Chapter 7. Calcium Carbonate Production and Contribution to Coastal Sediments Contributors: Colin D. Woodroffe, Frank R. Hall, John W. Farrell an Peter T. Harris (Lead member) 1. Calcium carbonate production in coastal environments Biological production of calcium carbonate in the oceans is an important process Although carbonate is produced in the open ocean (pelagic, see Chapter 5), thi chapter concentrates on production in coastal waters (neritic) because thi contributes sediment to the coast through skeletal breakdown producing sand an gravel deposits on beaches, across continental shelves, and within reefs. Marin organisms with hard body parts precipitate calcium carbonate as the minerals calcit or aragonite. Corals, molluscs, foraminifera, bryozoans, red algae (for example th algal rims that characterize reef crests on Indo-Pacific reefs) are particularl productive, as well as some species of green algae (especially Halimeda). Upo death, these calcareous organisms break down by physical, chemical, and biologica erosion processes through a series of discrete sediment sizes (Perry et al., 2011) Neritic carbonate production has been estimated to be approximately 2.5 Gt year (Milliman and Droxler, 1995; Heap et al., 2009). The greatest contributors are cora reefs that form complex structures covering a total area of more than 250,000 km (Spalding and Grenfell, 1997; Vecsei, 2004), but other organisms, such as oysters may also form smaller reef structures. Global climate change will affect carbonate production and breakdown in the ocean which will have implications for coastal sediment budgets. Rising sea level wil displace many beaches landwards (Nicholls et al., 2007). Low-lying reef islands calle sand cays, formed over the past few millennia on the rim of atolls, are particularl vulnerable, together with the communities that live on them. Rising sea level ca also result in further reef growth and sediment production where there are health coral reefs (Buddemeier and Hopley, 1988). In areas where corals have already bee killed or damaged by human activities, however, reefs may not be able to keep pac with the rising sea level in which case wave energy will be able to propagate mor freely across the reef crest thereby exposing shorelines to higher levels of wav energy (Storlazzi et al., 2011; see also Chapter 43). Reefs have experienced episodes of coral bleaching and mortality in recent year caused by unusually warm waters. Increased carbon dioxide concentrations are als causing ocean waters to become more acidic, which may affect the biologica production and supply of carbonate sand. Bleaching and acidification can reduc coral growth and limit the ability of reef-building corals and other organisms t produce calcium carbonate (Kroeker et al., 2010). In some cases, ocean acidificatio may lead to a reduced supply of carbonate sand to beaches, increasing the potentia for erosion (Hamylton, 2014). © 2016 United Nations 1.1 Global distribution of carbonate beaches Beaches are accumulations of sediment on the shoreline. Carbonate organisms particularly shells that lived in the sand, together with dead shells reworked fro shallow marine or adjacent rocky shores, can contribute to beach sediments Dissolution and re-precipitation of carbonate can cement sediments formin beachrock, or shelly deposits called coquina. On many arid coasts and islands lackin river input of sediment to the coast, biological production of carbonate is th dominant source of sand and gravel. Over geological time (thousands of years) thi biological source of carbonate sediment may have formed beaches that ar composed entirely, or nearly entirely, of calcium carbonate. Where large river discharge sediment to the coast, or along coasts covered in deposits of glacial til deposited during the last ice age, beaches are dominated by sediment derived fro terrigenous (derived from continental rocks) sources. Carbonate sediment comprise a smaller proportion of these beach sediments (Pilkey et al., 2011). Sand blown inland from carbonate beaches forms dunes and these may be extensiv and can become lithified into substantial deposits of carbonate eolianite (wind blown) deposits. Significant deposits of eolianite are found in the Mediterranean Africa, Australia, and some parts of the Caribbean (for example most of the islands o the Bahamas). The occurrence of carbonate eolianites is therefore a useful proxy fo mapping the occurrence of carbonate beaches (Brooke, 2001). Carbonate beaches may be composed of shells produced by tropical to sub-pola species, so their occurrence is not limited by latitude, although carbonate productio on polar shelves has received little attention (Frank et al., 2014). For example Ritchie and Mather (1984) reported that over 50 beaches in Scotland are compose almost entirely of shelly carbonate sand. There is an increase in carbonate conten towards the south along the east coast of Florida (Houston and Dean, 2014) Carbonate beaches, comprising 60-80 per cent carbonate on average, extend fo over 6000 km along the temperate southern coast of Australia, derived fro organisms that lived in adjacent shallow-marine environments (James et al., 1999 Short, 2006). Calcareous biota have also contributed along much of the wester coast of Australia; carbonate