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Here we report seasonally resolved sea surface temperatures for the southern Mozambique Channel in the SW Indian Ocean based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores. Particularly, we assess the suitability of both separate and combined Sr/Ca and Li/Mg proxies for improved multielement SST reconstructions. Overall, geochemical records from Europa Island Porites sp. highlight the potential of Sr/Ca and Li/Mg ratios as high-resolution climate proxies but also show significant differences in their response at this Indian Ocean subtropical reef site. Our reconstruction from 1970 to 2013 using the Sr/Ca SST proxy reveals a warming trend of 0.58 +/- 0.1 degrees C in close agreement with instrumental data (0.47 +/- 0.07 degrees C) over the last 42 years (1970-2013). In contrast, the Li/Mg showed unrealistically large warming trends, most probably caused by uncertainties around different uptake mechanisms of the trace elements Li and Mg and uncertainties in their temperature calibration. In our study, Sr/Ca is superior to Li/Mg to quantify absolute SST and relative changes in SST. However, spatial correlations between the combined detrended Sr/Ca and Li/Mg proxies compared to instrumental SST at Europa revealed robust cor-relations with local climate variability in the Mozambique Channel and teleconnections to regions in the Indian Ocean and southeastern Pacific where surface wind variability appeared to dominate the underlying pattern of SST variability. The strongest correlation was found between our Europa SST reconstruction and instrumental SST records from the northern tropical Atlantic. Only a weak correlation was found with ENSO, with recent warm anomalies in the geochemical proxies coinciding with strong El Nino or La Nina. We identified the Pacific-North American (PNA) atmospheric pattern, which develops in the Pacific in response to ENSO, and the tropical North Atlantic SST as the most likely causes of the observed

Here we report seasonally resolved sea surface temperatures for the southern Mozambique Channel in the SW Indian Ocean based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores. Particularly, we assess the suitability of both separate and combined Sr/Ca and Li/Mg proxies for improved multielement SST reconstructions. Overall, geochemical records from Europa Island Porites sp. highlight the potential of Sr/Ca and Li/Mg ratios as high-resolution climate proxies but also show significant differences in their response at this Indian Ocean subtropical reef site. Our reconstruction from 1970 to 2013 using the Sr/Ca SST proxy reveals a warming trend of 0.58 +/- 0.1 degrees C in close agreement with instrumental data (0.47 +/- 0.07 degrees C) over the last 42 years (1970-2013). In contrast, the Li/Mg showed unrealistically large warming trends, most probably caused by uncertainties around different uptake mechanisms of the trace elements Li and Mg and uncertainties in their temperature calibration. In our study, Sr/Ca is superior to Li/Mg to quantify absolute SST and relative changes in SST. However, spatial correlations between the combined detrended Sr/Ca and Li/Mg proxies compared to instrumental SST at Europa revealed robust cor-relations with local climate variability in the Mozambique Channel and teleconnections to regions in the Indian Ocean and southeastern Pacific where surface wind variability appeared to dominate the underlying pattern of SST variability. The strongest correlation was found between our Europa SST reconstruction and instrumental SST records from the northern tropical Atlantic. Only a weak correlation was found with ENSO, with recent warm anomalies in the geochemical proxies coinciding with strong El Nino or La Nina. We identified the Pacific-North American (PNA) atmospheric pattern, which develops in the Pacific in response to ENSO, and the tropical North Atlantic SST as the most likely causes of the observed

Here we report seasonally resolved sea surface temperatures for the southern Mozambique Channel in the SW Indian Ocean based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores. Particularly, we assess the suitability of both separate and combined Sr/Ca and Li/Mg proxies for improved multielement SST reconstructions. Overall, geochemical records from Europa Island Porites sp. highlight the potential of Sr/Ca and Li/Mg ratios as high-resolution climate proxies but also show significant differences in their response at this Indian Ocean subtropical reef site. Our reconstruction from 1970 to 2013 using the Sr/Ca SST proxy reveals a warming trend of 0.58 +/- 0.1 degrees C in close agreement with instrumental data (0.47 +/- 0.07 degrees C) over the last 42 years (1970-2013). In contrast, the Li/Mg showed unrealistically large warming trends, most probably caused by uncertainties around different uptake mechanisms of the trace elements Li and Mg and uncertainties in their temperature calibration. In our study, Sr/Ca is superior to Li/Mg to quantify absolute SST and relative changes in SST. However, spatial correlations between the combined detrended Sr/Ca and Li/Mg proxies compared to instrumental SST at Europa revealed robust cor-relations with local climate variability in the Mozambique Channel and teleconnections to regions in the Indian Ocean and southeastern Pacific where surface wind variability appeared to dominate the underlying pattern of SST variability. The strongest correlation was found between our Europa SST reconstruction and instrumental SST records from the northern tropical Atlantic. Only a weak correlation was found with ENSO, with recent warm anomalies in the geochemical proxies coinciding with strong El Nino or La Nina. We identified the Pacific-North American (PNA) atmospheric pattern, which develops in the Pacific in response to ENSO, and the tropical North Atlantic SST as the most likely causes of the observed

