, suggesting that forest management can alter food web dynamics along the river continuum. The dampening of downstream autochthony indicates that the increased allochthony observed in small streams in response to forest harvesting cumulates downstream through the river continuum.
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Ko C, Asano S, Lin M, Ikeya T, Peralta EM, Triño EMC, Uehara Y, Ishida T, Iwata T, Tayasu I, Okuda N. Rice paddy irrigation seasonally impacts stream benthic macroinvertebrate diversity at the catchment level. Ecosphere 2021. [DOI: 10.1002/ecs2.3468] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Affiliation(s)
- Chia‐Ying Ko
- Institute of Fisheries Science National Taiwan University No. 1, Sec. 4, Roosevelt Road Taipei10617Taiwan
- Department of Life Science National Taiwan University No. 1, Sec. 4, Roosevelt Road Taipei10617Taiwan
- Department of Biochemical Science and Technology National Taiwan University No. 1, Sec. 4, Roosevelt Road Taipei10617Taiwan
| | - Satoshi Asano
- Research Institute for Humanity and Nature 457‐4, Motoyama, Kamigamo Kyoto603‐8047Japan
| | - Meng‐Ju Lin
- Institute of Fisheries Science National Taiwan University No. 1, Sec. 4, Roosevelt Road Taipei10617Taiwan
| | - Tohru Ikeya
- Research Institute for Humanity and Nature 457‐4, Motoyama, Kamigamo Kyoto603‐8047Japan
| | - Elfritzson M. Peralta
- Department of Biological Sciences College of Science and Research Center for the Natural and Applied Sciences University of Santo Tomas España Boulevard Manila1015Philippines
| | - Ellis Mika C. Triño
- Department of Biological Sciences College of Science and Research Center for the Natural and Applied Sciences University of Santo Tomas España Boulevard Manila1015Philippines
| | - Yoshitoshi Uehara
- Research Institute for Humanity and Nature 457‐4, Motoyama, Kamigamo Kyoto603‐8047Japan
| | - Takuya Ishida
- Graduate School of Advanced Science and Engineering Hiroshima University 1‐7‐1 Kagamiyama Higashi‐Hiroshima Hiroshima739‐8521Japan
| | - Tomoya Iwata
- Faculty of Life and Environmental Sciences University of Yamanashi 4‐4‐37 Takeda Kofu400‐8510Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature 457‐4, Motoyama, Kamigamo Kyoto603‐8047Japan
| | - Noboru Okuda
- Research Institute for Humanity and Nature 457‐4, Motoyama, Kamigamo Kyoto603‐8047Japan
- Research Center for Inland Seas Kobe University Nada Ward Kobe657‐8501Japan
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5
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Erdozain M, Kidd KA, Emilson EJS, Capell SS, Luu T, Kreutzweiser DP, Gray MA. Forest management impacts on stream integrity at varying intensities and spatial scales: Do biological effects accumulate spatially? THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 763:144043. [PMID: 33383512 DOI: 10.1016/j.scitotenv.2020.144043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 06/12/2023]
Abstract
The effects of forest harvesting on headwaters are quite well understood, yet our understanding of whether impacts accumulate or dissipate downstream is limited. To address this, we investigated whether several biotic indicators changed from smaller to larger downstream sites (n = 6) within three basins that had intensive, extensive or minimal forest management in New Brunswick (Canada). Biofilm biomass and grazer abundance significantly increased from upstream to downstream, whereas organic matter decomposition and the autotrophic index of biofilms decreased. However, some spatial trends differed among basins and indicated either cumulative (macroinvertebrate abundance, predator density, sculpin GSI) or dissipative (autotrophic index, cotton decomposition) effects downstream, potentially explained by sediment and nutrient dynamics related to harvesting. No such among-basin differences were observed for leaf decomposition, biofilm biomass, macroinvertebrate richness or sculpin condition. Additionally, results suggest that some of the same biological impacts of forestry observed in small headwaters also occurred in larger systems. Although the intensive and extensive basins had lower macroinvertebrate diversity, there were no other signs of biological impairment, suggesting that, overall, current best management practices protect biological integrity downstream despite abiotic effects.
