This project is a four-year, fully-funded studentship based in the School of Geography, Geology, and the Environment.
Professor Jens Zinke and Dr Arnoud Boom
- Study a set of unique coral cores covering up to 200 years of ocean climate history from Miri-Sibuti Coral Reefs National Park (MSCRNP).
- Assess anthropogenic impacts and their effects on sediment and nutrient delivery to the coral reefs and their signatures in coral core geochemistry.
- Carry out and develop analytical experience with a range of high precision analytical instruments research with cutting edge stable isotope and trace element geochemistry at UoL and partners in Australia and Germany.
- Undertake innovative climate and geochemical proxy data analysis and develop paleoclimate reconstructions of temperature, hydroclimate, river runoff and eutrophication.
Southeast Asia (SEA) has the most extensive and diverse coral reefs in the world, making up approximately 28% of the global total (Burke et al., 2011). Most of them are located in the humid tropical insular part of SEA; the so-called Maritime Continent (Fig. 1). The Maritime Continent has experienced fast economic development and urbanization in the past 40 years, drastically increasing anthropogenically induced pressures on the marine ecosystems and causing significant ecological damage (Tun et al., 2008). Borneo has experienced the highest levels of deforestation among all humid tropical regions of the world, with approximately 26% of old-growth rainforest being lost since the early 1970s (Gaveau et al., 2014, 2016).
Forest loss in Borneo has resulted from human-induced actions like widespread timber exploitation and oil palm cultivation, as well as climate-induced events like severe droughts and wildfires, particularly in ENSO years (Chen et al., 2016; Gaveau et al., 2014, 2016; Sloan et al., 2017). The Malaysian state of Sarawak is a hotspot of deforestation containing concentration areas with over 5% annual forest loss due to unsustainable and damaging logging practices (Miettinen et al., 2011). Deforestation in tropical regions with high precipitation is a major cause for the siltation of watersheds by leaving cleared areas prone to soil erosion (Storlazzi et al., 2015; Vijith and Dodge-Wan, 2018). Terrestrial sediment- and pollutant-runoff into the coastal waters, and sediment resuspension caused by land use changes and dredging, are serious issues for the status of coral reefs. By covering coral colonies and hardground, as well as by staying suspended in the waterbody and thereby increasing turbidity, eroded sediments have various negative effects on coral growth, reproduction and recruitment, resilience to diseases and photosynthesis by symbiotic zooxanthellae (Fabricius, 2005). The combination of both local-scaled human-imposed stresses and global-scaled climatic stresses and their complex and synergetic interactions puts coral reefs in a crisis.
The reefs in Miri-Sibuti Coral Reefs National Park (MSCRNP), off the northwestern Sarawak coast of Borneo are poorly studied. Weather station data is scarce in Borneo. There is limited in situ SST and light level (turbidity) data available for the coastal waters of MSCRNP from several Masters thesis (Krawczyk et al., 2018). Mostly satellite-derived SST data is available since 1981, however these data must be treated with caution for coastal areas. Thus, the lack of detailed reef assessments and poor climatic data limits the analysis of temporal change of the coral reefs’ status in MSCRNP. Within this proposed project we aim to develop a spatio-temporal reconstruction of dynamics regarding SST, sea surface salinity (SSS), light availability, nutrient discharge and river sediment runoff based on a multi proxy analysis of coral cores from various sites in MSCRNP, Borneo (Malaysia). Sr/Ca analysis is used for local SST reconstruction (Zinke et al., 2016). Combined Sr/Ca and oxygen isotope analysis is utilized to reconstruct the oxygen isotopic composition of the seawater related to changes in the hydrological balance (Ren et al., 2002). Carbon isotope analysis serves for the determination of long-term changes in oceanic uptake of atmospheric CO2 and seasonal fluctuations in light intensity, linked to cloud cover and river runoff, and terrestrial carbon influx (Sun et al., 2008; Grove et al., 2012). Ba/Ca is used to track sediment discharge in river runoff (McCulloch et al., 2003). Nitrogen isotopes will be used to track natural and anthropogenic signatures associated with marine productivity and fertilizer use on land (Duprey et al., 2016). All proxies are compared to other data products of SST, SSS and precipitation. Proxy data are further investigated for signals of large-scale climatic teleconnections related to important climate drivers.
The PhD project is part of Professor Zinke’s Royal Society Wolfson Fellowship, which aims to take the pulse of the tropical oceans through the coral’s lense.
A solid background in Earth Sciences, Palaeobiology and Climate Sciences, and skills in statistical analysis are essential requirements.
Geochemical measurements will be performed in laboratories in at the University of Leicester (UOL), Curtin University Perth (Australia) and Max-Planck Institute Mainz (Germany).
