Posts Tagged 'review'



Visualizing a field of research with scientometrics: climate change associated with major aquatic species production in the world

Climate change research on major aquatic species assists various stakeholders (e.g. policymakers, farmers, funders) in better managing its aquaculture activities and productivity for future food sustainability. However, there has been little research on the impact of climate change on aquatic production, particularly in terms of scientometric analyses. Thus, using the bibliometric and scientometric analysis methods, this study was carried out to determine what research exists on the impact of climate change on aquatic production groups. We focused on finfish, crustaceans, and molluscs. Data retrieved from Web of Science was mapped with CiteSpace and used to assess the trends and current status of research topics on climate change associated with worldwide aquatic production. We identified ocean acidification as an important research topic for managing the future production of aquatic species. We also provided a comprehensive perspective and delineated the need for: i) more international collaboration for research activity focusing on climate change and aquatic production in order to achieve the United Nations Sustainable Development Goal by 2030; ii) the incorporation of work from molecular biology, economics, and sustainability.

Continue reading ‘Visualizing a field of research with scientometrics: climate change associated with major aquatic species production in the world’

A global horizon scan of issues impacting marine and coastal biodiversity conservation

The biodiversity of marine and coastal habitats is experiencing unprecedented change. While there are well-known drivers of these changes, such as overexploitation, climate change and pollution, there are also relatively unknown emerging issues that are poorly understood or recognized that have potentially positive or negative impacts on marine and coastal ecosystems. In this inaugural Marine and Coastal Horizon Scan, we brought together 30 scientists, policymakers and practitioners with transdisciplinary expertise in marine and coastal systems to identify new issues that are likely to have a significant impact on the functioning and conservation of marine and coastal biodiversity over the next 5–10 years. Based on a modified Delphi voting process, the final 15 issues presented were distilled from a list of 75 submitted by participants at the start of the process. These issues are grouped into three categories: ecosystem impacts, for example the impact of wildfires and the effect of poleward migration on equatorial biodiversity; resource exploitation, including an increase in the trade of fish swim bladders and increased exploitation of marine collagens; and new technologies, such as soft robotics and new biodegradable products. Our early identification of these issues and their potential impacts on marine and coastal biodiversity will support scientists, conservationists, resource managers and policymakers to address the challenges facing marine ecosystems.

Continue reading ‘A global horizon scan of issues impacting marine and coastal biodiversity conservation’

Micro- and nanoplastics effects in a multiple stressed marine environment

Graphical abstract

Highlights

  • MNPs in the environment are complex mixtures of various size ranges, shapes, polymers
  • MNPs and global change driven stressors do not operate in isolation
  • Stress responses of biota due to MNPs should be contextualised in a changing environment
  • Reports indicate that MNPs interact with OW and OA and impact biota
  • Effects of MNPs combined with global change stressors at population level are unknown

Abstract

Micro- and nanoplastics (MNPs) pollution is an environmental issue of concern, but current effect assessments often overlook realistic scenarios, and a contextualised vision of the magnitude of the impact of complex mixtures of MNPs together with other environmental stressors is urgently needed. Plastic particles exist in the environment as complex mixtures of particles from various size ranges, shapes, and polymer types, but the potential effects of realistic MNPs mixtures and concentrations are still poorly understood, and current effects data is insufficient to produce high quality risk assessments. Organisms exposed to MNPs in the marine environment are simultaneously subjected to global change driven stressors, among others, such as ocean warming (OW), marine heat waves (MHW), ocean acidification (OA), and ocean deoxygenation (OD). Stress responses due to MNPs ingestion can, in particular cases, lead to a metabolic and energetic cost, which may be aggravated in the case of organisms already vulnerable due to simultaneous exposure to global change-related stressors. In this work, we discuss how MNPs effects could be assessed while considering plastics complexity and other environmental stressors. We identify knowledge gaps in MNPs assessments, acknowledge the importance of environmental data acquisition and availability for improved assessments, and consider how mechanistic ecological models can be used to unveil and to increase our understanding of MNPs effects on marine ecosystems. Understanding the importance of plastic pollution in the context of other stressors such as climate change and their potential combined effects on marine ecosystems is important. The assessment of realistic effects of MNPs on all biological levels of organisation should consider the co-occurrence in the environment of global change-related stressors. Even though the number of studies is still limited, recent effect assessment reports indicate that the MNPs interaction with global change stressors can affect processes in organisms such as ingestion and digestion, energy allocation, growth, and fecundity. The potential impact of this interaction at population levels is largely unknown and requires increased attention from the research community, to provide information to stakeholders on the vulnerability of marine species and ecosystems now and under future environmental conditions.

