Asian green mussels (Perna viridis) transplanted between Jakarta Bay and Lada Bay, West Java, Indonesia (April 2012 - November 2013)

The Asian green mussel Perna viridis is tolerant to environmental stress, but its robustness varies between populations from habitats that differ in quality. So far, it is unclear whether local adaptations through stressinduced selection or phenotypic plasticity are responsible for these inter-population differences. We tested for the relevance of both mechanisms by comparing survival under hypoxia in mussels that were transplanted from an anthropogenically impacted (Jakarta Bay, Indonesia) to a natural habitat (Lada Bay, Indonesia) and vice versa. Mussels were retrieved 8 weeks after transplantation and exposed to hypoxia in the laboratory. Additional hypoxia tests were conducted with juvenile mussels collected directly from both sites. To elucidate possible relationships between habitat quality and mussel tolerance, we monitored concentrations of inorganic nutrients, temperature, dissolved oxygen, salinity, phytoplankton density and the mussels' body condition index (BCI) for 20 months before, during and after the experiments. Survival under hypoxia depended mainly on the quality of the habitat where the mussels lived before the hypoxia tests and only to a small degree on their site of origin. Furthermore, stress tolerance was only higher in Jakarta than in Lada Bay mussels when the BCIs were substantially higher, which in turn correlated with the phytoplankton densities. We explain why phenotypic plasticity and high BCIs are more likely the causes of populationspecific differences in hypoxia tolerance in P. viridis than stress-induced selection for robust genotypes. This is relevant to understanding the role of P. viridis as mariculture organism in eutrophic ecosystems and invasive species in the (sub)tropical world.

Nitrite consumption and associated isotope changes during a river flood event in the Elbe river

In oceans, estuaries, and rivers, nitrification is an important nitrate source, and stable isotopes of nitrate are often used to investigate recycling processes (e.g. remineralisation, nitrification) in the water column. Nitrification is a two-step process, where ammonia is oxidised via nitrite to nitrate. Nitrite usually does not accumulate in natural environments, which makes it difficult to study the single isotope effect of ammonia oxidation or nitrite oxidation in natural systems. However, during an exceptional flood in the Elbe River in June 2013, we found a unique co-occurrence of ammonium, nitrite, and nitrate in the water column, returning towards normal summer conditions within 1 week. Over the course of the flood, we analysed the evolution of d15N-[NH4]+ and d15N-[NO2]- in the Elbe River. In concert with changes in suspended particulate matter (SPM) and d15N SPM, as well as nitrate concentration, d15N-NO3 - and d18O-[NO3] -, we calculated apparent isotope effects during net nitrite and nitrate consumption. During the flood event, > 97 % of total reactive nitrogen was nitrate, which was leached from the catchment area and appeared to be subject to assimilation. Ammonium and nitrite concentrations increased to 3.4 and 4.4 µmol/l, respectively, likely due to remineralisation, nitrification, and denitrification in the water column. d15N-[NH4]+ values increased up to 12 per mil, and d15N-[NO2]- ranged from -8.0 to -14.2 per mil. Based on this, we calculated an apparent isotope effect 15-epsilon of -10.0 ± 0.1 per mil during net nitrite consumption, as well as an isotope effect 15-epsilon of -4.0 ± 0.1 per mil and 18-epsilon of -5.3 ± 0.1 per mil during net nitrate consumption. On the basis of the observed nitrite isotope changes, we evaluated different nitrite uptake processes in a simple box model. We found that a regime of combined riparian denitrification and 22 to 36 % nitrification fits best with measured data for the nitrite concentration decrease and isotope increase.