The methods to generate coral proxy records include:
1) X-ray analysis to determine optimum sampling tracks along major growth axes of the coral cores (already completed at AIMS)
2) paired with XRD and microscopy to detect potential diagenesis in modern and fossil corals (UOL)
3) Bi-monthly sampling (1-2mm) of coral cores with an automated milling device to extract powder (UOL)
4) Geochemical preparation of samples for subsequent analysis in ultra-clean lab at UOL
5) High-precision measurement of elemental ratios (Sr/Ca, Mg/Ca) with sub-permil error using a inductively coupled plasma mass spectrometer (ICP-OES) and a inductively coupled plasma mass spectrometer (ICP-MS) at UOL (Sr/Ca, U/Ca, Mg/Ca, Ba/Ca, B/Ca, Li/Ca, Li/Mg); Laser-Ablation ICP-MS analysis at Curtin University (Australia) (Sr/Ca, U/Ca, Mg/Ca, Ba/Ca, B/Ca, Mn/Ca, Y/Ca, REEs)
6) Measurement of stable isotopes (18O, 13C) with Gasbench at FU Berlin and Sercon 20-20 at UOL
7) Measurement of nitrogen isotopes at Max-Planck Institute Mainz (Germany)
Fieldwork in Miri-Sibuti Coral Reefs National Park is planned in cooperation with Curtin University (Perth, Western Australia) and Curtin Sarawak University (Malaysia) in 2020/2021 in Miri. The student will gain experience in modern coral sampling, and has the chance to obtain a dive certificate. Aims of the fieldwork is to expand the available coral core archive by obtaining 2m long cores covering up to 200 years. In addition, we will collect and re-deploy in situ sensors for SST and light levels.
Burke, L., Reytar, K., Spalding, M. and Perry, A. (2011) Reefs at Risk Revisited. World Resources Institute, Washington, DC.
Chen, C.-C., Lin, H.-W., Yu, J.-Y. and Lo, M.-H. (2016) The 2015 Borneo fires: What have we learned from the 1997 and 2006 El Niños? Environmental Research Letters 11, 104003.
Duprey, N.N., Yasuhara, M. and Baker, D. M. (2016) Reefs of tomorrow: eutrophication reduces coral biodiversity in an urbanized seascape Global Change Biology 22, 3550–3565, doi: 10.1111/gcb.13432.
Fabricius, K.E. (2005) Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis. Marine Pollution Bulletin 50, 125-146.
Gaveau, D.L.A., Sheil, D., Husnayaen, Salim, M.A., Arjasakusuma, S., Ancrenaz, M., Pacheco, P. and Meijaard, E. (2016) Rapid conversions and avoided deforestation: examining four decades of industrial plantation expansion in Borneo. Scientific Reports 6, 32017.
Gaveau, D.L.A., Sloan, S., Molidena, E., Yaen, H., Sheil, D., Abram, N.K., Ancrenaz, M., Nasi, R., Quinones, M., Wielaard, N. and Meijaard, E. (2014) Four Decades of Forest Persistence, Clearance and Logging on Borneo. PLOS ONE 9, e101654.
Grove, C. A., J. Zinke, T. Scheufen, E. Epping, W. Boer, B. Randriamanantsoa and G-J. A. Brummer (2012) Spatial linkages between coral proxies of terrestrial runoff across a large embayment in Madagascar. Biogeosciences 9, 3063-3081.
McCulloch, M., Fallon, S., Wyndham, T., Hendy, E., Lough, J. and Barnes, D. (2003) Coral record of increased sediment flux to the inner Great Barrier Reef since European settlement. Nature 421, 727.
Miettinen, J., Shi, C. and Liew, S.C. (2011) Deforestation rates in insular Southeast Asia between 2000 and 2010. Global Change Biology 17, 2261-2270.
Ren, L., Linsley, B.K., Wellington, G.M., Schrag, D.P. and Hoegh-guldberg, O. (2003) Deconvolving the δ18O seawater component from subseasonal coral δ18O and Sr/Ca at Rarotonga in the southwestern subtropical Pacific for the period 1726 to 1997. Geochimica et Cosmochimica Acta 67, 1609-1621.
Sloan, S., Locatelli, B., Wooster, M.J. and Gaveau, D.L.A. (2017) Fire activity in Borneo driven by industrial land conversion and drought during El Nino periods, 1982-2010. Global Environ Chang 47, 95-109.
Storlazzi, C.D., Norris, B.K. and Rosenberger, K.J. (2015) The influence of grain size, grain color, and suspended-sediment concentration on light attenuation: Why fine-grained terrestrial sediment is bad for coral reef ecosystems. Coral Reefs 34, 967-975.
Sun, D., Su, R., McConnaughey, T.A. and Bloemendal, J. (2008) Variability of skeletal growth and δ13C in massive corals from the South China Sea: Effects of photosynthesis, respiration and human activities. Chemical Geology 255, 414-425.
Tun, K., Chou, L., Yeemin, T., Phongsuwan, N., Amri, A.Y., Ho, N., Sour, K., Long, N., Nanola, C. and Lane, D. (2008) Status of coral reefs in Southeast Asia, in: Wilkinson, C. (Ed.), Status of coral reefs of the world. Global Coral Reef Monitoring Network and Reef and Rainforest Research Centre, Townsville, Australia, pp. 131-144.
Vijith, H. and Dodge-Wan, D. (2018) Spatio-temporal changes in rate of soil loss and erosion vulnerability of selected region in the tropical forests of Borneo during last three decades. Earth Science Informatics 11, 171-181.
Zinke, J., Reuning, L., Pfeiffer, M., Wassenburg, J.A., Hardman, E., Jhangeer-Khan, R., Davies, G.R., Ng, C.K.C., Kroon, D. (2016) A sea surface temperature reconstruction for the southern Indian Ocean trade wind belt from corals in Rodrigues Island (19S, 63E). Biogeosciences 13, 5827-5847.