Congo Basin: from Carbon to Fishes COBAFISH
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Congo basin: From carbon to fishes COBAFISH E. VERHEYEN, W. WILLEMS, K. MARTENS, A.V. BORGES, F. DARCHAMBEAU, T. LAMBERT, J.-P. DESCY, S. PETROVIC, S. BOUILLON, C. TEODORU, D.X. SOTO, C. COCQUYT, J. C. TAYLOR, J. SNOEKS, E. DECRU, J. BAMPS, T. MOELANTS, L. ANDRÉ SCIENCE FOR A SUSTAINABLE DEVELOPMENT (SSD) Atmosphere and terrestrial and marine ecosystems FINAL REPORT Congo basin: From carbon to fishes COBAFISH SD/AR/05A Promotors Erik Verheyen, Royal Belgian Institute of Natural Sciences Alberto V. Borges, University of Liège Steven Bouillon, KU Leuven Christine Cocquyt, Botanic Garden Meise Jos Snoeks, Royal Museum for Central Africa Authors Erik Verheyen, Royal Belgian Institute of Natural Sciences Wim Willems, Royal Belgian Institute of Natural Sciences Koen Martens, Royal Belgian Institute of Natural Sciences Alberto V. Borges, University of Liège François Darchambeau, University of Liège Thibault Lambert, University of Liège Jean-Pierre Descy, University of Liège Sandro Petrovic, University of Liège Steven Bouillon, KU Leuven Cristian Teodoru, KU Leuven David X. Soto, KU Leuven Christine Cocquyt, Botanic Garden Meise Jonathan C. Taylor, Botanic Garden Meise Jos Snoeks, Royal Museum for Central Africa Eva Decru, Royal Museum for Central Africa Jolien Bamps, Royal Museum for Central Africa and Royal Belgian Institute of Natural Sciences Tuur Moelants, Royal Museum for Central Africa Luc André, Royal Museum for Central Africa Published in 2017 by the Belgian Science Policy Avenue Louise 231 Louizalaan 231 B-1050 Brussels Belgium Tel: +32 (0)2 238 34 11 – Fax: +32 (0)2 230 59 12 http://www.belspo.be Contact person: Georges Jamart +32 (0)2 238 36 90 Neither the Belgian Science Policy nor any person acting on behalf of the Belgian Science Policy is responsible for the use which might be made of the following information. The authors are responsible for the content. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without indicating the reference: E. Verheyen, W. Willems, K. Martens, A.V. Borges, F. Darchambeau, T. Lambert, J.-P. Descy, S. Petrovic, S. Bouillon, C. Teodoru, D.X. Soto, C. Cocquyt, J.C .Taylor, J. Snoeks, E. Decru, J. Bamps, T. Moelants, L. André. Congo basin: From carbon to fishes COBAFISH. Final Report. Brussels : Belgian Science Policy 2017 – 85 p. (Research Programme Science for a Sustainable Development) Project SD/AR/05A - Congo Basin: From carbon to Fishes - COBAFISH COORDINATOR: P1. Erik Verheyen, Royal Belgian Institute of Natural Sciences, Operational Direction Taxonomy and Phylogeny – Vertebrates, Vautierstraat 29, 1000 Brussels, Belgium, [email protected] OTHER PARTNERS: - P2. Alberto Borges, Université de Liège, Chemical Oceanography Unit, Institut de Physique (B5a), B-4000 Liège, [email protected] - P3. Steven Bouillon, KU Leuven, Department of Earth and Environmental Sciences, Celestijnenlaan 200E, B-3001 Leuven, [email protected] - P4. Christine Cocquyt, Botanic Garden Meise, [email protected] - P5. Jos Snoeks, Koninklijk Museum voor Midden-Africa, Unit Vertebrates,Tervuren, [email protected] AUTHOR(S): E. Verheyen1, W. Willems1, K. Martens1, A.V. Borges2, F. Darchambeau2, T. Lambert2, J.-P. Descy2, S. Petrovic2, S. Bouillon3, C. Teodoru3, D.X. Soto3, C. Cocquyt4, J. Taylor4, J. Snoeks5, E. Decru5, J., Bamps5, T. Moelants5, L. André5 Numbers in superscript refer to partner institution (1: Coordinator, 2: Partner 2, etc) PROJECT WEBSITE(S): http://www.congobiodiv.org/nl/projecten/cobafish SSD-Science for a Sustainable Development - Atmosphere and terrestrial and marine ecosystems 3 Project SD/AR/05A - Congo Basin: From carbon to Fishes - COBAFISH TABLE OF CONTENT SUMMARY ................................................................................................................. 7 1. INTRODUCTION .................................................................................................. 11 1.1 Context ............................................................................................................................. 11 1.2 Objectives.......................................................................................................................... 11 1.3 Expected outcomes ............................................................................................................ 12 2. METHODOLOGY AND RESULTS ....................................................................... 13 2.1 Scientific methodology ........................................................................................................ 13 2.2 Results .............................................................................................................................. 