Ocean acidification alters meiobenthic assemblage composition and organic matter degradation rates in seagrass sediments

Seagrass meadows are an important organic matter (OM) reservoir but, are currently being lost due to global and regional stressors. Yet, there is limited research investigating the cumulative impacts of anthropogenic stressors on the structure and functioning of seagrass benthic assemblages, key drivers of OM mineralization and burial. Here, using a 16-month field experiment, we assessed howmeiobenthic assemblages and extracellular enzymatic activities (as a proxy of OM degradation) in Posidonia oceanica sediments responded to ocean acidification (OA) and nutrient loadings, at CO2 vents. P. oceanica meadows were exposed to three nutrient levels (control, moderate, and high) at both ambient and low pH sites. OA altered meiobenthic assemblage structure, resulting in increased abundance of annelids and crustaceans, along with a decline in foraminifera. In addition, low pH enhanced OMdegradation rates in seagrass sediments by enhancing extracellular enzymatic activities, potentially decreasing the sediment carbon storage capacity of seagrasses. Nutrient enrichment had no effect on the response variables analyzed, suggesting that, under nutrient concentration unlikely to cause N or P imitation, a moderate increase of dissolved nutrients in the water column had limited influence onmeiobenthic assemblages. These findings showthatOAcan significantly alter meiobenthic assemblage structure and enhance OMdegradation rates in seagrass sediments. As meiofauna are ubiquitous key actors in the functioning of benthic ecosystems, we postulated that OA, altering the structure of meiobenthic assemblages andOMdegradation, could affect organic carbon sequestration over large spatial scales

Data from: Below-ground processes control the success of an invasive seaweed

1. Whilst the successful establishment and spread of invasive species can be determined by above ground processes, results are often equivocal. Emergent research, mostly from terrestrial ecosystems, demonstrates that below-ground processes (nutrient cycling, chemical properties) under microbial control can mediate interactions between native and invasive plants. Because microbes can control similar sediment properties in marine ecosystem that influence plant fitness, we argue that below-ground properties should also exert strong control interactions between native and invasive marine macrophytes. 2. We coupled surveys of microbial communities and chemistry of sediments collected from an invasive alga (Caulerpa cylindracea), a native competitor (the seagrass Posidonia oceanica) and unvegetated sediments with a large field experiment, in which we manipulated the presence/absence of the canopies of both species to determine the effects of above- and below-ground processes on the success of C. cylindracea. 3. P. oceanica and C. cylindracea sediments have microbial communities and predicted metabolic process that reflect aerobic and anaerobic conditions, respectively. Moreover, the nutritional quantity of organic matter was higher, but quality was lower in C. cylindracea sediments compared to the two native habitats. The growth of C. cylindracea fragments was equally low in the presence or absence of a P. oceanica canopy, whereas the growth of C. cylindracea was higher in the canopy removed vs. present treatment, possibly because, in the absence of a C. cylindracea canopy, fragments are released from intra-specific competition for resources. 4. Synthesis: Sediment/soil processes are increasingly recognised as important drivers of the success and hence impacts of invasive plants. We extended this theory to marine ecosystems and suggest biotic resistance to invasion may not always be attributable to intact canopies, but may also result from indirect effects of native macrophytes on sediment quality and microbial processes. This information may, in part, resolve why above-ground interactions don’t always explain invasive plant success and thus can be used to develop better informed management strategies

