Source: El Periódico - Las políticas climáticas que se centran en la agricultura y los bosques podrían llevar al aumento de los precios de los alimentos, pero reducir la deforestación e incrementar la captura de carbono en la agricultura podría reducir significativamente las emisiones de gases de efecto invernadero, evitando riesgos para la seguridad alimentaria, según un nuevo estudio publicado en 'Environmental Research Letters'.

ABSTRACT

Iron is a vital mineral for almost all living organisms and has a pivotal role in central metabolism. Despite its great abundance on earth, the accessibility for microorganisms is often limited, because poorly soluble ferric iron (Fe³⁺) is the predominant oxidation state in an aerobic environment. Hence, the reduction of Fe³⁺ is of essential importance to meet the cellular demand of ferrous iron (Fe²⁺) but might become detrimental as excessive amounts of intracellular Fe²⁺ tend to undergo the cytotoxic Fenton reaction in the presence of hydrogen peroxide. We demonstrate that the complex formation rate of Fe³⁺ and phenolic compounds like protocatechuic acid was increased by 46% in the presence of HCO₃^– and thus accelerated the subsequent redox reaction, yielding reduced Fe²⁺. Consequently, elevated CO₂/HCO₃^– levels increased the intracellular Fe²⁺ availability, which resulted in at least 50% higher biomass-specific fluorescence of a DtxR-based Corynebacterium glutamicum reporter strain, and stimulated growth. Since the increased Fe²⁺ availability was attributed to the interaction of HCO₃^– and chemical iron reduction, the abiotic effect postulated in this study is of general relevance in geochemical and biological environments.

IMPORTANCE In an oxygenic environment, poorly soluble Fe³⁺ must be reduced to meet the cellular Fe²⁺ demand. This study demonstrates that elevated CO₂/HCO₃^– levels accelerate chemical Fe³⁺ reduction through phenolic compounds, thus increasing intracellular Fe²⁺ availability. A number of biological environments are characterized by the presence of phenolic compounds and elevated HCO₃^– levels and include soil habitats and the human body. Fe²⁺ availability is of particular interest in the latter, as it controls the infectiousness of pathogens. Since the effect postulated here is abiotic, it generally affects the Fe²⁺ distribution in nature.

Peter J. Edmunds and Scott C. Burgess

Experiments with coral fragments (i.e. nubbins) have shown that net calcification is depressed by elevated P_CO2. Evaluating the implications of this finding requires scaling of results from nubbins to colonies, yet the experiments to codify this process have not been carried out. Building from our previous research demonstrating that net calcification of Pocillopora verrucosa (2–13 cm diameter) was unaffected by P_CO2 (400 and 1000 µatm) and temperature (26.5 and 29.7°C), we sought generality to this outcome by testing how colony size modulates P_CO2 and temperature sensitivity in a branching acroporid. Together, these taxa represent two of the dominant lineages of branching corals on Indo-Pacific coral reefs. Two trials conducted over 2 years tested the hypothesis that the seasonal range in seawater temperature (26.5 and 29.2°C) and a future P_CO2 (1062 µatm versus an ambient level of 461 µatm) affect net calcification of an ecologically relevant size range (5–20 cm diameter) of colonies of Acropora hyacinthus. As for P. verrucosa, the effects of temperature and P_CO2 on net calcification (mg day^–1) of A. verrucosa were not statistically detectable. These results support the generality of a null outcome on net calcification of exposing intact colonies of branching corals to environmental conditions contrasting seasonal variation in temperature and predicted future variation in P_CO2. While there is a need to expand beyond an experimental culture relying on coral nubbins as tractable replicates, rigorously responding to this need poses substantial ethical and logistical challenges.

Daniel P. Small, Piero Calosi, Samuel P. S. Rastrick, Lucy M. Turner, Stephen Widdicombe, and John I. Spicer

Regulation of extracellular acid–base balance, while maintaining energy metabolism, is recognised as an important aspect when defining an organism's sensitivity to environmental changes. This study investigated the haemolymph buffering capacity and energy metabolism (oxygen consumption, haemolymph [l-lactate] and [protein]) in early benthic juveniles (carapace length <40 mm) of the European lobster, Homarus gammarus, exposed to elevated temperature and P_CO2. At 13°C, H. gammarus juveniles were able to fully compensate for acid–base disturbances caused by the exposure to elevated seawater P_CO2 at levels associated with ocean acidification and carbon dioxide capture and storage (CCS) leakage scenarios, via haemolymph [HCO₃^–] regulation. However, metabolic rate remained constant and food consumption decreased under elevated P_CO2, indicating reduced energy availability. Juveniles at 17°C showed no ability to actively compensate haemolymph pH, resulting in decreased haemolymph pH particularly under CCS conditions. Early benthic juvenile lobsters at 17°C were not able to increase energy intake to offset increased energy demand and therefore appear to be unable to respond to acid–base disturbances due to increased P_CO2 at elevated temperature. Analysis of haemolymph metabolites suggests that, even under control conditions, juveniles were energetically limited. They exhibited high haemolymph [l-lactate], indicating recourse to anaerobic metabolism. Low haemolymph [protein] was linked to minimal non-bicarbonate buffering and reduced oxygen transport capacity. We discuss these results in the context of potential impacts of ongoing ocean change and CCS leakage scenarios on the development of juvenile H. gammarus and future lobster populations and stocks.

The new standards don’t do much to compel the aviation industry to reduce emissions.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

Dec 10, 2019

In this report, the authors conduct a benchmarking analysis for energy and CO2 emissions intensity of the steel industry among the largest steel-producing countries.

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