Interactions between seagrasses and seaweeds during surge nitrogen acquisition determine interspecific competition

Seagrasses dominate shallow coastal environments where nitrogen (N) availability in the water column is often sporadic and mainly in the form of pulses. We investigated the N uptake competition between seagrasses and seaweeds through a series of N-15 surge uptake experiments combining single-species and mixed incubations across ammonium concentrations. N surge uptake rates of seagrasses were 2 to 14-fold higher than those of seaweeds in the majority of combinations, showing that seagrasses are generally in a competitive advantage over seaweeds in N-poor environments with N-pulses. No threshold concentration of ammonium was found beyond which seaweeds performed better than seagrasses. Mixed incubations revealed interspecific interactions that affected rates positively and negatively. Uptake rates obtained in single-species incubations, therefore, cannot always be used to predict the outcome of uptake competition. Only two (Zostera marina vs. Ulva rotundata and Zostera marina vs. Codium decorticatum) of the nine combinations tested (Z. marina, Z. noltei and Cymodocea nodosa vs. U. rotundata, C. decorticatum and Dictyota dichotoma) were found to enhance macroalgal uptake. Our results showed that the surge uptake capacity of seagrasses represents an important mechanism in their N acquisition strategy that justifies their dominance in shallow oligotrophic environments.Portuguese Foundation for Science and Technology (FCT) [PTDC/MAR/098069/2008, SFRH/BPD/63703/2009]; FCT - Foundation for Science and Technology [CCMAR/Multi/04326/2013

Os contributos dos grupos heterogéneos para a aprendizagem e desenvolvimento em educação de infância

Relatório da prática profissional supervisionada apresentado à Escola Superior de Educação de Lisboa para obtenção de grau de mestre em Educação Pré-EscolarO presente relatório surge no âmbito da Unidade Curricular (UC) da Prática Profissional Supervisionada (PPS) em jardim de infância (JI), do Mestrado em Educação Pré-Escolar. Este documento visa espelhar, de forma crítica e reflexiva, o caminho trilhado durante cerca de seis meses e meio de intervenção pedagógica com um grupo de crianças com idades compreendidas entre os 2 e os 6 anos de idade. Tendo em consideração o atual panorama socioeducativo, a problemática estudada surgiu, simultaneamente, da observação do contexto, especificamente do facto de o grupo de crianças com o qual iria contactar ser heterogéneo a nível etário. E do meu interesse no tema, isto porque a heterogeneidade sempre foi um tópico que me interessou e intimidou, por saber os seus benefícios para as crianças, mas por duvidar da minha capacidade em gerir constantemente um grupo tão desafiante nível do seu desenvolvimento e aprendizagens, como seria natural de esperar. Assim, fiquei interessada em compreender quais seriam os benefícios dessas interações para a aprendizagem e desenvolvimento das crianças e como seria realizada a gestão e organização do grupo pela equipa educativa. Metodologicamente, a investigação segue as diretrizes do método de estudo de caso e enquadra-se num paradigma de natureza qualitativa. Os dados foram recolhidos através da observação, notas de campo e entrevistas, sendo, posteriormente, analisados com recurso à análise de conteúdo. A investigação que conduzi na valência de JI possibilitou escutar as vozes das crianças e, deste modo, envolvê-las na construção de conhecimento acerca de si e dos seus mundos sociais. É importante ressalvar que nas interações entre as crianças transpareceram o carinho, a empatia e a atenção entre os pares. Também a responsabilidade, capacidade de liderança, autonomia e partilha de conhecimentos foram pontos a destacar. No que diz respeito às perceções das crianças, foi claro que as mesmas preferem estar num grupo com crianças de idades diferentes, existindo uma clara preferência por ajudar as crianças mais novas e brincar com todas as crianças, existindo uma maior incidência para a preferência por brincar com as crianças mais velhas. Relativamente à perceção da equipa educativa, isto é, a educadora cooperante e a auxiliar de ação educativa, ambas valorizam os grupos heterogéneos, referindo, com facilidade, inúmeros benefícios que os mesmos apresentam para as crianças. A realização de uma prática educativa diferenciada, de modo a acolher os interesses e necessidades das crianças, foi não só defendida pela equipa educativa, como sentida por mim nos vários momentos que a mesma proporcionou ao grupo.ABSTRACT This report was assembled for the curricular unit of Supervised Professional Practice (SPP) in kindergarten, included in the master’s degree in Preschool Education. This document reflects, in a critical and reflective manner, the path taken during the six months and a half of pedagogical intervention with a group of children with ages between 2 and 6 years old. In the current socio-educational panorama, the studied problem arose, simultaneously, from the observation of the context, specifically, from the fact that the group of children with whom it would contact would be heterogeneous at an age level. And of my interest in the theme, because heterogeneity has always been a topic that interested and intimidated me, for knowing its benefits for children, but for doubting my ability to constantly manage a group with such a challenging level of development and learning, as would be natural to expect. In obtaining this information I was interested in understanding what the benefits of these interactions were, for the learning and developing process of the children and how the group would be managed and organized. Methodologically, the investigation follows the guidelines of the case study and is part of a qualitative paradigm. The data were collected through observation, field notes and interviews, after that, the data were analyzed using content analysis. On the other hand, the research I conducted in the valence of JI (kindergarten) made it possible to listen to the voices of the children and, thus, to involve them in the construction of knowledge about themselves and their social worlds. Therefore, it is important to note that the interactions between the children imparted affection, empathy, and attention among peers. Also, the sense of responsibility, capacity of leadership, autonomy, and the sharing of knowledge were points to highlight. As far as children's perceptions are concerned, they prefer to be in a group with children of different ages but prefer to help younger children and play with all the children, however, there were a clear preference for playing with older children. Regarding the perception of the educational team, they both value heterogeneous groups, easy referring to the countless benefits it has for the children. The carrying of a differentiated practice, to welcome the interests and needs of children, was not only defended by the educational team, as felt by me in the various moments that we´re provided to the group, by them, on a daily basis.N/

