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Your search keyword '"Inorganic nutrients"' showing total 13 results
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13 results on '"Inorganic nutrients"'

1. The influence of human activities on Pampean streams catchment: a biogeochemical approach.

Author

De Marco, Silvia G., Marcovecchio, Jorge E., Vallina, Micaela, Barral, M. Paula, Bo, M. Juliana, Camino, Mariana, Cionchi, José L., Lopez de Armentia, Adriana, and Spetter, Carla V.

Subjects
RIVERS, COASTS, LAND use, TOURIST attractions
Abstract

Pampean streams constitute a drainage network which discharges continental freshwater into the associated marine coastal zone. The present study concerned a set of streams within General Pueyrredón district, Southeastern province of Buenos Aires, Pampa's region, Argentina, which deserves particular attention, since they flow in the area of influence of Mar del Plata, one of the most important tourist destination in the country. Different physical–chemical (i.e., temperature, conductivity, pH, dissolved oxygen), hydrographical and eco-physiological parameters were studied within five streams along an annual cycle, searching for seasonal variations and possible relations with land use. The behavior of physical–chemical parameters was consistent with previous reports on similar environments; inorganic nutrients presented high levels along the whole period, and have never been completely depleted. Within N nutrients, nitrate demonstrated to be the dominant along the whole period, with global mean values of ~ 18 µM and reaching values up to ~ 50 µM (total discharge of N ~ 1.23 Ton DIN y−1). A very high load of organic matter (from ~ 2000 mg Cm−3 in the fall up to ~ 4000 mg Cm−3 during summer) is discharged from these streams into the marine coastal zone (which represents ~ 214 Ton POC y−1) and, even until now, response effects have not been recorded there. The obtained results allowed us to sustain that anthropic activities (i.e., agriculture, cattle raising), continental runoff and climate conditions seem to be the main drivers of the hydrographical/biogeochemical behavior of the studied streams. Therefore, changes concerning them should also be included in future monitoring programs. [ABSTRACT FROM AUTHOR]

Published
2020
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3. The Arctic Ocean Estuary.

Author

McClelland, James, Holmes, R., Dunton, K., and Macdonald, R.

Subjects
FRESHWATER ecology, STREAM measurements, SALINITY, CARBON content of water, BIOTIC communities, SILICA, SEA ice, EUTROPHICATION, CLIMATE change
Abstract

Large freshwater contributions to the Arctic Ocean from a variety of sources combine in what is, by global standards, a remarkably small ocean basin. Indeed, the Arctic Ocean receives ∼11% of global river discharge while accounting for only ∼1% of global ocean volume. As a consequence, estuarine gradients are a defining feature not only near-shore, but throughout the Arctic Ocean. Sea-ice dynamics also play a pivotal role in the salinity regime, adding salt to the underlying water during ice formation and releasing fresh water during ice thaw. Our understanding of physical-chemical-biological interactions within this complex system is rapidly advancing. However, much of the estuarine research to date has focused on summer, open water conditions. Furthermore, our current conceptual model for Arctic estuaries is primarily based on studies of a few major river inflows. Future advancement of estuarine research in the Arctic requires concerted seasonal coverage as well as a commitment to working within a broader range of systems. With clear signals of climate change occurring in the Arctic and greater changes anticipated in the future, there is good reason to accelerate estuarine research efforts in the region. In particular, elucidating estuarine dynamics across the near-shore to ocean-wide domains is vital for understanding potential climate impacts on local ecosystems as well as broader climate feedbacks associated with storage and release of fresh water and carbon. [ABSTRACT FROM AUTHOR]

Published
2012
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4. Combined effects of temperature, inorganic nutrients and organic matter on ecosystem processes in intertidal sediments

Author

Fitch, Jayne E. and Crowe, Tasman P.

