Daniel Mihai Toma

The new seafloor observatory (OBSEA) for remote and long-term coastal ecosystem monitoring

A suitable sampling technology to identify species and to estimate population dynamics based on individual counts at different temporal levels in relation to habitat variations is increasingly important for fishery management and biodiversity studies. In the past two decades, as interest in exploring the oceans for valuable resources and in protecting these resources from overexploitation have grown, the number of cabled (permanent) submarine multiparametric platforms with video stations has increased. Prior to the development of seafloor observatories, the majority of autonomous stations were battery powered and stored data locally. The recently installed low-cost, multiparametric, expandable, cabled coastal Seafloor Observatory (OBSEA), located 4 km off of Vilanova i la Gertrú, Barcelona, at a depth of 20 m, is directly connected to a ground station by a telecommunication cable; thus, it is not affected by the limitations associated with previous observation technologies. OBSEA is part of the European Multidisciplinary Seafloor Observatory (EMSO) infrastructure, and its activities are included among the Network of Excellence of the European Seas Observatory NETwork (ESONET). OBSEA enables remote, long-term, and continuous surveys of the local ecosystem by acquiring synchronous multiparametric habitat data and bio-data with the following sensors: Conductivity-Temperature-Depth (CTD) sensors for salinity, temperature, and pressure; Acoustic Doppler Current Profilers (ADCP) for current speed and direction, including a turbidity meter and a fluorometer (for the determination of chlorophyll concentration); a hydrophone; a seismometer; and finally, a video camera for automated image analysis in relation to species classification and tracking. Images can be monitored in real time, and all data can be stored for future studies. In this article, the various components of OBSEA are described, including its hardware (the sensors and the network of marine and land nodes), software (data acquisition, transmission, processing, and storage), and multiparametric measurement (habitat and bio-data time series) capabilities. A one-month multiparametric survey of habitat parameters was conducted during 2009 and 2010 to demonstrate these functions. An automated video image analysis protocol was also developed for fish counting in the water column, a method that can be used with cabled coastal observatories working with still images. Finally, bio-data time series were coupled with data from other oceanographic sensors to demonstrate the utility of OBSEA in studies of ecosystem dynamics.

Standards-Based Plug & Work for Instruments in Ocean Observing Systems

Ocean observing systems may include a wide variety of sensor and instrument types, each with its own capabilities, communication protocols, and data formats. Connecting disparate devices into a network typically requires specialized software drivers that translate command and data between the protocols of the individual instruments, and that of the platform on which they are installed. In addition, such platforms typically require extensive manual configuration to match the driver software and other operational details of each network port to a specific connected instrument. In this paper, we describe an approach to “plug & work” interoperability, using standardized protocols to greatly reduce the amount of instrument-specific software and manual configuration required for connecting instruments to an observatory system. Our approach has two main components. First, we use the sensor interface descriptor (SID) model, based on the Open Geospatial Consortiums (OGC) SensorML standard, to describe each instruments protocol and data format, and to provide a generic driver/parser. Second, a new OGC standard known as the programmable underwater connector with knowledge (PUCK) protocol enables storage and retrieval of the SID file from the instrument itself. We demonstrate and evaluate our approach by applying it to three commonly used marine instruments in the OBSEA (Barcelona, Spain) observatory test bed.

Instrument interface standards for interoperable ocean sensor networks

The utility and cost-effectiveness of instrument networks are enhanced by instrument interoperability. Todays oceanographic instruments are characterized by very diverse non-standard software protocols and data formats. This diversity of protocols poses serious challenges to integration of large-scale sensor networks. Standard instrument protocols are now being developed to address these challenges. Some of these standards apply at the IP-network level and enable integration of existing “lower level” proprietary instrument protocols and software components. Other approaches are intended to be implemented by the instrument device itself. These native instrument protocol standards offer the possibility of more uniform and simpler system architectures. We compare these various approaches, describe how they can be combined with one another, and describe some prototypes that implement them.

Piezoelectric energy harvesting from induced vortex in water flow

On this paper an evaluation of an energy harvesting system is presented. The system scavenges energy from a water flow using induced vortexes and piezoelectric materials. Cylinders of different size generate the vortexes and are attached to a cantilever that holds the piezoelectric generators. The evaluations consist on testing the performance of the cylinders and observe the frequencies and voltages generated. The preliminary results show that some of the configurations can generate a power of up to 0.31 μW.

Precision timing in ocean sensor systems

This paper discusses the use of the IEEE 1588 standard in ocean observatories. The performance result of prototype implementations of this standard in an Ethernet Marine Sensor Network (MSN) is presented. The performance tests emulate an underwater-cabled observatory with a Master Clock synchronized with GPS, located in an on-shore station, and with underwater instruments requiring high-precision PPS (pulse s−1) signals for synchronization purposes. These signals will be provided to the underwater station by an IEEE 1588 GPS Emulator connected to the observatorys Local Area Network (LAN). The experimental setup emulates the underwater-cabled observatory OBSEA where this technology will be installed due to synchronization requirements of marine instruments such as ocean bottom seismometers.