18 3. POLICY SUPPORT .............................................................................................. 67 4. DISSEMINATION AND VALORISATION ............................................................ 69 5. PUBLICATIONS ................................................................................................... 71 6. Acknowledgements ............................................................................................ 79 7. References .......................................................................................................... 81 ANNEXES ................................................................................................................ 85 SSD-Science for a Sustainable Development - Atmosphere and terrestrial and marine ecosystems 5 Project SD/AR/05A - Congo Basin: From carbon to Fishes - COBAFISH ACRONYMS and ABREVIATIONS BBPf: Belgian Biodiversity Platform bSiO2: biogenic silica C: carbon cDOM: chromophoric dissolved organic matter CH4: methane CHEMTAX: program for estimating class abundances from chemical markers CO2: carbon dioxide CSB: Centre de Surveillance de Biodiversité DGCD: Belgian Development Cooperation DIC: dissolved inorganic carbon DNA: Deoxyribonucleic acid DOC: dissolved organic carbon (concentrations expressed in mg L-1) DOM: dissolved organic matter DSi: dissolved silicon EA-IRMS: elemental analyzer – isotope ratio mass spectrometry FAO: Food and Agriculture Organization FCH4: CH4 flux across the air-water interface FCO2: CO2 flux across the air-water interface fDOM: fluorescent dissolved organic matter GHG’s: greenhouse gases HPLC: High Performance Liquid Chromatography IUCN: International Union for the Conservation of Nature JRC: Joint Research Centre k: gas transfer velocity LM: light microscope MAB: Man And Biosphere MOB: methane-oxidizing bacteria N: Nitrogen N2O: Nitrous oxide O2: Oxygen pCO2: partial pressure of CO2 POC: particulate organic carbon (concentrations expressed in mg L-1) R: pelagic community respiration SEM: scanning electron microscope Si: silicon SUVA254: specific ultraviolet absorbance of DOM at 254 nm, positively correlated with the degree of aromaticity of DOM. SR: Spectral ratio. Inversely correlated with the average molecular weight of DOM. TA: total alkalinity (in mmol kg-1) TSM: total suspended matter concentration (in mg L-1) WWF: World Wide Fund for Nature 13 δ CDOC: stable carbon isotopic composition of DOC, used as a tracer of DOM sources. ΔCH4: air-water gradient of CH4 ΔCO2: air-water gradient of CO2 SSD-Science for a Sustainable Development - Atmosphere and terrestrial and marine ecosystems 6 Project SD/AR/05A - Congo Basin: From carbon to Fishes - COBAFISH SUMMARY Context The Congo River harbours the richest known fish species diversity on the African continent. Its fish fauna also represents a major source of proteins for the riparian human population. Despite of this, the ecology, dynamics and ecosystem functioning of the Congo River remain poorly understood. The overall goal of the COBAFISH project is to link terrestrial inputs, primary producers (algae and aquatic macrophytes), macro-invertebrate and fish biodiversity to ecosystem dynamics and functioning in the Congo River in order to delineate factors that drive species and trophic biodiversity of fishes. Objectives To achieve this overall goal, COBAFISH addresses four key questions: (1) How diverse are fish communities in two sub-catchments of the Congo River (Lobilo and Lomami) in terms of biodiversity and functional/trophic diversity? (2) Which factors can be identified in regulating this diversity? (3) To which extent do fish communities in these river systems depend on autochtonous (aquatic) primary production or on lateral allochtonous (terrestrial) production? (4) What is the importance of seasonal flood events on global ecosystem functioning? Main conclusions Three extensive field campaigns were carried out (December 2012, September 2013, and March 2014). Three areas were thoroughly sampled for aquatic biogeochemistry, fish, aquatic macro-invertebrates and diatoms. Samples taken in the Lobilo River, which drains water from the UNESCO Man and Biosphere (MAB) Yangambi Reserve, represent the near-pristine condition, whereas the samples collected in the Lower Lomami River represents a human impacted area with different land-use patterns and vegetation. This allowed us to sample in stream water with different characteristics according to the features of the surrounding area/vegetation/land use. Primary production and phytoplankton biomass were highest in the Congo River maintream, and negligible in black water streams such as the Lobilo. Green algae (both