A tale of two Spartinas: Climatic, photobiological and isotopic insights on the fitness of non-indigenous versus native species

International audienceSalt marshes are facing a new threat: the invasion by non-indigenous species (NIS), Although its introduction time is not established yet, in 1999 Spartina versicolor was already identified as a NIS in the Mediterranean marshes, significantly spreading its area of colonization. Using the Mediterranean native Spartina maritima as a reference, the present research studied the ecophysiological fitness of this NIS in its new environment, as a tool to understand its potential invasiveness. It was found that Spartina versicolor had a stable photobiological pattern, with only minor fluctuations during an annual cycle, and lower efficiencies comparated to S. maritima. The NIS seems to be rather insensitive to the observed abiotic factors fluctuations (salinity and pH of the sediment), and thus contrasts with the native S. maritima, known to be salinity dependent with higher productivity values in higher salinity environments. Most of the differences observed between the photobiology of these species could be explained by their nitrogen nutrition (here evaluated by the δ15N stable isotope) and directly related with the Mediterranean climate. Enhanced by a higher N availability during winter, the primary production of S. maritima which lead to dilution of the foliar δ15N concentration in the newly formed biomass, similarly to what is observed along a rainfall gradient. On the other hand, S. versicolor showed an increased δ15N in its tissues along the annual rainfall gradient, probably due to a δ15N concentration effect during low biomass production periods (winter and autumn). Together with the photobiological traits, these isotopic data point out to a climatic misfit of S. versicolor to the Mediterranean climate compared to the native S. maritima. This appears to be the major constrain shaping the ecophysiological fitness of this NIS, its primary production and consequently, its spreading rate along the Mediterranean marshes

Cephalopods in the diet of nonbreeding black-browed and grey-headed albatrosses from South Georgia

The food and feeding ecology of albatrosses during the nonbreeding season is still poorly known, particularly with regard to the cephalopod component. This was studied in black-browed Thalassarche melanophris and grey-headed T. chrysostoma albatrosses by analysing boluses collected shortly after adults returned to colonies at Bird Island, South Georgia (54°S, 38°W), in 2009. Based on stable isotopic analyses of the lower beaks, we determined the habitat and trophic level (from δ13C and δ15N, respectively) of the most important cephalopods and assessed the relative importance of scavenging in terms of the albatrosses’ feeding regimes. Based on lower rostral lengths (LRLs), the main cephalopod species in the diets of both albatrosses was Kondakovia longimana, by frequency of occurrence (F > 90 %), number (N > 40 %) and mass (M > 80 %). The large estimated mass of many squid, including K. longimana, suggests that a high proportion (>80 % by mass) was scavenged, and that scavenging is much more important during the nonbreeding season than would be expected from breeding-season diets. The diversity of cephalopods consumed by nonbreeding birds in our study was similar to that recorded during previous breeding seasons, but included two new species [Moroteuthis sp. B (Imber) and ?Mastigoteuthis A (Clarke)]. Based on similarities in LRL, δ13C and δ15N, the squid consumed may have been from the same oceanic populations or region, with the exception of Taonius sp. B (Voss) and K. longimana, which, based on significant differences in δ15N values, suggest that they may have originated from different stocks, indicating differences in the albatrosses’ feeding regimes