contents average 50-70 per cent, backed by substantia eolianite cliffs composed of similar sediments along this arid coast (Short, 2010) Similar non-tropical carbonate production occurs off the northern coast of Ne Zealand (Nelson, 1988) and eastern Brazil (Carannante et al., 1988), as well a around the Mediterranean Sea, Gulf of California, North-West Europe, Canada, Japa and around the northern South China Sea (James and Bone, 2011). On large carbonate banks, biogenic carbonate is supplemented by precipitation o inorganic carbonate, including pellets and grapestone deposits (Scoffin, 1987). Bal (1967) identified marine sand belts, tidal bars, eolian ridges, and platform interio sand blankets comprising carbonate sand bodies present in Florida and the Bahamas This is also one of the locations where ooids (oolites) form through the concentri precipitation of carbonate on spherical grains. Inorganic precipitation in the Persia Gulf, including the shallow waters of the Trucial Coast, reflects higher wate temperature and salinity (Purser, 1973; Brewer and Dyrssen, 1985). © 2016 United Nations 1.2 Global distribution of atolls The most significant social and economic impact of a possible reduction in carbonat sand production is the potential decrease in supply of sand to currently inhabited low-lying sand islands on remote reefs, particularly atolls. Atolls occur in the war waters of the tropics and subtropics. These low-lying and vulnerable landforms ow their origin to reef-building corals (see Chapter 43 which discusses warm-wate corals in contrast to cold-water corals dealt with in Chapter 42). The origin of atoll was explained by Charles Darwin as the result of subsidence (sinking) of a volcani island. Following an initial eruptive phase, volcanic islands are eroded by waves an by slumping, and gradually subside, as the underlying lithosphere cools an contracts. In tropical waters, fringing coral reefs grow around the volcanic peak. A the volcano subsides the reef grows vertically upwards until eventually the summi of the volcano becomes submerged and only the ring of coral reef (i.e., an atoll) i left behind. The gradual subsidence can be understood in the context of plat tectonics and mantle “hot spots”. Many oceanic volcanoes occur in linear chain (such as the Hawaiian Islands and Society Islands) with successive islands being olde along the chain and moving into deeper water as the plate cools and contract (Ramalho et al., 2013). Most atolls are in the Pacific Ocean (in archipelagoes in the Tuamotu Islands Caroline Islands, Marshall Islands, and the island groups of Kiribati, Tuvalu an Tokelau) and Indian Ocean (the Maldives, the Laccadive Islands, the Chago Archipelago and the Outer Islands of the Seychelles). The Atlantic Ocean has fewe atolls than either the Pacific or Indian Oceans, with several in the Caribbean (Vecsei 2003; 2004). The northernmost atoll in the world is Kure Atoll at 28°24' N, alon with other atolls of the northwestern Hawaiian Islands in the North Pacific Ocean The southernmost are the atoll-like Elizabeth (29°58' S) and Middleton (29°29' S Reefs in the Tasman Sea, South Pacific Ocean (Woodroffe et al., 2004). Th occurrence of seamounts (submarine volcanoes) is two times higher in the Pacifi than in the Atlantic or Indian Oceans, explaining the greater frequency of atolls. Corals, which produce aragonite, are the principal reef-builders that shape an vertically raise the reef deposit, and there are secondary contributions from othe aragonitic organisms, particularly molluscs, as well as coralline algae, bryozoans an foraminifera which are predominantly made of calcite. Carbonate sand and gravel i derived from the breakdown of the reef. Bioerosion is an important process in reefs with bioeroders, such as algae, sponges, polychaete worms, crustaceans, se urchins, and boring molluscs (e.g., Lithophaga) reducing the strength of th framework and producing sediment that infiltrates and accumulates in the porou reef limestone (Perry et al., 2012). Erosion rates by sea urchins have been reporte to exceed 20 kg CaCO; m™” year™ in some reefs, and parrotfish may produce 9 k CaCO; m” year (Glynn, 1996). Over time, cementation lithifies the reef. Wherea the reef itself is the main feature produced by these calcifying reef organisms, loos carbonate sediment is also transported from its site of production. Transporte sediment can be deposited, building sand cays. Broken coral or larger boulder eroded from the reef by storms form coarser islands (termed motu in the Pacific) Sand and gravel can be carried across the reef and deposited together with fine mud filling in the lagoon (Purdy and Gischler, 2005). © 2016 United Nations Carbonate production on reefs has been measured by at least three differen approaches; hydrochemical analysis of changes in alkalinity of water moving across section of reef, radiometric dating of accretion rates in reef cores, and census-base approaches that quantify relative contributions made by different biota (includin destruction by bioeroders). These approaches indicate relatively consistent rates o ~10 kg CaCO; m” year™ on flourishing reef fronts, ~4 kg CaCO3 m” year“ on ree crests, and <1 kg CaCO3 m” year” in lagoonal areas (Hopley et al., 2007; Montaggion and Braithwaite, 2009; Perry et al., 2012; Leon and Woodroffe, 2013). These rate have been described in greater detail in specific studies (Harney and Fletcher, 2003 Hart and Kench, 2007), and have been used to produce regional extrapolations o net production (Vecsei, 2001, 2004). 