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Tag Archive: acidification

  1. Coastal water absorbing more carbon dioxide

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    • Findings may help scientists understand how much carbon dioxide can be released while still limiting global warming

    • while the amount of carbon dioxide in the open ocean is increasing at the same rate as in the atmosphere, these same carbon dioxide concentrations are increasing slower in the coastal ocean because the coastal ocean is shallower than the open ocean and can quickly transfer sequestered carbon dioxide to the deep ocean…
    • nutrient pollution entering coastal waters from things like fertilizer on land stimulate the growth of algae within the continental shelves, which subsequently removes more carbon dioxide from the atmosphere
    • the continental shelves are becoming a crucial element in the global carbon cycle and for the climate system; scientists should take into account the contribution of continental shelves to calculate global carbon budgets

    January 31, 2018 University of Delaware read full ScienceDaily article here

    Oceanographers reveal that the water over the continental shelves is shouldering a larger than expected portion of atmospheric carbon dioxide. The findings may have important implications for scientists focused on understanding how much carbon dioxide can be released into the atmosphere while still keeping warming limited.

    As more carbon dioxide enters the atmosphere, the global ocean soaks up much of the excess, storing roughly 30 percent of the carbon dioxide emissions coming from human activities.

    In this sense, the ocean has acted as a buffer to slow down the greenhouse gas accumulation in the atmosphere and, thus, global warming. However, this process also increases the acidity of seawater and can affect the health of marine organisms and the ocean ecosystem.

    New research by University of Delaware oceanographer Wei-Jun Cai and colleagues at Université Libre de Bruxelles, Texas A&M University-Corpus Christi, University of Hawaii at Manoa and ETH Zurich, now reveals that the water over the continental shelves is shouldering a larger portion of the load, taking up more and more of this atmospheric carbon dioxide….

    Goulven G. Laruelle, Wei-Jun Cai, Xinping Hu, Nicolas Gruber, Fred T. Mackenzie, Pierre Regnier. Continental shelves as a variable but increasing global sink for atmospheric carbon dioxide. Nature Communications, 2018; 9 (1) DOI: 10.1038/s41467-017-02738-z

  2. Like Oceans, Freshwater Is Also Acidifying

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    • Rising CO2 in lakes and reservoirs may harm animals that live in those ecosystems

    By Erica Gies on January 11, 2018  read full Scientific American article here

    ….Is [freshwater] also soaking up atmospheric carbon?A new paper published in Current Biology presents some of the first evidence that the answer may be yes, but perhaps not the same way as occurs in the ocean.

    In the new study researchers reported a significant increase of CO2 and a correlating pH decrease of about 0.3 in four reservoirs in Germany over 35 years. They analyzed data collected from 1981 to 2015 by the local Ruhr region agency that monitors drinking water, and were able to document the rising carbon dioxide levels over time by factoring in changes in temperature, water density, pH, ion species distribution and total inorganic content….

    …A crucial reason why the study of freshwater acidification has lagged until now is because determining how atmospheric carbon affects these ecosystems requires complex modeling…

    …The primary way freshwater ecosystems absorb CO2 created by humans burning fossil fuels is likely different than what happens in oceans. In lakes and reservoirs the extra atmospheric CO2 feeds the surrounding vegetation and the rising global temperature lengthens the growing season. As plants in and around the lake grow larger and/or proliferate, the amount of organic carbon available when they die and the rate at which they break down in soil increases. Precipitation then washes it into lakes and other freshwater systems….

    Linda C. Weiss, Leonie Pötter, Annika Steiger, Sebastian Kruppert, Uwe Frost, Ralph Tollrian. Rising pCO 2 in Freshwater Ecosystems Has the Potential to Negatively Affect Predator-Induced Defenses in Daphnia. Current Biology, 2018; DOI: 10.1016/j.cub.2017.12.022

  3. Underground magma triggered Earth’s worst mass extinction with greenhouse gases; similar to today’s symptoms

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    • it was principally greenhouse gas emissions triggered by magma intrusions that caused the extinction through abrupt global warming and ocean acidification
    • The more science learns of these past greenhouse gas-driven events, the more uncomfortable the parallels to today become.
    • Geologically fast build-up of greenhouse gas linked to warming, rising sea-levels, widespread oxygen-starved ocean dead zones and ocean acidification are fairly consistent across the mass extinction events, and those same symptoms are happening today as a result of human-driven climate change.