Subjects
*INTERTIDAL ecology, *BIOTIC communities, *CLIMATE change, *BENTHIC animals, *EFFECT of global warming on animals, *SEDIMENTS, *OXYGEN consumption, *PHYSIOLOGICAL stress, *ORGANIC compounds & the environment
Abstract

Abstract: Multiple anthropogenic stressors can interact, making it difficult to predict their combined impacts on ecosystem processes. Interactions between localised stressors can be further modified by variations in environmental conditions, such as those arising through climate change. This study investigated the individual and combined effects of increased temperature and nutrients and organic enrichment on ecosystem processes in intertidal sedimentary systems. Three levels of nutrient addition (0, 100 and 200g m−2) were crossed with two levels of organic matter (0 and 200g m−2) under two temperature regimes (10.0 and 16.5°C) in laboratory tanks. The influence of organic matter on ecosystem processes moderated by macrofauna did not vary with concentration of inorganic nutrients or temperature. Oxygen consumption, which has repeatedly been shown to increase with increased temperature, was in this case significantly increased by organic matter across all levels of temperature and nutrient enrichment. In addition, temperature affected nutrient cycling regardless of the addition of nutrients or organic matter. Understanding how the combined impacts of multiple stressors may vary depending on environmental conditions is essential for the development of strategies to sustainably manage ecosystems and conserve the delivery of ecosystem services. [Copyright &y& Elsevier]

Published
2011
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5. Cryptic Constituents: The Paradox of High Flux–Low Concentration Components of Aquatic Ecosystems

Author

Malin Olofsson, Mary E. Power, Michael T. Brett, Yvonne Vadeboncoeur, and David A. Stahl

Subjects
inorganic nutrients, Geography, Planning and Development, chemistry.chemical_element, Aquatic Science, Biochemistry, nitrogen, Carbon cycle, Nutrient, Dissolved organic carbon, Organic matter, TD201-500, Water Science and Technology, chemistry.chemical_classification, Biomass (ecology), Water supply for domestic and industrial purposes, Ecology, carbon, Aquatic ecosystem, Hydraulic engineering, turnover rates, chemistry, Environmental science, Terrestrial ecosystem, TC1-978, Carbon, primary production
Abstract

The interface between terrestrial ecosystems and inland waters is an important link in the global carbon cycle. However, the extent to which allochthonous organic matter entering freshwater systems plays a major role in microbial and higher-trophic-level processes is under debate. Human perturbations can alter fluxes of terrestrial carbon to aquatic environments in complex ways. The biomass and production of aquatic microbes are traditionally thought to be resource limited via stoichiometric constraints such as nutrient ratios or the carbon standing stock at a given timepoint. Low concentrations of a particular constituent, however, can be strong evidence of its importance in food webs. High fluxes of a constituent are often associated with low concentrations due to high uptake rates, particularly in aquatic food webs. A focus on biomass rather than turnover can lead investigators to misconstrue dissolved organic carbon use by bacteria. By combining tracer methods with mass balance calculations, we reveal hidden patterns in aquatic ecosystems that emphasize fluxes, turnover rates, and molecular interactions. We suggest that this approach will improve forecasts of aquatic ecosystem responses to warming or altered nitrogen usage.

Published
2021
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6. Tidal time-scale variation of inorganic nutrients and organic matter in Bahia Blanca mesotidal estuary, Argentina.

Author

Marcovecchio, Jorge, Spetter, Carla, Botté, Sandra, Delucchi, Federico, Arias, Andrés, Fernández Severini, Melisa, Negrin, Vanesa, Popovich, Cecilia, and Freije, R.Hugo

Subjects
*PLANT nutrients, *NATURE & nurture, *ECOLOGY, *RESEARCH, *MAGNITUDE estimation, *BRACKISH water ecology, *HYDRODYNAMICS
Abstract