Continue reading ‘Micro- and nanoplastics effects in a multiple stressed marine environment’

EcoPhysioMechanics: integrating energetics and biomechanics to understand fish locomotion under climate change 

Ecological physiologists and biomechanists have been broadly investigating swimming performance in a diversity of fishes, however the connection between form, function and energetics of locomotion has been rarely evaluated in the same system and under climate change scenarios. In this perspective I argue that working within the framework of ‘EcoPhysioMechanics’, i.e., integrating energetics and biomechanics tools, to measure locomotor performance and behavior under different abiotic factors, improves our understanding of the mechanisms, limits and costs of movement. To demonstrate how ecophysiomechanics can be applied to locomotor studies, I outline how linking biomechanics and physiology allows us to understand how fishes may modulate their movement to achieve high speeds or reduce the costs of locomotion. I also discuss how the framework is necessary to quantify swimming capacity under climate change scenarios. Finally, I discuss current dearth of integrative studies and gaps in empirical datasets that are necessary to understand fish swimming under changing environments.

Continue reading ‘EcoPhysioMechanics: integrating energetics and biomechanics to understand fish locomotion under climate change ‘

Sustainable development of climate-resilient aquaculture and culture-based fisheries through adaptation of abiotic stresses: a review

Climate change is an inevitable event that obstructs the output of aquaculture farms and culture-based fisheries in open waters. It poses a serious threat to global food security, altering biodiversity, ecosystems, and global fish output by displacing fish stocks from their natural habitats. When compared to freshwater aquaculture, marine/coastal aquaculture is more affected. To combat the effects of climate change, several mitigation methods and adaptations are being implemented, emphasizing future demands of affordable protein. Selective breeding, species diversification, and aquaculture systems like integrated multi-trophic aquaculture, aquaponics, and recirculating aquaculture system are some of the most widely accepted and adapted solutions. Further research on intervention in seed and feed in terms of quality improvement, bioresource utilization, and technological and genetic improvement is required. Climate change policies from the government are also essential. The present study differs from previous reviews by portraying the various abiotic stress factors contributing to the drastic climate change, encompassing adaptation strategies followed in distinct aquaculture sources such as freshwater, inland saline water, brackish water, coastal waters, and culture-based capture fisheries with its future implications.

Continue reading ‘Sustainable development of climate-resilient aquaculture and culture-based fisheries through adaptation of abiotic stresses: a review’

Systematic review and meta-analysis of ocean acidification effects in Halimeda: implications for algal carbonate production

Highlights

  • Calcification responses to OA vary widely among Halimeda species (neutral, negative).
  • For some species, these responses also seem to be region-dependent.
  • Experimental evidence suggests future declines in Halimeda-derived CaCO3 production.
  • Occurrence and magnitude of declines will be determined by community composition.