Here we report seasonally resolved sea surface temperatures for the southern Mozambique Channel in the SW Indian Ocean based on multi-trace-element temperature proxy records preserved in two Porites sp. coral cores. Particularly, we assess the suitability of both separate and combined Sr/Ca and Li/Mg proxies for improved multielement SST reconstructions. Overall, geochemical records from Europa Island Porites sp. highlight the potential of Sr/Ca and Li/Mg ratios as high-resolution climate proxies but also show significant differences in their response at this Indian Ocean subtropical reef site. Our reconstruction from 1970 to 2013 using the Sr/Ca SST proxy reveals a warming trend of 0.58 +/- 0.1 degrees C in close agreement with instrumental data (0.47 +/- 0.07 degrees C) over the last 42 years (1970-2013). In contrast, the Li/Mg showed unrealistically large warming trends, most probably caused by uncertainties around different uptake mechanisms of the trace elements Li and Mg and uncertainties in their temperature calibration. In our study, Sr/Ca is superior to Li/Mg to quantify absolute SST and relative changes in SST. However, spatial correlations between the combined detrended Sr/Ca and Li/Mg proxies compared to instrumental SST at Europa revealed robust cor-relations with local climate variability in the Mozambique Channel and teleconnections to regions in the Indian Ocean and southeastern Pacific where surface wind variability appeared to dominate the underlying pattern of SST variability. The strongest correlation was found between our Europa SST reconstruction and instrumental SST records from the northern tropical Atlantic. Only a weak correlation was found with ENSO, with recent warm anomalies in the geochemical proxies coinciding with strong El Nino or La Nina. We identified the Pacific-North American (PNA) atmospheric pattern, which develops in the Pacific in response to ENSO, and the tropical North Atlantic SST as the most likely causes of the observed

Tropical reef systems are transitioning to a new era in which the interval between recurrent bouts of coral bleaching is too short for a full recovery of mature assemblages. We analyzed bleaching records at 100 globally distributed reef locations from 1980 to 2016. The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years. As global warming has progressed, tropical sea surface temperatures are warmer now during current La Niña conditions than they were during El Niño events three decades ago. Consequently, as we transition to the Anthropocene, coral bleaching is occurring more frequently in all El Niño–Southern Oscillation phases, increasing the likelihood of annual bleaching in the coming decades.

Tropical reef systems are transitioning to a new era in which the interval between recurrent bouts of coral bleaching is too short for a full recovery of mature assemblages. We analyzed bleaching records at 100 globally distributed reef locations from 1980 to 2016. The median return time between pairs of severe bleaching events has diminished steadily since 1980 and is now only 6 years. As global warming has progressed, tropical sea surface temperatures are warmer now during current La Niña conditions than they were during El Niño events three decades ago. Consequently, as we transition to the Anthropocene, coral bleaching is occurring more frequently in all El Niño–Southern Oscillation phases, increasing the likelihood of annual bleaching in the coming decades.

A concerted effort has begun to gather and preserve archives of marine samples and descriptive data, giving scientists ready access to insights on ancient environments.

A concerted effort has begun to gather and preserve archives of marine samples and descriptive data, giving scientists ready access to insights on ancient environments.

Experiments have shown that ocean acidification due to rising atmospheric carbon dioxide concentrations has deleterious effects on the performance of many marine organisms(1-4). However, few empirical or modelling studies have addressed the long-term consequences of ocean acidification for marine ecosystems(5-7). Here we show that as pH declines from 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750 ppm, consistent with some scenarios for the end of this century) some organisms benefit, but many more lose out. We investigated coral reefs, seagrasses and sediments that are acclimatized to low pH at three cool and shallow volcanic carbon dioxide seeps in Papua New Guinea. At reduced pH, we observed reductions in coral diversity, recruitment and abundances of structurally complex framework builders, and shifts in competitive interactions between taxa. However, coral cover remained constant between pH 8.1 and similar to 7.8, because massive Porites corals established dominance over structural corals, despite low rates of calcification. Reef development ceased below pH 7.7. Our empirical data from this unique field setting confirm model predictions that ocean acidification, together with temperature stress, will probably lead to severely reduced diversity, structural complexity and resilience Of Indo-Pacific coral reefs within this century

Experiments have shown that ocean acidification due to rising atmospheric carbon dioxide concentrations has deleterious effects on the performance of many marine organisms(1-4). However, few empirical or modelling studies have addressed the long-term consequences of ocean acidification for marine ecosystems(5-7). Here we show that as pH declines from 8.1 to 7.8 (the change expected if atmospheric carbon dioxide concentrations increase from 390 to 750 ppm, consistent with some scenarios for the end of this century) some organisms benefit, but many more lose out. We investigated coral reefs, seagrasses and sediments that are acclimatized to low pH at three cool and shallow volcanic carbon dioxide seeps in Papua New Guinea. At reduced pH, we observed reductions in coral diversity, recruitment and abundances of structurally complex framework builders, and shifts in competitive interactions between taxa. However, coral cover remained constant between pH 8.1 and similar to 7.8, because massive Porites corals established dominance over structural corals, despite low rates of calcification. Reef development ceased below pH 7.7. Our empirical data from this unique field setting confirm model predictions that ocean acidification, together with temperature stress, will probably lead to severely reduced diversity, structural complexity and resilience Of Indo-Pacific coral reefs within this century

Coral reefs are exceptional environments where changes in calcification, photosynthesis, and respiration induce large temporal variations of pH. We argue that boron isotopic variations in corals provide a robust proxy for paleo-pH which, together with the likely concomitant changes in the reconstructed partial pressure of CO2 (PCO2) calculated by Matear and McNeil, fall within ranges that are typical of modern coral reef ecosystems