Archive for January, 2013



Effects of ocean warming and acidification on embryos and non-calcifying larvae of the invasive sea star Patiriella regularis

Little is known about the effects of potential synergies between concurrent ocean warming and acidification on marine benthos. We investigated the effects of warming and acidification on development to the non-calcifying larval stage in the sea star Patiriella regularis, in embryos reared from fertilization in present and future (2100+) conditions. Fertilization using gametes from multiple parents, to represent populations of spawners, was resilient to both stressors, as were cleavage stage embryos. Warming increased developmental rate across all pH levels. For blastulae, there was a complex interaction between stressors, with +4°C/pH 7.6 lethal to many embryos. A 4°C warming increased mortality by the gastrulation stage by 13 to 25% across all pH levels. In conjunction with warming, pH 7.6 increased mortality by 25 to 27% across all temperatures. For embryos that reached the 3 d bipinnaria stage, warming reduced the percentage of normal larvae and larval size, with no effect of acidification. These results highlight the importance of considering both warming and acidification, and effects on early embryos, in assessing life history responses to ocean change. Bipinnaria reared to Day 28 to determine the effects of acidification on non-calcifying feeding larvae provided a comparison with results for calcifying echinoplutei. pH 7.6 resulted in smaller larvae and increased mortality by 30%. After 24 d, near-future ocean acidification levels (pH 7.8) also resulted in smaller larvae. The effects of acidification in reducing growth in larvae that do not calcify indicates that the stunting response of echinoderm feeding larvae to pH/pCO2 is strongly influenced by hypercapnic changes in metabolism and teratogenic effects. The results have implications for P. regularis in its invasive range in Australia, where this species is likely to be deleteriously affected by ocean warming.

Continue reading ‘Effects of ocean warming and acidification on embryos and non-calcifying larvae of the invasive sea star Patiriella regularis’

Geoengineering impact of open ocean dissolution of olivine on atmospheric CO2, surface ocean pH and marine biology

Ongoing global warming induced by anthropogenic emissions has opened the debate as to whether geoengineering is a ‘quick fix’ option. Here we analyse the intended and unintended effects of one specific geoengineering approach, which is enhanced weathering via the open ocean dissolution of the silicate-containing mineral olivine. This approach would not only reduce atmospheric CO2 and oppose surface ocean acidification, but would also impact on marine biology. If dissolved in the surface ocean, olivine sequesters 0.28 g carbon per g of olivine dissolved, similar to land-based enhanced weathering. Silicic acid input, a byproduct of the olivine dissolution, alters marine biology because silicate is in certain areas the limiting nutrient for diatoms. As a consequence, our model predicts a shift in phytoplankton species composition towards diatoms, altering the biological carbon pumps. Enhanced olivine dissolution, both on land and in the ocean, therefore needs to be considered as ocean fertilization. From dissolution kinetics we calculate that only olivine particles with a grain size of the order of 1 μm sink slowly enough to enable a nearly complete dissolution. The energy consumption for grinding to this small size might reduce the carbon sequestration efficiency by ~30%.

Continue reading ‘Geoengineering impact of open ocean dissolution of olivine on atmospheric CO2, surface ocean pH and marine biology’

Insignificant buffering capacity of Antarctic shelf carbonates

We combined data sets of measured sedimentary CaCO3 and satellite-derived pelagic primary production to parameterize the relation between CaCO3 content on the Antarctic shelves and primary production in the overlying water column. CaCO3 content predicted in this way was in good agreement with the measured data. The parameterization was then used to chart CaCO3 content on the Antarctic shelves all around the Antarctic, using the satellite-derived primary production. The total inventory of CaCO3 in the bioturbated layer of Antarctic shelf sediments was estimated to be 0.5 Pg C. This quantity is comparable to the total CO2 uptake by the Southern Ocean in only one to a few years (dependent on the uptake estimate and area considered), indicating that the dissolution of these carbonates will neither delay ocean acidification in this area nor augment the Southern Ocean CO2 uptake capacity.

Key Points

  • Sedimentary CaCO3 can be predicted from Primary Production in the water column
  • The inventory of CaCO3 in surface sediments on Antarctic shelves is 0.5 Pg C
  • Dissolution of CaCO3 cannot buffer pH or CO2 in the Southern Ocean

Continue reading ‘Insignificant buffering capacity of Antarctic shelf carbonates’

The impact of ocean acidification, increased seawater temperature and a bacterial challenge on the immune response and physiology of the blue mussel, Mytilus edulis

Anthropogenic activities are fundamentally altering the chemistry of the world’s oceans. Many of these modifications could have a significant impact on the health of marine organisms. Yet, despite being proposed as one of the most significant threats that marine ecosystems face, to date very little is known about the impact of anthropogenic climate change, and ocean acidification in particular, on host defence. The aims of this thesis are to investigate the impact of environmental stressors on the invertebrate immune response, providing empirical data on how anthropogenically induced stressors will impact the invertebrate immune system and how this will impact organism condition and subsequent physiological trade-offs. Exposure to reduced seawater pH and increased temperature significantly reduced the immune response in the blue mussel, Mytilus edulis. This reduction in immune response could indicate stress-induced immune dysfunction. However, the immune system protects an organism from infectious disease, ensuring survival, and should therefore be evaluated functionally rather than immunologically. By subsequently exposing mussels to a bacterial challenge this study demonstrated that an earlier study which measured a reduction in host defence represented a trade-off of immune system maintenance costs, with mussels maintaining a capacity to up-regulate immune defence when required. However, whilst this immune plasticity ensures mussels are able to survive a pathogen exposure, such a strategy appears to be physiologically costly. This cost is seen as a reduction in reproductive investment, an altered energy metabolism and an altered fatty acid composition in organisms exposed to low pH. Therefore the overarching picture that emerges is, without measuring physiological processes functionally, and in neglecting any physiological trade-offs, it is possible that many studies may misinterpret the complex physiological responses of marine organisms to ocean acidification.