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Affiliation(s)
- Maitane Erdozain
- Canadian Rivers Institute and Biology Department, University of New Brunswick, 100 Tucker Park Road, Saint John, New Brunswick E2L 4L5, Canada.
| | - Karen A Kidd
- Canadian Rivers Institute and Biology Department, University of New Brunswick, 100 Tucker Park Road, Saint John, New Brunswick E2L 4L5, Canada; Department of Biology and School of Earth, Environment and Society, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
| | - Erik J S Emilson
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St. East, Sault Ste. Marie, Ontario P6A 2E5, Canada
| | - Scott S Capell
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St. East, Sault Ste. Marie, Ontario P6A 2E5, Canada
| | - Taylor Luu
- Department of Biology and School of Earth, Environment and Society, McMaster University, 1280 Main St. W., Hamilton, Ontario L8S 4K1, Canada
| | - David P Kreutzweiser
- Natural Resources Canada, Canadian Forest Service, Great Lakes Forestry Centre, 1219 Queen St. East, Sault Ste. Marie, Ontario P6A 2E5, Canada
| | - Michelle A Gray
- Canadian Rivers Institute and Faculty of Forestry and Environmental Management, University of New Brunswick, 28 Dineen Drive, Fredericton, New Brunswick E3B 5A3, Canada
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Nitzsche KN, Shin K, Kato Y, Kamauchi H, Takano S, Tayasu I. Magnesium and zinc stable isotopes as a new tool to understand Mg and Zn sources in stream food webs. Ecosphere 2020. [DOI: 10.1002/ecs2.3197] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Affiliation(s)
- Kai Nils Nitzsche
- Research Institute for Humanity and Nature (RIHN) 457‐4 Motoyama, Kamigamo Kita‐ku Kyoto603‐8047Japan
| | - Ki‐Cheol Shin
- Research Institute for Humanity and Nature (RIHN) 457‐4 Motoyama, Kamigamo Kita‐ku Kyoto603‐8047Japan
| | - Yoshikazu Kato
- Research Institute for Humanity and Nature (RIHN) 457‐4 Motoyama, Kamigamo Kita‐ku Kyoto603‐8047Japan
| | - Hiromitsu Kamauchi
- Research Institute for Humanity and Nature (RIHN) 457‐4 Motoyama, Kamigamo Kita‐ku Kyoto603‐8047Japan
| | - Shotaro Takano
- Institute for Chemical Research Kyoto University Uji Kyoto611‐0011Japan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature (RIHN) 457‐4 Motoyama, Kamigamo Kita‐ku Kyoto603‐8047Japan
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7
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Erdozain M, Kidd K, Kreutzweiser D, Sibley P. Increased reliance of stream macroinvertebrates on terrestrial food sources linked to forest management intensity. ECOLOGICAL APPLICATIONS : A PUBLICATION OF THE ECOLOGICAL SOCIETY OF AMERICA 2019; 29:e01889. [PMID: 30929306 DOI: 10.1002/eap.1889] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Accepted: 03/04/2019] [Indexed: 06/09/2023]
Abstract
Our understanding of how forest management practices affect the relative importance of autochthonous vs. allochthonous resource use by headwater stream food webs is relatively poor. To address this, we used stable isotope (C, N, and H) analyses of food sources and macroinvertebrates from 15 streams in New Brunswick (Canada) and assessed how different catchment conditions arising from the gradient in forest management intensity affect the contribution of autochthonous resources to these food webs. Aquatic primary production contributed substantially to the biomass of invertebrates in these headwater streams, especially for scrapers and collector-gatherers (25-75%). However, the contribution of algae to food webs decreased as forest management intensity (road density and associated sediments, water cations/carbon, and dissolved organic matter humification) increased, and as canopy openness decreased. This trend was probably due to an increase in the delivery of organic and inorganic terrestrial materials (dissolved and in suspension) in areas of greater harvesting intensity and road density, which resulted in more heterotrophic biofilms. Overall, results suggest that, despite the presence of riparian buffers, forest management can affect stream food web structure via changes in energy flows, and that increased protection should be directed at minimizing ground disturbance in areas with direct hydrological connection to streams and at reducing dissolved and particulate matter inputs from roads and stream crossings in catchments with high degrees of management activity.