Land-derived materials are regulated by coastal and shelf environmental conditions before being transported to the open sea. It is of great concern to understand the processes and to establish the extent in which they modify terrestrial compound fluxes, such as nutrients, that end up in the oceans. At present, one of the topics that arouses the highest interest within environmental coastal studies is the direction and magnitude of inorganic nutrients and the exchange fluxes of organic matter between the water column and the associated tidal plains during the daily tidal cycle. These processes, together with the local hydrographic conditions, define the key role of this type of environment: its function as a nutrient and organic matter reservoir and/or as a source. A research programme directed to understand this mechanism within mesotidal estuaries was developed in the Bahia Blanca estuary, on the coast of Buenos Aires (Argentina). On a tidal time-scale basis, levels of DIN (nitrate + nitrite + ammonium), DIP, DISi, and organic matter were measured in the estuarine water column and tidal plain porewater, for two years. Results showed no significant variations during the tidal cycle, even though the temporal variation of these compounds was clearly identified. In addition, the biological production of the estuary was considered and taken into account, so as to understand the organic matter cycle within the system. Particular conditions of the environment (sediment characteristics, porewater chemical environment, hydrodynamics, anthropogenic sources, etc.) were also considered to help fully understand the results. [ABSTRACT FROM AUTHOR]

Published
2009
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7. Net Sediment N2 Fluxes in a Coastal Marine System—Experimental Manipulations and a Conceptual Model.

Author

Fulweiler, Robinson, Nixon, Scott, Buckley, Betty, and Granger, Stephen

Subjects
*ORGANIC compounds, *DENITRIFICATION, *NITRATES, *SEDIMENTS, *AMMONIA, *ESTUARIES, *PHOSPHATES, *AMMONIUM, *DENITRIFYING bacteria
Abstract

Environmental factors, including the supply of organic matter and inorganic nutrient concentrations, are thought to influence rates of two opposing processes in the nitrogen (N) cycle, denitrification and N fixation. Using sediment cores from a temperate estuary we examined the effects of nitrate, phosphate, and ammonium enrichment of the overlying water on the net N2 flux across the sediment–water interface. In addition, we used sediment cores and large marine mesocosms to determine the effect of organic matter amendment. The addition of nitrate (50 μM), ammonium (50 μM), and phosphate (10 μM) to the overlying water had no effect on the net N2 flux. However, high ammonium fluxes (145 μmol m−2 h−1) were observed in the nitrate-amended cores, which is suggestive of dissimilatory nitrate reduction to ammonium. Organic matter enrichment first increased rates of N fixation, but ultimately switched the sediments from being a net source (N fixation dominated) to a net sink (denitrification dominated) of N. We observed a threshold where N fixation took place when organic matter deposition fell below about 0.3 g C m−2 day−1. On the basis of these results and the findings of others, we developed a conceptual model that links net sediment N2 flux with the organic matter production of a system. [ABSTRACT FROM AUTHOR]

Published
2008
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9. Wind-induced changes in the dynamics of fluorescent organic matter in the coastal NW Mediterranean

Author

Àngel López-Sanz, Eva María Calvo, Patricia De La Fuente, Josep M. Gasol, Cèlia Marrasé, Carles Pelejero, Jordi Salat, Josep Pascual, Mar Nieto-Cid, Fran L. Aparicio, Elvia D. Sánchez-Pérez, Ministerio de Economía y Competitividad (España), Generalitat de Catalunya, Consejo Superior de Investigaciones Científicas (España), and European Commission

Subjects
0106 biological sciences, Mediterranean climate, Salinity, Environmental Engineering, 010504 meteorology & atmospheric sciences, meteorological data, DOC, 01 natural sciences, acidification, Mediterranean sea, Water column, Wind events, Dissolved organic carbon, Inorganic nutrients, FDOM, Environmental Chemistry, Organic matter, Waste Management and Disposal, 0105 earth and related environmental sciences, organic matter, chemistry.chemical_classification, 010604 marine biology & hydrobiology, Biogeochemistry, DOC FDOM, dynamics, Pollution, NW Mediterranean, Oceanography, chemistry, Upwelling, Environmental science, sensible heat, Seawater
Abstract

