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Coral reefs are exceptionally biodiverse and human dependence on their ecosystem services is high. Reefs experience significant direct and indirect anthropogenic pressures, and provide a sensitive indicator of coastal ocean health, climate change, and ocean acidification, with associated implications for society. Monitoring coral reef status and trends is essential to better inform science, management and policy, but the projected collapse of reef systems within a few decades makes the provision of accurate and actionable monitoring data urgent. The Global Coral Reef Monitoring Network has been the foundation for global reporting on coral reefs for two decades, and is entering into a new phase with improved operational and data standards incorporating the Essential Ocean Variables (EOVs) (www.goosocean.org/eov) and Framework for Ocean Observing developed by the Global Ocean Observing System. Three EOVs provide a robust description of reef health: hard coral cover and composition, macro-algal canopy cover, and fish diversity and abundance. A data quality model based on comprehensive metadata has been designed to facilitate maximum global coverage of coral reef data, and tangible steps to track capacity building. Improved monitoring of events such as mass bleaching and disease outbreaks, citizen science, and socio-economic monitoring have the potential to greatly improve the relevance of monitoring to managers and stakeholders, and to address the complex and multi-dimensional interactions between reefs and people. A new generation of autonomous vehicles (underwater, surface, and aerial) and satellites are set to revolutionize and vastly expand our understanding of coral reefs. Promising approaches include Structure from Motion image processing, and acoustic techniques. Across all systems, curation of data in linked and open online databases, with an open data culture to maximize benefits from data integration, and empowering users to take action, are priorities. Action in the next decade will be essential to mitigate the impacts on coral reefs from warming temperatures, through local management and informing national and international obligations, particularly in the context of the Sustainable Development Goals, climate action, and the role of coral reefs as a global indicator. Mobilizing data to help drive the needed behavior change is a top priority for coral reef observing systems. This paper benefited from the financial support to the authors provided by their institutions and the grants for research, monitoring and/or coordination they have secured. The development of this manuscript has been supported through ongoing work of the Global Coral Reef Monitoring Network and the Global Ocean Observing System�s Biology and Ecosystems Panel, supported by the International Coral Reef Initiative, United Nations Environment Programme, the United Nations Educational, Scientific and Cultural Organization�s Intergovernmental Oceanographic Commission, and Future Earth among others. Scopus

A new system requiring greatly reduced operator intervention has been developed for the determination of dissolved inorganic carbon concentration in marine waters. Based on a coulometric method, the system has an accuracy and precision comparable to more complex and expensive methods currently employed. A syringe pump equipped with a 12-port distribution valve is used to precisely dispense an acid solution and sample into a gas stripper. The system can autonomously measure eight discrete samples in duplicate or triplicate with no operator input. The best precision (%RSD) obtained was 0.022% (n = 14) or less than ±1.0 μmol kg(-1). The system is calibrated against a certified reference material (CRM). Average offset from the CRM was 1.2 μmol kg(-1). Sample throughput was 4 samples per h. Carryover effects are negligible but field sample analyses suggest that prefiltering may be necessary in highly turbid waters.

The evolution of an entirely green analytical system for industrial quality control of carbonated drinks is described. The developed flow system is capable of providing analytical data of the dissolved CO2, sucrose, and color of a sample consecutively in real-time. The system has been carefully designed on the basis of “reagent-free”, meaning that no added chemicals are required for the analysis. The system first vaporizes CO2 from the soft drink in a gas–liquid separation chamber, with a channel for a flow of pure water as the CO2 acceptor. The dissolved CO2 alters the conductivity of the water stream, which is directly related to the concentration of CO2 in the soft drink. The sucrose content is measured based on the “schlieren effect”, the sample plug flows out of the vaporization chamber into a colorimeter with a near-infrared/light-emitting diode (NIR/LED) as light source. The schlieren effect arises at the boundary of pure water and soft drink with refraction of light in proportion to the sugar concentration. The system also measures the absorbance of the sample using an RGB-LED. The related principles and preliminary experiments as proof of concept are described as well as the construction of the flow system for this completely reagent-free analyzer. A simple flow injection system using the schlieren effect was also developed for rapid quantitative analysis of sugar in noncarbonated soft drinks.

