Arxiu d'etiquetes: research methodology

The submarine observer

Just as explained in the article “Technology to the rescue of data” the OBSEA platform is an underwater observatory placed on the Catalan coast. The aim of this article is to provide a general description of the observatory, the sensors and a brief comment of the studies and uses that are being done currently.

The platform

The OBSEA (Western Mediterranean Expandable SEAfloor OBservatory) is an underwater observatory designed, deployed and managed by the technologic group SARTI from the Universitat Politècnica de Catalunya (UPC). It is placed 4km off Vilanova i la Geltrú coast at 20m depth, in a fishing protected area, and has an optical fibre cable connecting it to the terrestrial laboratory that provides the required energy for the correct performance of the different sensors and allows a transmission of data from the platform to the lab. Thus the information is received in real time and the problematic related with instrumentation powered by batteries is avoided. Furthermore,  it also allows to the engineers of the SARTI to make software modifications and checkings of the electronic devices with no need of taking out of the water the observatory.

Plataforma OBSEA
OBSEA platform (Image: SARTI-UPC)

Instrumentation and studies

The whole electronic system is installed in a watertight cylinder for protecting it, and the instrumentation connections, from short-circuiting. At the same time, this cylinder is placed inside a metallic structure that protects it from external factors and fixes it to the seabed.

External structure of the OBSEA (3D Image: Renderparty)
External structure of the OBSEA (3D Image: Renderparty)

One of the most important sensors when studding the ocean is the CTD (Conductivity Temperature Depth), it is used in multitude of studies, from biologic to physic. With this device one can get direct information about temperature, conductivity and pressure, and other parameters can be calculated: salinity from conductivity, depth from pressure,…

Video camera with a 360º axis rotation(Image: SARTI-UPC)
Video camera with a 360º axis rotation(Image: SARTI-UPC)

Two video cameras provides images in real time of the observatory surroundings. Meanwhile one has an axis rotation of 360º the other one is fixed in one position. These cameras allow the realization of very different projects, from biologic and behavioural studies of the fauna linked to the observatory and its environment, to projects focused on the citizen participation on the scientific world, through the identification of the species that appear on the images, and are the key factor of a group in Facebook where the users post peculiar images pictured by these cameras and the scientist answer the questions presented.

A hydrophone gets and characterizes acoustically ambient noise and, thanks to a specific software, is a capable of discriminate between biologic and anthropogenic noise. This sensor is currently used by studying the cetaceous of the area and the possible relation between the fish assemblages living around the observatory, the cetaceous (predators) and the maritime transit.

AWAC instal·lat a l'OBSEA (Imatge: SARTI-UPC)
AWAC connected to the OBSEA (Image: SARTI-UPC)
Sismògraf instal·lat a l'OBSEA (Imatge: SARTI-UPC)
Seismograph connected to the OBSEA (Image: SARTI-UPC)

The AWAC is a current profiler and a wave measurement system, it allows the measurement the speed and direction of the water at different depth, from the seabed to the surface. It is also capable of differentiate between different types of waves: long storm waves, short windy waves or waves generated by ship.

The pH sensor gives information of water acidity.

The observatory also has installed a seismograph prepared for detecting any tectonic movement produced anywhere in the planet. The obtained data is checked with a universal database in order of being referenced and verified. This seismograph was capable of detecting, among others, the seismic movements produced during the 2011 Japan earthquake and tsunami or produced for the platform of Castor Project (Catalan coast).

Finally, it is of relevance the extension of the OBSEA, a buoy. This buoy is permanently connected to the observatory and has a complete meteorological station for measuring, among others, air temperature, wind speed and direction, atmospheric pressure,…

Boia oceanogràfica connectada a l'OBSEA
Oceanographic buoy connected to the OBSEA (Image 3D: Renderparty)

The OBSEA platform allows the obtaining of data from many different types (biological, oceanographic, atmospheric,…) and, more important, continuously and in real time. This functionality made the OBSEA a key tool in the development of the actual and future oceanographic studies.


Aguzzi J, Mànuel A, Condal F, Guillén J, Nogueras M, Del Río J, Costa C, Menesatti P, Puig P, Sardà F, Toma D and Palanques A (2011). The New Seafloor Observatory (OBSEA) for Remote and Long-Term Coastal Ecosystem Monitoring. Sensors vol. 11, pp: 5850−5872.




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Satellite tagging

In this post we are going to talk about satellite tagging, a methodology for the studying of cetacean animals.


