Optimization and Demonstration of In Situ Chemical Sensors for Marine Waters

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

Atmospheric water-soluble organic nitrogen (WSON) in the eastern Mediterranean: origin and ramifications regarding marine productivity

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

Optimization and Demonstration of In Situ Chemical Sensors for Marine Waters

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

Wochenbericht L19-11

09.09. bis 12.09.201

Improving Optical Measurements: Non-Linearity Compensation of Compact Charge-Coupled Device (CCD) Spectrometers

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

Doğu Akdeniz deki Atmosferik Parçacıkların, Kuru ve Yaş Çökellerin Kimyasal Karakterinin Belirlenmesi ve Türleştirilmesi: Menşe, Kaynak Bölgeler, Biyo-kullanılabilirlik ve Atmosferik Girdilerin Denizsel Üretime Etkisi

TÜBİTAK ÇAYDAG15.03.2016Ocak 2014 ve Nisan 2015 tarihleri arasında yoğun bir şekilde aerosol (iri, ince ve bulk) ve kuru ve yaş-çökel (yağmur) örneklemeleri yapılmıştır. Atmosferik parçacıkların kütle derişimleri, suda-çözünebilir majör türler, suda-çözünebilir organik azot, üre ve aminoasit konsantrasyonları belirlenmiştir. Son on yılda partikül madde kompozisyonun belirgin bir şekilde değiştiği gözlenirken özellikle ikincil aerosoller sülfat, amonyum ve nitrat derişimlerinin % 50’lere varan düşüşler sergiledikleri belirlenmiştir. Suda-çözünebilir organik azot’un hem atmosferik parçacık (% 37) hem de yağmur (% 29) fazında toplam azota, sudaçözünebilir inorganik azotlar kadar katkı yapabileceği bulgulanmıştır. Tespit edilen üre derişimlerinin aerosol ve yağmurda organik azota sırasıyla % 17 ve % 6 katkı yaptığı bulunurken aminoasit azot katkılarının pek önemli olmadığı gözlenmiştir. Polifosfatların suda-çözünebilir fosfatlara % 20’ler seviyesinde katkı yapabileceği anlaşılırken göz ardı edilemeyecekleri ortaya konmuştur. Suda-çözünebilir organik azotun büyük bir kısmının tarımsal aktivitelerden kaynaklandığı ne var ki, ürenin hem mineral toz hem de tarımsal kökene sahip olduğu bulgulanmıştır. Fosforun; mineral toz (% 34) ve tarımsal (% 33) olmak üzere başlıca iki ana kaynağı olduğu anlaşılmıştır. Alüminyum iz metalinin büyük bir kısmı anyonik forumda gözlenirken demirin anyonik formunun katyonik formuna kıyasla 1,2 kat daha yüksek olduğu görülmüştür. Hem Kıyı hem de Açık istasyonlardan elde edilen yüzey sularına iki değişik içeriğe sahip toz eklenmiştir. Deneyler süresince klorofil miktarının artış sergilediği gözlenirken fosforun ortamdan çekilerek 0,3 nM seviyelerine düşürüldüğü tespit edilmiştir. Denizsel alan çalışmaları, 10 Nisan ve 29-30 Nisan 2015 tarihlerinde yüzey sularında tespit edilen Chl-a artışının, yağan yağmurlarla ilişkili olabileceği göstermiştir.Intensive samplings of both aerosol (fine/coarse and bulk) and rainwater were carried out between January 2014 and April 2015. Determination of mass composition, water soluble major species, water soluble organic nitrogen, urea and amino acid concentrations in atmospheric particles was carried out. Significant changes have been observed in the composition of particulate matter in the last ten years, especially the concentrations of secondary aerosols such as sulfate, amonnium and nitrate were determined to have decreased down to 50% of previous levels. It was found out that contribution of water soluble organic nitrogen is comparable to those of water soluble inorganic nitrogen in both aerosols (37%) and rainwater (29%). While it was observed that urea comprised 17% and 7% of total organic nitrogen in aerosol and rainwater, respectively, contribution of amino acids was found to be insignificant. It has been established that contribution of polyphosphates to water soluble phospates can reach up to a non-negligible 20%. Majority of water soluble organic nitrogen was found to originate from agricultural activities, while urea, was found to be of mixed origin, with comparable contributions from mineral dust and agricultural activities. The two main sources of phosphorus was determined to be mineral dust and agriculture, accounting for 34 and 33 % of total concentration, respectively. It has been observed that major fraction of soluble Al is found in anionic form, while the concentration of anionic soluble Fe is 1.2 times greater than of cationic Fe. Surface waters which were obtained from both coastal and open waters were treated with atmospheric dust of two different compositions. In the course of experiments, chlorophyll was recorded to increase in all treatments while phosphorus was assimilated from the medium down to 0,3 nM. The possible relationship between rain event and Chl-a increase in the surface waters observed in the cruises of April 10 and 29-30 2015 has been documented

