Category Archives: Oceans

Increase in atmospheric CO2 attributed to deep Pacific Ocean

Jianghui Du, Brian A. Haley, Alan C. Mix, Maureen H. Walczak & Summer K. Praetorius. Flushing of the deep Pacific Ocean and the deglacial rise of atmospheric CO2 concentrations Nature Geoscience (2018)

During the last deglaciation (19,000–9,000 years ago), atmospheric CO2 increased by about 80 ppm. Understanding the mechanisms responsible for this change is a central theme of palaeoclimatology, relevant for predicting future CO2 transfers in a warming world. Deglacial CO2 rise hypothetically tapped an accumulated deep Pacific carbon reservoir, but the processes remain elusive as they are underconstrained by existing tracers. Here we report high-resolution authigenic neodymium isotope data in North Pacific sediment cores and infer abyssal Pacific overturning weaker than today during the Last Glacial Maximum but intermittently stronger during steps of deglacial CO2 rise. Radiocarbon evidence suggestive of relatively ‘old’ deglacial deep Pacific water is reinterpreted here as an increase in preformed 14C age of subsurface waters sourced near Antarctica, consistent with movement of aged carbon out of the deep ocean and release of CO2 to the atmosphere during the abyssal flushing events. The timing of neodymium isotope changes suggests that deglacial acceleration of Pacific abyssal circulation tracked Southern Hemisphere warming, sea-ice retreat and increase of mean ocean temperature. The inferred magnitude of circulation changes is consistent with deep Pacific flushing as a significant, and perhaps dominant, control of the deglacial rise of atmospheric CO2.

Tuvalu is growing, not sinking

“The Pacific nation of Tuvalu—long seen as a prime candidate to disappear as climate change forces up sea levels—is actually growing in size, new research shows.” click here

Record warm waters off California coast

“California has seen a range of natural extremes this summer, from heat waves to wildfires. The state can now add to the list record-warm ocean temperatures. On August 1, 2018, researchers from the Scripps Institution of Oceanography observed water temperatures of 25.9 degrees Celsius (78.6 degrees Fahrenheit) along the coast at La Jolla, exceeding the previous record of 25.8°C (78.4°F) set in 1931.” click here

Ocean cycles synchronous with global temperature fluctuations

“Now isn’t it a bit odd that the authors made absolutely no mention of the ocean cycles in the abstract? As our regular readers know, the ocean cycles run surprisingly synchronous with the fluctuations in global temperatures, i.e. the key factors here are the AMO and PDO.” click here

Ocean warming only 0.02C since mid-1990s

Carl Wunsch. Towards determining uncertainties in global oceanic mean values of heat, salt, and surface elevation. Journal Tellus A:Dynamic Meteorology and Oceanography Volume 70, 2018 Issue 1, Pages 1-14. https://doi.org/10.1080/16000870.2018.1471911

Lower-bounds on uncertainties in oceanic data and a model are calculated for the 20-year time means and their temporal evolution for oceanic temperature, salinity, and sea surface height, during the data-dense interval 1994–2013. The essential step of separating stochastic from systematic or deterministic elements of the fields is explored by suppressing the globally correlated components of the fields. Justification lies in the physics and the brevity of a 20-year estimate relative to the full oceanic adjustment time, and the inferred near-linearity of response on short time intervals. Lower-bound uncertainties reflecting the only stochastic elements of the state estimate are then calculated from bootstrap estimates. Trends are estimated as  in elevation, 0.0011 ±  0.0001 °C/y, and (−2.825 ± 0.17) × 10−5 for surface elevation, temperature and salt, with formal 2-standard deviation uncertainties. The temperature change corresponds to a 20-year average ocean heating rate of  W/m2 of which 0.1 W/m2 arises from the geothermal forcing. Systematic errors must be determined separately.

