Browsing by Author "Dias, Ester"
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- Allochthonous-derived organic matter subsidizes the food sources of estuarine jellyfishPublication . Morais, Pedro; Dias, Ester; Cruz, Joana; Chainho, P.; Costa, J. L.; Angélico, M. M.; Barbosa, Ana; Teodosio, MariaJellyfish modulate the energy fluxes between compartments of aquatic ecosystems and the period that energy remains within each compartment. However, the contribution of different sources of organic matter (OM) to the production of most estuarine jellyfish species is unknown. Therefore, this study aimed to identify and quantify the putative sources of OM for Blackfordia virginica (Cnidaria, Hydrozoa) Mayer, 1910 in two temperate estuaries, based on the analyses of carbon and nitrogen stable isotope ratios. Zooplankton was the main source of OM assimilated by B. virginica in both Mira and Guadiana estuaries. However, particulate organic matter (POM) also contributed to B. virginica biomass, up to 26 and 37% in Mira and Guadiana estuaries, respectively. The POM pool was apparently comprised by terrestrial derived OM, as based on stable isotope ratios and C:NPOM. Terrestrial-derived OM is an undescribed carbon source for estuarine jellyfish. Our results support a working hypothesis stating that terrestrial-derived OM might support good physiological condition of B. virginica during periods of low metazooplankton abundance, through a detritus based microbial food web transformation. Subsequent studies on trophic pathways ought to evaluate the temporal contribution of autochthonous and allochthonous OM and its consequences, accounting for the connectivity across ecosystems (terrestrial-estuarine-marine) and the interactions within compartments (pelagic-benthic).
- Assessing the morphological variability of unio delphinus spengler, 1783 (Bivalvia: Unionidae) using geometric morphometryPublication . Morais, Pedro; Rufino, Marta M.; Reis, Joaquim; Dias, Ester; Sousa, RonaldoThe morphological variability of freshwater bivalve species, observed between and within river basins, may hamper their correct identification, even by experienced researchers. Classic morphometric measurements, i.e. shell length, height and thickness, or their ratios, are generally insufficient to distinguish populations and/or species. These issues may be overcome using a geometric morphometric method, which allows analysis of the overall shape of the individual, independently of its size. Thus, we aimed to test the usefulness of two geometric morphometric tools, landmarks and sliding semilandmarks, to evaluate the morphological variability of Unio delphinus Spengler, 1783 in three habitats of the Guadiana Basin (SW Iberian Peninsula, Europe): estuary, river and stream. We used 13 landmarks located on the shell interior (at the teeth, muscle scars and pallial line) and 35 sliding semilandmarks for the shell contour. These morphometric analyses showed that the shell shape of U. delphinus differs significantly among different habitats. Estuarine and stream shells are the most disparate (James index = 649.114, permutation P-value <0.001) and variability is not related to variations in shell size. The main differences in shell morphology are the following: (1) estuarine shells are more elongate, while riverine shells are more subovate; (2) the anterior curvature at the umbo is steeper in estuarine and riverine shells; (3) estuarine shells have an arched curvature at the ventral part of the shell, which is absent in specimens from the other habitats. Our data suggest that the morphology of U. delphinus shells might be influenced by the water flow characteristics of each habitat, since shells exhibited characteristics that are typically observed in freshwater mussels from lotic and lentic habitats.
- Benthic food webs support the production of sympatric flatfish larvae in estuarine nursery habitatPublication . Dias, Ester; Morais, Pedro; Faria, Ana M.; Antunes, C.; Hoffman, Joel C.Identifying nursery habitats is of paramount importance to define proper management and conservation strategies for flatfish species. Flatfish nursery studies usually report upon habitat occupation, but few attempted to quantify the importance of those habitats to larvae development. The reliance of two sympatric flatfish species larvae, the European flounder Platichthys flesus and the common sole Solea solea, on the estuarine food web (benthic versus pelagic), was determined through carbon and nitrogen stable isotope analysis. The organic matter sources supporting the production of P.flesus and S.solea larvae biomass originates chiefly in the benthic food web. However, these species have significantly different C-13 and N-15 values which suggest that they prey on organisms that use a different mixture of sources or assimilate different components from similar OM pools (or both).