Procedures to Improve Sensor Data Quality

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

Validation of sensor and instrumentation innovations

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 condition

DOĞU AKDENİZ’DEKİ ATMOSFERİK PARÇACIKLARIN, KURU VE YAŞ ÇÖKELLERİNDE MAKRO BESİN TUZU İÇERİKLERİNİN BELİRLENMESİ VE TÜRLEŞTİRİLMESİ: KAYNAK BÖLGELER, BİYO-KULLANILABİLİRLİK VE ATMOSFERİK GİRDİLERİN DENİZSEL ÜRETİME ETKİSİ

Two stage aerosol (coarse: PM10-2.5 and fine: PM2.5) and rainwater samples were collected at a rural site (Erdemli) located on the coast of the eastern Mediterranean, between January 2014 and April 2015. Concentrations of the water-soluble nitrogen species (organic nitrogen (WSON), nitrate, ammonium, total nitrogen (WSTN) and urea) were measured in a total of 740 aerosol and 23 rainwater samples. Among the nitrogen species, WSON (24.6 ± 16.3 nmol N m-3) denoted the highest arithmetic mean and followed by ammonium and nitrate concentrations in aerosol samples. Approximately 61% of the WSON was associated with coarse particles though the remaining fraction (39%) was accompanied with fine particles. Correspondingly, WSON contributions to WSTN in coarse and fine mode were found to be around 47.6 and 28.1 %. The volume weighted mean concentration of WSON was around 21.5 μM N in rainwater. Relative contribution of WSON to WSTN (73.5 μM N) was 29.3 % in rainwater. The urea mean concentration in coarse mode with standard deviations of 2.7 ± 2.7 nmol N m-3 and in fine mode 1.7 ± 1.7 nmol N m-3. Around 61 % of the urea was associated with coarse mode aerosol, whilst the remaining 39 % was associated with fine mode aerosol. Urea relative contributions to WSTN in coarse and fine mode were 8.5 and 4.9 %, and to WSON in coarse and fine mode were 18 and 18 %, respectively. The daily variability in the concentration of water-soluble nitrogen species including WSON and urea may be an order of magnitude. The lowest concentrations of water-soluble nitrogen species were found to be associated with rainy days. Relatively higher values of these water-soluble species were observed in summer and these concentrations might be attributed to the lack of wet deposition and re-suspension of cultivated soil. However, water-soluble organic nitrogen and urea exhibited the highest concentrations when air masses back trajectories originated from desert regions located at North Africa and the Middle East. For instance, one of the highest WSON (66.1 nmol N m-3) and urea (19.8 nmol N m-3) concentrations were observed on March 2, 2014 when the air mass back trajectories originated from Sahara and the Middle East deserts. Monthly mean concentrations of WSON and urea in coarse mode indicated inverse correlations with rain amount which suggested that these particles were removed from atmospheric compartment efficiently by wet deposition. Moreover, WSON and urea in coarse particles demonstrated inverse relationship with temperature and it might be ascribed to re-suspension of cultivated soil. During the study period 45 dusty days were determined by a sharp increase in the concentration of nns-Ca2+. Regarding dust and non-dust event, WSON and urea demonstrated 1.3 and 2 times higher concentrations during dust events compared to those of observed for non-dust events, respectively. The mineral dust episodes also affected the relative distributions of particles, coarse mode being dominant during the