This work presents a flow analysis method for direct quantitation of calcium carbonate in cement without pretreatment of the sample. The method is based on online vaporization of CO 2 gas following acidification of the sample inside a small chamber that has a flow of acceptor solution passing around it. Solubilization of the CO 2 gas into the acceptor stream changes the conductivity of the acceptor solution causing an increase of signal at the capacitively coupled contactless conductivity detection (C 4 D) placed at the outlet of the vaporization chamber. This chamber is an adaption from previous work reported on ‘membraneless vaporization’ (MBL-VP). The method can be used in the quality control of production of mixed cement. These cement materials usually have calcium carbonate contents at high concentration range (e.g., 33–99% (w/w) CaCO 3 ). Analysis of samples by this method is direct and convenient as it requires no sample pretreatment. The method is low-cost with satisfactory accuracy and acceptable precision.

A shipboard fluorometric flow analyzer has been developed for near-real-time, high-resolution underway measurement of ammonium in seawater. The fluorometric method is based on the reaction of ammonium with o-phthaldialdehyde (OPA) and sulfite. The reagents used in this method have been modified to suit seawater analysis. This method shows no refractive index and salinity effect from seawater samples. The potential interferences in seawater have been studied, and their effects have been reduced. The instrument response is linear over a wide range of ammonium concentration. The limit of detection of 1.1 nM was estimated in laboratory using ammonium standards prepared in distilled water. It should be noted that application of this method to low-level ammonium measurement requires a correction of interference species, such as amino acids. The sample throughput is 3600 h(-1). The system can be used for both freshwater and seawater samples and has been used to monitor the distribution of ammonium in Florida coastal waters around an oceanic wastewater outfall.

We describe a robust, highly sensitive instrument for the determination of ambient ammonia. The instrument uses two syringe pumps to handle three liquids. The flow configuration is a hybrid between traditional flow injection (FI) and sequential injection (SI) schemes. This hybrid flow analyzer spends approximately 87% of its time in the continuous flow FI mode, providing the traditional FI advantages of high baseline stability and sensitivity. The SI fluid handling operation in the remaining time makes for flexibility and robustness. Atmospheric ammonia is collected in deionized water by a porous membrane diffusion scrubber at 0.2 L/min with quantitative collection efficiency, derivatized on-line to 1-sulfonatoisoindole, and measured by fluorometry. In the typical range for ambient ammonia (0-20 ppbv), response is linear (r2 = 0.9990) with a S/N = 3 limit of detection of 135 pptv (15 nM for 500 microL of injected NH4+(aq)) with an inexpensive light emitting diode photodiode-based detector. Automated operation in continuously repeated, 8-min cycles over 9 days shows excellent overall precision (n = 1544 p(NH)3 = 5 ppbv, RSD = 3%). Precision for liquid-phase injections is even better (n = 1520, [NH4+(aq)] = 2.5 microM, RSD = 2%). The response decreases by 3.6% from 20 to 80% relative humidity.

In this work, we have modified the technique of all injection analysis (AIA) by changing the position of the detector. The detection is then located as a part of the circulatory loop. With this new detector position, we could monitor for many numbers of circulation. The sensitivity was improved by using the cumulative signal data obtained when the number of circulation rounds was increased. The dilution effect using this new detector location was also less than that with the previous system. We employed a four-channel peristaltic pump to aspirate four types of liquids into the system together at one time. The AIA method was then developed for determination of phosphorus in soils and sediment extracts. The method was optimized for the new harmonized scheme of extraction that has been developed by the European Commission.

Techniques that have been variously termed oscillometric detection or (capacitively coupled) contactless conductivity detection (C(4)D) are known actually to respond to the admittance. It is not often appreciated that the frequency range (f) over which such systems respond (quasi)linearly with the cell conductance decreases acutely with increasing cell resistance. Guidance on optimum operating conditions for high cell resistance, such as for very small capillaries/channels and/or solutions of low specific conductance (σ), is scant. It is specially necessary in this case to take the capacitance of the solution into account. At high frequencies and low σ values, much of the current passes through the solution behaving as a capacitor and the capacitance is not very dependent on the exact solution specific conductance, resulting in poor, zero, or even negative response. We investigated, both theoretically and experimentally, capillaries with inner radii of 5-160 μm and σ ≈ 1-1400 μS/cm, resulting in cell resistances of 51 GΩ to 176 kΩ. A 400-element discrete model was used to simulate the behavior. As model inputs, both the wall capacitance and the stray capacitance were measured. The solution and leakage capacitances were estimated from extant models. The model output was compared to the measured response of the detection system over broad ranges of f and σ. Other parameters studied include capillary material and wall thickness, electrode spacing and length, Faraday shield thickness, excitation wave forms, and amplitude. The simulations show good qualitative agreement with experimental results and correctly predict the negative response behavior observed under certain conditions. We provide optimum frequencies for different operating conditions.