Abstract

Ocean acidification (OA) has been identified as one of the major climate-change related threats, mainly due to its significant impacts on marine calcifiers. Among those are the calcareous green algae of the genus Halimeda that are known to be major carbonate producers in shallow tropical and subtropical seas. Hence, any negative OA impacts on these organisms may translate into significant declines in regional and global carbonate production. In this study, we compiled the available information regarding Halimeda spp. responses to OA (experimental, in situ), with special focus on the calcification responses, one of the most studied response parameters in this group. Furthermore, among the compiled studies (n = 31), we selected those reporting quantitative data of OA effects on algal net calcification in an attempt to identify potential general patterns of species- and/or regional-specific OA responses and hence, impacts on carbonate production. While obtaining general patterns was largely hampered by the often scarce number of studies on individual species and/or regions, the currently available information indicates species-specific susceptibility to OA, seemingly unrelated to evolutionary lineages (and associated differences in morphology), that is often accompanied by differences in a species’ response across different regions. Thus, for projections of future declines in Halimeda-associated carbonate production, we used available regional reports of species-specific carbonate production in conjunction with experimental OA responses for the respective species and regions. Based on the available information, declines can be expected worldwide, though some regions harbouring more sensitive species might be more impacted than others.

Continue reading ‘Systematic review and meta-analysis of ocean acidification effects in Halimeda: implications for algal carbonate production’

Ocean acidification: trends, effects and what we have left to learn

Since the Industrial Revolution, the burning of fossil fuels has caused the concentration of carbon dioxide (CO2) in the atmosphere to increase progressively, from about 278 ppm (parts per million by volume) to the current 414 ppm (the average for 2020 at Mauna Loa Observatory, Hawaii). The concentration would be even higher if it were not for the oceans, which currently absorb about a quarter of the CO2 that humans emit into the atmosphere. In return, however, this absorption is causing changes in the chemistry of seawater. When CO2 passes from air to water, it is involved in a series of chemical reactions and equilibria that result in an increase in acidity and therefore a decrease in pH.

Continue reading ‘Ocean acidification: trends, effects and what we have left to learn’

Perceived intensification in harmful algal blooms is a wave of cumulative threat to the aquatic ecosystems

Aquatic pollution is considered a major threat to sustainable development across the world, and deterioration of aquatic ecosystems is caused usually by harmful algal blooms (HABs). In recent times, HABs have gained attention from scientists to better understand these phenomena given that these blooms are increasing in intensity and distribution with considerable impacts on aquatic ecosystems. Many exogenous factors such as variations in climatic patterns, eutrophication, wind blowing, dust storms, and upwelling of water currents form these blooms. Globally, the HAB formation is increasing the toxicity in the natural water sources, ultimately leading the deleterious and hazardous effects on the aquatic fauna and flora. This review summarizes the types of HABs with their potential effects, toxicity, grazing defense, human health impacts, management, and control of these harmful entities. This review offers a systematic approach towards the understanding of HABs, eliciting to rethink the increasing threat caused by HABs in aquatic ecosystems across the world. Therefore, to mitigate this increasing threat to aquatic environments, advanced scientific research in ecology and environmental sciences should be prioritized.

Continue reading ‘Perceived intensification in harmful algal blooms is a wave of cumulative threat to the aquatic ecosystems’

Antarctic climate change and the environment: a decadal synopsis and recommendations for action

Scientific evidence is abundantly clear and convincing that due to the current trajectory of human-derived emissions of CO₂ and other greenhouse gases, the atmosphere and ocean will continue to warm, the ocean will continue to acidify, atmospheric and ocean circulation patterns will be altered, the cryosphere will continue to lose ice in all forms, and sea level will rise.

While uncertainties remain about various aspects of the Earth System, what is known is beyond dispute. The trends, based on observations and confirmed by modelling, will accelerate if high rates of CO₂ and other greenhouse gas emissions continue.

The IPCC AR6 WGII Summary for Policymakers (SPM D.5.3) unambiguously emphasises this conclusion: The cumulative scientific evidence is unequivocal: Climate change is a threat to human well-being and planetary health. Any further delay in concerted anticipatory global action on adaptation and mitigation will miss a brief and rapidly closing window of opportunity to secure a liveable and sustainable future for all.

Human influence on the climate is clear, with observed changes in the climate and in greenhouse gas concentrations unequivocally attributable to human activities.