dust-events. The lowest WSON concentration was associated with air masses originated from Russia while the highest values were observed airflow from the Middle East and North Africa. The calculated PM10-2.5/ PM2.5 ratios of WSON for these airflows were higher than 1.15, denoting dominance of coarse fraction. The lowest urea concentrations were found when airflow derived from Russia, Northern Turkey and Middle East, with concentrations of 2.7, 2.9 and 2.3 nmol N m-3, respectively. Whereas, there was a distinct difference between their PM10-2.5/ PM2.5 ratio, suggesting airflow from Russia and Northern Turkey was equally influenced by fine and coarse particles whilst air masses from Middle East was mainly dominated by coarse particles. It might be argued that airflow originating from Middle East had more natural sources compared to anthropogenic sources. Positive matrix factorization (PMF) analysis was applied to clarify sources of WSON and urea. Results denoted that 77 % and 10 % of the WSON was derived from the re-suspension of cultivated soil and sea-salt particles, respectively. Nevertheless, 27 % of the urea was held by re-suspension of cultivated soil while 49 % of urea was found to be associated with nitrate, implying reaction between alkaline urea and acidic nitrate. Atmospheric fluxes of WSON and nitrate were almost equally influenced by dry and wet deposition, whereas ammonium flux was dominated by wet deposition (92 %). Annually, the atmospheric fluxes of WSON and nitrate were calculated 20.5 and 21.6 mmol m-2 yr-1, respectively, whilst the atmospheric ammonium flux was found 15.6 mmol m-2 yr-1. Based upon to detected new production in the surface waters of the Eastern Mediterranean, the atmospheric water-soluble nitrogen fluxes were determined to assist 33 % of the production in coastal waters and 76 % of the production in open waters. The observed new production between June and October when stratification occurs was found to be around 2 C mg m-2 day-1. During this period, atmospheric nitrogen can support new production in the Cilicia Basin up to 6 times.İki kademeli aerosol (İri: PM10-2.5 ve İnce: PM2.5) ve yağmur suyu örnekleri, Ocak 2014 ve Nisan 2015 tarihleri arasında, Doğu Akdeniz’in kıyısındaki Erdemli kırsal bölgesinde toplanmıştır. Toplam 740 aerosol ve 23 yağmur suyu örneğinde suda-çözünebilir azot türleri (organik azot (SÇOA), nitrat, amonyum, toplam azot (SÇTA) ve üre) konsantrasyonları belirlenmiştir. Azot türleri arasında, en yüksek aritmetik ortalamayı SÇOA (24.6 ± 16.3 nmol N m-3) gösterirken sırasıyla amonyum ve nitrat takip etmiştir. SÇOA’nın yaklaşık % 61’i iri parçacıklara eşlik ederken, kalan % 39’u ince parçacıklarla ilişkilendirilmiştir. SÇOA’nın SÇTA’ya katkısı iri ve ince parçacıklarda sırasıyla % 47.6 ve % 28.1’dir. Yağmur suyunda belirlenen SÇOA’un hacim ağırlıklı ortalama konsantrasyonu 21.5 μM N’dir. Göreceli katkılar düşünüldüğünde yağmur suyu örneklerinde SÇTA’nın (73.5 μM N) % 29.3’ünün SÇOA’dan kaynaklandığı tespit edildi. İri ve ince parçacıklarda belirlenen ortalama üre konsantrasyonu sırasıyla 2.7 ± 2.7 nmol N m-3 ve 1.7 ± 1.7 nmol N m-3’dir. Ürenin % 61’i iri parçacıklarla ilişkiliyken, kalan 39 %’u ince parçacıklarla ilişkilidir. SÇTA’a ürenin göreceli katkısı iri parçacıklarda % 8.5, ince parçacıklarda % 4.9 ve SÇOA’ya ürenin göreceli katkısı hem iri hem ince parçacıklarda %18 olarak hesaplanmıştır. Suda-çözünebilir azot türlerinin, SÇOA ve üre de dahil