A portable ammonium analyser was developed and used to measure in situ ammonium in the marine environment. The analyser incorporates an improved LED photodiode-based fluorescence detector (LPFD). This system is more sensitive and considerably smaller than previous systems and incorporates a pre-filtering subsystem enabling measurements in turbid, sediment-laden waters. Over the typical range for ammonium in marine waters (0–10 mM), the response is linear (r(2) = 0.9930) with a limit of detection (S/N ratio > 3) of 10 nM. The working range for marine waters is 0.05–10 mM. Repeatability is 0.3% (n =10) at an ammonium level of 2 mM. Results from automated operation in 15 min cycles over 16 days had good overall precision (RSD = 3%, n = 660). The system was field tested at three shallow South Florida sites. Diurnal cycles and possibly a tidal influence were expressed in the concentration variability observed.

This work presents a new flow injection strategy, called ‘cross injection analysis’ or CIA, an alternative cost-effective approach in flow analysis. The flow platform is made from a rectangular acrylic block, approximately 5×3×1.5 cm ( x × y × z ), with crossing cylindrical channels drilled out along the x - and y -axis of the block. The outlet from the single x -axis channel is connected to a detector flow cell. This channel is filled with the carrier solution. The flow in the x -axis channel is driven by a computer controlled single-channel peristaltic pump. The multiple y -axis channels, running perpendicular to the x -channel, are connected to a multi-channel peristaltic pump. These channels contain the sample and reagent solutions that flow across the intersection zones of the channels. To mix the sample and reagent with subsequent detection of the reaction zone, flow is applied along the x -axis channel, while flow in the y -axis channels is stopped. We successfully demonstrated the validity of the CIA technique by the spectrometric determination of Fe(II) using 1,10-phenanthroline and the speciation of Fe(II) and Fe(III). To place the CIA technique within the context of flow analysis, a brief overview of the evolution of flow injection analysis and its later innovative development is included.

Our goal is to develop a portable autonomous ammonium sensor. Such a sensor could be deployed for periods of up to a month aboard ships, moorings or drifting buoys or used as a component in lowered or towed oceanographic instrument packages for vertical profiling. Our technical objective is to develop a robust, relatively simple, inexpensive, low power and compact instrument with a detection limit in the nM range and a sampling frequency of at least 6 samples per hour. Robustness, simplicity, low construction cost, lower power and small size are the practical desiderata for commercial application. Commercialization and the lowered instrument costs that will result are essential to permit wider application throughout the oceanographic community.

This work proposes a flow system suitable for the rapid screening of formaldehyde contaminated in food. The system is based on the concept of a flow analyzer with a Hantzsch reaction. An operating procedure was developed for multiple tasking and high sample throughput. This resulted in a significant sample throughput of 51 samples h(-1). Under the optimized conditions, linear calibration from 10 to 100 microM was obtained. The system gave a limit of detection and a limit of quantitation of 0.06 and 0.10 mg kg(-1), respectively. The system was successfully applied to re-hydrated dry squids, vegetables and mushrooms.

A simple, effective mixing chamber used in conjunction with a syringe pump for flow analysis is described and evaluated. A mixing chamber was constructed using a conventional 5 mL pipette tip and its performance compared with a widely used mixing coil. The results demonstrate that the mixing coil does not rapidly and completely mix solutions. Utilizing a configuration that reversed solution positions in the chamber with each mixing cycle, the proposed mixing chamber achieved complete mixing in a significantly shorter time than the mixing coil. The influence of injected sample volume on absorbance signals was evaluated by calculating an S1/2 value for the system. As tested with a minimal rinse, the system has no discernable carryover. Testing this new approach in our previously described silicate measurement system resulted in a more than twofold improvement in sensitivity.

This work presents a new sequential injection analysis (SIA) method and a module for simultaneous and real-time monitoring of three key parameters for the beverage industry, i.e., the sugar content (measured in Brix), color and dissolved CO(2). Detection of the light reflection at the liquid interface (the schlieren effect) of sucrose and water was utilized for sucrose content measurement. A near infrared LED (890+/-40 nm) was chosen as the light source to ensure that all the ingredients and dyes in soft drinks will not interfere by contributing light absorption. A linear calibration was obtained for sucrose over a wide concentration range (3.1-46.5 Brix). The same module can be used to monitor the color of the soft drink as well as the dissolved CO(2) during production. For measuring the color, the sample is segmented between air plugs to avoid dispersion. An RGB-LED was chosen as the light source in order to make this module applicable to a wide range of colored samples. The module also has a section where dissolved CO(2) is measured via vaporization of the gas from the liquid phase. Dissolved CO(2), in a flowing acceptor stream of water resulting in the change of the acceptor conductivity, is detected using an in-house capacitively coupled contactless conductivity detector (C(4)D). The module includes a vaporization unit that is also used to degas the carbonated drink, prior the measurements of sucrose and color within the same system. The method requires no chemicals and is therefore completely friendly to the environment.