- Dataset of the complete mitogenome of the deep-sea sailfin roughshark, Oxynotus paradoxus Frade, 1929Publication . Matos, Ana; Gomes-dos-Santos, André; Graça Aranha, Sofia; Dias, Ester; Veríssimo, Ana; Teodosio, Maria; Figueiredo, Ivone; Castro, L. Filipe C.; Froufe, ElsaChondrichthyans comprise a diverse group of vertebrate species with extraordinary ecological relevance. Yet, multiple members of this evolutionary lineage are associated with sig-nificant extinction risk. The sailfin roughshark Oxynotus para-doxus is a deep-water benthic shark currently listed as vul-nerable due to population declines in parts of its range. Here we provide the first complete mitochondrial genome of O. paradoxus, comprising also the first record for the genus and family Oxynotidae. These data can facilitate future monitor-ing of the genetic diversity in this and related species. Ge-nomic DNA was extracted from O. paradoxus collected in the eastern North Atlantic off western Portugal (37.59 degrees N, 9.51 degrees W) and sent for Illumina Paired-End (2 x 150 bp) library con-struction and whole genome sequencing on a Novaseq60 0 0 platform. Trimmomatic (version 0.38) was used to remove adapters and MitoZ (version 3.4) to assemble and anno-tate the mitogenome. This mitogenome with 17 100 bp has a total of 38 genes, 13 of which are protein-coding genes, 23 transfer RNA genes, and 2 ribosomal RNA genes. Eight transfer RNAs and 1 protein-coding gene (NADH de-hydrogenase subunit 6, NAD6) are in the complementary strand. In the provided phylogenetic inference, with all avail-able and verified Squalomorphii mitogenomes, the four or-ders are well separated, and as expected, O. paradoxus is placed in the Squaliformes order. This data reinforces the need for more genomic resources for the Oxynotidae family.(c) 2023 The Author(s). Published by Elsevier Inc. This is an open access article under the CC BY-NC-ND license ( http://creativecommons.org/licenses/by-nc-nd/4.0/ )
- Estuarine consumers utilize marine, estuarine and terrestrial organic matter and provide connectivity among these food websPublication . Dias, Ester; Morais, Pedro; Cotter, Anne M.; Antunes, C.; Hoffman, Joel C.The flux of organic matter (OM) across ecosystem boundaries can influence estuarine food web dynamics and productivity. However, this process is seldom investigated taking into account all the adjacent ecosystems (e.g. ocean, river, land) and different hydrological settings (i.e. river discharge). Therefore, we aimed to quantify the contribution of autochthonous and allochthonous OM to the lower food web along the estuarine salinity gradient, under different river discharge conditions. The carbon (C) and nitrogen (N) stable isotope ratios of pelagic (zooplankton) and benthic (Corbicula fluminea) primary consumers indicated that they rely on a mixture of autochthonous and allochthonous OM, including terrestrial-derived OM. Unexpectedly, the highest contribution of terrestrial-derived OM to the estuarine food web was observed during a low river discharge period (up to 70%), that succeeded a large winter flood, showing that extreme weather events may produce prolonged effects on estuarine food webs. The contribution of marine-derived OM was higher during low river discharge periods (up to 88%) and was restricted to the seaward end of the estuary. Concomitantly, the contribution of phytoplankton to primary consumers was the highest observed (up to 91%). Further, both pelagic and benthic consumers also relied on benthic C (i.e. sediment OM and microphytobenthos). This study demonstrates that primary consumers enhance connectivity between estuarine ecosystems by utilizing subsidies of terrestrial and marine origin, and also between estuarine habitats through reliance on pelagic and benthic OM.