Sediment microbial communities at CO2 seeps in Papua New Guinea

To understand how ocean acidification (OA) influences sediment microbial communities, naturally CO2-rich sites are increasingly being used as OA analogues. However, the characterization of these naturally CO2-rich sites is often limited to OA-related variables, neglecting additional environmental variables that may confound OA effects. Here, we used an extensive array of sediment and bottom water parameters to evaluate pH effects on sediment microbial communities at hydrothermal CO2 seeps in Papua New Guinea. The geochemical composition of the sediment pore water showed variations in the hydrothermal signature at seep sites with comparable pH, allowing the identification of sites that may better represent future OA scenarios. At these sites, we detected a 60% shift in the microbial community composition compared with reference sites, mostly related to increases in Chloroflexi sequences. pH was among the factors significantly, yet not mainly, explaining changes in microbial community composition. pH variation may therefore often not be the primary cause of microbial changes when sampling is done along complex environmental gradients. Thus, we recommend an ecosystem approach when assessing OA effects on sediment microbial communities under natural conditions. This will enable a more reliable quantification of OA effects via a reduction of potential confounding effects. This pangaea entry contains the data on the microbial community structure and bottom water parameters.

Seawater carbonate chemistry and community metabolism during an experiment with a coral reef, 2003

The effect of elevated pCO2 on the metabolism of a coral reef community dominated by macroalgae has been investigated utilizing the large 2650 m3 coral reef mesocosm at the Biosphere-2 facility near Tucson, Arizona. The carbonate chemistry of the water was manipulated to simulate present-day and a doubled CO2 future condition. Each experiment consisted of a 1-2 month preconditioning period followed by a 7-9 day observational period. The pCO2 was 404 ± 63 ?atm during the present-day pCO2 experiment and 658 ± 59 ?atm during the elevated pCO2 experiment. Nutrient levels were low and typical of natural reefs waters (NO3? 0.5-0.9 ?M, NH4+ 0.4 ?M, PO43? 0.07-0.09 ?M). The temperature and salinity of the water were held constant at 26.5 ± 0.2°C and 34.4 ± 0.2 ppt. Photosynthetically available irradiance was 10 ± 2 during the present-day experiment and 7.4 ± 0.5 mol photons m?2 d?1 during the elevated pCO2 experiment. The primary producer biomass in the mesocosm was dominated by four species of macroalgae; Haptilon cubense, Amphiroa fragillisima, Gelidiopsis intricata and Chondria dasyphylla. Algal biomass was 10.4 mol C m?2 during the present-day and 8.7 mol C m?2 and during the elevated pCO2 experiments. As previously observed, the increase in pCO2 resulted in a decrease in calcification from 0.041 ± 0.007 to 0.006 ± 0.003 mol CaCO3 m?2 d?1. Net community production (NCP) and dark respiration did not change in response to elevated pCO2. Light respiration measured by a new radiocarbon isotope dilution method exceeded dark respiration by a factor of 1.2 ± 0.3 to 2.1 ± 0.4 on a daily basis and by 2.2 ± 0.6 to 3.9 ± 0.8 on an hourly basis. The 1.8-fold increase with increasing pCO2 indicates that the enhanced respiration in the light was not due to photorespiration. Gross production (GPP) computed as the sum of NCP plus daily respiration (light + dark) increased significantly (0.24 ± 0.03 vs. 0.32 ± 0.04 mol C m?2 d?1). However, the conventional calculation of GPP based on the assumption that respiration in the light proceeds at the same rate as the dark underestimated the true rate of GPP by 41-100% and completely missed the increased rate of carbon cycling due to elevated pCO2. We conclude that under natural, undisturbed, nutrient-limited conditions elevated CO2 depresses calcification, stimulates the rate of turnover of organic carbon, particularly in the light, but has no effect on net organic production. The hypothesis that an increase pCO2 would produce an increase in net production that would counterbalance the effect of decreasing saturation state on calcification is not supported by these data.

Biogeochemical and physico-chemical characteristics in the gulf of Trieste, Italy

In this paper we investigated, for two years and with a bi-monthly frequency, how physical, chemical, and biological processes affect the marine carbonate system in a coastal area characterized by high alkalinity riverine discharge (Gulf of Trieste, northern Adriatic Sea, Mediterranean Sea).

