Seasonal photosynthesis, respiration, and calcification of a temperate Maërl bed in southern Portugal

Rhodolith (maerl) beds are biodiversity hotspots with a worldwide distribution. Maerl is the general term for free-living non-geniculate rhodoliths or coralline red algae. In southern Portugal, maerl beds are mainly composed of Phymatolithon lusitanicum, recently identified as a new species and commonly misidentified as Phymatolithon calcareum. Photosynthesis, respiration, and growth rates of the algae were measured seasonally, as well as the photosynthetic pigment composition. To characterize the seasonal and interannual patterns of key abiotic conditions in the largest described maerl bed of the Portuguese coast, temperature, irradiance, and dissolved oxygen were continuously monitored over a 2-year period. At the bed depth (22 m), temperature ranged between 14 degrees C in winter and 24 degrees C in summer, irradiance varied from 5 to 75 mu.mol m(-2) s(-1) , and dissolved oxygen from 5.8 to 7.25 mg O-2 L-1. We found a strong linear relationship (r(2) = 0.95) between gross primary production (GPP) and relative electron transport rates (rETRs). Both methods led to similar results and an average molar ratio of 0.24. Photosynthesis and respiration increased in summer and decreased in autumn and winter. In the summer of 2013, the growth rates were twofold higher (1.34 mu.mol CaCO3 g(-1) day(-1)) than in the other seasons. In winter and spring, to compensate for light deprivation and low temperature, algae increased their chlorophyll a and carotenoid concentrations while also decreasing their phycobilin concentration, in this case probably due to nutrient limitation. To isolate the role of temperature on the algae's metabolism, the photosynthetic and respiration rates of individual thalli were measured at eight different temperatures in the laboratory (from 12 degrees C to 26 degrees C). Phymatolithon lusitanicum photosynthesis increased twofold after a threshold of 18 degrees C (from 2.2 at 18 degrees C to 3.87 mu mol O-2 m(-2) s(-1) at 20 degrees C), whereas respiration increased fourfold with temperature after a threshold of 22 degrees C (from -0.38 at 18 degrees C to -1.81 (mu mol O-2 m(-2) s(-1) at 24 degrees C). The significant increases on respiration, photosynthetic rates, and maximum growth with temperature reveal that the metabolic rates of P. lusitanicum are highly sensitive to ocean warming.UIDB/04326/2020info:eu-repo/semantics/publishedVersio

Temperature amplifies the effect of high CO2 on the photosynthesis, respiration, and calcification of the coralline algae Phymatolithon lusitanicum

The combination of ocean acidification (OA) and global warming is expected to have a significant effect on the diversity and functioning of marine ecosystems, particularly on calcifying algae such as rhodoliths (maërl) that form extensive beds worldwide, from polar to tropical regions. In addition, the increasing frequency of extreme events, such as heat waves, threatens coastal ecosystems and may affect their capacity to fix blue carbon. The few studies where the simultaneous effects of both temperature and CO2 were investigated have revealed contradictory results. To assess the effect that high temperature spells can have on the maërl beds under OA, we tested the short-time effects of temperature and CO2 on the net photosynthesis, respiration, and calcification of the recently described species Phymatolithon lusitanicum, the most common maërl species of southern Portugal. Photosynthesis, calcification, and respiration increased with temperature, and the differences among treatments were enhanced under high CO2. We found that in the short term, the metabolic rates of Phymatolithon lusitanicum will increase with CO2 and temperature as will the coupling between calcification and photosynthesis. However, under high CO2, this coupling will favor photosynthesis over calcification, which, in the long term, can have a negative effect on the blue carbon fixing capacity of the maërl beds from southern Portugal.FCT UID/Multi/04326/2019info:eu-repo/semantics/publishedVersio