- Feeding ecology of sicydium bustamantei (Greeff 1884, Gobiidae) post-larvae: the “Little Fish” of São Tomé IslandPublication . Baptista, Vânia; Dias, Ester; Cruz, Joana; Branco, Maria; Vieira, Sara; Teodosio, Maria AlexandraThe rivers of São Tomé Island are colonized by Sicydium bustamantei (Greeff 1882), an amphidromous fish that spawns in those areas. After hatching, larvae drift to the ocean with the river flow. In the marine realm, the planktonic larvae develop and migrate to freshwater as post-larvae. The migrations of post-larvae support important local fisheries at the mouth of rivers in tropical volcanic islands. Amphidromous post-larvae rely on plankton as their main source of organic matter. However, the biology and ecology of S. bustamantei in the West African islands are understudied, despite its importance for local fisheries. Thus, this study aimed to start bridging this gap by studying its feeding ecology. Our objectives were to identify the main prey of S. bustamantei post-larvae, combining gut content with stable isotope analyses. The gut contents included zooplankton (Chaetognatha, Ostracoda, and unidentified crustaceans), debris from plant and/or macroalgae-derived material, and microplastics (including microfibers). The stable isotopes analysis indicated that zooplankton and macroalgae detritus were the main sources of organic matter assimilated by this species. We also demonstrated that S. bustamantei post-larvae are omnivorous and secondary consumers. These data provide pioneering information that can be used in management plans that still need to be developed.
- Gelificação dos oceanos – e a culpa não é da alforrecaPublication . Morais, Pedro; Amorim, Katherine; Dias, Ester; Cruz, Joana; Barbosa, Ana; Teodosio, MariaOcean jellification is associated with increasing occurrence of jellyfishes. Jellyfish are gelatinous organisms, with a life cycle composed by sessile stage (polyp) and free living stage (medusa). Blooms jellies, which may have negative impact on fisheries and tourism, are strongly driven by the availability of food, since predators are relatively reduce. The diet of jellies includes small crustacean, egg and fish larvae. Yet, recent UAlg studies showed a much more diverse diet (ex: drifting microbes, terrestrial detritus). Major contributors for ocean jellification are closed connect to men activities and include: (1) excessive input of nutrients (ex: sewage agriculture fertilizers), (2) overfishing of fishes and sea turtles; (3) introduction of artificial structures and (4) changes in hydrological cycle (ex: river dams).
- A glimpse into the trophic ecology of deep‐water sharks in an important crustacean fishing groundPublication . Graça Aranha, Sofia; Teodosio, MA; Baptista, Vânia; Erzini, Karim; Dias, EsterDeep-water sharks are among the most vulnerable deep-water taxa because of their extremely conservative life-history strategies (i.e., late maturation, slow growth, and reproductive rates), yet little is known about their biology and ecology. Thus, this study aimed at investigating the trophic ecology of five deep-water shark species, the birdbeak dogfish (Deania calcea), the arrowhead (D. profundorum), the smooth lanternshark (Etmopterus pusillus), the blackmouth catshark (Galeus melastomus) and the knifetooth dogfish (Scymnodon ringens) sampled onboard a crustacean bottom-trawler off the south-west coast of Portugal. We combined carbon and nitrogen stable isotopes with RNA and DNA (RD) ratios to investigate the main groups of prey assimilated by these species and their nutritional condition, respectively. Stable isotopes revealed overall small interspecific variability in the contribution of different taxonomic groups to sharks' tissues, as well as in the origin of their prey. S. ringens presented higher delta N-15 and delta C-13 values than the other species, suggesting reliance on bathyal cephalopods, crustaceans and teleosts; the remaining species likely assimilated bathy-mesopelagic prey. The RD ratios indicated that most of the individuals had an overall adequate nutritional condition and had recently eaten. This information, combined with the fact that stable isotopes indicate that sharks assimilated prey from the local or nearby food webs (including commercially important shrimps), suggests a potential overlap between this fishing area and their foraging grounds, which requires further attention.