Year-round chemical aerosol records at Kohnen, Antarctica obtained by automatic samplings

Aimed at year-round recording of the chemical aerosol composition in central Antarctica, an unattended operating aerosol sampler was successfully deployed at the EPICA deep drilling site in Dronning Maud Land (Kohnen Station). Analyses of teflon/nylon filter packs consecutively collected over bi-weekly intervals during the February 2003 to December 2005 period allowed to evaluate seasonal concentration variations of methane sulphonate (MS), Cl-, NO3-, non-sea salt (nss-)SO4**2- and Na+, while NH4+ and mineral dust related ion results remained below detection limits. For MS and nss-SO4**2 distinct late summer maxima around 44 and 200 ng/m**3, respectively, were found, while (total) NO3- showed a broad November maximum of about 52 ng m**-3. In contrast, the highest concentrations of Na+ with peak values of up to 160 ng/m**3 were observed during the winter half year. The seasonality of these species broadly coincided with long-term observations at the coastal Neumayer Station, including surprisingly comparable NO3- levels. However, the biogenic sulphur and sea salt concentrations were lower at Kohnen by typically a factor of 2-3 and 10, respectively. The arrival of sea ice derived sea salt particles at Kohnen could not clearly detected, since even during mid-winter the nss-SO4**2- to Na+ ratio was generally too high to unambiguously identify a sulphur depleted sea salt SO4**2- fraction.

Balanço energético da operação de uma caldeira a biomassa

A pressão causada sobre os recursos energéticos é impulsionada pela evolução demográfica e pelo crescimento económico, que se vem registando principalmente nos países em desenvolvimento. Segundo várias estatísticas, a procura pela energia incide principalmente sobre os combustíveis fósseis, os quais, representam cerca de do mix de consumo mundial de energia primária. A incerteza sobre as reservas das fontes energéticas não renováveis, e os problemas ambientais derivados da sua conversão noutros tipos de energia, levaram a uma implementação de medidas com rumo à sustentabilidade e eficiência energética. Desta forma, o aumento da utilização sobre as fontes energéticas renováveis é de extrema importância. A biomassa é uma das fontes energéticas de maior relevo. A utilização de biomassa em caldeiras, oferece benefícios económicos, sociais e ambientais, tais como poupança financeira no combustível, conservação dos recursos fósseis e redução de emissões poluentes. As caldeiras desenvolvidas por empresas como a Ventil, são uma solução para a produção de energia térmica pela combustão da biomassa. Estes sistemas caracterizam-se por serem energeticamente eficientes nas várias componentes da sua operação. Assim, pretende-se fazer uma caracterização dos consumos energéticos associados à operação de uma caldeira Ventil de, nomeadamente o consumo de energia elétrica de equipamentos associados. Também será considerado um balanço energético da caldeira e determinado o seu rendimento. Desta forma, concluiu-se que a potência do sistema é de MJ/s, apresentando um rendimento de. Foram detetados motores mal dimensionados e apresentadas alternativas de substituição. Com um investimento de seria possível reduzir a fatura energética em, obtendo um payback de anos. No entanto, a fatura energética do sistema ultrapassa os anuais, sendo que do investimento é na compra do combustível e os restantes são relativos ao consumo de energia elétrica.

Composición química del agua de lluvia y de niebla recolectada en la reserva biológica Monteverde

Se determinó la composición química del agua de lluvia y de niebla en tres sitios en la Reserva Biológica Monteverde, Puntarenas; entre octubre 2009 y enero 2010. Debido a su estado de conservación y a su ubicación geográfica sobre la deriva continental, la Reserva Biológica Monteverde ofrece un sitio de estudio ideal, para el estudio de la composición de las aguas atmosféricas (agua de lluvia y de niebla). Las muestras de agua de niebla se recolectaron al utilizar muestreadores de niebla con líneas de teflón, mientras que las de agua de lluvia se recogieron al emplear muestreadores de lluvia simples y uno de cascada. En ambos tipos de agua se analizaron las especies iónicas más relevantes: H3O+, NH4 +, Ca2+, Mg2+, K+, Na+, Cl-, NO3 - y SO4 2-, al utilizar cromatografía de iones y detección por conductividad eléctrica. Las concentraciones promedio de estas especies en el agua de lluvia estuvieron entre 0,54 ± 0,02 μeq L-1 y 101± 3 μeq L-1, mientras que en el agua de niebla variaron entre 1,00 ± 0,02 μeq L-1 y 93 ± 4 μeq L-1. Además, se presentan el balance iónico y los factores de enriquecimiento con respecto al mar y el suelo de ambos tipos de muestras.

Reator de leito estruturado com recirculação submetido à aeração intermitente no tratamento de esgoto sanitário

The release of nitrogen compounds in water bodies can result in many environmental problems, so treat wastewater, such as sewage in order to remove not only organic matter but also nitrogen has been studied a few decades. From the above, the objective of this study was to evaluate the performance of a structured bed reactor, continuous flow, with recirculation, in removing organic matter and nitrogen present in wastewater under different cycles of intermittent aeration (AI) and to evaluate the influence of these cycles in the development of nitrifying bacteria (Oxidizing Bacteria Ammonia - BOA and Bacteria Oxidizing Nitrite - BON) and denitrifying (DESN) adhered (Support Material - MS) and suspension (Effluent - EF and sludge - LD). The reactor used has usable volume of 9.4 L. As support materials (MS) polyurethane foam was used, cut and fixed in PVC rods. 3 were worked aeration phases (AE) and non-aeration (AN) at different stage: Stage 1 (4 h EA / AN 2H); Stage 2 (2H EA / AN 1 h) and Phase 3 (2H EA / AN 2 h). During all hydraulic detention time phases was kept at 16 h and the effluent recirculated at a rate of 3 times the inflow. Were analyzed: pH, total alkalinity, temperature, chemical oxygen demand (COD), Biochemical Oxygen Demand (BOD), nitrogen Kjeldhl Total (NKT), ammonia-N-N-NH4+, nitrito-N-NO2+andnitrato-NO3-. The concentration of BOA, BON and DESN was determined using the number More Provável.gSSV-1 (NMP.gSSV-1). In phase 1 the percentage removal NTK N-NH4+ and NT was 76±10%, 70±21% and 67±10% respectively. In Phase 2 80±15% of removel NKT, 86±15% of N-NH4+ e 68±9% of removel NT e na Fase 3 de 58±20%, 72±28% and 41±6% of NKT, N-NH4+ of NT, respectively. The denitrification efficiency in stage 3 was over 70%, indicating that occurred in the reactor the process of simultaneous nitrification and denitrification (NDS). DQOT the removal percentages were 88 ± 4% in Phase 1, 94 ± 7 in Phase 2 and 90± 11% in Phase 3. The multivariate ANOVA applied to NMP.gSSV-1, it indicated that there was significant (F: 20,2, p <0,01) between the analyzed concentration of organisms AI in different cycles, but the differences between NMP.gSSV-1 depends not only isolated factors but of which means, and phase groups being analysis. From the results it is concluded that the working system is efficient in terms of nitrogen removal and organic matter, and that the stage with the highest availability of Dissolved Oxygen (DO) and C/N ratio (Step 2), was the one obtained the lower concentrations of organic matter effluents and N-NH4+. Hinted that there was a significant difference between the concentration (NMP.100mL-1) of the analyzed organizations (BOA, BON and DESN), but this difference does not depend on factors alone but of which means (MS, EF or LD), stages (1, 2 or 3) and groups (BOA, BON and DESN) is being considered.

Nitrogênio mineral em um latossolo em função de sistemas de manejo do solo e de culturas de cobertura de inverno

The increasing advancement of agriculture makes providing adequate conditions for the growth and development of plants is the primary purpose of soil management systems. Much of the success of PD is attributed to cultural remains left by cover crops that do not require high nitrogen inputs and can thus be used to reduce nitrogen input in the agro- ecosystem. The nitrogen is one of the elements applied in agriculture, it is absorbed in higher quantities and limiting the yield of grain crops such as corn. Thus, there has been the influence of the no-till and conventional tillage combined with different crops of winter cover and bare soil when in succession to corn, on mineral nitrogen content. The experimental work was made at the experimental station of the Agronomic Institute of Paraná - Iapar. The implemented design was blocks at random split plot with three replications in factorial 6 x 2 x 3 x 5. The main plots were as treatment, beyond the bare soil, 5 winter species (ryegrass, vetch, vetch + oat, oat and radish), while in the subplots were used two tillage systems (No-till and conventional tillage). Three collections made were (before management, the urea before and after the urea), these being held in 5 depths (0-5, 5-10, 10-20, 20-40 and 40-60 cm). So a layer 0-5 cm and a que presents increased amount to NH4 + ion. The use of associated PD system in the presence of winter cover crops decreased as NO3 - losses in soil profile.

Estudo comparativo de dois tipos de cultivo: monocultivo (camarões) versus cultivo integrado (algas/camarões)

The integrated culture of seaweed and aquatic animals is an ancient practice in Asian countries. The expansion of this practice to western countries is consequence of the recognition of this system as a sustainable alternative that allows economical diversification and mitigation of environmental impacts generated by effluents of aquaculture. This study evaluated the growth of the seaweed Gracilaria caudata and of the shrimp Litopenaeus vannamei in monoculture (shrimps) and integrated culture (shrimps and algae) systems, and accessed the effect of the seaweed in the water quality. There were two treatments in the experiment: monoculture (shrimps) and integrated culture (shrimps/ algae). The organisms were cultured in 6 aquaria (10L) filled with seawater (35.0±0.0 PSU and 28.1±0.4°C) for 28 days. The nutrients of water (PO43-, NH4+, NO2-, NO3- and DIN), the biomass and the relative growth rate (RGR, % day-1) of seaweed and shrimps were measured weekly. The parameters pH, temperature, salinity and dissolved oxygen were measured daily. The concentration of NH4+ in integrated culture (62.8±25.2µM) was lower (Mann-Whitney p<0.001) than in monoculture (85.6±24.3µM). The mean of PO4- in monoculture (10.4±4.6µM) was markedly higher (Mann-Whitney; p=0.024) than that in integrated culture (8.7±4.1µM). The level of dissolved oxygen in integrated culture (6.0±0.6mg/L) was higher (t-Student; P=0.014) than that in shrimp monoculture (5.8±0.6mg/L). The mean values of the parameters pH, NO2-, NO3- and DIN were 7.5±0.2, 10.1±12.2µM, 24.5±3.2µM and 120.17±30.76µM in monoculture, and 7.5±0.2, 10.5±13.2µM, 27.4±3.5µM and 100.76±49.59µM in integrated culture. There were not differences in these parameters between treatments. The biomass and RGR of seaweed reached 15.0±1.9g and 7.4±2.8% day-1 at the end of the experiment. The performance of shrimp was favorable in monoculture (1.5±0.8g; 5.7±1.6% dia-1) and in integrated culture (1.5±0.7g; 5.2±1.2% dia-1), and the rate of survival was 100% in both treatments. The tolerance and favorable performance of Gracilaria caudata suggest that this seaweed might be integrated into shrimp (Litopenaeus vannamei) culture systems

Estudo do crescimento, eficiência de biofiltração e cinética de absorção de nutrientes (N-NH, N-NO e P-PO4³) da macroalga Gracilaria cervicornis (Turner) J. Agardh

