A semi-quantitative spectrophotometric, dye-binding assay for determination of Coomassie Blue stainable particles

Coomassie stainable particles (CSP) are protein-containing transparent particles that can be stained with Coomassie brilliant blue (CBB) and are found abundantly in aquatic systems; however, their distribution and role remain poorly known, in part due to the lack of an efficient method to study them. We developed a new, simple, and low cost semi-quantitative spectrophotometric method for determination of CSP in aquatic systems. The method is analogous to that used to quantify polysaccharide-rich gel particles called transparent exopolymeric particles (TEP). CSP concentration is determined relative to bovine serum albumin (BSA) standard aggregates (in a manner similar to how TEP is quantified relative to xanthan gum). The method is based on the linear relationship between CSP concentration and the absorbance of the eluted dye from a CBB-protein complex, which has an absorbance maximum (λmax) at 615 nm. The limit of detection and the precision (%RSD) for the proposed method are 6 μg BSA equivalent and 11%, respectively. The new spectrophotometric method was validated with the existing microscopic method. This new method to quantify CSP is simple, enables rapid measurements, and allows a more efficient comparison with TEP concentrations than the present microscopic method. The spectrophotometric analyses will further the investigation of the abundance, distribution, and role of CSP in the biogeochemistry of the ocean

Effects of Higher CO2 and Temperature on Exopolymer Particle Content and Physical Properties of Marine Aggregates

We investigated how future ocean conditions, and specifically the interaction between temperature and CO2, might affect marine aggregate formation and physical properties. Initially, mesocosms filled with coastal seawater were subjected to three different treatments of CO2 concentration and temperature: (1) 750 ppm CO2, 16°C, (2) 750 ppm CO2, 20°C, and (3) 390 ppm CO2, 16°C. Diatom-dominated phytoplankton blooms were induced in the mesocosms by addition of nutrients. In aggregates produced in roller tanks using seawater taken from the mesocosms during different stages of the bloom, we measured sinking velocity, size, chlorophyll a, particulate organic carbon and nitrogen, and exopolymer particle content; excess density and mass were calculated from the sinking velocity and size of the aggregates. As has been seen in previous experiments, no discernable differences in overall nutrient uptake, chlorophyll-a concentration, or exopolymer particle concentrations could be related to the acidification treatment in the mesocosms. In addition, in the aggregates formed during the roller tank experiments (RTEs), we observed no statistically significant differences in chemical composition among the treatments during Pre-Bloom, Bloom, and Post-Bloom periods. However, physical characteristics were different and showed a synergistic effect of warmer temperature and higher CO2 during the Pre-Bloom period; at this time, temperature had a larger effect than CO2 on aggregate sinking velocity. In RTEs with warmer and acidified treatment (future conditions), aggregates were larger, heavier, and settled faster than aggregates formed at present-day or only acidified conditions. During the Post-Bloom, however, aggregates formed under present and future conditions had similar physical properties. In acidified tanks at ambient temperature, aggregates were slower, smaller and less dense than those formed at the same temperature but under present CO2 or under warmer and acidified conditions. Thus, the sinking velocity of aggregates formed in acidified tanks at ambient temperature was slower than the other two cases. Our findings point out the potential of ocean acidification and warming to modify physical properties of sinking aggregates but also emphasize the need of future experiments investigating multiple environmental stressors to clarify the importance of each factor