Human-induced climate change has caused extensive negative impacts, including losses to people and to nature, some of which are irreversible, such as the extinction of species.

Climate change is increasingly exacerbating the impact of other human-caused effects on nature and human well-being, and the impacts are expected to grow with increasing climate change magnitude.

Observations, modelling and global assessments describe significant changes in Antarctic physical and living systems, both marine and terrestrial.

Changes in Antarctic and Southern Ocean environments are linked to and influence climate impact drivers globally.

The most significant potential influence of Antarctica’s changes will be on global mean sea level change and its influence on society and nature in all coastal regions of the globe.

Further global impacts influenced by Antarctic change include extreme climate and weather events, droughts, wildfires and floods, and ocean acidification. These impacts cause ecosystem disruption and loss of biodiversity beyond the Antarctic region.

Continue reading ‘Antarctic climate change and the environment: a decadal synopsis and recommendations for action’

The effect of ocean acidification on skeletal structures

It is well known that the increasing partial pressure of atmospheric CO2 (pCO2) is reducing surface ocean pH, a process known as ocean acidification (OA). This results in a reduced saturation of the seawater with respect to the CaCO3 polymorphs aragonite, high-Mg calcite, and low-Mg calcite that are involved in the biological formation of calcareous skeletons and shells. The effect of OA on calcium carbonate precipitation and subsequent dissolution in carbonate depositional systems, such as coral reefs, is a hotly debated topic. While early studies suggested that certain carbonate-secreting organism groups may be strongly affected by OA or even become extinct [1,2], others observed highly variable, species-specific responses to OA, whereby some taxa are negatively affected, some are positively affected, and others are unaffected [3,4,5].

Continue reading ‘The effect of ocean acidification on skeletal structures’

Meta-analysis suggests negative, but pCO2 specific, effects of ocean acidification on the structural and functional properties of crustacean biomaterials

Crustaceans comprise an ecologically and morphologically diverse taxonomic group. They are typically considered resilient to many environmental perturbations found in marine and coastal environments, due to effective physiological regulation of ions and hemolymph pH, and a robust exoskeleton. Ocean acidification can affect the ability of marine calcifying organisms to build and maintain mineralized tissue and poses a threat for all marine calcifying taxa. Currently, there is no consensus on how ocean acidification will alter the ecologically relevant exoskeletal properties of crustaceans. Here, we present a systematic review and meta-analysis on the effects of ocean acidification on the crustacean exoskeleton, assessing both exoskeletal ion content (calcium and magnesium) and functional properties (biomechanical resistance and cuticle thickness). Our results suggest that the effect of ocean acidification on crustacean exoskeletal properties varies based upon seawater pCO2 and species identity, with significant levels of heterogeneity for all analyses. Calcium and magnesium content was significantly lower in animals held at pCO2 levels of 1500–1999 µatm as compared with those under ambient pCO2. At lower pCO2 levels, however, statistically significant relationships between changes in calcium and magnesium content within the same experiment were observed as follows: a negative relationship between calcium and magnesium content at pCO2 of 500–999 µatm and a positive relationship at 1000–1499 µatm. Exoskeleton biomechanics, such as resistance to deformation (microhardness) and shell strength, also significantly decreased under pCO2 regimes of 500–999 µatm and 1500–1999 µatm, indicating functional exoskeletal change coincident with decreases in calcification. Overall, these results suggest that the crustacean exoskeleton can be susceptible to ocean acidification at the biomechanical level, potentially predicated by changes in ion content, when exposed to high influxes of CO2. Future studies need to accommodate the high variability of crustacean responses to ocean acidification, and ecologically relevant ranges of pCO2 conditions, when designing experiments with conservation-level endpoints.

