Tag Archives: oceans

Coral reefs thrive near high CO2 seafloor vents

“Though it’s believed the 130 ppm increase in atmospheric CO2 concentration since 1750 has caused the ocean waters to “acidify”, on a daily basis 50-380°C metallic acid enriched by CO2 concentrations reaching 60,000 to 95,000 ppm pours through seafloor vents. Nearby coral reefs “thrive” in these high-CO2 conditions.” click here

Hydrothermal vents cause ocean warming

“A well-defined ocean warming trend originating off the United States East Coast is likely from super-heated and methane-enriched fluids emitted from numerous seafloor hydrothermal vents/hot springs.” click here

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Source: Climate Dispatch

Pacific and Indian Ocean atoll islands are either stable or increasing in area

Virginie K. E. Duvat. A global assessment of atoll island planform changes over the past decades. WIREs Climate Change, Volume 10, Issue 1, 2018  https://doi.org/10.1002/wcc.557

Over the past decades, atoll islands exhibited no widespread sign of physical destabilization in the face of sea‐level rise. A reanalysis of available data, which cover 30 Pacific and Indian Ocean atolls including 709 islands, reveals that no atoll lost land area and that 88.6% of islands were either stable or increased in area, while only 11.4% contracted. Atoll islands affected by rapid sea‐level rise did not show a distinct behavior compared to islands on other atolls. Island behavior correlated with island size, and no island larger than 10 ha decreased in size. This threshold could be used to define the minimum island size required for human occupancy and to assess atoll countries and territories’ vulnerability to climate change. Beyond emphasizing the major role of climate drivers in causing substantial changes in the configuration of islands, this reanalysis of available data indicates that these drivers explain subregional variations in atoll behavior and within‐atoll variations in island and shoreline (lagoon vs. ocean) behavior, following atoll‐specific patterns. Increasing human disturbances, especially land reclamation and human structure construction, operated on atoll‐to‐shoreline spatial scales, explaining marked within‐atoll variations in island and shoreline behavior. Collectively, these findings highlight the heterogeneity of atoll situations. Further research needs include addressing geographical gaps (Indian Ocean, Caribbean, north‐western Pacific atolls), using standardized protocols to allow comparative analyses of island and shoreline behavior across ocean regions, investigating the role of ecological drivers, and promoting interdisciplinary approaches. Such efforts would assist in anticipating potential future changes in the contributions and interactions of key drivers.

Ocean temperature trends correspond with low climate sensitivity

“My conclusion is that the observed trends in both surface and deep-layer temperature in the global oceans correspond to low climate sensitivity, only about 50% of what IPCC climate models produce. This is the same conclusion as Lewis & Curry made using similar energy budget considerations, but applied to two different averaging periods about 100 years apart rather than (as I have done) in a time-dependent forcing-feedback model.”  click here

Ocean debris originates from ships, not from land

Peter G. Ryan, Ben J. Dilley, Robert A. Ronconi, and Maëlle Connan. Rapid increase in Asian bottles in the South Atlantic Ocean indicates major debris inputs from ships, PNAS, October 15, 2019, 116(42), 20892-20897; https://doi.org/10.1073/pnas.1909816116

Most plastic debris floating at sea is thought to come from land-based sources, but there is little direct evidence to support this assumption. Since 1984, stranded debris has been recorded along the west coast of Inaccessible Island, a remote, uninhabited island in the central South Atlantic Ocean that has a very high macrodebris load (∼5 kg·m−1). Plastic drink bottles show the fastest growth rate, increasing at 15% per year compared with 7% per year for other debris types. In 2018, we examined 2,580 plastic bottles and other containers (one-third of all debris items) that had accumulated on the coast, and a further 174 bottles that washed ashore during regular monitoring over the course of 72 d (equivalent to 800 bottles·km−1·y−1). The oldest container was a high-density polyethylene canister made in 1971, but most were polyethylene terephthalate drink bottles of recent manufacture. Of the bottles that washed up during our survey, 90% were date-stamped within 2 y of stranding. In the 1980s, two-thirds of bottles derived from South America, carried 3,000 km by the west wind drift. By 2009, Asia had surpassed South America as the major source of bottles, and by 2018, Asian bottles comprised 73% of accumulated and 83% of newly arrived bottles, with most made in China. The rapid growth in Asian debris, mainly from China, coupled with the recent manufacture of these items, indicates that ships are responsible for most of the bottles floating in the central South Atlantic Ocean, in contravention of International Convention for the Prevention of Pollution from Ships regulations.

Solar activity, atmospheric-oceanic variability drives temperatures

LIANG JIAO, SHENGJIE WANG, YUAN JIANG, XUERUI LIU. A 333-YEAR RECORD OF THE MEAN MINIMUM TEMPERATURE RECONSTRUCTION IN THE WESTERN TIANSHAN MOUNTAINS, CHINA. GEOCHRONOMETRIA 46 (2019): 37–48 DOI 10.1515/geochr-2015-0104

 

In this paper, a fragile ecological area in the Western Tianshan National Nature Reserve of China was selected as the research region, and Picea schrenkiana, which is sensitive to climate change, was selected as the research object. The mean minimum temperature in the growing season of the previous year (May to September) was the main limiting factor for tree radial growth based on an analysis of the relationship between chronological series and climatic factors during 1959–2012 (r = –0.792, p < 0.05). Moreover, the relationship was stable, which showed that tree rings can be used as alternative materials for climate reconstruction. Therefore, the mean minimum temperature of the previous year in 1680–2012 was reconstructed, and the explained variance of the reconstruction equation was 62.7% (R2adj = 62.0%, F = 85.8). The 31 dramatically altered years were found via char- acteristic year analyses, and extreme changes occurred most often under relatively warm conditions. The mean minimum temperature in the reconstruction shows a clear warming trend by the 11-year moving average of the reconstructive series since the 1950s (the temperature increase: 0.341°C/decade). The driving factors of the mean minimum temperature were influenced mainly by the interaction of solar activity and large-scale atmospheric–oceanic variability, especially the westerly circulations.

The Great Barrier Reef adapts to ecosystem changes

“The Great Barrier Reef spans 2,000 kilometers and five degrees Celsius from 27 to 32°C and we’re still finding reefs we didn’t even know about. The pH swings on a daily basis, and fish do better when it does. One coral has adapted to ocean “acidification” in 6 months. Other fish remarkably adapted from salt to freshwater in just fifty years. As Peter Ridd says: Of all the ecosystems in the world, the reef is one that’s best at adapting to climate change.click here