2. Changes known and foreseen —sea-level rise and ocean acidification. Several climate change and oceanographic drivers threaten the integrity of fragil carbonate coastal ecosystems. Anticipated sea-level rise will have an impact on th majority of coasts around the world. In addition, carbonate production is likely to b affected by changes in other climate drivers, including warming and acidification Tropical and subtropical reefs would appear to be some of the worst affecte systems. However, it is also apparent that already many degraded systems can b attributed to impacts from social and economic drivers of change; pollution overfishing and coastal development have deteriorated reef systems and man severely eroded beaches can be attributed to poor coastal management practices. 2.1 Potential impacts of sea-level rise on beaches Sea-level rise poses threats to many coasts. Between 1950 and 2010, global sea leve has risen at an average rate of 1.8 + 0.3 mm year’; approximately 10 cm o anthropogenic global sea-level rise is therefore inferred since 1950. Over the nex century, the mean projected sea-level rise for 2081-2100 is in the range 0.26-0.54 relative to 1986-2005, for the low-emission scenario (RCP 2.6). The rate of rise i anticipated to increase from ~3.1 mm year™ indicated by satellite altimetry to 7-1 mm year by the end of the century (Church et al., 2013). The rate experienced o any particular coast is likely to differ from the global mean trend as a result of loca and regional factors, such as rates of vertical land movement or subsidence. Beac systems can be expected to respond to this gradual change in sea level, and the low lying reef islands on atolls appear to be some of the most vulnerable coastal system (Nicholls et al., 2007). Based on predictions from the Bruun Rule, a simple heuristic that uses slope of th foreshore and conservation of mass, sea-level rise will cause erosion and ne recession landwards for many beaches (Bruun, 1962). Although this approach ha been widely applied, it has been criticized as unrealistic for many reasons, includin that it does not adequately incorporate consideration of site-specific sediment © 2016 United Nations budgets (Cooper and Pilkey, 2004). Few analyses consider the contribution o biogenic carbonate and none foreshadow the consequences of any reduction i supply of carbonate sand. This is partly because of time lags between production o carbonate and its incorporation into beach deposits, which is poorly constrained i process studies and which is subject to great variability between different coasta settings, ranging from years to centuries (Anderson et al., 2015). In view o uncertainties in rates of sediment supply and transport, probabilistic modeling o shoreline behavior may be a more effective way of simulating possible responses including potential accretion where sediment supply is sufficient (Cowell et al. 2006). 2.2 Potential impacts of sea-level rise on reef islands Small reef islands on the rim of atolls appear to be some of the most vulnerable o coastal environments; they are threatened by exacerbated coastal erosion inundation of low-lying island interiors, and saline intrusion into freshwater lense upon which production of crops, such as taro, depends (Mimura, 1999). Sand cays on atolls as well as on other reefs, have accumulated incrementally over recen millennia because reefs attenuate wave energy sufficiently to create physicall favourable conditions for deposition of sand islands (Woodroffe et al., 2007), as wel as enabling growth of sediment-stabilizing seagrasses and mangrove ecosystem (Birkeland, 1996). Sand cays are particularly low-lying, rarely rising more than a fe metres above sea level; for example, <8 per cent of the land area of Tuvalu an Kiribati is above 3 m above mean sea level, and in the Maldives only around 1 pe cent, reaches this elevation (Woodroffe, 2008). This has led to dramatic warnings i popular media and inferences in the scientific literature that anthropogenic climat change may lead to reef islands on atolls submerging beneath the rising ocean, wit catastrophic social and economic implications for populations of these atoll nation (Barnett and Adger, 2003; Farbotko and Lazrus, 2012). However, reef islands may be more resilient than implied in these dire warning (Webb and Kench, 2010). Unlike the majority of temperate beaches that have a finit volume of sediment available, biogenic production of carbonate sediments mean that there may be an ongoing supply of sediment to these islands. Although coral is major contributor, it is not necessarily the principal constituent of beaches; larg benthic foraminifera (particularly Calcarina, Amphistegina and Baculogypsina contribute more than 50 per cent of sediment volume on many islands on Pacifi atolls (Woodroffe and Morrison, 2001; Fujita et al., 2009). One survey of Pacific cora islands (Webb and Kench, 2010) reported that 86 per cent of islands had remaine stable or increased in area over recent decades, and only 14 per cent of island