Show your beaks and we tell you what you eat: Different ecology in sympatric Antarctic benthic octopods under a climate change context

Sympatry can lead to higher competition under climate change and other environmental pressures, including in South Georgia, Antarctica, where the two most common octopod species, Adelieledone polymorpha and Pareledone turqueti, occur side by side. Since cephalopods are typically elusive animals, the ecology of both species is poorly known. As beaks of cephalopods are recurrently found in top predator's stomachs, we studied the feeding ecology of both octopods through the evaluation of niche overlapping and specific beak adaptations that both species present. A multidisciplinary approach combining carbon (δ13C) and nitrogen (δ15N) stable isotope signatures, mercury (Hg) analysis and biomaterials' engineering techniques was applied to investigate the beaks. An isotopic niche overlap of 95.6% was recorded for the juvenile stages of both octopod species, dropping to 19.2% for the adult stages. Both A. polymorpha and P. turqueti inhabit benthic ecosystems around South Georgia throughout their lifecycles (δ13C: −19.21 ± 1.87‰, mean ± SD for both species) but explore trophic niches partially different during adult life stages (δ15N: 7.01 ± 0.40‰, in A. polymorpha, and 7.84 ± 0.65‰, in P. turqueti). The beaks of A. polymorpha are less dense and significantly less stiff than in P. turqueti. Beaks showed lower mercury concentration relative to muscle (A. polymorpha - beaks: 0.052 ± 0.009  μg g−1, muscle: 0.322 ± 0.088  μg g−1; P. turqueti - beaks: 0.038 ± 0.009  μg g−1; muscle: 0.434 ± 0.128  μg g−1). Overall, both octopods exhibit similar habitats but different trophic niches, related to morphology/function of beaks. The high Hg concentrations in both octopods can have negative consequences on their top predators and may increase under the present climate change context.British Antarctic Survey for assisting in the collection of the specimens for this work. Many thanks to 3B's Research Group (University of Minho) and MAREFOZ who were responsible for analysing the physical properties of beaks and stable isotope signatures. A special thank you to our colleague José Queirós from MARE-UC (Coimbra, Portugal) for his suggestions and guidance. A debt of gratitude is also owed to Dr. A. Louise Allcock (NUI Galway) for her useful guidelines. This work is an international effort under the Scientific Committee on Antarctic Research (SCAR) associated programs, expert and action groups, namely SCAR AnT-ERA, SCAR EGBAMM and ICED. J.C. Xavier was supported by the Investigator Programme (IF/00616/2013) of the Foundation for Science and Technology (FCT-Portugal) and PROPOLAR, and F.R. Ceia was supported by a postdoctoral fellowship (SFRH/BPD/95372/2013) attributed by FCT-Portugal and the European Social Fund (POPH, EU). This study benefited from the strategic program of MARE, financed by FCT-Portugal (MARE- UID/MAR/04292/2019). We also acknowledge FCT-Portugal through a PhD grant to J. Seco (SRFH/PD/BD/113487

A global analysis of Y-chromosomal haplotype diversity for 23 STR loci

In a worldwide collaborative effort, 19,630 Y-chromosomes were sampled from 129 different populations in 51 countries. These chromosomes were typed for 23 short-tandem repeat (STR) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS385ab, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, GATAH4, DYS481, DYS533, DYS549, DYS570, DYS576, and DYS643) and using the PowerPlex Y23 System (PPY23, Promega Corporation, Madison, WI). Locus-specific allelic spectra of these markers were determined and a consistently high level of allelic diversity was observed. A considerable number of null, duplicate and off-ladder alleles were revealed. Standard single-locus and haplotype-based parameters were calculated and compared between subsets of Y-STR markers established for forensic casework. The PPY23 marker set provides substantially stronger discriminatory power than other available kits but at the same time reveals the same general patterns of population structure as other marker sets. A strong correlation was observed between the number of Y-STRs included in a marker set and some of the forensic parameters under study. Interestingly a weak but consistent trend toward smaller genetic distances resulting from larger numbers of markers became apparent.Peer reviewe

