1. Massive Porites sp. corals as indicators of historical changes in river runoff: A case study for Antongil Bay (Masoala National Park, NE Madagascar ) J. Zinke 1, C. Grove 2, G. J. Brummer 2 1 Vrije Universiteit Amsterdam, The Netherlands 2 Royal NIOZ, The Netherlands in cooperation with WCS Madagascar

2. Ecological Response of Reefs: global & local impacts ALGAE Algal Reef GLOBAL Climate Change Global Warming (coral bleaching) Increased pCO 2 (ocean acidification) Sea Level Rise HERBIVORES Fish, Invertebrates competition CROWN OF THORNS reproduction CORALS Adults Juveniles for space Healthy Reef LOCAL IMPACTS CORAL PREDATORS – Crown of Thorns (COTS) FISHING/TRAWLING – Reef ecology RIVER RUNOFF - Sediments, Nutrients, Freshwater input

3. Study area: NE Madagascar, Antongil Bay, St. Marie, Ifaty

4. Main climatic variables in the region: Rainfall and SST Rainfall (cyclonic) impacts on: 1) Freshwater runoff and sedimentation of river systems 2) Ocean chemistry and physical conditions 3) Nutrient and pollutant export rates Sea surface temperature patterns affect rainfall variability Climate change impacts on reefal ecosystem: 1) Multiple stress factors: SST, salinity, sediments, pollutants, nutrients Impact on livelihoods: 1) large-scale flooding of villages 2) Erosion of agricultural land, loss of fertile soil 3) Sewage export impacts on fisheries

5. Objectives Madagascar Recontruction of surface ocean chemistry, temperature and salinity related to global and local factors: To provide baseline of natural variability against which anthropogenic impacts can be assessed Learn about spatial and temporal changes in climate Study sedimentation, pollutant and nutrient export and how it relates to climate variability Quantify the impacts of climatic and environmental changes on coastal ecosystems

6. Our monitoring tool: Massive corals Porites sp. Life span: up to 400 years Geochemical proxies in corals: -Sr/Ca for SST -Oxygen isotopes for salinity -Combination Sr/Ca and d18O for hydrology - Ba/Ca, Y, Mn for river runoff -Cu, Zn etc. for biological activity - Luminescence for runoff - Density and Calcification for status of coral health

7. Zinke et al., 2004

8. Ifaty and Reunion corals record link to Pacific Decadal Oscillation (18-25 years)

9. Ba/Ca as a proxy for sediment river discharge McCulloch et al., 2003, Nature 421 Ba is highly abundant in river sediment load Ba is released when river water flows into seawater (salinity, pH gradient) Freshwater plumes into the coastal ocean are correlated with higher Ba/Ca ratios in corals Floods after drought years contain more Ba than in normal years

10. Increase in temperature and sedimentation over 20th century: Antongil Bay

11. Ba/Ca: late summer/winter maxMn: summer max Seasonal timing of runoff

12. Luminescence banding related to river runoff: Quantification of runoff intensity in single years

13. XRF-scanning luminesecence (Royal NIOZ Netherlands): subweekly resolution

14. Calcification rate and density decrease over the 20th century: Ocean Acidification? MAS1 coral, Masoala Park

15. Gaps in monitoring and research: monitoring natural variability of sedimentation, nutrient and pollutant export to provide natural levels combine environmental monitoring with ecosystem studies (reef monitoring) monitor SST and salinity to evaluate choice of MPA’s climatological monitoring land and ocean (isotopes in precipitation, isotopes in groundwater/seawater) combine terrestrial (tree rings, stalagmites, lakes) and marine studies (corals, bivalves) to investigate land-ocean interaction (gradients) hydrological modelling of climate and land-use impacts