Below-ground processes control the success of an invasive seaweed

Whilst the successful establishment and spread of invasive species can be determined by above-ground processes, results are often equivocal. Emergent research, mostly from terrestrial ecosystems, demonstrates that below-ground processes (nutrient cycling, chemical properties) under microbial control can mediate interactions between native and invasive plants. Because microbes can control similar sediment properties in marine ecosystem that influence plant fitness, we argue that below-ground properties should also exert strong control interactions between native and invasive marine macrophytes. We coupled surveys of microbial communities and chemistry of sediments collected from an invasive alga (Caulerpa cylindracea), a native competitor (the seagrass Posidonia oceanica) and unvegetated sediments with a large field experiment, in which we manipulated the presence/absence of the canopies of both species to determine the effects of above- and below-ground processes on the success of C. cylindracea. Posidonia oceanica and C. cylindracea sediments have microbial communities and predicted metabolic process that reflect aerobic and anaerobic conditions, respectively. Moreover, the nutritional quantity of organic matter was higher, but quality lower in C. cylindracea sediments compared to the two native habitats. The growth of C. cylindracea fragments was equally low in the presence or absence of a P. oceanica canopy, whereas the growth of C. cylindracea was higher in the canopy removed vs. present treatment, possibly because, in the absence of a C. cylindracea canopy, fragments are released from intraspecific competition for resources. Synthesis. Sediment/soil processes are increasingly recognized as important drivers of the success and hence impacts of invasive plants. We extended this theory to marine ecosystems and suggest biotic resistance to invasion may not always be attributable to intact canopies, but may also result from indirect effects of native macrophytes on sediment quality and microbial processes. This information may, in part, resolve why above-ground interactions do not always explain invasive plant success and thus can be used to develop better informed management strategies

Interdisciplinary approach to cell–biomaterial interactions: biocompatibility and cell friendly characteristics of RKKP glass–ceramic coatings on titanium

In this work, titanium (Ti) supports have been coated with glass–ceramic films for possible applications as biomedical implant materials in regenerative medicine. For the film preparation, a pulsed laser deposition (PLD) technique has been applied. The RKKP glass–ceramic material, used for coating deposition, was a sol–gel derived target of the following composition: Ca-19.4, P-4.6, Si-17.2, O-43.5, Na-1.7, Mg-1.3, F-7.2, K-0.2, La-0.8, Ta-4.1 (all in wt%). The prepared coatings were compact and uniform, characterised by a nanometric average surface roughness. The biocompatibility and cell-friendly properties of the RKKP glass–ceramic material have been tested. Cell metabolic activity and proliferation of human colon carcinoma CaCo-2 cells seeded on RKKP films showed the same exponential trend found in the control plastic substrates. By the phalloidin fluorescence analysis, no significant modifications in the actin distribution were revealed in cells grown on RKKP films. Moreover, in these cells a high mRNA expression of markers involved in protein synthesis, proliferation and differentiation, such as villin (VIL1), alkaline phosphatase (ALP1), β-actin (β-ACT), Ki67 and RPL34, was recorded. In conclusion, the findings, for the first time, demonstrated that the RKKP glass–ceramic material allows the adhesion, growth and differentiation of the CaCo-2 cell line

The Impact of Native Fallot Anatomy on Future Therapeutic Requirements and Outcomes at Follow-up

Abstract Background: In patients with repaired Fallot, subsequent surgical or interventional procedures and adverse cardiac events are frequent. We aimed to evaluate the impact of a simple pre-operative anatomic classification based on the size of the pulmonary valve annulus and branches on future therapeutic requirements and outcomes.Method This is a single-center retrospective analysis of patients operated for Fallot before the age of 2 years, from January 1990. Pre-operative anatomy, surgical and interventional procedures and adverse events were extrapolated from clinical records. Results: Among the 312 patients, a description of the PV and PAs native anatomy was known in 239 patients (male:147, 61.5%), which were divided in the following 3 groups: group 1 (65 patients) with normal size of both pulmonary valve and pulmonary artery branches; group 2 (108 patients) with pulmonary valve hypoplasia but normal size pulmonary artery branches; group 3 (66 patients) with concomitant hypoplasia of the pulmonary valve and pulmonary artery branches. During the 12.7 years (IQR 6.7-17) follow-up time, 23% of patients required at least one surgical or interventional procedure. At Kaplan-Meier analysis, there was a significant difference in requirement of future surgical or interventional procedures among the 3 groups (p&lt;0,001). At multivariate Cox regression analysis, hypoplasia of pulmonary valve and artery branches was an independent predictor of subsequent procedures (HR:3.1,CI:1.06-9.1, p=0.03). Conclusion native anatomy in Tetralogy of Fallot patients affects surgical strategy and follow-up. It would be therefore advisable to tailor patient’s counseling and follow-up according to native anatomy, rather than following a standardized protocol.</jats:p