Ocean Bottom Seismometer: Design and Test of a Measurement System for Marine Seismology

The Ocean Bottom Seismometer (OBS) is a key instrument for the geophysical study of sea sub-bottom layers. At present, more reliable autonomous instruments capable of recording underwater for long periods of time and therefore handling large data storage are needed. This paper presents a new Ocean Bottom Seismometer designed to be used in long duration seismic surveys. Power consumption and noise level of the acquisition system are the key points to optimize the autonomy and the data quality. To achieve our goals, a new low power data logger with high resolution and Signal–to-Noise Ratio (SNR) based on Compact Flash memory card is designed to enable continuous data acquisition. The equipment represents the achievement of joint work from different scientific and technological disciplines as electronics, mechanics, acoustics, communications, information technology, marine geophysics, etc. This easy to handle and sophisticated equipment allows the recording of useful controlled source and passive seismic data, as well as other time varying data, with multiple applications in marine environment research. We have been working on a series of prototypes for ten years to improve many of the aspects that make the equipment easy to handle and useful to work in deep-water areas. Ocean Bottom Seismometers (OBS) have received growing attention from the geoscience community during the last forty years. OBS sensors recording motion of the ocean floor hold key information in order to study offshore seismicity and to explore the Earth’s crust. In a seismic survey, a series of OBSs are placed on the seabed of the area under study, where they record either natural seismic activity or acoustic signals generated by compressed air-guns on the ocean surface. The resulting data sets are subsequently used to model both the earthquake locations and the crustal structure.

Requirements and approaches for a more cost-efficient assessment of ocean waters and ecosystems, and fisheries management

Development of a new generation of multifunctional sensor systems is underway to address ocean monitoring challenges. These range from more precise monitoring of the marine environment to an improved management of fisheries and, among other things, address improved life cycle cost-efficiency. These advances will be achieved through innovations such as multiplatform integration, greater reliability through better antifouling management and greater sensor and data interoperability. Requirements for the sensors have been refined through surveys and discussions with science and industry users. This paper will describe these developments in the NeXOS project.

Use of Low-Cost Acquisition Systems with an Embedded Linux Device for Volcanic Monitoring

This paper describes the development of a low-cost multiparameter acquisition system for volcanic monitoring that is applicable to gravimetry and geodesy, as well as to the visual monitoring of volcanic activity. The acquisition system was developed using a System on a Chip (SoC) Broadcom BCM2835 Linux operating system (based on DebianTM) that allows for the construction of a complete monitoring system offering multiple possibilities for storage, data-processing, configuration, and the real-time monitoring of volcanic activity. This multiparametric acquisition system was developed with a software environment, as well as with different hardware modules designed for each parameter to be monitored. The device presented here has been used and validated under different scenarios for monitoring ocean tides, ground deformation, and gravity, as well as for monitoring with images the island of Tenerife and ground deformation on the island of El Hierro.

Middleware for Plug and Play Integration of Heterogeneous Sensor Resources into the Sensor Web

The study of global phenomena requires the combination of a considerable amount of data coming from different sources, acquired by different observation platforms and managed by institutions working in different scientific fields. Merging this data to provide extensive and complete data sets to monitor the long-term, global changes of our oceans is a major challenge. The data acquisition and data archival procedures usually vary significantly depending on the acquisition platform. This lack of standardization ultimately leads to information silos, preventing the data to be effectively shared across different scientific communities. In the past years, important steps have been taken in order to improve both standardization and interoperability, such as the Open Geospatial Consortium’s Sensor Web Enablement (SWE) framework. Within this framework, standardized models and interfaces to archive, access and visualize the data from heterogeneous sensor resources have been proposed. However, due to the wide variety of software and hardware architectures presented by marine sensors and marine observation platforms, there is still a lack of uniform procedures to integrate sensors into existing SWE-based data infrastructures. In this work, a framework aimed to enable sensor plug and play integration into existing SWE-based data infrastructures is presented. First, an analysis of the operations required to automatically identify, configure and operate a sensor are analysed. Then, the metadata required for these operations is structured in a standard way. Afterwards, a modular, plug and play, SWE-based acquisition chain is proposed. Finally different use cases for this framework are presented.

Study on Heat Dissipation and Cooling Optimization of the Junction Box of OBSEA Seafloor Observatory

Multidisciplinary underwater observatories represent an exceptional technological resource that can signify a qualitative forward step in marine scientific research as well as operational oceanography and climate change study. A cabled underwater observatory system that can provide broad bandwidth communication and power to oceanographic instruments is developed. The observatory consists of a subsea junction box that is fixed at a cable terminal, enabling real-time communication, power conversion, and power distribution of up to eight oceanographic instruments and one connection for a junction box. Therefore, the observatory has the capacity to cover a large range of distance-time observations, and to provide new opportunities for research and technological innovation. However, there are some issues to consider when designing the electronic system for the underwater observatory. The main concern is the location of the equipment in a hostile environment with difficult access for inspection and repair. Hence, appropriate heat management of the electronic apparatus has a significant influence on the useful life of this equipment. Specific validation and study of the behavior of the system prior the deployment, and permanent equipment status monitoring is essential to assure fault-free operation over the longest possible period of time. In this study, we present the thermal studies carried out on the junction box of the Observatorio Submarino Expandible Cableado (OBSEA) (expandable underwater cabled observatory) and the monitoring procedures are established. The underwater observatory has been deployed off the coast of the Balearic Sea and has been operating in real conditions for more than three years without interruption. The results show that this underwater observatory system is adequate for subsea real-time and long-term observations.