Mäerl calcification, photosynthesis and respiration in an acidified ocean

With the increase of atmospheric CO2 and the associated acidification of the oceans, rhodolith (mäerl) beds are under severe threat. The general lack of consensus regarding the foreseeable effects of Ocean Acidification (OA) on coralline algae is largely due to the divergences of results obtained in different scientific experiments. These divergences may be related to differences in temperature, irradiance, CO2 levels, time of exposure and also on technical difficulties concerning the experimental methodologies used. This thesis aimed to determine the photosynthesis, calcification and respiration rates of the mäerl species Phymatolithon lusitanicum under natural conditions in Southern Portugal and to assess the effect that ocean acidification will have on these processes under different irradiances, temperatures, CO2 concentrations and times of exposure. Dark respiration and photosynthesis increased with temperature in summer and spring and decreased in winter and autumn while calcification rates did not change seasonally. A direct CO2 control system was developed and found to be reliable to assess the short and long term effect of OA on coralline algae. In the short term, photosynthesis and calcification increased with CO2 and temperature, but after prolonged exposure this pattern was reversed and algae exposed to high CO2 showed lower photosynthetic and calcification rates and accumulated growth with respect to control algae, effects that were enhanced with increasing irradiances. Dark respiration was unaffected by CO2 but increased with temperature. The results suggest that temperature, irradiance, CO2 level and time of exposure are determinant factors in ocean acidification experiments with coralline algae. Both temperature and high light intensified the effect of high CO2 on Phymatolithon lusitanicum and these will be determinant factors on the long-term resilience of Lusitanian rhodolith beds to OA.Face ao aumento do CO2 atmosférico e consequente acidificação dos oceanos os bancos de rodolitos (mäerl) estão severamente ameaçados. A falta de consenso relativamente aos efeitos previsíveis da acidificação do oceano nas algas calcárias deve-se sobretudo às muitas divergências encontradas entre as diferentes experiências científicas conduzidas ao longo dos últimos anos. Estas divergências estarão provavelmente relacionadas com diferenças na temperatura, irradiância, nível de CO2, tempo de exposição e metodologias utilizadas. Esta tese teve como objectivo principal determinar as taxas de fotossíntese, respiração e calcificação da espécie de mäerl mais comum nos bancos de rodolitos do Sul de Portugal, Phymatolithon lusitanicum, nas suas condições naturais e também investigar os efeitos que a acidificação oceânica terá nestes processos sob diferentes condições de irradiância, temperatura, concentração de CO2 e tempo de exposição. A respiração e a fotossíntese aumentaram com a temperatura no verão e na primavera, e diminuíram no inverno e no outono, embora a calcificação não tenha apresentado variações sazonais. Um sistema experimental de mesocosmos com controlo direto de CO2 foi desenvolvido e validado para avaliar o efeito da acidificação oceânica nas algas calcárias a curto e longo prazo. A curto prazo, a fotossíntese e a calcificação aumentaram tanto com o CO2 como com a temperatura, mas a longo prazo este padrão inverteu-se e as algas expostas a CO2 elevado mostraram menores taxas fotossintéticas e de calcificação e também menor crescimento acumulado do que as algas controlo, tendo o efeito do CO2 sido amplificado pela irradiância elevada. A respiração no escuro não foi afectada pelo CO2 mas aumentou com a temperatura. Os resultados sugerem que a temperatura, irradiância, o nível de CO2 e o tempo de exposição são fatores determinantes em experiências de acidificação do oceano com algas calcárias. Tanto a temperatura como a irradiância amplificam o efeito do CO2 em P. lusitanicum e estes serão factores determinantes na resiliência a longo prazo dos bancos de rodolitos lusitanos à acidificação oceânica