This paper describes a robust, sensitive method for measurement of low silicate in natural water. The method is based on the reaction of silicate with ammonium molybdate to form a yellow silicomolybdate complex, which is then reduced to silicomolybdenum blue by ascorbic acid. This method shows no refractive index effect and a small salinity effect that can be corrected for seawater samples. It was found that the use of poly-vinyl alcohol can prevent the precipitation formation in the ammonium molybdate solution and improve the stability of the silicomolybdenum blue complex. The sensitivity of this method is substantially enhanced by using a liquid-waveguide capillary cell. The detection limit is 0.1 μM, and working range is 0.1–10 μM for using 2-m liquid-waveguide capillary cell (LWCC). The method can be used for both freshwater and seawater samples and has been used to study the distribution of silicate in surface seawater of Gulf Stream in Florida straight.

A new apparatus, called 'membraneless vaporization' (MBL-VP) unit was designed and developed for direct analysis of solid samples. Solid analyte was converted into a gaseous form which then reacts with an indicator reagent. Change in absorbance was used to quantitate the analyte. Stirring with a magnetic bar was employed to facilitate the evaporation of the gas. Unlike the pervaporation technique, hydrophobic membrane was not required for this MBL-VP technique. Application of the membraneless technique for direct determination of calcium carbonate in calcium supplements, has shown to be very precise (R.S.D.=2.5% for 0.16 mmol CO3(2-)), with detection limit of 0.5 mg CaCO3. Results by this method agreed well with flame atomic absorption spectrometric method. Sample throughput was 20 samples h(-1).

This work describes the development of a telemetric system in conjunction with a computer sound card for recording of signals. For signal transmission, a transmission wireless microphone was utilized, making the telemeter compatible with the sound card normally equipped inside a personal computer. The developed telemeter is a low-cost apparatus capable of remote monitoring. With the sampling rate of 10 Hz, 100% accuracy was obtained up to a distance of 30 m. The precision was good (%RSD = 0.03–0.09), with relatively low noise. The effective signal range was from 0 to 2 V, with approximately 1100 working steps (greater than 10 bit A/D). The telemetric system was shown to be suitable for wireless recording of outputs from spectrophotometer and pH meter. Potential applications in chemical analysis were demonstrated.

This work describes development of a flow injection (FI) system for determination of iodide, based on the chemiluminescence (CL) reaction between iodine and luminol. Iodide in the sample zone is oxidized to iodine. Employment of a gas-diffusion (GD) unit allows for selective detection of the generated CL (425nm). Preliminary results showed for concentrations of less than 2mgL(-1), that signals were irreproducible and that the calibration was not linear. In order to solve these problems, a method of 'membrane conditioning' was investigated, in which iodide stream was continuously merged with oxidant to generate I(2) that conditioned the GD membrane and tubing. This minimized surface interaction between the active surface and the I(2) generated from the samples, thus improving both precision and sensitivity. By employing membrane conditioning, it has been possible to reliably detect concentrations down to 0.1mgL(-1). At the optimized condition, an excellent linear calibration (r(2) = 0.999) was obtained from 0.1 to 1.0mgL(-1). The method was successfully applied to determine iodide in some pharmaceutical products such as potassium iodide tablets and a liquid patent medicine. However, for vitamin tablets, ascorbic acid was found to interfere seriously by causing a negative signal.

An autonomous batch analyzer (ABA) is described for the measurement of ammonium in natural waters. The system combines previously described batch analysis and continuous flow analysis methods. With its simpler design, the system is robust, flexible, inexpensive, and requires minimal maintenance. The sampling frequency is ca. 8 h−1 and the limit of detection ca. 1 nM which is comparable to the most sensitive flow through or batch analysis methods previously described. Reproducibility is 0.6% (n = 10) at an ammonium level of 200 nM. There are three working ranges: 5–1000 nM, 20–4000 nM, and 0.2–25 μM. In addition, the system produces a calibration curve by autodilution from a single stock standard solution with the same accuracy as traditional manual calibration methods. Representative field data and comparisons with standard EPA methods confirm the utility of the ABA.