The objective of this study was to examine the growth of Gracilaria cervicornis cultured in a shrimp (Litopenaeus vannamei) pond and to determine the absorption efficiency and the kinetics parameters (Vmax, Ks e Vmax:Ks) of this macroalgae for the nutrients N-NO3-, N-NH4+ and P-PO4-3, aiming at its use as bioremediatory of eutrophicated environments. For this study, two experiments (field and laboratory) were developed. In the field study, the seaweed was examined in relation to the growth and the biomass. In the laboratory experiment, the absorption efficiency of G. cervicornis was measured through the monitoring of the concentration of the three nutrients (N-NO3-, N-NH4+ e P-PO4-3) during 5 hours and the kinetic parameters were determined through the formula of Michaelis-Menten. The results obtained in this study demonstrated that G. cervicornis benefited from the available nutrients in the pond, increasing 52.4% of its biomass value after 30 days of culture. It was evidenced that the variability of the biomass could be explained through the salinity, availability of light (transparency and solid particle in suspension) and concentration of N-NO3- in the environment. In the laboratory experiment, the highest absorption efficiency was found in the treatments with low concentration (5 µmol.L-1), being evidenced a reduction of up to 85,3%, 97,5% and 81,2% of N-NH4+, N-NO3- and P-PO43-, respectively. Regarding the kinetic parameters, G. cervicornis presented better ability in absorbing N-NH4+ in high concentrations (Vmax = 158,5 µmol g-1 dry wt h-1) and P-PO43- in low concentrations (Ks = 5 µmol.L-1 e Vmax:Ks = 10,3). The results of this study show that G. cervicornis could be cultivated in shrimp ponds, presents a good capacity of absorption for the tested nutrients and is a promising candidate for biorremediation in shrimp pond effluent

Balanço de nutrientes em explorações agrícolas da Ilha Terceira

Dissertação de Mestrado, Engenharia Agronómica, 20 de Julho de 2016, Universidade dos Açores.

ABUNDÂNCIA NATURAL DE 15N E FORMAS DE NITROGÊNIO EM ARGISSOLO CULTIVADO COM EUCALIPTO E ACÁCIA

O nitrogênio e um dos nutrientes mais demandados pelas espécies vegetais, sua presença no solo, sob formas orgânicas ou minerais disponíveis para as plantas, está vinculada à qualidade e quantidade dos resíduos vegetais aportados ao solo. O estudo teve o objetivo de avaliar a influência do cultivo do eucalipto e da acácia na composição das formas orgânicas e inorgânicas de N e, na abundância natural de 15N em um Argissolo Amarelo. Para isso, foram coletadas amostras de solo e serapilheira em monocultivos do Eucalyptus urograndis (clone do Eucalyptus urophylla S. T. Blake x Eucalyptus grandis W. Hill ex Spreng) de ciclo curto (sete anos), sistemas de cultivo de rotação com acácia ( Acacia mangium Willd.) após monocultivo de eucalipto, monocultivo de eucalipto de ciclo longo (24 anos) e mata nativa (Mata Atlântica) como condição original de solo do litoral Norte do Espírito do Santo. Foram avaliados os teores de C orgânico total, N total, N-NH4+, N-NO3-, relação C/N, fracionamento do N orgânico e abundância natural de 15N no solo e serapilheira. Das formas de N-orgânico hidrolisado, o N-amino foi a fração que apresentou maior contribuição (39%), seguida pela fração de N-não identificado (27%), da fração N-amida (18%) e N-hexosamina (15%). O povoamento de acácia promoveu menor abundância natural de 15N e maiores teores de N total e C orgânico no solo e aumentou as formas orgânicas de N-hidrolisado, quando comparado àqueles de eucalipto de ciclo curto. Isso indica o aumento de formas lábeis de N orgânico no solo para as plantas e redução da humificação da matéria orgânica do solo (MOS) de acácia. Nesse sentido, a rotação de cultivos florestais com acácia após eucalipto de ciclo curto contribuiu para o aumento de formas orgânicas no solo, importantes para a nutrição de plantas, por serem potenciais fontes de nutrientes às plantas em curto período de tempo.