Archive for the 'Science' Category



Strengthened scientific support for the Endangerment Finding for atmospheric greenhouse gases

We assess scientific evidence that has emerged since the U.S. Environmental Protection Agency’s 2009 Endangerment Finding for six well-mixed greenhouse gases and find that this new evidence lends increased support to the conclusion that these gases pose a danger to public health and welfare. Newly available evidence about a wide range of observed and projected impacts strengthens the association between the risk of some of these impacts and anthropogenic climate change, indicates that some impacts or combinations of impacts have the potential to be more severe than previously understood, and identifies substantial risk of additional impacts through processes and pathways not considered in the Endangerment Finding.

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Diel CO2 cycles and parental effects have similar benefits to growth of a coral reef fish under ocean acidification

Parental effects have been shown to buffer the negative effects of within-generation exposure to ocean acidification (OA) conditions on the offspring of shallow water marine organisms. However, it remains unknown if parental effects will be impacted by the presence of diel CO2 cycles that are prevalent in many shallow water marine habitats. Here, we examined the effects that parental exposure to stable elevated (1000 µatm) and diel-cycling elevated (1000 ± 300 µatm) CO2 had on the survival and growth of juvenile coral reef anemonefish, Amphiprion melanopus. Juvenile survival was unaffected by within-generation exposure to either elevated CO2 treatment but was significantly increased (8%) by parental exposure to diel-cycling elevated CO2. Within-generation exposure to stable elevated CO2 caused a significant reduction in juvenile growth (10.7–18.5%); however, there was no effect of elevated CO2 on growth when diel CO2 cycles were present. Parental exposure to stable elevated CO2 also ameliorated the negative effects of elevated CO2 on juvenile growth, and parental exposure to diel CO2 cycles did not alter the effects of diel CO2 cycles on juveniles. Our results demonstrate that within-generation exposure to diel-cycling elevated CO2 and parental exposure to stable elevated CO2 had similar outcomes on juvenile condition. This study illustrates the importance of considering natural CO2 cycles when predicting the long-term impacts of OA on marine ecosystems.

Continue reading ‘Diel CO2 cycles and parental effects have similar benefits to growth of a coral reef fish under ocean acidification’

Environmental framing on Twitter: impact of Trump’s Paris Agreement withdrawal on climate change and ocean acidification dialogue

The role of social media in communicating emerging environmental issues has received little attention. One such issue is ocean acidification (OA), the process by which carbon dioxide (CO2) acidifies oceans. Although scientists consider OA to be as dangerous as climate change (CC) and both problems are caused by excess CO2 emissions, public awareness of OA is low. We investigated public discussions about CC and OA on Twitter, identifying frames and tweeter characteristics. Tweeting patterns before and after President Trump’s 1 June 2017 announcement of the U.S.’s withdrawal from the international Paris Climate Agreement were compared because of the potential for diverse framing of this globally communicated event. For CC tweets, Political/Ideological Struggle (PIS) and Disaster (DS) frames were prevalent, with PIS frames increasing threefold after Trump’s announcement. DS, Settled Science (SS), and Promotional frames were prevalent among OA tweets, with SS decreasing and PIS increasing after the announcement. Our findings suggest that Trump’s decision sparked discourse on CC and facilitated expressions of politicized opinions on Twitter. We conclude that with a careful understanding of issue familiarity among its publics, social media can be effective for disseminating information and opinion of established and emerging environmental issues, complementing traditional media outlets.

Continue reading ‘Environmental framing on Twitter: impact of Trump’s Paris Agreement withdrawal on climate change and ocean acidification dialogue’

The sea-air CO2 net fluxes in the South Atlantic Ocean and the role played by Agulhas eddies

Highlights

• A mean FCO2 of −3.76 mmol m−2 d−1 was obtained in the FORSA cruise track.
• An Agulhas eddy can uptake up to −3.16 kg CO2 d−1, leading to −2.5 t CO2 lifetime−1.
• The seawater temperature is the main driver of the CO2 variability in the SAO.