Socioterritorial vulnerability factors to tsunami in Arauco, south central Chile

The socioterritorial vulnerability produced by the tsunami is analyzed in Arauco, Biobío region (37ºS), considering as extreme local scenarios the events produced by the tsunami of 1960 and 2010. Representative variables of the physic, socio economical and educational vulnerability were used-which were included in databases to be utilized by the SIG. The study area was divided in 152 blocks, and later the data of each variable per block was obtained through the census (2002) and a survey that was applied to the population. It was established that the extreme event for the location was the tsunami of 1960, and the 84% of blocks have a total medium vulnerability. The results have been analyzed in function to the development of the human scale approach, due to the socio economical characteristics of the population. Starting from this analysis, measures for mitigations have been proposed to be incorporated in the risk management in the area.Se analiza la vulnerabilidad socioterritorial ante un evento de tsunami en la localidad de Arauco, Región del Bío-Bío (37ºS), considerando como escenario local extremo los eventos tsunamigénicos de 1960 y 2010. Se utilizaron variables representativas de la vulnerabilidad física, socio-económica y educativa incorporadas a bases de datos para su uso en SIG. El área de estudio se dividió en 152 manzanas y posteriormente se obtuvo el dato de cada variable por manzana a través del Censo (2002) y de la aplicación de encuestas a la población. Se estableció que el evento extremo para la localidad correspondió al tsunami de 1960 y que el 84% de las manzanas poseen una vulnerabilidad total media. Los resultados son analizados en función del enfoque del desarrollo a escala humana, dadas las características socio-económicas de la población. A partir de dicho análisis, se proponen medidas de mitigación para ser incorporadas a la gestión del riesgo en el área

On the effect of low oxygen concentrations on bacterial degradation of sinking particles

In marine oxygen (O2) minimum zones (OMZs), the transfer of particulate organic carbon (POC) to depth via the biological carbon pump might be enhanced as a result of slower remineralisation under lower dissolved O2 concentrations (DO). In parallel, nitrogen (N) loss to the atmosphere through microbial processes, such as denitrification and anammox, is directly linked to particulate nitrogen (PN) export. However it is unclear (1) whether DO is the only factor that potentially enhances POC transfer in OMZs, and (2) if particle fluxes are sufficient to support observed N loss rates. We performed a degradation experiment on sinking particles collected from the Baltic Sea, where anoxic zones are observed. Sinking material was harvested using surface-tethered sediment traps and subsequently incubated in darkness at different DO levels, including severe suboxia (<0.5 mg l−1 DO). Our results show that DO plays a role in regulating POC and PN degradation rates. POC(PN) degradation was reduced by approximately 100% from the high to low DO to the lowest DO. The amount of NH4+ produced from the pool of remineralising organic N matched estimations of NH4+ anammox requirements during our experiment. This anammox was likely fueled by DON degradation rather than PON degradation

Composition and Vertical Flux of Particulate Organic Matter to the Oxygen Minimum Zone of the Central Baltic Sea: Impact of a sporadic North Sea inflow

Particle sinking is a major form of transport for photosynthetically fixed carbon to below the euphotic zone via the biological carbon pump (BCP). Oxygen (O2) depletion may improve the efficiency of the BCP. However, the mechanisms by which O2 deficiency can enhance particulate organic matter (POM) vertical fluxes are not well understood. Here, we investigate the composition and vertical fluxes of POM in two deep basins of the Baltic Sea (GB: Gotland Basin and LD: Landsort Deep). The two basins showed different O2 regimes resulting from the intrusion of oxygen-rich water from the North Sea that ventilated the water column below 140 m in GB, but not in LD, during the time of sampling. In June 2015, we deployed surface-tethered drifting sediment traps in oxic surface waters (GB: 40 and 60 m; LD: 40 and 55 m), within the oxygen minimum zone (OMZ; GB: 110 m and LD: 110 and 180 m) and at recently oxygenated waters by the North Sea inflow in GB (180 m). The primary objective of this study was to test the hypothesis that the different O2 conditions in the water column of GB and LD affected the composition and vertical flux of sinking particles and caused differences in export efficiency between those two basins. The composition and vertical flux of sinking particles were different in GB and LD. In GB, particulate organic carbon (POC) flux was 18 % lower in the shallowest trap (40 m) than in the deepest sediment trap (at 180 m). Particulate nitrogen (PN) and Coomassie stainable particle (CSP) fluxes decreased with depth, while particulate organic phosphorus (POP), biogenic silicate (BSi), chlorophyll a (Chl a) and transparent exopolymeric particle (TEP) fluxes peaked within the core of the OMZ (110 m); this coincided with the presence of manganese oxide-like (MnOx-like) particles aggregated with organic matter. In LD, vertical fluxes of POC, PN and CSPs decreased by 28 %, 42 % and 56 %, respectively, from the surface to deep waters. POP, BSi and TEP fluxes did not decrease continuously with depth, but they were higher at 110 m. Although we observe a higher vertical flux of POP, BSi and TEPs coinciding with abundant MnOx-like particles at 110 m in both basins, the peak in the vertical flux of POM and MnOx-like particles was much higher in GB than in LD. Sinking particles were remarkably enriched in BSi, indicating that diatoms were preferentially included in sinking aggregates and/or there was an inclusion of lithogenic Si (scavenged into sinking particles) in our analysis. During this study, the POC transfer efficiency (POC flux at 180 m over 40 m) was higher in GB (115 %) than in LD (69 %), suggesting that under anoxic conditions a smaller portion of the POC exported below the euphotic zone was transferred to 180 m than under reoxygenated conditions present in GB. In addition, the vertical fluxes of MnOx-like particles were 2 orders of magnitude higher in GB than LD. Our results suggest that POM aggregates with MnOx-like particles formed after the inflow of oxygen-rich water into GB, and the formation of those MnOx–OM-rich particles may alter the composition and vertical flux of POM, potentially contributing to a higher transfer efficiency of POC in GB. This idea is consistent with observations of fresher and less degraded organic matter in deep waters of GB than LD