12 páginas, 11 figuras, Marine biogeochemistry dynamics in coastal marine areas is strongly influenced by episodic events such as rain, intense winds, river discharges and anthropogenic activities. We evaluated in this study the importance of these forcing events on modulating seasonal changes in the marine biogeochemistry of the northwestern coast of the Mediterranean Sea, based on data gathered from a fixed coastal sampling station in the area. A 4-year (2011–2014) monthly sampling at four depths (0.5 m, 20 m, 50 m and 80 m) was performed to examine the time variability of several oceanographic variables: seawater temperature, salinity, inorganic nutrient concentrations (NO3−, PO43 − and SiO2), chlorophyll a (Chl a), dissolved organic carbon (DOC) and fluorescent dissolved organic matter (FDOM). FDOM dynamics was predominantly influenced by upwelling events and mixing processes, driven by strong and characteristic wind episodes. SW wind episodes favored the upwelling of deeper and denser waters into the shallower shelf, providing a surplus of autochthonous humic-like material and inorganic nutrients, whereas northerlies favored the homogenization of the whole shelf water column by cooling and evaporation. These different wind-induced processes (deep water intrusion or mixing), reported along the four sampled years, determined a high interannual environmental variability in comparison with other Mediterranean sampling sites, The continuity of the sampling program has been possible thanks to the funding of projects: ECOSER (CTM2011-15937-E), DOREMI (CTM2012-342949), SUAVE (CTM2014/23456/1) and ANIMA (CTM2015-65720) from the Spanish Ministerio de Economía y Competitividad (MINECO) and the Grup de Recerca Consolidat 2014SGR1179 and 2014SGR1029 financed by the Agència de Gestió d'Ajuts Universitaris i de Recerca (AGAUR) from the Generalitat de Catalunya. F.L.A. benefited from a JAE-pre pre-doctoral fellowship (JAEPre_2011_00923) from the Agencia Estatal Consejo Superior de Investigaciones Científicas (CSIC). M.N.-C. was funded by the project FERMIO (MINECO, CTM2014-57334-JIN) co-financed with FEDER funds

Published
2017

11. Microphytobenthos in the Gulf of Trieste (Northern Adriatic Sea): Relationship with Labile Sedimentary Organic Matter and Nutrients

Author

E. Sdrigotti, Stefano Covelli, C. Welker, Jadran Faganeli, Welker, C., Sdrigotti, E., Covelli, Stefano, and Faganeli, J.

Subjects
chemistry.chemical_classification, microphytobenthos, inorganic nutrients, biology, Heterotroph, Sediment, Aquatic Science, Oceanography, biology.organism_classification, chemistry.chemical_compound, labile sedimentary organic matter, Northern Adriatic Sea, Nutrient, chemistry, Nitrate, Algae, Benthic zone, inorganic nutrient, Sedimentary organic matter, Organic matter, microphytobentho
Abstract

Seasonal and inter-annual variations of microphytobenthos and inorganic nutrients were examined in sediments sited at 20 m depth in the Gulf of Trieste (Northern Adriatic Sea). Seasonal changes in water-soluble carbohydrates and proteins were studied in order to obtain information on quality and quantity of labile organic matter and the role of microphytobenthos in producing these compounds. Annual variations in microphytobenthos abundance in the surface sediment layer (0–1 cm) in the months from November 1992 to October 1993 and from July 1995 to June 1996 were similar. The vertical distribution of microphytobenthos abundance revealed a decrease with sediment depth. The depth profiles of water-soluble carbohydrates concentrations revealed a marked decrease with sediment depth. The profiles of protein concentration showed a more irregular pattern than carbohydrates without a progressive decline with sediment depth. In the upper 7 cm of surface sediment, a significant correlation between microphytobenthos abundance and both water-soluble carbohydrates and protein concentration was noticed during the months from July 1995 to March 1996. This positive relationship between the biopolymeric fraction and the microphytobenthos abundance suggest that water-soluble charbohydrates, as exocellular polymeric substances, mostly originate from the metabolic activity of microphytobenthos, whereas the proteins might be a good indicator of the microalgal biomass. Proteins in lower sediment layers could be associated with benthic heterotrophs too. The inorganic nutrient concentration, at the sediment overlying water, evidenced temporal variations with similar annual patterns. Positive correlation between microphytobenthos abundance and ammonium and silicate concentrations, at the water-sediment interface, were found. The lack of correlation between microphytobenthos and nitrite/nitrate concentration can be explained considering that, for their growth, microalgae use ammonium rather than nitrite/nitrate ions as inorganic N sources. The silicate concentration was clearly linked to microphytobenthos abundance since benthic microalgae were mainly composed of diatoms. The significant correlation between microphytobenthos and phosphate, observed when the N:P ratio was lower than 34:1, may be related to phosphorous limitation.