Réseaux trophiques des écosystèmes intertidaux : étude par les isotopes stables et l'analyse des réseaux

This dissertation examines the estuarine food web related to the eelgrass Zostera noltii and quantifies the ecological trophic role of benthic macrofauna consumers, in intertidal areas of the Mondego estuary, covering different time periods from 1993 to 2008. It specifically focuses (i) on the incorporation of the nitrogen derived from human activities, considering the N uptake as an eutrophication index, and (ii) on the role of the eelgrass in the benthic food web. In addition, six mass-balanced models were developed to assess the effects of (i) a period of nutrient enrichment, (ii) the implementation of mitigation measures, and (iii) a centenary flood, on the benthic estuarine food web properties.Cette thèse de Doctorat examine le réseau trophique estuarien lié aux herbiers à zostères, Zostera noltii et quantifie le rôle trophique des consommateurs de la macrofaune benthique, dans deux zones intertidales de l’estuaire du Mondego, à différentes périodes de 1993 à 2008. Elle s’intéresse spécifiquement (i) à l’incorporation de l’azote issu des activités humaines, en considérant l’assimilation d’azote comme un indicateur de l’eutrophication et (ii) au rôle des zostères dans le réseau trophique benthique. Six modèles ont été développés afin d’analyser les effets, (i) d’un enrichissement en nutriments, (ii) des mesures de mitigation, et (iii) d’une inondation centennale, sur les propriétés du réseau trophique benthique estuarien. La présence de Z. noltii change peu la structure du réseau trophique planctonique, soutenu en partie par la matière organique particulaire et supporte principalement des poissons comme prédateurs. Les autres consommateurs montrent une grande variabilité de signature isotopique, ce qui suggère qu’ils peuvent changer de régime alimentaire en fonction des changements de l’environnement. En revanche, les δ13C et δ15N des producteurs et consommateurs de l’estuaire du Mondego montrent très peu de variation saisonnière, malgré une saisonnalité météorologique marquée, ainsi qu’une forte variation saisonnière des paramètres de la colonne d’eau (apports en sels nutritifs et concentration en chlorophylle a). Les modèles à l’état stable montrent enfin que la structure trophique de la communauté benthique de l’estuaire du Mondego est affectée différemment par chacun des évènements particuliers étudiés

Food webs in intertidal ecosystems : a stable isotope approach and trophic network analysis

Tese de doutoramento em Biologia (Ecologia) apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbr

Feeding ecology of the green crab, Carcinus maenas (L., 1758) in a temperate estuary, Portugal

The feeding ecology of Carcinus maenas was studied between June 2003 and June 2004 in three areas in the Mondego estuary, Portugal. Samples were collected monthly, during the night, at high water of spring tides using a 2 m beam trawl. Among 837 stomachs examined, 25 different food items were identified. Crangon crangon, Hediste diversicolor, and Teleostei were the most important food items by occurrence, numbers, and weight. As an opportunistic feeder, differences in diet found between areas and seasons reflected prey availability. No differences were found in prey selection according to sex and carapace width of individuals. The feeding intensity of moulting and ovigerous crabs was lower. The incidence of cannibalism was higher than reported in the literature. C. maenas seems to be a main top predator in the food web of the Mondego estuarine ecosystemA ecologia alimentar de Carcinus maenas foi estudada entre Junho de 2003 e Junho de 2004 em três locais no estuário do Mondego, Portugal. As amostras foram colhidas mensalmente, durante a noite, na vazante de marés vivas usando um arrasto de vara com 2 m. Entre os 837 estômagos examinados, 25 itens alimentares diferentes foram identificados. Crangon crangon, Hediste diversicolor e Teleostei foram os itens alimentares mais importantes por ocorrência, número e peso. Sendo um consumidor oportunista, as diferenças na dieta encontradas entre locais e estações do ano refectem a disponibilidade das presas no meio. Não foram encontradas diferenças na selecção de presas de acordo com o sexo e a largura da carapaça dos indivíduos. A intensidade alimentar dos caranguejos em muda e fêmeas ovigeras foi baixa. A incidência de canibalismo foi mais elevada do que reportado na literatura. C. maenas parece ser um predador topo na teia alimentar do ecossistema estuarino do Mondeg