 

Poor waste collection primarily responsible for marine pollution

“Executive summary

A marine plastic litter crisis has been declared and the mass media around the world has given their front pages over to the story for a while now. The European Union – among other actors – has declared a war against marine litter. Annually over 10 million metric tons (Mt) of plastic litter end up in oceans, harming wildlife. The International Solid Waste Association (ISWA) – the most competent specialist organization in the field – has summarized the origins of the marine litter crisis: 75% of land based marine litter in low to upper-middle income economies comes from litter and uncollected waste, while the remaining 25% of the land-based sources is plastic which leaks from within the waste management system. In other words, the ISWA report shows that 25% of the leakage is attributable to the waste management option preferred by green ideologues; meanwhile, waste incineration can prevent any leakage of plastic if municipal solid waste (MSW) is incinerated along with sewage sludge. Despite this, incineration is vehemently opposed by green ideologues and also by the EU, which chooses to believe in the mirage of a circular economy. The vast majority of the marine litter problem is attributable to poor waste collection and other sanitary practices in Asian, and to a lesser extent African, towns and cities in coastal areas and along rivers. The problem is particularly acute in China. The neglect of urban sanitary policy – the backbone of development agendas until that time – started when the ‘mother of sustainability’, Norway’s Prime Minister Gro Harlem Brundtland, personally refused to have it be part of her World Commission’s work program and ultimately its 1987 report, which famously led to the adoption of ‘sustainable development’ goals by the UN General Assembly. This report describes the absurdities, inefficiencies, double or even triple waste management structures and horrible consequences of the EU’s erratic green waste policy (such as the terrible waste catastrophe in Naples in 2008), its fact-free claim that its waste policy helps to implement the Paris climate agreement, and its dumping of 3 Mt of plastic in China each year, with horrific consequences for the marine environment and health. The EU has now started to sideline – in the name of circular economy – the highly successful waste incineration policy implemented in seven EU member states – Austria, Belgium, Denmark, Finland, Germany, the Netherlands and Sweden – which all have major waste incineration capacity and now landfill less than 3% of their MSW.” click here

Great Barrier Reef corals can withstand pH variations

McCulloch M.T. et al. (2018) Boron Isotopic Systematics in Scleractinian Corals and the Role of pH Up-regulation. In: Marschall H., Foster G. (eds) Boron Isotopes. Advances in Isotope Geochemistry. Springer, Cham  https://doi.org/10.1007/978-3-319-64666-4_6

The boron isotopic composition (δ11B) of scleractinian corals has been used to track changes in seawater pH and more recently as a probe into the processes controlling bio-calcification. For corals that precipitate aragonite skeletons, up-regulation of pH appears to be a general characteristic, typically being ~0.3 to ~0.6 pH units higher than ambient seawater. The relationship between the pH of the corals calcifying-fluid (pHcf) and seawater pHT (total scale) is shown to be dependent on both physiological as well environmental factors. In laboratory experiments conducted on symbiont-bearing (zooxanthellate) corals under conditions of constant temperature and seawater pH, changes in the δ11B derived calcifying fluid pHcf is typically 1/3 to 1/2 of that of ambient seawater. Similar linear relationships are found for cold water corals that live in relatively stable, cold, deep-water environments but at significantly elevated levels of pHcf(~0.5–1 pH units above seawater), a likely response to the lower pH of their deep-sea environments. In contrast, zooxanthellae-bearing corals living in shallow-water reef environments that experience significant natural variations in temperature, light, nutrients and seawater pH, show different types of responses. For example, over seasonal time-scales Poritescorals from the Great Barrier Reef (GBR) have a large range in pHcf of ~8.3 to ~8.5, significantly greater (~×2 to ~×3) than that of reef-water (pHT ~8.01 to ~8.08), and an order of magnitude greater than that expected from ‘static’ laboratory experiments. Strong physiological controls, but of a different character, are found in corals grown in a Free Ocean Carbon Enrichment Experiment (FOCE) conducted in situ within the Heron Island lagoon (GBR). These corals exhibit near constant pHcf values regardless of external changes in temperature and seawater pH. This pattern of strong physiologically controlled ‘pHhomeostasis’, with elevated but constant pHcf has been found despite large natural seasonal variations in the pH (±0.15 pH units) of the lagoon waters, as well as the even larger super-imposed decreases in seawater pH (~0.25 pH units) designed to simulate year 2100 conditions. In natural reef environments we thus find that the processes influencing the up-regulation of pHcf in symbiont-bearing corals are subject to strong physiological controls, behaviour that is not well simulated in the current generation of aquaria-based experiments with fixed seawater pH and temperature. Conversely, cold-water corals that lack symbionts and inhabit the relatively stable deep-sea environments hold the best prospects for providing reliable reconstructions of seawater pH. Clearly, further studies utilising the δ11B-pHcfproxy combined with other DIC/carbonate-ion proxies (e.g. B/Ca), but conducted under realistic ‘natural’ conditions, are required to elucidate the processes controlling coral bio-calcification and to better understand the vulnerability of scleractinian corals to anthropogenic driven warming and ocean acidification.