DOOp, an automated wrapper for DAOSPEC

Large spectroscopic surveys such as the Gaia-ESO Survey produce huge quantities of data. Automatic tools are necessary to efficiently handle this material. The measurement of equivalent widths in stellar spectra is traditionally done by hand or with semi-automatic procedures that are time-consuming and not very robust with respect to the repeatability of the results. The program DAOSPEC is a tool that provides consistent measurements of equivalent widths in stellar spectra while requiring a minimum of user intervention. However, it is not optimised to deal with large batches of spectra, as some parameters still need to be modified and checked by the user. Exploiting the versatility and portability of BASH, we have built a pipeline called DAOSPEC Option Optimiser (DOOp) automating the procedure of equivalent widths measurement with DAOSPEC. DOOp is organised in different modules that run one after the other to perform specific tasks, taking care of the optimisation of the parameters needed to provide the final equivalent widths, and providing log files to ensure better control over the procedure. In this paper, making use of synthetic and observed spectra, we compare the performance of DOOp with other methods, including DAOSPEC used manually. The measurements made by DOOp are identical to the ones produced by DAOSPEC when used manually, while requiring less user intervention, which is convenient when dealing with a large quantity of spectra. DOOp shows its best performance on high-resolution spectra (R>20 000) and high signal-to-noise ratio (S/N>30), with uncertainties ranging from 6 m{\AA} to 2 m{\AA}. The only subjective parameter that remains is the normalisation, as the user still has to make a choice on the order of the polynomial used for the continuum fitting. As a test, we use the equivalent widths measured by DOOp to re-derive the stellar parameters of four well-studied stars

Alteraçőes na estrutura e funcionamento de um banco de Halodule Wrightii (Cymodoceaceae) durante um florescimento massivo de epífitas na baía de Paranaguá (Paraná, Brasil) /

Orientador: Paulo da Cunha LanaDissertaçao (mestrado) - Universidade Federal do Paraná, Setor de Ciencias da Terra, Centro de Estudos do Mar, Programa de Pós-Graduaçao em Sistemas Costeiros e Oceânicos. Defesa: Pontal do Paraná, 2008Inclui bibliografia e anexo

Recreational harvesting of the wedge clam (Donax trunculus) in southern Portugal: characterization of the activity based on harvesters’ perception and local ecological knowledge

This study was the first attempt to characterize the recreational harvesting of the wedge clam (Donax trunculus). For this purpose, 403 face-to-face interviews were performed in the summers of 2018 and 2019 in southern Portugal. The majority of the harvesters frequented the selected beaches during holidays and collected wedge clams as a hobby for an appetizer. The respondents reported an inter-annual variation in their catches of wedge clam with a decreasing abundance in 2018 followed by a recovery in 2019, but with more recreational harvesters collecting undersized individuals. Although most harvesters declared to consume D. trunculus, only a few bought wedge clams being the clams' size a secondary factor in their valorization. The majority of the recreational harvesters did not know the species' minimum conservation reference size nor the legally allowed maximum daily catch. It was estimated that recreational harvesters can collect 13 tonnes of wedge clams during the summer season along the southeastern coast of Algarve. Even though manual harvesting is not an efficient fishing technique, the lack of selectivity of harvesters can eventually compromise the resilience of D. trunculus populations. Despite most respondents affirmed to get informed about marine biotoxins, most surveys were done during periods of interdiction for shellfish harvesting. The present results revealed that the population is still unaware of the health risks of consuming shellfish contaminated with biotoxins. Educational activities and awareness campaigns are required to further inform recreational harvesters about the regulations in force for this activity and the sanitary threats of marine biotoxins.VENUS” Ref. 0139_VENUS_5_E. 2017–2019; VENUS ref. IPMA-2018-008-BI;info:eu-repo/semantics/publishedVersio