Abstract

The South Atlantic Ocean is vitally important to the global overturning circulation, which is influenced by heat, salt and other properties carried by Agulhas eddies. However, this influence is not yet fully understood, mainly in the context of the biogeochemistry changes on the CO2 system. This study uses in situ data obtained during the Following Ocean Rings in the South Atlantic cruise, which occurred between Cape Town, South Africa and Arraial do Cabo, Brazil in July 2015 when six eddies and the surrounding waters were sampled. The seawater and atmospheric CO2 molar fraction, surface temperature and salinity were continuously measured to calculate the oceanic and atmospheric CO2 partial pressures (pCO2sw and pCO2atm, respectively). This study investigated the role played by the Agulhas eddies in the sea-air CO2 net flux (FCO2) and modeled the seawater CO2 as a function of environmental parameters. The mean pCO2sw and pCO2atm for the entire region were 351.5 and 390.6 μatm, respectively. The mean difference (ΔpCO2) was −39.1 μatm. The CO2 uptake was dominated by temperature (r = 0.88) during the period analyzed. The mean FCO2 was −3.76 and −3.62 mmol m−2 d−1 using two different KT-models. We show that an Agulhas eddy can contribute to an ocean uptake of −3.16 kg CO2 d−1, leading to the capture of approximately 2.52 t CO2 lifetime−1. Thus, providing evidence that the Agulhas eddies propagation can likely play a key role on the rapid seawater acidification of the South Atlantic Central Water. A multiple linear regression model was developed that could reliably reconstruct the cruise survey with better results than previously published.

Continue reading ‘The sea-air CO2 net fluxes in the South Atlantic Ocean and the role played by Agulhas eddies’

Regional action plan on ocean acidification for Latin America and the Caribbean

Representatives of 14 countries from Latin America and the Caribbean attended the first regional meeting of the Ocean Acidification international Reference User Group (OAiRUG), hosted by Invemar in Santa Marta, Colombia, held on 19th – 21st March 2018. Funded by the Prince Albert II Foundation as part of a long-term strategy of His Serene Highness, with additional support from the International Atomic Energy Agency, and held in collaboration IUCN and the Latin American Ocean Acidification Network (LAOCA), the purpose of the meeting was to bring together leading international and regional scientists, experts from affected maritime industries, leaders in environmental protection and management, and representatives from civil society to create a step-change in how the region can respond to this modern-day ocean-impact challenge. Attended by over 50 invited delegates, for the first time the OAiRUG proceedings were also streamed live by Invemar to Facebook and the Colombia National Parks channel attracting an online audience of over 8000 people across the three days.

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Environmental and physiochemical controls on coral calcification along a latitudinal temperature gradient in Western Australia

The processes that occur at the micro‐scale site of calcification are fundamental to understanding the response of coral growth in a changing world. However, our mechanistic understanding of chemical processes driving calcification is still evolving. Here, we report the results of a long‐term in situ study of coral calcification rates, photo‐physiology, and calcifying fluid (cf) carbonate chemistry (using boron isotopes, elemental systematics, and Raman spectroscopy) for seven species (four genera) of symbiotic corals growing in their natural environments at tropical, subtropical, and temperate locations in Western Australia (latitudinal range of ~11°). We find that changes in net coral calcification rates are primarily driven by pHcf and carbonate ion concentration []cf in conjunction with temperature and DICcf. Coral pHcf varies with latitudinal and seasonal changes in temperature and works together with the seasonally varying DICcf to optimize []cf at species‐dependent levels. Our results indicate that corals shift their pHcf to adapt and/or acclimatize to their localized thermal regimes. This biological response is likely to have critical implications for predicting the future of coral reefs under CO2‐driven warming and acidification.

Continue reading ‘Environmental and physiochemical controls on coral calcification along a latitudinal temperature gradient in Western Australia’

OA-ICC bibliographic database updated

An updated version of the OA-ICC bibliographic database is available online.

The database currently contains more than 5,400 references and includes citations, abstracts and assigned keywords. Updates are made every month.

The database is available as a group on Mendeley. Subscribe online or, for a better user experience, download the Mendeley Desktop application and sync with the group Ocean Acidification (OA-ICC). Please see the “User instructions” for further details.

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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book