Continue reading ‘Meta-analysis suggests negative, but pCO2 specific, effects of ocean acidification on the structural and functional properties of crustacean biomaterials’

The need for unrealistic experiments in global change biology

Highlights

  • Most multidriver temperature×CO2 phytoplankton experiments use only two levels of each driver.
  • Current studies cannot produce interaction surfaces for CO2 and temperature due to undersampling driver levels.
  • Categorisations of temperature×CO2 interactions are sensitive to small errors and biological variation.
  • Regression designs make more robust estimates of multidriver interactions than analysis of variance (ANOVA) driven designs.

Abstract

Climate change is an existential threat, and our ability to conduct experiments on how organisms will respond to it is limited by logistics and resources, making it vital that experiments be maximally useful. The majority of experiments on phytoplankton responses to warming and CO2 use only two levels of each driver. However, to project the characters of future populations, we need a mechanistic and generalisable explanation for how phytoplankton respond to concurrent changes in temperature and CO2. This requires experiments with more driver levels, to produce response surfaces that can aid in the development of predictive models. We recommend prioritising experiments or programmes that produce such response surfaces on multiple scales for phytoplankton.

Continue reading ‘The need for unrealistic experiments in global change biology’

The legal implications of ocean acidification: beyond the climate change regime

This chapter explicates the important relations between the oceans, biodiversity and climate regimes, in the process especially highlighting the legal connections. Due to emissions of carbon dioxide from the burning of fossil fuels, changes in ocean chemistry are occurring at an accelerating rate. In particular, as the oceans absorb that carbon, they become acidic; today they are almost one-third more acidic than they were 200 years ago. Impacts on marine organisms and ecosystems are increasingly apparent, ranging from adverse effects on plankton to reductions in shellfish harvests. This chapter argues that ocean acidification is creating specific new challenges for international law. While extant multilateral environmental agreements can serve as the basis for marine governance in this context, it is still unclear which should take the lead and what kind of new rules will need to be agreed upon to do so effectively. An obvious issue is that the cause of this problem – carbon emissions governed by the climate change regime – and the impacts – acidification of oceans and seas – are the subjects of different regimes. Drawing on the experience of the Convention on Biological Diversity, this chapter points to avenues for strengthening the oceans and climate regimes so that they can effectively respond to acidification.

Continue reading ‘The legal implications of ocean acidification: beyond the climate change regime’

Reviews and syntheses: a framework to observe, understand, and project ecosystem response to environmental change in the East Antarctic Southern Ocean

Systematic long-term studies on ecosystem dynamics are largely lacking for the East Antarctic Southern Ocean, although it is well recognized that such investigations are indispensable to identify the ecological impacts and risks of environmental change. Therefore, here we develop a framework for establishing a long-term cross-disciplinary study and argue why the eastern Weddell Sea and the easterly adjacent sea off Dronning Maud Land (WSoDML) is a well suited area for such an initiative. As in the Eastern Antarctic in general, climate and environmental change have so far been comparatively muted in this area. A systematic long-term study of its environmental and ecological state can thus provide a baseline of the current situation, an assessment of future changes, and sound data can act as a model to develop and calibrate projections. Establishing a long-term observation (LTO) and long-term ecological research (LTER) programme now would allow the study of climate-driven ecosystem changes and interactions with impacts arising from other anthropogenic activities, from their very onset. Through regular autonomous and ship-based LTO activities, changes in ocean dynamics, geochemistry, biodiversity and ecosystem functions and services can be systematically explored and mapped. This observational work should be accompanied by targeted LTER efforts, including experimental and modelling studies. This approach will provide a level of long-term data availability and ecosystem understanding that are imperative to determine, understand, and project the consequences of climate change and support a sound science-informed management of future conservation efforts in the Southern Ocean.