exhibited a net reduction in area; however, the greatest increases in area resulte from artificial reclamation (Biribo and Woodroffe, 2013). Further studies of shorelin changes on atoll reef islands using multi-temporal aerial photography and satellit imagery indicate accretion on some shorelines and erosion on others, but with th most pronounced changes associated with human occupation and impacts (Rankey 2011; Ford, 2012; Ford 2013; Hamylton and East, 2012; Yates et al., 2013). © 2016 United Nations The impacts of future sea-level rise on individual atolls remain unclear (Donner 2012). Healthy reef systems may be capable of keeping pace with rates of sea-leve rise. There is evidence that reefs have coped with much more rapid rates of ris during postglacial melt of major ice sheets than are occurring now or anticipated i this century. Reefs have responded by keeping up, catching up, or in cases of ver rapid rise giving up, often to backstep and occupy more landward location (Neumann and Macintyre, 1985; Woodroffe and Webster, 2014). Geologica evidence suggests that healthy coral reefs have exhibited accretion rates in th Holocene of 3 to 9 mm year” (e.g., Perry and Smithers, 2011), comparable t projected rates of sea-level rise for the 21* century. However, reef growth is likely t lag behind sea-level rise in many cases resulting in larger waves occurring over th reef flat and affecting the shoreline (Storlazzi et al., 2011; Grady et al., 2013). It i unclear whether these larger waves, and the increased wave run-up that is likely, wil erode reef-island beaches, overtopping some and inundating island interiors, o whether they will more effectively move sediments shoreward and build ridge crest higher (Gourlay and Hacker, 1991; Smithers et al., 2007). Dickinson (2009) inferre that reef islands on atolls will ultimately be unable to survive because once sea leve rises above their solid reef-limestone foundations, which formed during the mid Holocene sea-level highstand 4,000 to 2,000 years ago, formerly stable reef island will be subject to erosion by waves. 2.3 Impact of climate change and ocean acidification on production The impact of climate change on the rate of biogenic production of carbonat sediment is also little understood, but it seems likely to have negative consequences Although increased temperatures may lead to greater productivity in some cases, fo example by extending the latitudinal limit to coral-reef formation, ocean warmin has already been recognised to have caused widespread bleaching and death o corals (Hoegh-Guldberg, 1999; Hoegh-Guldberg, 2004; Hoegh-Guldberg et al., 2007) Ocean acidification will have further impacts, and may inhibit some organisms fro secreting carbonate shells; for example reduction in production of the Pacific oyste has been linked to acidification (Barton et al., 2012). Decreased seawater p increases the sensitivity of reef calcifiers to thermal stress and bleaching (Anthony e al., 2008). Based on the density of coral skeleton in >300 long-lived Porites coral from across the Great Barrier Reef, De’ath et al. (2009) inferred that a decline i calcification of ~14 per cent had occurred since 1990 manifested as a reduction i the extension rate at which coral grows, which they attributed to temperature stres and declining saturation state of seawater aragonite (which is related to a decreas in pH). However, this extent of the apparent decline has been questioned because o inclusion of many young corals (Ridd et al., 2013); it is not observed in coral collected more recently from inshore (D’Olivo et al., 2013). There has been some debate about the role of carbonate sediments acting as chemical buffer against ocean acidification; in this scenario, dissolution o metastable carbonate mineral phases produces sufficient alkalinity to buffer pH an carbonate saturation state of shallow-water environments. However, it is apparen that dissolution rates are slow compared with shelf water-mass mixing processes such that carbonate dissolution has no discernable impact on pH in shallow waters © 2016 United Nations that are connected to deep-water, oceanic environments (Andersson and Mckenzie 2012). The seawater chemistry within a reef system can be significantly differen from that in the open ocean, perhaps partially offsetting the more extreme effect (Andersson et al., 2013; Andersson and Gledhill, 2013). Corals have the ability t modulate pH at the site of calcification (Trotter et al. 2011; Venn et al. 2011; Falte et al., 2013). Internal pH in both tropical and temperate coral is generally 0.4 to 1. units higher than in the ambient seawater, whereas foraminifera exhibit no elevatio in internal pH (McCulloch et al., 2012). Changes in the severity of storms will affect coral reefs; storms erode some islan shorelines, but also provide inputs of broken coral to extend other islands (Marago et al., 1973; Woodroffe, 2008). Alterations in ultra-violet radiation may also have a impact, as UV has been linked to coral bleaching. Furthermore, if reefs are not in healthy condition due to thermal stress (bleaching) coupled with acidification an other anthropogenic stresses (pollution, overfishing, etc.), then reef growth an carbonate production may not keep pace with sea-level rise. This could, in the long term, reduce carbonate sand supply to reef islands causing further erosion, althoug ongoing erosion of cemented reef substrate is also a source of sediment on reefs indicating that supply of carbonate sand to beaches is dependent upon severa interrelated environmental processes. Disruption of any one (or combination) of th controlling processes (carbonate production, reef growth, biological stabilization bioerosion, physical erosion and transport) may result in reduction of carbonat sand supply to beaches. 