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Affiliation(s)
- Maitane Erdozain
- Canadian Rivers Institute and Biology Department, University of New Brunswick, 100 Tucker Park Road, Saint John, New Brunswick, E2L 4L5, Canada
| | - Karen Kidd
- Canadian Rivers Institute and Biology Department, University of New Brunswick, 100 Tucker Park Road, Saint John, New Brunswick, E2L 4L5, Canada
- Department of Biology, School of Geography and Earth Sciences, McMaster University, 1280 Main Street West, Hamilton, Ontario, L8S 4L8, Canada
| | - David Kreutzweiser
- Canadian Forest Service, Great Lakes Forestry Centre, Natural Resources Canada, 1219 Queen Street East, Sault Ste. Marie, Ontario, P6A 2E5, Canada
| | - Paul Sibley
- School of Environmental Sciences, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Kato Y, Kondoh M, Ishikawa NF, Togashi H, Kohmatsu Y, Yoshimura M, Yoshimizu C, Haraguchi TF, Osada Y, Ohte N, Tokuchi N, Okuda N, Miki T, Tayasu I. Using food network unfolding to evaluate food–web complexity in terms of biodiversity: theory and applications. Ecol Lett 2018; 21:1065-1074. [DOI: 10.1111/ele.12973] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2017] [Revised: 12/27/2017] [Accepted: 03/26/2018] [Indexed: 01/07/2023]
Affiliation(s)
- Yoshikazu Kato
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
| | - Michio Kondoh
- Faculty of Science and Technology Ryukoku University 1‐5 Yokoya Seta Oe‐cho Shiga520‐2194 Japan
| | - Naoto F. Ishikawa
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
- Japan Agency for Marine‐Earth Science and Technology 2‐15 Natsushima‐cho Yokosuka Kanagawa237‐0061 Japan
| | - Hiroyuki Togashi
- Tohoku National Fisheries Research Institute Japan Fisheries Research and Education Agency 3‐27‐ 5, Shinhama‐cho Shiogama Miyagi985‐0001 Japan
- Field Science Education and Research Center Kyoto University Oiwake‐cho, Kitashirakawa, Sakyo‐ku Kyoto606‐8502 Japan
| | - Yukihiro Kohmatsu
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
- Research Center for Pan‐Pacific Civilizations Ritsumeikan University 56‐1 Toji‐in Kitamachi, Kita‐ku Kyoto603‐8577 Japan
| | - Mayumi Yoshimura
- Research Planning and Coordination Department Forestry and Forest Products Research Institute Matsunosato 1 Tukuba305‐8687 Japan
- Kansai Research Center, Forestry and Forest Products Research Institute 68 Nagaikyutaroh, Momoyama, Fushimi‐ku Kyoto612‐0855 Japan
| | - Chikage Yoshimizu
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
| | - Takashi F. Haraguchi
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
| | - Yutaka Osada
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
| | - Nobuhito Ohte
- Department of Social Informatics Graduate School of Informatics Kyoto University Yoshida‐Honcho, Sakyo‐ku Kyoto606‐8501 Japan
- Department of Forest Science Graduate School of Agricultural and Life Sciences The University of Tokyo 1‐1‐1 Yayoi, bunkyo‐ku Tokyo113‐8657 Japan
| | - Naoko Tokuchi
- Field Science Education and Research Center Kyoto University Oiwake‐cho, Kitashirakawa, Sakyo‐ku Kyoto606‐8502 Japan
| | - Noboru Okuda
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
| | - Takeshi Miki
- Institute of Oceanography National Taiwan University No. 1 Sec. 4 Roosevelt Rd Taipei10617 Taiwan
- Research Center for Environmental Changes Academia Sinica 128 Academia Road, Section 2, Nankang Taipei11529 Taiwan
| | - Ichiro Tayasu
- Research Institute for Humanity and Nature 457‐4 Motoyama, Kamigamo, Kita‐ku Kyoto603‐8047 Japan
- Center for Ecological Research Kyoto University 2‐509‐3 Hirano Otsu Shiga520‐2113 Japan
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Robson BJ, Lester RE, Baldwin DS, Bond NR, Drouart R, Rolls RJ, Ryder DS, Thompson RM. Modelling food-web mediated effects of hydrological variability and environmental flows. WATER RESEARCH 2017; 124:108-128. [PMID: 28750285 DOI: 10.1016/j.watres.2017.07.031] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 07/14/2017] [Accepted: 07/15/2017] [Indexed: 06/07/2023]
Abstract
Environmental flows are designed to enhance aquatic ecosystems through a variety of mechanisms; however, to date most attention has been paid to the effects on habitat quality and life-history triggers, especially for fish and vegetation. The effects of environmental flows on food webs have so far received little attention, despite food-web thinking being fundamental to understanding of river ecosystems. Understanding environmental flows in a food-web context can help scientists and policy-makers better understand and manage outcomes of flow alteration and restoration. In this paper, we consider mechanisms by which flow variability can influence and alter food webs, and place these within a conceptual and numerical modelling framework. We also review the strengths and weaknesses of various approaches to modelling the effects of hydrological management on food webs. Although classic bioenergetic models such as Ecopath with Ecosim capture many of the key features required, other approaches, such as biogeochemical ecosystem modelling, end-to-end modelling, population dynamic models, individual-based models, graph theory models, and stock assessment models are also relevant. In many cases, a combination of approaches will be useful. We identify current challenges and new directions in modelling food-web responses to hydrological variability and environmental flow management. These include better integration of food-web and hydraulic models, taking physiologically-based approaches to food quality effects, and better representation of variations in space and time that may create ecosystem control points.