- Harnessing the power of social media to obtain biodiversity data about cetaceans in a poorly monitored areaPublication . Morais, Pedro; Afonso, Luís; Dias, EsterThe study and conservation of cetaceans benefit from systematic studies and non systematic records about sightings and strandings. However, iEcology (internet ecology) was critical for numerous ecological studies and should be in the toolkit of cetacean ecologists. We hypothesize that iEcology is irreplaceable to obtain diversity data about cetaceans in poorly monitored regions that coincide with touristic destinations, where whale-watching companies go out to sea regularly and post their sightings on social media. Our study assessed the advantages and disadvantages of iEcology while obtaining the first broadscale and long-term assessment about cetaceans’ diversity off the Algarve, a European tourist destination with numerous whale-watching companies. We retrieved 1,299 time-referenced records about 15 species posted on Facebook and Instagram between 2011 and 2020. Data collected from Biodiversity4All, an online citizen science biodiversity database, disclosed georeferenced records about nine species made between 2008 and 2020, however, the number of records was 15.8 times lower than social media posts. We obtained information about 16 species, two of which were never mentioned in the scientific literature [Balaenoptera musculus, Balaenoptera edeni (record made in 2021)] and five species were only mentioned in the gray literature. Previous assessments were restricted in time, published in the gray literature, and only reported six and 11 species. So, social media was essential to obtain the first broadscale and long-term assessment of cetaceans’ diversity off the Algarve. The main advantages of iEcology were the possibility to obtain data collected over one decade and its low cost. The main disadvantages are the impossibility to obtain georeferenced records from social media, the difficulty to estimate the number of individuals in large groups, and the presence of rare species can be inflated if multiple whale-watching companies report the same individual(s) while they migrate along the coast. Nonetheless, these disadvantages can be mitigated. Overall, we endorse the use of iEcology to increase the ecological knowledge about cetaceans which might be the only tool to study them in numerous regions across the world. The contributions of whale-watching companies are invaluable, so we recommend the implementation of a standardized cetacean observation log as a relevant source of data for conservation.
- Innate feeding plasticity and animal prey support invasiveness of aquatic species in a southwestern European estuaryPublication . da Silva Encarnação, João Pedro; Dias, Ester; Engelen, Aschwin; Serrao, Ester A.; Morais, Pedro; Teodosio, MariaNon-indigenous species often rely on trophic plasticity to adjust to available food sources and even to avoid interspecific competition while overcoming environmental constraints during the establishment phase and, eventually, as they become invasive. The Atlantic blue crab Callinectes sapidus Rathbun, 1896 is expanding quickly in southwestern Europe and northwestern Africa, raising concerns about its impacts. Its feeding ecology in non-native areas is poorly understood, so this study aimed to 1) unveil the diet and feeding strategy used by the Atlantic blue crab in a highly invaded European estuary, 2) evaluate if their invasiveness was facilitated by an invasion meltdown process concerning trophic facilitation, and 3) determine its trophic position. Metagenomic analyses of gut content and stable isotopes showed that the species relied on opportunistic and carnivorous feeding traits and preyed mainly on native animal species, such as fish, shrimps, and oysters. We did not observe evidence of a widespread invasion meltdown process through trophic facilitation mediated by other invaders. The Atlantic blue crab’s trophic niche overlapped with two native crab species, particularly the European green crab Carcinus maenas (Linnaeus, 1758), while it’s high trophic position (4.3 ± 0.5) reflected the reliance on animal prey. These evidence suggests that trophic plasticity likely contributed to the invasiveness of the Atlantic blue crab because of its ability to exploit readily available prey. The Atlantic blue crab metapopulation is expanding and increasing over a vast region, and unfortunately a series of cascading effects throughout the food web can still be expected, as observed elsewhere.