Continue reading ‘Reviews and syntheses: a framework to observe, understand, and project ecosystem response to environmental change in the East Antarctic Southern Ocean’

The marine carbonate system along the northern Antarctic peninsula: current knowledge and future perspectives

Among the regions of the Southern Ocean, the northern Antarctic Peninsula (NAP) has emerged as a hotspot of climate change investigation. Nonetheless, studies have indicated issues and knowledge gaps that must be addressed to expand the understanding of the carbonate system in the region. Therefore, we focused on identifying current knowledge about sea-air CO2 fluxes (FCO2), anthropogenic carbon (Cant) and ocean acidification along NAP and provide a better comprehension of the key physical processes controlling the carbonate system. Regarding physical dynamics, we discuss the role of water masses formation, climate modes, upwelling and intrusions of Circumpolar Deep Water, and mesoscale processes. For FCO2, we show that the summer season corresponds to a strong sink in coastal areas, leading to CO2 uptake that is greater than or equal to that of the open ocean. We highlight that the prevalence of summer studies prevents comprehending processes occurring throughout the year and the net annual CO2 balance in the region. Thus, temporal investigations are necessary to determine natural environmental fluctuations and to distinguish natural variability from anthropogenically driven changes. We emphasize the importance of more studies regarding Cant uptake rate, accumulation, and export to global oceans.

Continue reading ‘The marine carbonate system along the northern Antarctic peninsula: current knowledge and future perspectives’

Becoming nose-blind—climate change impacts on chemical communication

Chemical communication via infochemicals plays a pivotal role in ecological interactions, allowing organisms to sense their environment, locate predators, food, habitats, or mates. A growing number of studies suggest that climate change-associated stressors can modify these chemically mediated interactions, causing info-disruption that scales up to the ecosystem level. However, our understanding of the underlying mechanisms is scarce. Evidenced by a range of examples, we illustrate in this opinion piece that climate change affects different realms in similar patterns, from molecular to ecosystem-wide levels. We assess the importance of different stressors for terrestrial, freshwater, and marine ecosystems and propose a systematic approach to address highlighted knowledge gaps and cross-disciplinary research avenues.

Continue reading ‘Becoming nose-blind—climate change impacts on chemical communication’

Chapter 5 – microbial adaptation to climate change and its impact on sustainable development

Microbial community has always been integrated with the ecological systems and is responsible for the maintenance of the natural balances. The current era of anthropogony has brought drastic consequences in the order of climate change. There have been many variations in the habitats of microorganisms, be it acidification of oceans or drought stress in soils of the agricultural lands. The adverse effects of these uncalled changes might lead to great losses of the ecosystem as some of these directly affect the growth and survival of the beneficial microorganisms. In order to maintain a healthy biome and balance, it is a necessity for the microbes to either inherit or develop the resistance or adaptation for the physical changes and acclimatize in order to maintain the biodiversity and conservation in an ecosystem. This chapter reviews some of the beneficial adaptation measures taken by the microorganisms to combat the climatic changes and environmental stress such as increase in the temperature or CO2 levels in the atmosphere which in turn helps the ecosystem to achieve sustainable development. It includes the microbes in varying ecosystems such as aquatic and terrestrial. It also details about the mechanisms in which the microbes help boost the ecosystem and what is the relevance of these adaptations in the upcoming challenges associated with climate change. Lastly, it highlights some of the measures or strategies including the next generation technologies which can be used to overcome the climatic change consequences in plants and animals by altering and modifying some of the adaptation techniques, making them better. These novel upcoming methods might be the solution for a better adaptation in the coming future years.

Continue reading ‘Chapter 5 – microbial adaptation to climate change and its impact on sustainable development’