Gut Microbiota and Obesity: Prebiotic and Probiotic Effects

Malnutrition through excessive food consumption is a worldwide pandemic. Changes in lifestyle, diet and physical activity have resulted in an exponential increase in the number of obese people around the world. Multiple factors influence the development of this disease, and recently it has been suggested that gut microbiota (GM) plays an important role in nutrient absorption and energy regulation of individuals, thus affecting their nutritional status. It has been proven that gut microbiota is different in individuals with a normal nutritional status compared to those who are obese. Therefore, to study bacterial populations that make up the microbiota and to understand how prebiotics and probiotics affect the increase of these bacteria has become a promising alternative to treat obesity. This chapter looks at defining the established relationship between probiotics, prebiotics and gut microbiota that develop in obese people and people of normal weight, with the aim of providing future dietary recommendations to treat this medical condition

Uncoupled seasonal variability of transparent exopolymer and Coomassie stainable particles in coastal Mediterranean waters: Insights into sources and driving mechanisms

Transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) are gel-like particles, ubiquitous in the ocean, that affect important biogeochemical processes including organic carbon cycling by planktonic food webs. Despite much research on both groups of particles (especially TEP) over many years, whether they exist as distinctly stainable fractions of the same particles or as independent particles, each with different driving factors, remains unclear. To address this question, we examined the temporal dynamics of TEP and CSP over 2 complete seasonal cycles at 2 coastal sites in the Northwestern Mediterranean Sea, the Blanes Bay Microbial Observatory (BBMO) and the L’Estartit Oceanographic Station (EOS), as well as their spatial distribution along a coast-to-offshore transect. Biological, chemical, and physical variables were measured in parallel. Surface concentrations (mean + standard deviation [SD]) of TEP were 36.7 + 21.5 µg Xanthan Gum (XG) eq L–1 at BBMO and 36.6 + 28.3 µg XG eq L–1 at EOS; for CSP, they were 11.9 + 6.1 µg BSA eq L–1 at BBMO and 13.0 + 5.9 µg BSA eq L–1 at EOS. Seasonal variability was more evident at EOS, where surface TEP and CSP concentrations peaked in summer and spring, respectively, and less predictable at the shore-most station, BBMO. Vertical distributions between surface and 80 m, monitored at EOS, showed highest TEP concentrations within the surface mixed layer during the stratification period, whereas CSP concentrations were highest before the onset of summer stratification. Phytoplankton were the main drivers of TEP and CSP distributions, although nutrient limitation and saturating irradiance also appeared to play important roles. The dynamics and distribution of TEP and CSP were uncoupled both in the coastal sites and along the transect, suggesting that they are different types of particles produced and consumed differently in response to environmental variability

Cultural and generational factors shape Asians’ sustainable food choices:Insights from choice experiments and information nudges