3. Economic and social implications of carbonate sand production. More than 90 per cent of the population of atolls in the Maldives, Marshall Islands and Tuvalu, as well many in the Cayman Islands and Turks and Caicos (which all hav populations of less than 100,000), live at an elevation <10 m above sea level an appear vulnerable to rising sea level, coastal erosion and inundation (McGranahan e al., 2007). The social disruption caused by relocating displaced people to differen islands or even to other countries is a problem of major concern to many countrie (Farbotko and Lazrus, 2012, see also Chapter 26). Beach aggregate mining is a small scale industry on many Pacific and Caribbean islands employing local people (McKenzie et al., 2006), but mining causes environmental damage when practised o an industrial scale (Charlier, 2002; Pilkey et al., 2011, see also Chapter 23). In th Caribbean, illegal beach mining is widespread but there is little information on wha proportion is carbonate (Cambers, 2009). Beach erosion reduces the potentia opportunities associated with tourism (see Chapter 27), and decreases habitat fo shorebirds and turtles (Fish et al., 2005; Mazaris et al., 2009). Without coral reefs producing sand and gravel for beach nourishment and protectin the shoreline from currents, waves, and storms, erosion and loss of land are mor likely (see also Chapter 39). In Indonesia, Cesar (1996) estimated that the loss due t decreased coastal protection was between 820 United States dollars (for remot areas) and 1,000,000 dollars per kilometre of coastline (in areas of major touris infrastructure) as a consequence of coral destruction (based on lateral erosion rates © 2016 United Nations of 0.2 m year™, and a 10 per cent discount rate [similar to an interest rate] over 25-year period). In the Maldives, mining of coral for construction has had sever impacts (Brown and Dunne, 1988), resulting in the need for an artificial substitut breakwater around Malé at a construction cost of around 12,000,000 dollar (Moberg and Folke, 1999). 4. Conclusions, Synthesis and Knowledge Gaps There has been relatively little study of rates of carbonate production, and furthe research is needed on the supply of biogenic sand and gravel to coastal ecosystems Most beaches have some calcareous biogenic material within them; carbonate is a important component of the shoreline behind coral-reef systems, with reef island on atolls entirely composed of skeletal carbonate. The sediment budgets of these systems need to be better understood; direc observations and monitoring of key variables, such as rates of calcification, would b very useful. Not only is little known about the variability in carbonate production i shallow-marine systems, but their response to changing climate and oceanographi drivers is also poorly understood. In the case of reef systems, bleaching as a result o elevated sea temperatures and reduced calcification as a consequence of ocea acidification seem likely to reduce coral cover and production of skeletal material Longer-term implications for the sustainability of reefs and supply of sediment t reef islands would appear to decrease resilience of these shorelines, althoug alternative interpretations suggest an increased supply of sediment, either becaus reef flats that are currently exposed at low tide and therefore devoid of coral, ma be re-colonized by coral under higher sea level, or because the disintegration of dea stands of coral may augment the supply of sediment. Determining the trend in shoreline change, on beaches in temperate settings and o reef islands on atolls or other reef systems, requires monitoring of beach volumes a representative sites. This has rarely been undertaken over long enough time periods or with sufficient attention to other relevant environmental factors, to discern pattern or assign causes to inferred trends. Although climate and oceanographi drivers threaten such systems, the most drastic erosion appears to be the result o more direct anthropogenic stressors, such as beach mining, or the construction o infrastructure or coastal protection works that interrupt sediment pathways an disrupt natural patterns of erosion and deposition. © 2016 United Nations References Anderson, T.R., Fletcher, C.H., Barbee, M.M., Frazer, L.N., Romine, B.M., (2015) Doubling of coastal erosion under rising sea level by mid-century in Hawaii Natural Hazards, doi 10.1007/s11069-015-1698-6. Andersson, A.J., Mackenzie, F.T., (2012). Revisiting four scientific debates in ocea acidification research. Biogeosciences 9: 893-905. Andersson, A.J., Gledhill, D., (2013). Ocean acidification and coral reefs: effects o breakdown, dissolution, and net ecosystem calcification. Annual Reviews of Marin Science 5, 321-48. Andersson, A.J., Yeakel, K.L., Bates, N.R., de