Chapter 13 – ocean systems

The ocean comprises ~71% of the Earth’s surface area and is in constant interaction with the atmosphere above and the land surface at the coastal interface, allowing a continuous exchange of greenhouse gases (GHGs) between the spheres. The ocean plays an important role in absorbing and storing carbon dioxide (CO2) from fossil fuel combustion, land-use change, and cement production. Since the industrial revolution, the ocean has stored ~31% of human emitted CO2 adding to a total storage of anthropogenic CO2 of 152 ± 20 Pg C (PgC = Petagrams of carbon) from 1850 to 2007 and is currently removing about 2.6 ± 0.6 Pg C of excess CO2 every year from the atmosphere. On longer timescales (i.e., centuries to millennia), the ocean carbon sink acts as a primary regulator of the Earth’s climate. While the ocean carbon sink mitigates climate change, absorption of anthropogenic CO2 leads to ocean acidification with potentially harmful effects for marine ecosystems. The ocean also contributes to the cycles of other greenhouse gases. Specifically, it is a weak source of methane. The contribution of the ocean to the net global methane budget, however, is substantially smaller than the oceanic uptake of CO2. The ocean was a net source of methane (CH4) to the atmosphere of ~13 Tg CH4 year−1 (Tg CH4 = Teragrams of CH4) with a possible range of 9–22 Tg CH4 year−1 over the period 2000–20. Hence, the methane fluxes from the ocean to the atmosphere are an order of magnitude smaller than the anthropogenic emissions over the same period. Likewise, the ocean comprises a natural source of nitrous oxide (N2O) of ~ 3.4 Tg N year−1 between 2007 and 2016, although with a substantial possible range between 2.5 and 4.3 Tg N year−1.

Continue reading ‘Chapter 13 – ocean systems’

Sinking diatoms trap silicon in deep seawater of acidified oceans

The seas are acidifying as a result of carbon dioxide emissions. It now emerges that this will alter the solubility of the shells of marine organisms called diatoms — and thereby change the distribution of nutrients and plankton in the ocean.

The ecologically dominant phytoplankton in much of the ocean are a group of unicellular organisms known as diatoms. Writing in Nature, Taucher et al. present a study that uses a combination of experimental, observational and modelling approaches to examine how the diatom-driven effects of ocean acidification — a consequence of rising carbon dioxide concentrations in seawater — will affect biogeochemical cycles. The separate lines of evidence suggest that ocean acidification will have far-reaching effects on the export of elements to the deep ocean.

Diatoms are highly efficient at converting dissolved CO2 into organic carbon through photosynthesis, whereupon this organic carbon becomes incorporated into particles that sink rapidly to the deep ocean. Diatoms therefore serve as primary engines of a ‘biological pump’ that exports carbon to the deep ocean for sequestration. Each diatom cell is enclosed in a shell of silica (SiO2, where Si is silicon), and the solubility of the silicon in this biomineral is pH-sensitive — it becomes less soluble as seawater acidity rises. Although these features of diatoms are familiar to marine scientists, their combined implications for future biogeochemical cycles in the context of ocean acidification had not been explored.

Enter Taucher and colleagues. They carried out a series of five experiments in various parts of the ocean in which natural phytoplankton communities were grown in large enclosures (with volumes of 35–75 cubic metres) known as mesocosms, which simulated future ocean acidification. When the authors measured the elemental composition of the diatom-derived debris at the bottom of the mesocosms, they observed much higher ratios of silicon to nitrogen than the ratios of particles suspended near the surface. This suggested that, at low seawater pH, diatom silica shells were dissolving much more slowly than nitrogen-containing compounds in the same sinking material. In other words, silicon was being exported from the surface to deeper waters preferentially to nitrogen. The authors validated this finding using records of silicon-to-nitrogen ratios in sinking biological detritus in the open ocean, measured as a function of seawater pH, and obtained from particle-collecting sediment traps deployed by research vessels.

Continue reading ‘Sinking diatoms trap silicon in deep seawater of acidified oceans’

Publisher correction: the marine nitrogen cycle: new developments and global change

Correction to: Nature Reviews Microbiology https://doi.org/10.1038/s41579-022-00687-z, published online 07 February 2022.

In Figure 4 of the original article, one of the arrows was erroneously labelled Nitrification instead of Low O2. This has now been corrected in all versions of the Review. The publisher apologizes to the authors and to readers for this error.

Continue reading ‘Publisher correction: the marine nitrogen cycle: new developments and global change’

  • Reset

Subscribe

OA-ICC Highlights


%d bloggers like this: