Occurrence of antibiotics and bacterial resistance in wastewater and sea water from the Antarctic

The potential presence of introduced antibiotics in the aquatic environment is a hot topic of concern, particularly in the Antarctic, a highly vulnerable area protected under the Madrid protocol. The increasing presence of human population, especially during summer, might led to the appearance of pharmaceuticals in wastewater. The previous discovery of Escherichia coli strains resistant to antibiotics in sea water and wastewater collected in King George Island motivated our investigation on antibiotics occurrence in these samples. The application of a multi-residue LCMS/MS method for 20 antibiotics, revealed the presence of 8 compounds in treated wastewater, mainly the quinolones ciprofloxacin and norfloxacin (92% and 54% of the samples analyzed, average concentrations 0.89 μg/L and 0.75 μg/L, respectively) and the macrolides azithromycin and clarithromycin (15% positive samples, and average concentrations near 0.4 μg/L), and erythromycin (38% positive samples, average concentration 0.003 μg/L). Metronidazole and clindamycin were found in one sample, at 0.17 and 0.1 μg/L, respectively; and trimethoprim in two samples, at 0.001 μg/L. Analysis of sea water collected near the outfall of the wastewater discharges also showed the sporadic presence of 3 antibiotics (ciprofloxacin, clindamycin, trimethoprim) at low ng/L level, illustrating the impact of pharmaceuticals consumption and the poor removal of these compounds in conventional WWTPs. The most widespread antibiotic in sea water was ciprofloxacin, which was found in 15 out of 34 sea water samples analyzed, at concentrations ranging from 4 to 218 ng/L. Bacteria resistance was observed for some antibiotics identified in the samples (e.g. trimetropim and nalidixic acid –a first generation quinolone). However, resistance to some groups of antibiotics could not be correlated to their presence in the water samples due to analytical limitations (penicillins, tetraciclines). On the contrary, for some groups of antibiotics detected in samples (macrolides), the antibacterial activity against E. Coli was not investigated because these antibiotics do not include this bacterial species in their spectrum of activity. Our preliminary data demonstrate that antibiotics occurrence in the Antarctic aquatic environment is an issue that needs to be properly addressed. Periodical monitoring of water samples and the implementation of additional treatments in the WWTPs are recommended as a first step to prevent potential problems related to the presence of antibiotics and other emerging contaminants in the near future in Antarctica

La salut dels oceans

Mesa redonda online “La salud de los océanos” para el Máster de Comunicación Científica, Médica y Ambiental de la Barcelona School of Management (BSM-UPF) y con motivo del Día Mundial de los Océanos[ES] ¿Están en riesgo los ecosistemas marinos? Las emisiones de CO2, los plásticos, el cambio climático, la contaminación y la sobreexplotación de los recursos naturales son ejemplos de amenazas que ponen en riesgo la salud de los mares y océanos. Una de estas amenazas además, se ha visto aumentada con la situación actual que vivimos por coronavirus. El uso de mascarillas y guantes desechables y de productos de un solo uso ha aumentado por parte de la ciudadanía, y empiezan a aparecer estos residuos también en los ecosistemas marinos. ¿En qué situación se encuentran los océanos?[CAT] Estan en risc els ecosistemes marins? Les emissions de CO₂, els plàstics, el canvi climàtic, la contaminació i la sobreexplotació dels recursos naturals són exemples d’amenaces que posen en risc la salut de mars i oceans. Una d’aquestes amenaces a més, s’ha vist augmentada amb la situació actual que vivim pel coronavirus. L’ús de màscares, guants i productes d’un sol ús ha augmentat per part de la ciutadania, i comencen a aparèixer com a residus també en els ecosistemes marins. En quina situació es troben els oceans

Effects of low salinity on adult behavior and larval performance in the intertidal gastropod Crepipatella peruviana (Calyptraeidae).

Shallow-water coastal areas suffer frequent reductions in salinity due to heavy rains, potentially stressing the organisms found there, particularly the early stages of development (including pelagic larvae). Individual adults and newly hatched larvae of the gastropod Crepipatella peruviana were exposed to different levels of salinity stress (32(control), 25, 20 or 15), to quantify the immediate effects of exposure to low salinities on adult and larval behavior and on the physiological performance of the larvae. For adults we recorded the threshold salinity that initiates brood chamber isolation. For larvae, we measured the impact of reduced salinity on velar surface area, velum activity, swimming velocity, clearance rate (CR), oxygen consumption (OCR), and mortality (LC50); we also documented the impact of salinity discontinuities on the vertical distribution of veliger larvae in the water column. The results indicate that adults will completely isolate themselves from the external environment by clamping firmly against the substrate at salinities ≤24. Moreover, the newly hatched larvae showed increased mortality at lower salinities, while survivors showed decreased velum activity, decreased exposed velum surface area, and decreased mean swimming velocity. The clearance rates and oxygen consumption rates of stressed larvae were significantly lower than those of control individuals. Finally, salinity discontinuities affected the vertical distribution of larvae in the water column. Although adults can protect their embryos from low salinity stress until hatching, salinities <24 clearly affect survival, physiology and behavior in early larval life, which will substantially affect the fitness of the species under declining ambient salinities

Reproductive biology of the encapsulating, brooding gastropod Crepipatella dilatata Lamarck (Gastropoda, Calyptraeidae).