Published
2002
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12. Tidal time-scale variation of inorganic nutrients and organic matter in Bahia Blanca mesotidal estuary, Argentina

Author

Andres Hugo Arias, Jorge Eduardo Marcovecchio, Carla Vanesa Spetter, R. Hugo Freije, Cecilia A. Popovich, Vanesa Lorena Negrin, Melisa Daiana Fernandez Severini, Sandra Elizabeth Botté, and Federico Delucchi

Subjects
inorganic nutrients, Ciencias de la Tierra y relacionadas con el Medio Ambiente, chemistry.chemical_compound, Water column, Nutrient, Tidal cycle, Nitrate, Organic matter, Ecology, Evolution, Behavior and Systematics, General Environmental Science, organic matter, Hydrology, chemistry.chemical_classification, geography, geography.geographical_feature_category, Ecology, Estuary, chemistry, Scale variation, mesotidal estuary, General Earth and Planetary Sciences, Environmental science, Hydrography, tidal cycle, Meteorología y Ciencias Atmosféricas, CIENCIAS NATURALES Y EXACTAS
Abstract

Land-derived materials are regulated by coastal and shelf environmental conditions before being transported to the open sea. It is of great concern to understand the processes and to establish the extent in which they modify terrestrial compound fluxes, such as nutrients, that end up in the oceans. At present, one of the topics that arouses the highest interest within environmental coastal studies is the direction and magnitude of inorganic nutrients and the exchange fluxes of organic matter between the water column and the associated tidal plains during the daily tidal cycle. These processes, together with the local hydrographic conditions, define the key role of this type of environment: its function as a nutrient and organic matter reservoir and/or as a source. A research programme directed to understand this mechanism within mesotidal estuaries was developed in the Bahía Blanca estuary, on the coast of Buenos Aires (Argentina). On a tidal time-scale basis, levels of DIN (nitrate + nitrite + ammonium), DIP, DISi, and organic matter were measured in the estuarine water column and tidal plain porewater, for two years. Results showed no significant variations during the tidal cycle, even though the temporal variation of these compounds was clearly identified. In addition, the biological production of the estuary was considered and taken into account, so as to understand the organic matter cycle within the system. Particular conditions of the environment (sediment characteristics, porewater chemical environment, hydrodynamics, anthropogenic sources, etc.) were also considered to help fully understand the results. Fil: Marcovecchio, Jorge Eduardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Tecnológica Nacional; Argentina. Universidad FASTA "Santo Tomas de Aquino"; Argentina Fil: Spetter, Carla Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentina Fil: Botté, Sandra Elizabeth. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentina Fil: Delucchi, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentina Fil: Arias, Andres Hugo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina. Universidad Nacional del Sur; Argentina Fil: Fernandez Severini, Melisa Daiana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Negrin, Vanesa Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Bahía Blanca. Instituto Argentino de Oceanografía. Universidad Nacional del Sur. Instituto Argentino de Oceanografía; Argentina Fil: Popovich, Cecilia Angelines. Universidad Nacional del Sur; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina Fil: Freije, Rubén Hugo. Universidad Nacional del Sur; Argentina

Published
2009
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