Nanogram-scale boron isotope analysis through micro-distillation and Nu Plasma 3 MC-ICP-MS.

The determination of boron isotopes (δB) represents a powerful tool for a variety of applications such as the reconstruction of past ocean pH and atmospheric pCO from the analysis of marine biogenic carbonates. In recent years, MC-ICP-MS has gained popularity over other techniques thanks to its superior sample throughput and high ionization efficiency. This study evaluates, for the first time, the performance of the Nu Instruments Plasma 3 MC-ICP-MS for measuring δB using different sample introduction systems and detector configurations.

Abiotic plastic leaching contributes to ocean acidification.

Ocean acidification and plastic pollution are considered as potential planetary boundary threats for which crossing certain thresholds could be very harmful for the world's societies and ecosystems well-being. Surface oceans have acidified around 0.1 units since the Industrial Revolution, and the amount of plastic reaching the ocean in 2018 was quantified to 13 million metric tonnes.

Molecular basis of ocean acidification sensitivity and adaptation in .

Predicting the potential for species adaption to climate change is challenged by the need to identify the physiological mechanisms that underpin species vulnerability. Here, we investigated the sensitivity to ocean acidification in marine mussels during early development, and specifically the trochophore stage. Using RNA and DNA sequencing and RNA hybridization, we identified developmental processes associated with abnormal development and rapid adaptation to low pH.

COVID-19 lockdown moderately increased oligotrophy at a marine coastal site.

COVID-19 has led to global population lockdowns that have had indirect effects on terrestrial and marine fauna, yet little is known on their effects on marine planktonic communities. We analysed the effect of the spring 2020 lockdown in a marine coastal area in Blanes Bay, NW Mediterranean. We compared a set of 23 oceanographic, microbial and biogeochemical variables sampled right after the strict lockdown in Spain, with data from the previous 15 years after correcting for long-term trends.

Viral-Mediated Microbe Mortality Modulated by Ocean Acidification and Eutrophication: Consequences for the Carbon Fluxes Through the Microbial Food Web.

Anthropogenic carbon emissions are causing changes in seawater carbonate chemistry including a decline in the pH of the oceans. While its aftermath for calcifying microbes has been widely studied, the effect of ocean acidification (OA) on marine viruses and their microbial hosts is controversial, and even more in combination with another anthropogenic stressor, i.e.

Effects of low pH and feeding on calcification rates of the cold-water coral .

Cold-Water Corals (CWCs), and most marine calcifiers, are especially threatened by ocean acidification (OA) and the decrease in the carbonate saturation state of seawater. The vulnerability of these organisms, however, also involves other global stressors like warming, deoxygenation or changes in sea surface productivity and, hence, food supply via the downward transport of organic matter to the deep ocean. This study examined the response of the CWC to low pH under different feeding regimes through a long-term incubation experiment.

Wind-induced changes in the dynamics of fluorescent organic matter in the coastal NW Mediterranean.

Marine biogeochemistry dynamics in coastal marine areas is strongly influenced by episodic events such as rain, intense winds, river discharges and anthropogenic activities. We evaluated in this study the importance of these forcing events on modulating seasonal changes in the marine biogeochemistry of the northwestern coast of the Mediterranean Sea, based on data gathered from a fixed coastal sampling station in the area. A 4-year (2011-2014) monthly sampling at four depths (0.

Eutrophication and acidification: Do they induce changes in the dissolved organic matter dynamics in the coastal Mediterranean Sea?

Two mesocosms experiments were conducted in winter 2010 and summer 2011 to examine how increased pCO2 and/or nutrient concentrations potentially perturbate dissolved organic matter dynamics in natural microbial assemblages. The fluorescence signals of protein- and humic-like compounds were used as a proxy for labile and non-labile material, respectively, while the evolution of bacterial populations, chlorophyll a (Chl a) and dissolved organic carbon (DOC) concentrations were used as a proxy for biological activity. For both seasons, the presence of elevated pCO2 did not cause any significant change in the DOC dynamics (p-value<0.

Increased reservoir ages and poorly ventilated deep waters inferred in the glacial Eastern Equatorial Pacific.

Consistent evidence for a poorly ventilated deep Pacific Ocean that could have released its radiocarbon-depleted carbon stock to the atmosphere during the last deglaciation has long been sought. Such evidence remains lacking, in part due to a paucity of surface reservoir age reconstructions required for accurate deep-ocean ventilation age estimates. Here we combine new radiocarbon data from the Eastern Equatorial Pacific (EEP) with chronostratigraphic calendar age constraints to estimate shallow sub-surface reservoir age variability, and thus provide estimates of deep-ocean ventilation ages.

Response of rare, common and abundant bacterioplankton to anthropogenic perturbations in a Mediterranean coastal site.

Bacterioplankton communities are made up of a small set of abundant taxa and a large number of low-abundant organisms (i.e. 'rare biosphere').

The geological record of ocean acidification.

Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record contains long-term evidence for a variety of global environmental perturbations, including ocean acidification plus their associated biotic responses. We review events exhibiting evidence for elevated atmospheric CO(2), global warming, and ocean acidification over the past ~300 million years of Earth's history, some with contemporaneous extinction or evolutionary turnover among marine calcifiers.

Eastern equatorial pacific productivity and related-CO2 changes since the last glacial period.

Understanding oceanic processes, both physical and biological, that control atmospheric CO(2) is vital for predicting their influence during the past and into the future. The Eastern Equatorial Pacific (EEP) is thought to have exerted a strong control over glacial/interglacial CO(2) variations through its link to circulation and nutrient-related changes in the Southern Ocean, the primary region of the world oceans where CO(2)-enriched deep water is upwelled to the surface ocean and comes into contact with the atmosphere. Here we present a multiproxy record of surface ocean productivity, dust inputs, and thermocline conditions for the EEP over the last 40,000 y.

Paleo-perspectives on ocean acidification.

The anthropogenic rise in atmospheric CO(2) is driving fundamental and unprecedented changes in the chemistry of the oceans. This has led to changes in the physiology of a wide variety of marine organisms and, consequently, the ecology of the ocean. This review explores recent advances in our understanding of ocean acidification with a particular emphasis on past changes to ocean chemistry and what they can tell us about present and future changes.

Preindustrial to modern interdecadal variability in coral reef pH.

The oceans are becoming more acidic due to absorption of anthropogenic carbon dioxide from the atmosphere. The impact of ocean acidification on marine ecosystems is unclear, but it will likely depend on species adaptability and the rate of change of seawater pH relative to its natural variability. To constrain the natural variability in reef-water pH, we measured boron isotopic compositions in a approximately 300-year-old massive Porites coral from the southwestern Pacific.

Pressurized liquid extraction of selected molecular biomarkers in deep sea sediments used as proxies in paleoceanography.

Pressurized liquid extraction has been performed on a suite of deep-sea sediments to assess its capability as an extraction technique in the analysis of molecular biomarkers used in paleoceanography. Specific compounds assessed comprise long-chain alkenones, n-alkanes, n-alcohols and, additionally, one diol and one keto-ol. These have been extracted by both pressurized liquid extraction and ultrasonication for comparison.