    1 August 2017 by Howard Lee Read full GuardianUK article here

    ….Of some 18 major and minor mass extinctions since the dawn of complex life, most happened at the same time as a rare, epic volcanic phenomenon called a Large Igneous Province (LIP)Many of those extinctions were also accompanied by abrupt climate warming, expansion of ocean dead zones and acidification, like today.

    Earth’s most severe mass extinction, the “Great Dying,” began 251.94 million years ago at the end of the Permian period, with the loss of more than 90% of marine species…. why was the mass extinction event much shorter than the eruptions? And why did the extinction happen some 300,000 years after the lava began to flow?

    In a new study published in Nature Communications, Seth Burgess of the US Geological Survey, along with James Muirhead of Syracuse University and Samuel Bowring of MIT, think they have the answer.

    ….In other words, it wasn’t the lava, it was the underground magma that started the killing, by releasing greenhouse gases.

    Norwegian scientist Henrik Svensen had earlier identified hundreds of unusual volcanic vents called “diatreme pipes” all over Siberia that connected underground intrusions of magma (“sills”) to the atmosphere, showing signs of violent gas explosions. This new work emphasizes the importance of Svensen’s 2009 conclusions:

    The diatremes that have been mapped are the geologic representation of that gas escape on a catastrophic level. Our hypothesis is that the first sills to be intruded are the ones that really do the killing [by] large scale gas escape likely via these diatremes.

    Svensen, who was not involved in Burgess’ study, commented:

    The Burgess et al paper is a crucial step towards a new understanding of the role of volcanism in driving extinctions. It’s not the spectacular volcanic eruptions that we should pay attention too – it’s their quiet relative, the sub-volcanic network of intrusions, that did the job. The new study shows convincingly that we are on the right track.

    Greenhouse gas as a killer

    While other scientists have proposed that an array of killers may have been involved in the end-Permian mass extinction, from mercury poisoning to ultraviolet rays and ozone collapse to acid rain, Burgess argues that it was principally greenhouse gas emissions triggered by magma intrusions that caused the extinction through abrupt global warming and ocean acidification.

    Geologically fast build-up of greenhouse gas linked to warming, rising sea-levels, widespread oxygen-starved ocean dead zones and ocean acidification are fairly consistent across the mass extinction events, and those same symptoms are happening today as a result of human-driven climate change. Even though the duration of those past events was longer, and the volume of emissions was larger than we will produce, we are emitting greenhouse gases around 10 times faster than the most recent, mildest example – the PETM. The rapidity of today’s emissions prompted scientists Richard Zeebe and James Zachos to observe in a 2013 paper:

    The Anthropocene will more likely resemble the end-Permian and end-Cretaceous disasters, rather than the PETM.

    When the promises made for the 2016 Paris Agreement on climate change are added up, they aim to limit peak warming this century to about 3.3ºC compared to about 4.2ºC for the business-as-usual scenario, and the 2ºC limit the world is aiming to stay under. It’s sobering to compare those numbers to the majority of mass extinctions in the geological record which were characterized by abrupt warmings typically around 6-7ºC.

    S. D. Burgess, J. D. Muirhead & S. A. Bowring. Initial pulse of Siberian Traps sills as the trigger of the end-Permian mass extinction. Nature Communications 8, Article number: 164 (2017) doi:10.1038/s41467-017-00083-9

     

     

  4. Small ‘weedy’ fish species to take over future oceans; acidic waters will reduce fish diversity, mid-sized predators associated with kelp

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    July 6, 2017 University of Adelaide  see full ScienceDaily article here

    The ocean acidification expected in the future will reduce fish diversity significantly, with small ‘weedy’ species dominating marine environments, researchers have demonstrated for the first time…..researchers studied species interactions in natural marine environments at underwater volcanic vents, where concentrations of CO2 match those predicted for oceans at the end of the century. They were compared with adjacent marine environments with current CO2 levels….
    ….”Small weedy species would normally be kept under control by their predators — and by predators we mean the medium-sized predators that are associated with kelp. But ocean acidification is also transforming ecosystems from kelp to low grassy turf, so we are losing the habitat that protects these intermediate predators, and therefore losing these species
    One way this biodiversity loss could be delayed is by reducing overfishing of intermediate predators.We showed how diminishing predator numbers has a cascading effect on local species diversity,” Professor Nagelkerken says. “Strong controls on overfishing could be a key action to stall diversity loss and ecosystem change in a high CO2 world.”A video about the research can be seen at https://youtu.be/oJE595-ALYoIvan Nagelkerken, Silvan U. Goldenberg, Camilo M. Ferreira, Bayden D. Russell, Sean D. Connell. Species Interactions Drive Fish Biodiversity Loss in a High-CO 2 World. Current Biology, 2017; DOI: 10.1016/j.cub.2017.06.023
  5. Marine reserves help mitigate against climate change, say scientists

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    June 5, 2017 University of York  full ScienceDaily article here

    Highly protected marine reserves can help mitigate against the impacts of climate change, a study by a team of international scientists has concluded….The study….evaluated existing peer reviewed studies on the impact of marine reserves around the world.Currently, only 3.5 per cent of the ocean has been set aside for protection with just 1.6 per cent fully protected from exploitation. International groups are working to raise the total to 10 per cent by 2020, while delegates to the International Union for the Conservation of Nature’s 2016 World Conservation Congress agreed that at least 30 per cent should be protected by 2030.

    Scientists say Marine Reserves and Marine Protected Areas (MPAs):

    • Protect coasts from sea-level rise, storms and other extreme weather events
    • Help offset climate-change induced declines in ocean and fisheries productivity
    • Provide refuges for species as they adjust their ranges to changing conditions
    • Can help combat acidification

    Callum M. Roberts, Bethan C. O’Leary, Douglas J. McCauley, Philippe Maurice Cury, Carlos M. Duarte, Jane Lubchenco, Daniel Pauly, Andrea Sáenz-Arroyo, Ussif Rashid Sumaila, Rod W. Wilson, Boris Worm, and Juan Carlos Castilla. Marine reserves can mitigate and promote adaptation to climate change. PNAS, June 2017 DOI: 10.1073/pnas.1701262114

  6. Ocean acidification reduces shell formation in tiny foraminifera indicating big changes to global carbon cycle

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    May 25, 2017 University of California – Davis Bodega Marine Lab    ScienceDaily
    … For the study, published in the journal Scientific Reports, scientists raised foraminifera — single-celled organisms about the size of a grain of sand — at the UC Davis Bodega Marine Laboratory under future, high CO2 conditions. These tiny organisms, commonly called “forams,” are ubiquitous in marine environments and play a key role in food webs and the ocean carbon cycle….UC Davis scientists found that under high CO2, or more acidic, conditions, the foraminifera had trouble building their shells and making spines, an important feature of their shells….[and] showed signs of physiological stress, reducing their metabolism and slowing their respiration to undetectable levels.

    This is the first study of its kind to show the combined impact of shell building, spine repair, and physiological stress in foraminifera under high CO2 conditions. The study suggests that stressed and impaired foraminifera could indicate a larger scale disruption of carbon cycling in the ocean….

    …As a marine calcifier, foraminifera use calcium carbonate to build their shells, a process that plays an integral part in balancing the carbon cycle. Normally, healthy foraminifera calcify their shells and sink to the ocean floor after they die, taking the calcite with them. This moves alkalinity, which helps neutralize acidity, to the seafloor. When foraminifera calcify less, their ability to neutralize acidity also lessens, making the deep ocean more acidic. …”That acidified water from the deep will rise again. If we do something that acidifies the deep ocean, that affects atmospheric and ocean carbon dioxide concentrations on time scales of thousands of years.” [Catherine] Davis said the geologic record shows that such imbalances have occurred in the world’s oceans before, but only during times of major change. “This points to one of the longer time-scale effects of anthropogenic climate change that we don’t understand yet,” Davis said.

    …strong winds periodically push nutrient-rich water from the deep ocean up to the surface– Upwelling supports some of the planet’s most productive fisheries and ecosystems. But additional anthropogenic, or human-caused, CO2 in the system is expected to impact fisheries and coastal ecosystems…. UC Davis’ Bodega Marine Laboratory in Northern California is near one of the world’s most intense coastal upwelling areas. At times, it experiences conditions most of the ocean isn’t expected to experience for decades or hundreds of years.

    Seasonal upwelling means that we have an opportunity to study organisms in high CO2, acidic waters today — a window into how the ocean may look more often in the future,” said co-author Tessa Hill, an associate professor in earth and planetary sciences at UC Davis. “We might have expected that a species of foraminifera well-adapted to Northern California wouldn’t respond negatively to high CO2 conditions, but that expectation was wrong. This study provides insight into how an important marine calcifier may respond to future conditions, and send ripple effects through food webs and carbon cycling.”

    Catherine V. Davis, Emily B. Rivest, Tessa M. Hill, Brian Gaylord, Ann D. Russell, Eric Sanford. Ocean acidification compromises a planktic calcifier with implications for global carbon cycling. Scientific Reports, 2017; 7 (1) DOI: 10.1038/s41598-017-01530-9

    Abstract: ….We cultured a globally important calcifying marine plankter (the foraminifer, Globigerina bulloides) under an ecologically relevant range of seawater pH (7.5 to 8.3 total scale). Multiple metrics of calcification and physiological performance varied with pH. At pH > 8.0, increased calcification occurred without a concomitant rise in respiration rates. However, as pH declined from 8.0 to 7.5, calcification and oxygen consumption both decreased, suggesting a reduced ability to precipitate shell material accompanied by metabolic depression. Repair of spines, important for both buoyancy and feeding, was also reduced at pH < 7.7. The dependence of calcification, respiration, and spine repair on seawater pH suggests that foraminifera will likely be challenged by future ocean conditions. Furthermore, the nature of these effects has the potential to actuate changes in vertical transport of organic and inorganic carbon, perturbing feedbacks to regional and global marine carbon cycling. The biological impacts of seawater pH have additional, important implications for the use of foraminifera as paleoceanographic indicators.

  7. Some marine creatures may be more resilient to harsher ocean conditions than expected

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    Posted: 15 Feb 2017 05:41 AM PST full article here

    As the world continually emits carbon dioxide into the atmosphere, the oceans are taking a hit, absorbing some of it and growing more acidic. Among other effects, scientists have found that coral reefs and oyster hatcheries are deteriorating as a result. However, scientists studying a type of sea snail report a bit of bright news: The animal can adapt by rejiggering its shell-making process and other functions

    …While ocean acidification appears to cause damage to many calcifying organisms, recent studies have suggested that some of those organisms may be more resistant to acidification than previously thought. Sean D. Connell and colleagues wanted to find out how this might be possible.

    The researchers exposed sea snails called periwinkles to the ocean conditions predicted for 2100, when some waters at a pH of 8.10 today are expected to reach a pH of 7.85. Although the animals’ metabolism declined, they were able to speed up their shell-making by producing less-dense inner shells. In addition, they developed less-soluble shells, which are more resistant to future, harsher ocean conditions. The researchers say these changes suggest that the periwinkle, and potentially other calcifying organisms, could have the ability to adapt to the acidifying oceans….

    Jonathan Y. S. Leung, Bayden D. Russell, Sean D. Connell. Mineralogical Plasticity Acts as a Compensatory Mechanism to the Impacts of Ocean Acidification. Environmental Science & Technology, 2017; DOI: 10.1021/acs.est.6b04709

  8. Why the ocean has absorbed more carbon over the past decade

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    Posted: 08 Feb 2017 01:46 PM PST  full article here

    With the ocean absorbing more carbon dioxide over the past decade, less of the greenhouse gas is reaching the Earth’s atmosphere. That’s decidedly good news, but it comes with a catch: Rising levels of carbon dioxide in the ocean promote acidification, which breaks down the calcium carbonate shells of some marine organisms….

    new research….demonstrates that a slowdown of the ocean’s overturning circulation is the likely catalyst. Their findings appear in the journal Nature. “Such a slowdown is consistent with the projected effects of anthropogenic climate change, where warming and freshening of the surface ocean from melting ice caps leads to weaker overturning circulation,” DeVries explained….

    ….According to DeVries, this finding may seem counterintuitive. Prevailing scientific wisdom asserts that the deceleration of circulation diminishes the ocean’s ability to absorb anthropogenic CO2 from the atmosphere as surface waters warm and become saturated with CO2.  “While that is true, there is another effect that appears to be more important in the short term,” DeVries said. “The weaker overturning circulation brings less naturally CO2-rich deep waters to the surface, which limits how much of that gas in the deep ocean escapes to the atmosphere. That causes the ocean to absorb more CO2 from the atmosphere.

    Tim DeVries, Mark Holzer, Francois Primeau. Recent increase in oceanic carbon uptake driven by weaker upper-ocean overturning. Nature, 2017; 542 (7640): 215 DOI: 10.1038/nature21068

  9. Maine’s coastal waters unhealthy from carbon, acidity. Are seaweed gardens the answer?

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    Bill Trotter, BDN Staff Feb 7 2017  See full article here

    BOOTHBAY, Maine — Seaweed cultivation has been promoted in recent years in Maine as a way to produce local nutritious food and to boost the coastal economy.

    Now, seaweed harvesters say their industry provides yet another benefit: environmental protection, in the form of improving water quality.

    A new study from Bigelow Laboratory for Marine Sciences in Boothbay indicates growing and harvesting seaweed may be an antidote for increasing carbon and acidity levels in the ocean, which is harming a variety of marine life.

    Since January 2016, the lab has been studying the effect of kelp growth on surrounding carbon levels at the Ocean Approved seaweed farm off Great Chebeague Island in Casco Bay…. According to Price, in the six months that scientists measured carbon dioxide levels in and around the 3-acre kelp farm, they found the kelp was absorbing carbon at the same rate carbon levels are expected to increase in the Gulf of Maine over the next 100 years from global use of fossil fuels….

  10. Unexpected result: Ocean acidification can also promote shell formation

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    Posted: 27 Jan 2017 08:29 AM PST  see full article here

    More carbon dioxide in the air also acidifies the oceans. It seemed to be the logical conclusion that shellfish and corals will suffer, because chalk formation becomes more difficult in more acidic seawater. But now a group of scientists discovered to their own surprise that some tiny unicellular shellfish (foraminifera) make better shells in an acidic environment. This is a completely new insight….

    …”If the classic hypothesis holds and more carbon dioxide leads to less lime production, the oceans can continue to take up CO2 from the atmosphere. But what if the majority of the organisms can regulate the chemical form of their inorganic carbon by biochemical processes like our foraminifers did, and continue to form lime structures in a more acidic ocean? Over time, the concentration of dissolved carbon dioxide in the oceans may start to increase. Consequently, the ability of the oceans to take up a large part of the carbon dioxide in the air may start to decrease. This would mean that more carbon dioxide would remain in the air, leading to a more rapid warming of our planet.”

    Takashi Toyofuku, Miki Y. Matsuo, Lennart Jan de Nooijer, Yukiko Nagai, Sachiko Kawada, Kazuhiko Fujita, Gert-Jan Reichart, Hidetaka Nomaki, Masashi Tsuchiya, Hide Sakaguchi, Hiroshi Kitazato. Proton pumping accompanies calcification in foraminifera. Nature Communications, 2017; 8: 14145 DOI: 10.1038/ncomms14145