olmak üzere, konsantrasyonlarındaki günlük değişim bir kaç mertebeyi bulabilir. Bu türlerin en düşük derişimleri yağmurlu günlerle ilişkili bulunmuştur. Suda-çözünebilir azot türlerinde göreceli yüksek derişimlerin yazın gözlenmesi, yaş çökelmenin olmamasında ve ekilen toprağın yeniden süspansiye olmasına atfedilmiştir. Ne ki, SÇOA (66.1 nmol N m-3) ve üre (19.8 nmol N m-3) için en yüksek konsantrasyonlar Kuzey Afrika ve Orta Doğu çöl bölgelerinden kaynaklanan hava kütlelerinde gözlenmiştir. Örneğin, en yüksek SÇOA (66.1 nmol N m-3) ve üre (19.8 nmol N m-3) konsantrasyonlarından biri 2 Mart 2014’te, Sahra ve Orta Doğu çöllerinden kaynaklanan hava kütlesi geri yörüngeleriyle ilişkilendirilmiştir. İri parçacıklarda belirlenen aylık ortalama SÇOA ve üre konsantrasyonlarının yağmur miktarı ile ters ilişkili olması bu parçacıkların atmosferik kompartmandan yağmur ile etkili bir şekilde uzaklaştırıldığını göstermektedir. Yine iri parçacıklarda belirlenen aylık ortalama SÇOA ve üre konsantrasyonlarının sıcaklık ile ters ilişkili olması ekili toprağın yeniden süspansiye olmasına atfedilebilir. Çalışma süresince, nss-Ca2+ konsantrasyonundaki ani artışlar ile 45 adet toz olayı tespit edilmiştir. Tozsuz günlere kıyasla, SÇOA ve üre konsantrasyonları toz epizodlarında sırasıyla 1.3 ve 2 kat artış göstermiştir. Mineral toz olayı ayrıca parçacıkların iri ve ince modlarda göreceli dağılımlarını da etkilemiştir, toz etkinliklerinde parçacıkların çoğu iri modda bulunmuştur. En düşük SÇOA derişimleri Rusya’dan gelen hava kütlesiyle ilişkilendirilirken, en yüksek SÇOA derişimleri Orta Doğu ve Kuzey Afrika’dan gelen hava kütlelerinde gözlenmiştir. Bu hava kütlelerinde SÇOA için, PM10-2.5 / PM2.5 oranı, 1.15’ten yüksek olarak hesaplanmış ve iri parçacıkların baskın olduğunu belirlenmiştir. En düşük üre konsantrasyonları Rusya, Kuzey Türkiye ve Orta Doğu’dan kaynaklanan hava kütleleriyle ilişkiliyken sırasıyla konsantrasyonlar 2.7, 2.9 ve 2.3 nmol N m-3’dir. Oysa, PM10-2.5 / PM2.5 oranları belirgin bir fark gösterirken; Rusya ve Kuzey Türkiye’den gelen hava kütleleri iri ve ince parçacıklardan eşit olarak, Orta Doğu kaynaklı hava kütleleri daha çok iri parçacıklardan etkilenmiştir. Orta Doğu’dan gelen hava kütlelerinin antropojenik kaynaklara kıyasla daha çok doğal kaynaklardan etkilendiği ileri sürülebilir. SÇOA ve ürenin kaynaklarını belirlemek için Pozitif Matriks Faktörizasyon (PMF) uygulanmıştır. Elde edilen sonuçlar, SÇOA’nın % 77’sinin ekili toprağın yeniden süspansiye olmasından ve % 10’unun deniz-tuzu parçacıklarından kaynaklandığını göstermiştir. Bununla beraber, ürenin % 27’si ekili toprağın yeniden süspansiye olmasına ve % 49’u asidik nitrat ve alkali üre arasındaki reaksiyona atfedilmiştir. SÇOA ve nitratın atmosferik akıları kuru ve yaş çökellerden neredeyse eşit olarak etkilenirken, amonyum akısı yaş çökel tarafından domine edilmiştir (%92). SÇOA ve nitratın yıllık atmosferik akısı sırasıyla 20.5 ve 21.6 mmol N m-2 yıl-1 olarak hesaplanırken amonyumun yıllık atmosferik akısı 15.6 mmol N m-2 yıl-1 olarak hesaplanmıştır. Doğu Akdeniz’in kıyı ve açık yüzey sularında belirlenen yeni üretimin, sırasıyla % 33 ve % 76’sının atmosferik azot akılarınca sağlanabileceği hesaplanmıştır. Tabakalaşmanın gözlendiği Haziran ve Ekim ayları arasında yeni üretimin yaklaşık olarak 2 C mg m-2 gün-1 bulunmuştur. Bu dönemde, atmosferik azot Kilikya Havzası'nda yeni üretimi 6 kata kadar destekleyebilir.M.S. - Master of Scienc