Putron, S.J., (2013). Partial offsets in ocea acidification from changing coral reef biogeochemistry. Nature Climate Change 4, 56 61. Anthony, K., Kline, D., Diaz-Pulido, G., Dove, S., Hoegh-Guldberg, O., (2008). Ocea acidification causes bleaching and productivity loss in coral reef builders Proceedings of the National Academy of Science 105, 17442-17446. Ball, M.M., (1967). Carbonate sand bodies of Florida and the Bahamas. Journal o Sedimentary Petrology 37, 556-591. Barnett, J., Adger, N., (2003). Climate dangers and atoll countries. Climatic Change 61, 321-337. Barton, A., Hales, B., Waldbusser, G.G., Langdon, C., Feely, R.A., (2012). The Pacifi oyster, Crassostrea gigas, shows negative correlation to naturally elevate carbon dioxide levels: implications for near-term ocean acidification effects Chinese Journal of Limnology and Oceanography 57, 698-710. Biribo, N., Woodroffe, C.D., (2013). Historical area and shoreline change of ree islands around Tarawa Atoll, Kiribati. Sustainability Science 8, 345-362. Birkeland, C. (ed.) (1996). Life and Death of Coral Reefs. (New York, Chapman & Hall). Brewer, P.G., Dyrssen, D., (1985). Chemical oceanography of the Persian Gulf. Progress i Oceanography 14, 41-55. Brooke, B., (2001). The distribution of carbonate eolianite. Earth-Science Reviews 55, 135 164. Brown, B.E., Dunne, R.P., (1988). The environmental impact of coral mining in th Maldives. Environmental Conservation 15, 159-166. Bruun, P., (1962). Sea-level rise as a cause of shore erosion. American Society of Civi Engineering Proceedings, Journal of Waterways and Harbors Division 88, 117 130. Buddemeier, R.W., Hopley, D., (1988). Turn-ons and turn-offs: causes an mechanisms of the initiation and termination of coral reef growth Proceedings of the 6th International Coral Reef Congress 1, 253-261. © 2016 United Nations Cambers, G. (2009). Caribbean beach changes and climate change adaptation Aquatic Ecosystem Health & Management, 12, 168-176. Carannante, G., Esteban, M., Milliman, J.D., Simone, L. (1988). Carbonate lithofacie as paleolatitude indicators: problems and limitations. Sedimentary Geolog 60, 333-346. Cesar, H., (1996). Economic analysis of Indonesian coral reefs. World Bank Environmen Department, Washington DC, USA., p. 103. Charlier, R.H., (2002). Impact on the coastal environment of marine aggregates mining International Journal of Environmental Studies 59, 297-322. Church, J.A., Clark, P.U., Cazenave, A., Gregory, J.M., Jevrejeva, S., Levermann, A. Merrifield, M.A., Milne, G.A., Nerem, R.S., Nunn, P.D., Payne, A.J., Pfeffer, W.T. Stammer, D., Unnikrishnan, A.S., 2013. Sea Level Change, in: Stocker, T.F., Plattner, G.-K., Tignor, M., Allen, S.K., Boschung, J., Nauels, A., Xia, Y., Bex, V. Midgley, P.M. (Eds.), Climate Change 2013: The Physical Science Basis. Contributio of Working Group | to the Fifth Assessment Report of the Intergovernmental Panel o Climate Change. Cambridge University Press, Cambridge, United Kingdom and Ne York, NY, USA, pp. 1137-1216. Cooper, J.A.G., Pilkey, O.H., (2004). Sea-level rise and shoreline retreat: time t abandon the Bruun Rule. Global and Planetary Change 43, 157-171. Cowell, P.J., Thom, B.G., Jones, R.A., Everts, C.H., Simanovic, D., (2006). Management o uncertainty in predicting climate-change impacts on beaches. Journal of Coasta Research 22, 232-245. De’ath, G., Lough, J.M., Fabricus, K.E., (2009). Declining coral calcification on th Great Barrier Reef. Science 323, 116-119. Dickinson, W.R., (2009). Pacific atoll living: How long already and until when? GSA Today 19 4-10. D'Olivo, J.P., McCulloch, M.T., Judd, K., (2013). Long-term records of cora calcification across the central Great Barrier Reef: assessing the impacts o river runoff and climate change. Coral Reefs 32, 999-1012. Donner, S., (2012). Sea level rise and the ongoing battle of Tarawa. EOS, Transaction of the American Geophysical Union 93, 169-176. Falter, J., Lowe, R., Zhang, Z., McCulloch, M., (2013). Physical and biological control on the carbonate chemistry of coral reef waters: effects of metabolism, wav forcing, sea level, and geomorphology. PLoS One 8, e53303. Farbotko, C., Lazrus, H. (2012). The first climate refugees? Contesting globa narratives of climate change in Tuvalu. Global Environmental Change 22, 382 390. Fish, M.R., Cote, I.M., Gill, J.A., Jones, A.P., Renshoff, S., Watkinson, A. (2005) Predicting the impact of sea-Level rise on Caribbean sea turtle nestin habitat. Conservation Biology 19, 482-491. © 2016 United Nations 1 Ford, M., (2012). Shoreline changes on an urban atoll in the central Pacific Ocean Majuro Atoll, Marshall Islands. Journal of Coastal Research 28, 11-22. Ford, M., (2013). Shoreline changes interpreted from multi-temporal aeria photographs and high resolution satellite images: Wotje Atoll, Marshal Islands. Remote Sensing of Environment 135, 130-140. Frank, T.D., James, N.P., Bone, Y., Malcolm, |., Bobak, L.E., (2014). Late Quaternar carbonate deposition at the bottom of the world. Sedimentary Geology, 306 1-16. Fujita K., Osawa, Y., Kayanne, H., Ide, Y., Yamano, H. (2009). Distribution an sediment production of large benthic foraminifers on reef flats of the Majur Atoll, Marshall Islands. Coral Reefs 28, 29-45. Glynn, P.W., (1996). Coral reef bleaching: facts, hypotheses