FAMA: An automatic code for stellar parameter and abundance determination

The large amount of spectra obtained during the epoch of extensive spectroscopic surveys of Galactic stars needs the development of automatic procedures to derive their atmospheric parameters and individual element abundances. Starting from the widely-used code MOOG by C. Sneden, we have developed a new procedure to determine atmospheric parameters and abundances in a fully automatic way. The code FAMA (Fast Automatic MOOG Analysis) is presented describing its approach to derive atmospheric stellar parameters and element abundances. The code, freely distributed, is written in Perl and can be used on different platforms. The aim of FAMA is to render the computation of the atmospheric parameters and abundances of a large number of stars using measurements of equivalent widths as automatic and as independent of any subjective approach as possible. It is based on the simultaneous search for three equilibria: excitation equilibrium, ionization balance, and the relationship between \fei\ and the reduced equivalent widths. FAMA also evaluates the statistical errors on individual element abundances and errors due to the uncertainties in the stellar parameters. The convergence criteria are not fixed 'a priori' but are based on the quality of the spectra. In this paper we present tests performed on the Solar spectrum EWs which tests the dependency on the initial parameters, and the analysis of a sample of stars observed in Galactic open and globular clusters.Comment: A&A accepted, 12 pages, 6 figures, 3 table

Charge Transport Properties in CZT Detectors Grown by the Vertical Bridgman Technique

Great efforts are being presently devoted to the development of CdTe and CdZnTe detectors for a large variety of applications, such as medical, industrial, and space research. We present the spectroscopic properties of some CZT crystals grown by the standard vertical Bridgman method and by the boron oxide encapsulated vertical Bridgman method, which has been recently implemented at IMEM-CNR. By this technique the crystal is grown in an open quartz crucible fully encapsulated by a thin layer of liquid boron oxide. This technique prevent the crystal-crucible contact allowing larger single grains with lower dislocation density to be obtained. Several mono-electrode detectors were realized with two planar gold contacts. The samples are characterized by an active area of ≈4x4 mm2 or ≈7x7 mm2 and with thickness ranging from 1 to 2 mm. The charge transport properties of the detectors have been studied by mobility-lifetime (μτ) product measurements, carried out at the European Synchrotron Radiation Facility (Grenoble) in PTF configuration, where the impinging beam direction is orthogonal to the collecting electric field. We have performed several fine scans between the electrodes with a beam spot of 10x10 μm2 at different energies from 60 keV to 400 keV. In this work we present the test results in terms of μτ product of both charge carriers and an evaluation of the spectroscopic response uniformity across the sensitive volume of tested samples

Multiwalled carbon nanotubes hinder microglia function interfering with cell migration and phagocytosis

The intranasal drug delivery route provides exciting expectations regarding the application of engineered nanomaterials as nano-medicines or drug-delivery vectors into the brain. Among nanomaterials, multiwalled CNTs (MWCNTs) are some of the best candidates for brain cancer therapy since they are well known to go across cellular barriers and display an intrinsic ability to block cancer cell proliferation triggering apoptosis. This study reveals that microglial cells, the brain macrophages and putative vehicles for MWCNTs into the brain, undergo a dose-dependent cell division arrest and apoptosis when treated with MWCNTs. Moreover, it is shown that MWCNTs severely interfere with both cell migration and phagocytosis in live microglia. These results lead to a re-evaluation of the safety of inhaled airborne CNTs and provide strategic clues of how to biocompatibilize MWCNTs to reduce brain macrophage damage and to develop new nanodrugs

Case report: optic atrophy and nephropathy with m.13513G>A/MT-ND5 mtDNA pathogenic variant

Isolated complex I deficiency represents the most common mitochondrial respiratory chain defect involved in mitochondrial disorders. Among these, the mitochondrial DNA (mtDNA) m.13513G>A pathogenic variant in the NADH dehydrogenase 5 subunit gene (MT-ND5) has been associated with heterogenous manifestations, including phenotypic overlaps of mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes, Leigh syndrome, and Leber’s hereditary optic neuropathy (LHON). Interestingly, this specific mutation has been recently described in patients with adult-onset nephropathy. We, here, report the unique combination of LHON, nephropathy, sensorineural deafness, and subcortical and cerebellar atrophy in association with the m.13513G>A variant