Promoting sustainable diets is crucial for mitigating global greenhouse gas emissions. We investigated the potential for large-scale dietary shifts to address the impacts of climate change on agriculture and food through surveys and choice experiments in China, Japan, and Vietnam (n = 5,089). Our findings reveal that Asian consumers are largely unwilling to deviate from current dietary habits, particularly regarding the consumption of animal proteins. This reluctance persists despite significant preferences for environmental certification as a proxy for greater sustainability in food production, as expressed by wealthier and younger respondents. Information experiments demonstrate that altruistic messaging fails to induce change, and positive information about climate impacts weakens the influence of certification. However, self-enhancement framing, particularly effective with individuals aged 60 years and above, shows promise. Our findings provide valuable insights for researchers and policymakers seeking effective strategies to encourage sustainable diets, shedding light on challenges and potential avenues for successful intervention

Potential role of oxygen and inorganic nutrients on microbial carbon turnover in the Baltic Sea

Oxygen (O2) deficiency and nutrient concentrations in marine systems are impacting organisms from microbes to higher trophic levels. In coastal and enclosed seas, O2 deficiency is often related to eutrophication and high degradation rates of organic matter. To investigate the impact of O2 concentration on bacterial growth and the turnover of organic matter, we conducted multifactorial batch experiments with natural microbial communities of the central Baltic Sea. Water was collected from suboxic (<5 µmol L -1) depths in the Gotland Basin during June 2015. Samples were kept for four days under fully oxygenated and low O2 conditions (mean: 34 µmol L-1 O2), with or without nutrient (ammonium, phosphate, nitrate) and labile carbon (glucose) amendments. We measured bacterial abundance, bacterial heterotrophic production, extracellular enzyme rates (leucine-aminopeptidase) and changes in dissolved and particulate organic carbon concentrations. Our results show that the bacterial turnover of organic matter was limited by nutrients under both oxic and low O2 conditions. In nutrient and glucose replete treatments, low O2 concentrations significantly reduced the net uptake of dissolved organic carbon and lead to higher accumulation of more labile dissolved organic matter. Our results therewith suggest that the combined effects of eutrophication and deoxygenation on heterotrophic bacterial activity may potentially favor the accumulation of dissolved organic carbon in the Baltic Sea

Universidades generizadas y mercantilizadas. Implicancias para las mujeres trabajadoras en tiempo de pandemia

Este artículo busca conocer las experiencias de las mujeres trabajadoras de una universidad pública y estatal, en un espacio laboral generizado y mercantilizado, en el contexto de pandemia. Para esto, a través de una metodología cualitativa, se desarrollaron cuatro grupos focales con participación de académicas, administrativas y trabajadoras a honorarios. El análisis realizado constata la presencia de estructuras patriarcales que reifican las relaciones tradicionales de género, un agobio y sobrecarga que afecta a todas. Sin embargo, las experiencias son disímiles, dependiendo de la calidad contractual y funciones que se realizan en su interior. Finalmente, se propone a las universidades la elaboración de políticas sensibles al género, para mitigar las consecuencias de la pandemia en las trabajadoras.This article seeks to know the experiences of women working in a public state university, a gendered and commercialized workplace, in the context of a pandemic. For this, through a qualitative methodology, four focus groups were developed with the participation of academic, administrative and contingent workers. The analysis carried out confirms the presence of patriarchal structures that reify traditional gender relations, a burden and overload that affects everyone. However, the experiences are dissimilar, depending on the contract and corresponding responsibilities. Finally, the article proposes universities develop gender-sensitive policies to mitigate the consequences of the pandemic on female workers.Este artigo busca conhecer as experiências de mulheres trabalhadoras de uma universidade pública e estadual, em um espaço laboral generalizado e mercantilizado, em contexto de pandemia. Para isso, através de uma metodologia qualitativa, foram desenvolvidos quatro grupos focais com a participação de profissionais acadêmicas, administrativas e trabalhadoras horistas. A análise realizada constata a presença de estruturas patriarcais que reificam as relações tradicionais de gênero, um fardo e uma sobrecarga que afetam a todas. No entanto, as experiências são díspares, dependendo da qualidade contratual e das funções nele desempenhadas. Finalmente, se propõe às universidades a elaboração de políticas com perspectiva de gênero, para mitigar as consequências da pandemia sob as trabalhadoras