Continue reading ‘The impact of ocean acidification, increased seawater temperature and a bacterial challenge on the immune response and physiology of the blue mussel, Mytilus edulis’

The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro

The shallow submarine eruption which took place in October 10th 2011, 1.8 km south of the island of El Hierro (Canary Islands) allowed the study of the abrupt changes in the physical-chemical properties of seawater caused by volcanic discharges. In order to monitor the evolution of these changes, seven oceanographic surveys were carried out over six months (November 2011-April 2012) from the beginning of the eruptive stage to the post-eruptive phase. Here, we present dramatic changes in the water column chemistry including large decreases in pH, striking effects on the carbonate system, decreases in the oxygen concentrations and enrichment of Fe(II) and nutrients. Our findings highlight that the same volcano which was responsible for the creation of a highly corrosive environment, affecting marine biota, has also provided the nutrients required for the rapid recuperation of the marine ecosystem.

Continue reading ‘The natural ocean acidification and fertilization event caused by the submarine eruption of El Hierro’

Quantitative Proteomics or Biomineralization or Ocean Acidification: Postdoctoral position at HKU

A postdoctoral position is available to study marine invertebrate response to climate change at proteomics or biomineralization or physiology levels.

Continue reading ‘Quantitative Proteomics or Biomineralization or Ocean Acidification: Postdoctoral position at HKU’

Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration

About 30% of the anthropogenically released CO2 is taken up by the oceans, which causes surface ocean pH to decrease and is commonly referred to as Ocean Acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50% of biogenic calcium carbonate in the open oceans. We have compiled the state of the art of OA effects on foraminifera, because the majority of OA research on this group was published within the last 3 yr. Disparate responses of this important group of marine calcifiers to OA were reported, highlighting the importance of a process based understanding of OA effects on foraminifera. The benthic foraminifer Ammonia sp. was cultured using two carbonate chemistry manipulation approaches: While pH and carbonate ions where varied in one, pH was kept constant in the other while carbonate ion concentration varied. This allows the identification of teh parameter of the parameter of the carbonate system causing observed effects. This parameter identification is the first step towards a process based understanding. We argue that [CO32−] is the parameter affecting foraminiferal size normalized weights (SNW) and growth rates and based on the presented data we can confirm the strong potential of foraminiferal SNW as a [CO32−] proxy.

Continue reading ‘Effect of ocean acidification on the benthic foraminifera Ammonia sp. is caused by a decrease in carbonate ion concentration’

Acid oceans – incentivizing solutions today

Rapid acidification of our oceans presents a challenge well suited for utilizing the incentivized competition methodology to crowdsource the genius required to create the solutions sorely needed before it’s too late.

Our beautiful Blue Planet has another problem with acid in its waters. In the 1980s, “acid rain” was contaminating lakes and rivers across the Northeast. Eventually, a joint effort across state lines helped develop new air-quality standards, smokestack scrubbers and other improvements to avert the crisis, returning the region’s water systems to viability.

Scientists have begun sounding the alarm bell that we have a much bigger and more complicated issue developing with water becoming more acidic, this time in our oceans. As reported last Fall in a Los Angeles Times article (“A sea change to ocean chemistry,” Oct. 7, 2012), many of the world’s top ocean scientists gathered in Monterey, CA recently to discuss the growing evidence of ocean acidification. The news is not good.

Continue reading ‘Acid oceans – incentivizing solutions today’

Marine scientist talks of challenges posed by ocean acidification

A scientist with the federal Pacific Marine Environmental Lab says rising ocean acidification is a complex problem posing a threat to Alaska’s coastal waters, but if concerted, well-coordinated steps are taken, Alaska’s fisheries are sustainable.

Jeremy Mathis summed up his message to participants in the Alaska Marine Science Symposium in Anchorage on Jan. 22 like this: “The sky is not falling, but we do know that there is a major catastrophic event coming if changes are not implemented.”

Continue reading ‘Marine scientist talks of challenges posed by ocean acidification’

Scallops, too, are victims of greenhouse gas emissions

We’ve all heard about global warming, and we know the primary cause is our profligate release to the atmosphere of carbon dioxide (CO2) from the burning of fossil fuels. That warming continues to bite us: Last year was the warmest ever across the continental United States since records have been kept, and the fifth warmest in Canada.

But there is a hidden side to ongoing CO2 emissions and it’s now biting us, too. Roughly one-third of the CO2 emitted since the Industrial Revolution has dissolved into the sea and is slowly turning our oceans acidic.

Continue reading ‘Scallops, too, are victims of greenhouse gas emissions’


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