and implications. Globa Change Biology 2, 495-509. Gourlay, M.R., Hacker, J.L.F. (1991). Raine Island: coastal processes an sedimentology. CH40/91, Department of Civil Engineering, University o Queensland, Brisbane. Grady, A.E., Reidenbach, M.A., Moore, L.J., Storlazzi, C.D., Elias, E., (2013). Th influence of sea level rise and changes in fringing reef morphology o gradients in alongshore sediment transport. Geophysical Research Letters 40 3096-3101. Hamylton, S.M., East, H., (2012). A geospatial appraisal of ecological and geomorphi change on Diego Garcia Atoll, Chagos Islands (British Indian Ocean Territory) Remote Sensing 4, 3444-3461. Hamylton, S., (2014). Will coral islands maintain their growth over the next century A deterministic model of sediment availability at Lady Elliot Island, Grea Barrier Reef. PLoS ONE 9, e94067. Harney, J.N., Fletcher, C.H., (2003). A budget of carbonate framework and sedimen production, Kailua Bay, Oahu, Hawaii. Journal of Sedimentary Research 73 856-868. Hart, D.E., Kench, P.S., (2007). Carbonate production of an emergent reef platform Warraber Island, Torres Strait, Australia. Coral Reefs 26, 53-68. Heap, A.D., P.T. Harris, L. Fountain, (2009). Neritic carbonate for six submerged coral reef from northern Australia: Implications for Holocene global carbon dioxide Palaeogeography, Palaeoclimatology, Palaeoecology 283, 77-90. Hoegh-Guldberg, O., (1999). Climate change, coral bleaching and the future of th world's coral reefs. Marine and Freshwater Research 50, 839-866. Hoegh-Guldberg, O., (2004). Coral reefs in a century of rapid environmental change Symbiosis 37, 1-31. Hoegh-Guldberg, O., Mumby, P.J., Hooten, A.J., Steneck, R.S., Greenfield, P. Gomez, E., Harvell, C.D., Sale, P.F., Edwards, A.J., Caldeira, K., Knowlton, N. Eakin, C.M., Glesias-Prieto, R., Muthiga, N., Bradbury, R.H., Dubi, A., © 2016 United Nations 1 Hatziolos, M.E. (2007). Coral reefs under rapid climate change and ocea acidification. Science 318, 1737-1742. Houston, J.R., Dean, R.G. (2014). Shoreline change on the east coast of Florida Journal of Coastal Research 30, 647-660. Hopley, D., Smithers, S.G. and Parnell, K., (2007). Geomorphology of the Grea Barrier Reef: development, diversity and change. Cambridge University Press. James, N.P., Collins, L.B., Bone, Y., Hallock, P., (1999). Subtropical carbonates in temperate realm: modern sediments on the southwest Australian shelf Journal of Sedimentary Research 69, 1297-1321. James, N.P., Bone, Y., (2011). Neritic carbonate sediments in a temperate realm Springer, Dordrecht. Kroeker, K.J., Kordas, R.L., Crim, R.N., Singh, G.G. (2010). Meta-analysis reveal negative yet variable effects of ocean acidification on marine organisms Ecology Letters 13, 1419-1434. Leon, J.X., Woodroffe, C.D., (2013). Morphological characterisation of reef types i Torres Strait and an assessment of their carbonate production, Marin Geology 338, 64-75. Maragos, J.E., Baines, G.B.K. and Beveridge, P.J. (1973). Tropical cyclone creates new land formation on Funafuti atoll. Science 181: 1161-1164. Mazaris, A.D., Matsinos, G., Pantis, J.D. (2009). Evaluating the impacts of coasta squeeze on sea turtle nesting. Ocean & Coastal Management 52, 139-145. McCulloch, M., Falter, J.L., Trotter, J., Montagna, P., (2012). Coral resilience to ocea acidification and global warming through pH up-regulation. Nature Climat Change 2, 1-5. McGranahan, G., Balk, D., Anderson, B., (2007). The rising tide: assessing the risks of climat change and human settlements in low elevation costal zones. Environment an Urbanization 19, 17-37. McKenzie, E., Woodruff, A., McClennen, C., (2006). “Economic assessment of the true cost of aggregate mining in Majuro Atoll, Republic of the Marshall Islands’. SOPA Technical Report 383, p. 74. Milliman, J.D., and Droxler, A.W. (1995). Calcium carbonate sedimentation in th global ocean: Linkages between the neritic and pelagic environments Oceanography 8(3):92—94, http://dx.doi.org/10.5670/oceanog.1995.04. Mimura, N., (1999). Vulnerability of island countries in the South Pacific to sea leve rise and climate change. Climate Research 12, 137-143. Moberg, F. Folke, C., (1999). Ecological goods and services of coral reef ecosystems Ecological Economics 29, 215-233. Montaggioni, L.F., Braithwaite, C.J.R., (2009). Quaternary Coral Reef Systems history, development processes and controlling factors. Elsevier, Amsterdam. Nelson, C.S., (1988). An introductory perspective on non-tropical shelf carbonates Sedimentary Geology 60, 3-12. © 2016 United Nations 1 Neumann, A.C., Macintyre, I., (1985). Reef response to sea level rise: keep-up, catch up or give-up. Proceedings of the 5th International Coral Reef Congress 3 105-110. Nicholls, R.J., Wong P.P., Burkett V.R., Codignotto J.O., Hay J.E., McLean R.F. Ragoonaden, S. and Woodroffe, C.D., et al., Coastal systems and low-lyin areas. In: Parry, M.L., Canziani, O.F., Palutikof, J.P., van der Linden, P.J. Hanson, C.E., (Editors) (2007), Climate Change 2007: impacts, adaptation an vulnerability. Contribution of Working Group II to the Fourth Assessmen Report of the Intergovernmental Panel on Climate Change (IPCC). Cambridg University Press, pp. 315-357. Perry, C.T., Smithers, S.G., (2011). Cycles of coral reef ‘turn-on’, rapid growth and ‘turn-off over the past 