ALBERT

Description: Aerosol and rain sampling in two size fractions was carried out at a rural site located on the coast of the eastern Mediterranean, Erdemli, Turkey (36∘33′54′′ N, 34∘15′18′′ E). A total of 674 aerosol samples in two size fractions (337 coarse, 337 fine) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO3-, NH4+ and ancillary water-soluble ions using ion chromatography and water-soluble total nitrogen (WSTN) by applying a high-temperature combustion method. The mean aerosol water-soluble organic nitrogen (WSON) was 23.8 ± 16.3 nmol N m−3, reaching a maximum of 79 nmol N m−3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L−1. The WSON contributed 37 and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variation, mainly due to meteorology and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and resuspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m−3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m−3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal material (10 %) and sea salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WSTN flux.

Description: Charge-coupled device (CCD) spectrometers are widely used as detectors in analytical laboratory instruments and as sensors for in situ optical measurements. However, as the applications become more complex, the physical and electronic limits of the CCD spectrometers may restrict their applicability. The errors due to dark currents, temperature variations, and blooming can be readily corrected. However, a correction for uncertainty of integration time and wavelength calibration is typically lacking in most devices, and detector non-linearity may distort the signal by up to 5% for some measurements. Here, we propose a simple correction method to compensate for non-linearity errors in optical measurements where compact CCD spectrometers are used. The results indicate that the error due to the non-linearity of a spectrometer can be reduced from several hundred counts to about 40 counts if the proposed correction function is applied.

Description: Two-sized aerosol and rain sampling were carried out at a rural site located on the coast of the Eastern Mediterranean, Erdemli, Turkey (36°33′54″ N and 34°15′18″ E). A total of 674 aerosol samples in two size fraction (coarse = 337; fine = 337) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO3−, NH4+ and ancillary water-soluble ions by Ion Chromatography and water-soluble total nitrogen (WSTN) by applying a High Temperature Combustion Method. The mean aerosol WSON was 23.8 ± 16.3 nmol N m−3, reaching a maximum of 79 nmol N m−3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L−1. The WSON contributed 37 % and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variations mainly due to rain and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and re-suspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m−3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m−3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal (10 %) and sea-salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WTSN flux. Considering the Cilician Basin, the atmospheric water-soluble nitrogen flux would sustain 33 % and 76 % of the new production in the associated coastal and open waters, respectively.

Description: Validated prototypes of new and enhanced biogeochemical and biological sensors and instruments. Validation will be undertaken in the laboratory, in test scenarios, and by deployment in operational conditions

Description: 09.09. bis 12.09.2019

Description: Aerosol and rain sampling in two size fractions was carried out at a rural site located on the coast of the eastern Mediterranean, Erdemli, Turkey (36∘33′54'' N, 34∘15′18'' E). A total of 674 aerosol samples in two size fractions (337 coarse, 337 fine) and 23 rain samples were collected between March 2014 and April 2015. Samples were analyzed for NO−3, NH+4 and ancillary water-soluble ions using ion chromatography and water-soluble total nitrogen (WSTN) by applying a high-temperature combustion method. The mean aerosol water-soluble organic nitrogen (WSON) was 23.8 ± 16.3 nmol N m−3, reaching a maximum of 79 nmol N m−3, with about 66 % being associated with coarse particles. The volume weighted mean (VWM) concentration of WSON in rain was 21.5 µmol N L−1. The WSON contributed 37 and 29 % to the WSTN in aerosol and rainwater, respectively. Aerosol WSON concentrations exhibited large temporal variation, mainly due to meteorology and the origin of air mass flow. The highest mean aerosol WSON concentration was observed in the summer and was attributed to the absence of rain and resuspension of cultivated soil in the region. The mean concentration of WSON during dust events (38.2 ± 17.5 nmol N m−3) was 1.3 times higher than that of non-dust events (29.4 ± 13.9 nmol N m−3). Source apportionment analysis demonstrated that WSON was originated from agricultural activities (43 %), secondary aerosol (20 %), nitrate (22 %), crustal material (10 %) and sea salt (5 %). The dry and wet depositions of WSON were equivalent and amounted to 36 % of the total atmospheric WSTN flux.

Description: The oceans play an important role in aspects of global sustainability, including climate change, food security and human health. Because of its vast dimensions, internal complexity, and limited accessibility, efficient monitoring and predicting of the ocean forms a collaborative effort of regional and global scale. A key requirement for ocean observing is the need to follow well-defined approaches. Summarized under “Ocean Best Practices” (OBP) are all aspects of ocean observing that require proper and agreed-on documentation, from manuals and standard operating procedures for sensors, strategies for structuring observing systems and associated products, to ethical and governance aspects when executing ocean observing. In Task 6.2 we have developed new tools, and organized workshops with outcomes of Best Practice manuals and scientific publications. The focus has been on improving accuracy of trace element measurements in seawater and also of marine omics analysis, and enhancing reliability, interoperability and quality of sensor measurements for dissolved oxygen, nutrients and carbonate chemistry measurements.

Description: Charge-coupled device (CCD) spectrometers are widely used as detectors in analytical laboratory instruments and as sensors for in situ optical measurements. However, as the applications become more complex, the physical and electronic limits of the CCD spectrometers may restrict their applicability. The errors due to dark currents, temperature variations, and blooming can be readily corrected. However, a correction for uncertainty of integration time and wavelength calibration is typically lacking in most devices, and detector non-linearity may distort the signal by up to 5% for some measurements. Here, we propose a simple correction method to compensate for non-linearity errors in optical measurements where compact CCD spectrometers are used. The results indicate that the error due to the non-linearity of a spectrometer can be reduced from several hundred counts to about 40 counts if the proposed correction function is applied.

Description: The importance of autonomous in situ chemical sensors for ocean observations has increased drastically over the last decades. Yet, the huge potentials of sensor-based data collection remain underutilized by the scientific and regulatory communities, despite wider than ever usage of sensors. This thesis is part of a growing body of work to extend the usability of sensors and is embedded in the Ocean Best Practice approach, which could improve data quality in ocean observation in general. The here presented Ph.D. thesis covers multiple commercial sensors (LOC from ClearWater Sensors, Southampton, UK and OPUS from TriOS GmbH, Germany) for autonomous, high-resolution and in situ measurements of essential biogeochemical parameters (pH and nitrate) in marine waters. It was motivated by the necessity of improving the data quality of autonomous submersible optical sensors and broadening their utility. To achieve this, sensor deployments in various aquatic environments were conducted. Furthermore, the data obtained via sensors based on the same analytical principle was compared with each other, and with benchtop laboratory devices to assess the accuracy of the measurements. The achievements are associated with the acquisition of accurate and temporally well-resolved real-time data. A more reliable sensor-based data collection and improved deployability promotes a broader usage of autonomous sensors in general. Thus, a financially more sustainable ocean monitoring approach can be achieved, since a broader adaptation of autonomous sensors in research yields a higher cost efficiency.