Satellite tagging is an information obtaining process thanks to systems present in animals: in this case, present in cetaceans previously captured and installed the transmitter at dorsal fin (in porpoises, bottlenose dolphins and killer whales) or at blubber (in humpback whale, southern right whale and blue whale). In short-term behaviour studies, it’s possible to join the transmitters to skin with suction pads. This systems can accumulate the information (data loggers) or they can send it by satellite. Often, these systems have video camaras to show what the animals are watching each moment.

The information got with this method allows to study the movements, behaviour, population structure and the recovery of populations.



This system records lots of data with different equipments that give information about behaviour (sounds, swimming speed…), fisiology (heartbeat rate, body temperature, stomach temperature…) and the environment (depth, water temperature, light intensity, sounds…). The recording interval can be regulated, depending the goal of study.

This system has some advantages: to keep information spend less energy than its transmisson, are smaller and less bulky and it can save lots of information. The problem is the difficulty of getting the equipment again.



The most important is telemetry via satellite, with a transmitter that sends the data via satellite to a receiver station with a computer. These systems get information about the animal position, immersion depth, swimming speed and water temperature to study the environment factors that affect to distribution, movements and feeding behaviour.

Them use is restricted: they can just send the information in the water surface, the environment sounds are overlaped with cetacean sounds and they need lots of energy. The advantage is the hability of giving information in real time to a working center.


The bibliography used to write this post is:

ANILAM, RESEARCH AND CONSERVATION, Métodos de investigación de cetáceos:

AUSTRALIAN GOVERNMENT, DEPARTMENT OF THE ENVIRONMENT, Non-lethal research techniques for studying whales:

CIRCE, Metodologías aplicadas por CIRCE en sus programas de investigación:

TRUJILLO, F & DIAZGRANADOS, M. C., Curso de técnicas de estudio de mamíferos acuáticos: manual básico, La Isla de los Delfines – Fundación Omacha, 2005


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Introduction to research methodology

This post is an introduction to cetacean research methodology, where there is a list of different methods and what you can study with them. En the following publications, you will find an specific information of each one.


The study of cetaceans at sea consists on the study of its ecology, like an individual (feeding, social and reproductive behaviour) and like a group (space and time’s distribution, abundance and population tendencies). There are different methods to study cetaceans in theses different aspects:

1) Observations: you can study the abundance and distribution.

2) Acoustic research methods: you can study the distribution, abundance and feeding and reproductive behaviour.

3) Individual identification (Photo-identification and mark-recapture): you are able to study the abundance, movements, reproduction and survival.

4) Satellite tagging: you can study the movements, feeding behaviour and survivial.

5) Genetic methods: you are able to study the reproduction, genetics and diet.

6) Geographic Information Systems: you can study the area use, density, feeding and reproduction zones, movements and conservation.


The bibliography that have been used to develope this topic is the following:


AUSTRALIAN GOVERNMENT, DEPARTMENT OF THE ENVIRONMENT, Non-lethal research techniques for studying whales:

BERNASCONI, M et al. Use of active sonar for cetacean conservation and behaviorial-ecology studies: a paradox? Proceedings of the Institute of Acoustics, 2009, Vol. 31. Pt. 1

CAÑADAS, A et al. Recopilación, Análisis, Valoración y Elaboración de Protocolos sobre las Labores de Observación, Asistencia a Varamientos y Recuperación de Mamíferos y Tortugas Marinas de las Aguas Españolas. Sociedad Española de Cetáceos. 1999

CIRCE, Metodologías aplicadas por CIRCE en sus programas de investigación:

MARTINS, C.C.A GIS as a tool to identify priority areas for humpback whale conservation at Eastern Brazilian Coast. 2009

PITTMAN, S & COSTA, B. Linking Cetaceans tot their Environment: Spatial Data Acquisition, Digital Processing and Predictive Modeling for Marine Spatial Planning in the Northwest Atlantic. Biogeography Branch, Center for Coastal Monitoring & Assessment, National Oceanic and Atmospheric Administration, 2009, Chapter 21

THOMAS, Peter O. Metodology for behavioural studies of cetaceans: right whale mother – infant behaviour. Rep. Int. Whal. Commn. 1986

TRUJILLO, F & DIAZGRANADOS, M. C., Curso de técnicas de estudio de mamíferos acuáticos: manual básico, La Isla de los Delfines – Fundación Omacha, 2005


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