8500 years: a context for understanding modern ecological states an trajectories. Global Change Biology 17, 76-86. Perry, C.T., Kench, P.S., Smithers, S.G., Riegl, B., Yamano, H., O'Leary, M.J., (2011) Implications of reef ecosystem change for the stability and maintenance of coral ree islands. Global Change Biology 17, 3679-3696. Perry, C., Edinger, E., Kench, P., Murphy, G., Smithers, S., Steneck, R., Mumby, P., (2012) Estimating rates of biologically driven coral reef framework production and erosion a new census-based carbonate budget methodology and applications to the reefs o Bonaire. Coral Reefs 31, 853-868. Pilkey, O.H., Neal, W.J., Cooper, J.A.G., Kelley, J.T., (2011). The World's Beaches: A globa guide to the science of the shoreline. University of California Press. Purdy, E.G., Gischler, E., (2005). The transient nature of the empty bucket model o reef sedimentation. Sedimentary Geology 175, 35-47. Purser, B.H. (Ed) (1973). The Persian Gulf: Holocene carbonate sedimentation an diagenesis in a shallow epicontinental sea. Springer-Verlag. Ramalho, R.S., Quartau, R., Trenhaile, A.S., Mitchell, N.C., Woodroffe, C.D., Avila, S.P (2013) Coastal evolution on volcanic oceanic islands: a complex interpla between volcanism, erosion, sedimentation, sea-level change and biogeni production. Earth-Science Reviews, 127: 140-170.Rankey, E.C., (2011). Natur and stability of atoll island shorelines: Gilbert Island chain, Kiribati, equatorial Pacific. Sedimentology 58, 1831-1859. Rankey, E.C. (2011) Nature and stability of atoll island shorelines: Gilbert Islan chain, Kiribati, equatorial Pacific. Sedimentology 58, 1831-1859. Ridd, P.V., Teixeira da Silva, E., Stieglitz, T., (2013). Have coral calcification rate slowed in the last twenty years? Marine Geology 346, 392-399. Ritchie, W., Mather, A.S., (1984). “The beaches of Scotland”. Commissioned by th Countryside Commission for Scotland 1984, Report No. 109 http://www.snh.org.uk/pdfs/publications/commissioned_reports/ReportNo109.pdf Scoffin, T.P., An Introduction to Carbonate Sediments and Rocks. (1987). Chapman & Hall New York, 274 pp. © 2016 United Nations 1 Short, A.D., (2006). Australian beach systems, nature and distribution. Journal of Coasta Research 22, 11-27. Short, A.D., (2010). Sediment transport around Australia - sources, mechanisms rates and barrier forms. Journal of Coastal Research 26, 395-402. Smithers, S.G., Harvey, N., Hopley, D. and Woodroffe, C.D., (2007). Vulnerability o geomorphological features in the Great Barrier Reef to climate change. I Johnson J.E., Marshall, P.A. (Editors) in Climate Change and the Great Barrie Reef. Great Barrier Reef Marine Park Authority and Australian Greenhous Office, Australia, pp. 667-716. Spalding, M.D. and Grenfell, A.M., (1997). New estimates of global and regional cora reef areas. Coral Reefs 16, 225-230. Storlazzi, C.D., Elias, E., Field, M.E. and Presto, M.K., (2011). Numerical modeling o the impact of sea-level rise on fringing coral reef hydrodynamics an sediment transport. Coral Reefs 30, 83-96. Trotter, J., Montagna, P., McCulloch, M., Silenzi, S., Reynaud, S., Mortimer, G. Martin, S., Ferrier-Pages, C., Gattuso, J-P., Rodolfo-Metalpa, R., (2011) Quantifying the pH ’vital effect‘ in the temperate zooxanthellate cora Cladocora caespitosa: Validation of the boron seawater pH proxy. Earth an Planetary Science Letters, 303, 163-173. Vecsei, A., (2001). Fore-reef carbonate production: development of a regiona census-based method and first estimates. Palaeogeograph Palaeoclimatology Palaeoecology 175, 185-200. Vecsei, A., (2003). Systematic yet enigmatic depth distribution of the world's moder warm-water carbonate platforms: the ‘depth window’. Terra Nova 15, 170 175. Vecsei, A., (2004). A new estimate of global reefal carbonate production including the fore reefs. Global and Planetary Change 43, 1-18. Venn, A., Tambutté, E., Holcomb, M., Allemand, D., Tambutté, S., (2011). Live tissue imagin shows reef corals elevate pH under their calcifying tissue relative to seawater. PLo One 6, e20013. Webb, A.P., Kench, P., (2010). The Dynamic Response of Reef Islands to Sea Level Rise Evidence from Multi-Decadal Analysis of Island Change in the Central Pacific. Globa and Planetary Change 72, 234-246 Woodroffe, C.D., (2008). Reef-island topography and the vulnerability of atolls to sea-leve rise. Global and Planetary Change 62, 77-96. Woodroffe, C.D., Morrison, R.J., (2001). Reef-island accretion and soil development Makin Island, Kiribati, central Pacific. Catena 44, 245-261. Woodroffe, C.D., Kennedy, D.M., Jones, B.G., Phipps, C.V.G. (2004). Geomorphology an Late Quaternary development of Middleton and Elizabeth Reefs. Coral Reefs 23, 249 262. Woodroffe, C.D., Samosorn, B., Hua, Q., Hart, D.E., (2007). Incremental accretion of a sandy © 2016 United Nations 1 reef island over the past 3000 years indicated by component-specific radiocarbo dating, Geophysical Research Letters 34, LO3602, doi:10.1029/2006GL028875. Woodroffe, C.D., Webster, J.M., (2014). Coral reefs and sea-level change. Marine Geolog doi 10.1016/j.margeo.2013.12.006. Yates, M.L., Le Cozannet, G., Garcin, M., Salai, E., Walker, P., (2013). Multidecada atoll shoreline change on Manihi and Manuae, French Polynesia. Journal o Coastal Research 29 870-882. © 2016 United Nations 1