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Affiliation(s)
- Barbara J Robson
- CSIRO Land and Water, GPO Box 1700, Canberra, ACT, 2601, Australia.
| | - Rebecca E Lester
- Centre for Regional and Rural Futures, Deakin University, Locked Bag 20000, Geelong, Vic, 3220, Australia.
| | - Darren S Baldwin
- CSIRO Land and Water, GPO Box 1700, Canberra, ACT, 2601, Australia; The Murray-Darling Freshwater Research Centre, La Trobe University, PO Box 821, Wodonga, Vic, 3689, Australia; Charles Sturt University, Thurgoona, NSW, 2640, Australia
| | - Nicholas R Bond
- The Murray-Darling Freshwater Research Centre, La Trobe University, PO Box 821, Wodonga, Vic, 3689, Australia
| | - Romain Drouart
- CSIRO Land and Water, GPO Box 1700, Canberra, ACT, 2601, Australia; Ecole des Mines d'Alès, 6 Avenue de Clavières, 30319, Alès Cedex, France
| | - Robert J Rolls
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
| | - Darren S Ryder
- School of Environmental and Rural Science, University of New England, Armidale, NSW, 2351, Australia
| | - Ross M Thompson
- Institute for Applied Ecology, University of Canberra, Canberra, ACT, 2601, Australia
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Morling K, Herzsprung P, Kamjunke N. Discharge determines production of, decomposition of and quality changes in dissolved organic carbon in pre-dams of drinking water reservoirs. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 577:329-339. [PMID: 27817920 DOI: 10.1016/j.scitotenv.2016.10.192] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Revised: 10/24/2016] [Accepted: 10/25/2016] [Indexed: 06/06/2023]
Abstract
Pre-dams are small reservoirs constructed upstream of the main drinking water reservoirs and are used for nutrient removal and sediment trapping. Little is known about the role of pre-dams regarding the production and decomposition of dissolved organic carbon (DOC) in relation to discharge and how this affects the quality of DOC in the water. We combined quantitative and qualitative investigations under different hydrological conditions at three pre-dams exhibiting a gradient from oligotrophic/high-DOC to eutrophic/low-DOC. All pre-dams were mainly autotrophic in their upper water layers. The ratio of OC production to total gained OC (i.e. OC import+OC production) decreased with increasing discharge. On average, 0-30% of the total gained OC was produced within the pre-dams. The amount of microbially decomposed DOC increased with the average water residence time (WRT) and with the trophic status of the pre-dams. Radiocarbon analyses of respired CO2 revealed that heterotrophic bacteria preferentially utilized old DOC components (195-395years before present) under base flow conditions, whereas younger components (modern, i.e. OC produced after 1950) were utilized at high discharge. DOC quality changed significantly over the year within the pre-dams: High proportions of algae-derived DOC were observed during base flow in summer, and the freshness index (β/α ratio) decreased significantly with higher discharges. DOC production and quality changes in response to hydrological conditions should be considered for future water quality management in reservoirs, as climate scenarios for temperate regions predict decreased runoffs leading to longer WRT and increased eutrophication and production of algae-derived OC.
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Affiliation(s)
- Karoline Morling
- Department of Lake Research, UFZ - Helmholtz Centre for Environmental Research, Brückstr. 3a, 39114 Magdeburg, Germany.
| | - Peter Herzsprung
- Department of Lake Research, UFZ - Helmholtz Centre for Environmental Research, Brückstr. 3a, 39114 Magdeburg, Germany
| | - Norbert Kamjunke
- Department of Lake Research, UFZ - Helmholtz Centre for Environmental Research, Brückstr. 3a, 39114 Magdeburg, Germany; Department of River Ecology, UFZ - Helmholtz Centre for Environmental Research, Brückstr. 3a, 39114 Magdeburg, Germany
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