A perspec ve on climate and oceanographic drivers of coral resilience in the Halmahera Sea Cabell Davis1, Anne Cohen1, R. Dwi Susanto2, Rubao Ji1, Robert Beardsley1, Changsheng Chen3, David McKinnie4 Indonesian Collaborators: Zainal Arifin5, Augy Syahailatua5, Yuda Cahyarini5, Sugiarta Wirasantosa6, Ridwan Djamaluddin7
Introduc on Upwelling and coral growth – Global evidence Field campaign Ocean warming and acidifica on are increasing the frequency of coral bleaching Our data from tropical Pacific and Central Red Sea reveal strong correla ons In 2015 (Feb and Aug), we will run oceanographic transects through the three main events, slowing skeletal growth, and increasing dissolu on of corals and reef matrix. between water column Chla and both skeletal and ssue growth of corals (Fig. 5). study sites, where corals will be sampled (Fig. 7). The sites represent a produc vity Emerging evidence suggests certain systems may be more resilient than others. gradient across the HSRA, having Chla levels that are always low (S1, <0.2 μg/l) and
High resilience of the Halmahera Sea, Raja Ampat, (HSRA) area Fig 5 Tissue layer seasonally (Feb vs Sep) varying (S2, range 0.2-0.7μg/l; S3, range 0.3-0.95μg/l) (Fig. 7). thickness (le ) and Fig. 7 (le ) annual calcifica on The Halmahera Sea, Raja Ampat area HSRA, in Oceanographic survey
rate (right) of track (white line) and Porites corals, eastern Indonesia (Fig. 1) appears to have key loca ons of proposed plo ed against (μg/l) study sites(S1-S3) elements of coral reef resilience: good SeaWiFS Chla or in
Chla across the HSRA. situ measurements (right) SeaWiFS Chla reproduc on, connec vity and recruitment, and where available7 (μg/l) in the HSRA strong recovery from localized damage1-4. during two monsoon SeaWiFS seasons (climatology; Fig. 1 Loca on of HSRA black = Feb, white = Hypotheses S1 S2 S3 Sep). Highest Biodiversity 1) Monsoon-driven upwelling in the HSRA enriches plankton concentra ons, Oceanographic sampling, large vessel 11 Considered the global epicenter of marine biodiversity, the HSRA harbors over 1300 enhancing coral growth and resilience to bleaching and acidifica on. o Video Plankton Recorder (Fig 8): T, S, NO3, Chla, turbidity, PAR, plankton, par cles. o Moored ADCP and T/S sensors at S1-S2 (Feb through Sep). species of fish, 700 mollusk species, and ~600 hard coral species (3/4 of known 2) Coral growth is linked to decadal-mul -decadal changes in monsoon strength. o CTD rose e casts and plankton net tows for chemistry and plankton species. zooxanthellate hermatypic sclerac nian species) (Fig. 2). Fig. 8. Video Plankton Recorder (VPRII) A Proposed Study samples hydrography, nitrate, fluorescence, Objec ves turbidity, PAR, and images phytoplankton, zooplankton, and marine snow. It has o Field and modeling studies to be er understand the oceanography of the HSRA automa c image recogni on and real- me Hydrography and circula on underway data display.
Veron et al, 2011 Seasonal upwelling and internal waves Enhancement of nutrients and plankton Coral and local environmental sampling, small vessel o Measure coral growth and resilience o Cores from replicate massive corals at each site each season across the HSRA’s natural gradient in water column produc vity o Measure ssue volume, skeletal growth, and stress bands (Fig. 9) during both the NW and SE monsoons o Local nutrient, carbonate, and plankton sampling at each site near corals over decades to centuries from long skeletal cores Fig. 2 Global biodiversity of hard corals, showing epicenter in HSRA5 with example images (Davis). o Relate observed pa erns coral growth and resilience to field and model data of oceanographic variables (T, S, currents, Chla, turbidity, PAR, N, P, Z, D) at each site. Monsoon-driven mesotrophic water column produc on
This high biodiversity is accompanied by monsoon-driven enrichment of HSRA Oceanography poorly known phytoplankton biomass (Fig. 3), with high zooplankton and fish biomass. The HSRA is thought to be the main entry point of S Pacific water to the Indonesian Throughflow (ITF) (Fig. 2), but data for this area are sparse and it is the least known (Wet) (Dry) (NW winds) (SE winds) part of the ITF8. Likewise monsoon-driven Ekman upwelling has not been studied in this region despite its apparent importance to produc vity (Fig. 6). Furthermore, Fig. 9 (le ) Tissue thickness (Porites) from high (upper) and low Chla regions7. (center) while large amplitude internal des are dominant features of Indonesian seas, Automated calcifica on rate and stress-band analysis of CT scan data generated from a coral core7. (right) White stress band (indicated by arrow) in a 2-D slice of a 3-D CT scan of a Porites core12. studies of these processes in the HSRA are lacking9. 3D High-resolu on mul -scale hydrodynamics-plankton model o 3D hydrography and circula on – FVCOM13 o Coupled biogeochemical model with species model o Non-hydrosta c version for internal waves o Provides mechanis c understanding of mul variate coral environment over hours to decades, for comparison with observed coral growth pa erns. Fig. 3 SeaWiFS chlorophyll a (μg/l), in HSRA during two monsoon seasons.6 Monsoon winds weakening? μZ Wind-stress data (SODA) indicates century-scale weakening of SE monsoon (Fig. 4) .
Fig. 6 (le ) ITF and Pacific currents8,10. (right) Internal wave in Lombok Strait9
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