Among calyptraeid gastropods, males become females as they get older, and egg capsules containing developing embryos are maintained beneath the mother's shell until the encapsulated embryos hatch. Crepipatella dilatata is an interesting biological model considering that is an estuarine species and thus periodically exposed to elevated environment-physiological pressures. Presently, there is not much information about the reproductive biology and brooding parameters of this gastropod. This paper describes field and laboratory observations monitoring sex changes, brooding frequencies, sizes of brooding females, egg mass characteristics, and embryonic hatching conditions. Our findings indicate that C. dilatata is a direct-developing protandric hermaphrodite, changing from male to female when individuals were between 18 and 20 mm in shell length. At our study site in Quempillén estuary, females were found to be brooding almost continuously throughout the year, having an average maximum of 85% of simultaneous brooding, with a short rest from April through June. No relationship was found between the number of capsules per egg mass and the size of the brooding female. However, capsule size and the number of embryos and nurse eggs were strongly related to female size. The offspring hatched with an average shell length > 1 mm. About 25% of the hatched capsules were found to contain both metamorphosed (juveniles) and non-metamorphosed (veliger) individuals. The sizes of the latter were < 1000 μm. The length of hatching juveniles was inversely related to the number of individuals per capsule, which seems related to differences in the availability of nurse eggs per embryo. Although fecundity per reproductive event of this species is relatively low (maximum approx. 800 offspring per egg mass) compared with those of calyptraeid species showing mixed development, the overall reproductive potential of C. dilatata seems to be high considering that females can reproduce up to 5 times per year, protecting their encapsulated embryos from physical stresses until well-developed juveniles are released into the population, avoiding a dangerous pelagic period prior to metamorphosis

<i>Crepipatella peruviana:</i> Effect of low salinity on velar activity expressed as the percentage of veligers with extended velar lobes.

<p>Each bar represents the mean activity+one SD (total n = 4 replicates per treatments, with 50 veligers per replicate). Different letters above the bars indicate significant differences among means (p<0.05).</p

Results of a Two-way ANOVA performed on data from the experiment measuring the vertical distributions of <i>C. peruviana</i> veligers in environments of discontinuous salinity (32/32 (control), 32/25, 32/20, 32/15).

<p>Results of a Two-way ANOVA performed on data from the experiment measuring the vertical distributions of <i>C. peruviana</i> veligers in environments of discontinuous salinity (32/32 (control), 32/25, 32/20, 32/15).</p

<i>Crepipatella peruviana:</i> Effect of low salinity on veliger mortality (LC50).

<p>Each bar represents means and SD (total n = 3 replicates per treatments, with 100 veligers per replicate). Different letters above the bars indicate significant differences (p<0.05).</p

Effects of Ultraviolet Radiation on Sediment Burial Parameters and Photo-Oxidative Response of the Intertidal Anemone <i>Anthopleura hermaphroditica</i>

Anthopleura hermaphroditica is an intertidal anemone that lives semi-buried in soft sediments of estuaries and releases its brooded embryos directly to the benthos, being exposed to potentially detrimental ultraviolet radiation (UVR) levels. In this study, we investigated how experimental radiation (PAR: photosynthetically active radiation; UVA: ultraviolet A radiation; and UVB: ultraviolet B radiation) influences burrowing (time, depth and speed) in adults and juveniles when they were exposed to PAR (P, 400–700 nm), PAR + UVA (PA, 315–700 nm) and PAR + UVA + UVB (PAB, 280–700 nm) experimental treatments. The role of sediment as a physical shield was also assessed by exposing anemones to these radiation treatments with and without sediment, after which lipid peroxidation, protein carbonyls and total antioxidant capacity were quantified. Our results indicate that PAB can induce a faster burial response compared to those anemones exposed only to P. PAB increased oxidative damage, especially in juveniles where oxidative damage levels were several times higher than in adults. Sediment offers protection to adults against P, PA and PAB, as significant differences in their total antioxidant capacity were observed compared to those anemones without sediment. Conversely, the presence or absence of sediment did not influence total antioxidant capacity in juveniles, which may reflect that those anemones have sufficient antioxidant defenses to minimize photooxidative damage due to their reduced tolerance to experimental radiation. Burrowing behavior is a key survival skill for juveniles after they have been released after brooding

<i>Crepipatella peruviana:</i> Effect of ambient salinity on larval swimming velocity measured as the distance displaced by the veligers in a specified time.

<p>* Indicates absence of displacement. Each bar represents means and SD (total n = 4 replicates per treatment, with 10 veligers per replicate). Different letters above the bars indicate significant differences between means (p<0.05).</p

<i>Crepipatella peruviana</i>: Ability of adult females to maintain elevated salinity in the pallial cavity under conditions of low external salinity.

<p>Salinity was reduced from 32 to 15 at hour 2, as indicated. Each point represents the mean and SD (total n = 60, with 10 replicates for each time point).</p