Arxiu d'etiquetes: NEPTUNE

Biology and extraterrestrial life

Frequently we can read on the news newly discovered planets that could harbor extraterrestrial life. Often we have new information about Mars, other worlds with water and extremely resistant living beings, like tardigrades. But is life possible outside the Earth? What is life? What is needed to sustain life? Astrobiology tries to answer this questions. Do you want to find out more?

ASTROBIOLOGY AND EXOBIOLOGY

Astrobiology is a set of different scientific disciplines that studies the existence of life in the universe. To achieve this it combines knowledge of biology, physics, chemistry, astronomy, ecology, geography, geology, planetary science and molecular biology. Within astrobiology, exobiology studies the possibilities of life outside our planet. It should not be confused with ufology, a pseudoscience. Astrobiology tries to answer such exciting questions as:
– What is life?
– How did life appear on Earth?
– How does life evolve, and what is its adaptability?
– What is the future of life on Earth and other places?
– Is there life in other worlds?

No, neither is this a Martian nor is it astrobiology. Source: Quo

WHAT IS LIFE?

Although it seems like a banal question, life is not easy to define. Apparently, we can recognize if something is alive or not if it can perform certain functions and has certain features. Living beings have vital functions:

  • Nutrition: they can obtain energy from the environment to grow, survive and reproduce.
  • Reproduction: they can create copies similar to themselves.
  • Interaction: they can perceive what is going on the environment and inside themselves.
  • Organization: living beings are formed by one or more cells
  • Variation: variability between individuals allows species to evolve.

Problems begin when with beings that don’t have all the characteristics. The most classic example would be viruses: they are unable to reproduce on their own and lack cellular structure. Another example would be erythrocytes (red blood cells) of mammals, cells without genetic material or mitochondria.

Microphotography of the Ebola virus under electronic microscope (Public photo of the CDC)

WHAT IS NEEDED FOR LIFE TO EXIST?

We only know one type of life: the terrestrial one. This is why astrobiologists need to take it as a reference to know what to look for elsewhere. Could there be other forms of life different than terrestrial? Maybe, but it would be almost impossible to recognize them. If you do not know what you are looking for, you may find it but do not realize it.

It is considered that in order for life to appear and develop, it is necessary:

  • A liquid where chemical reactions take place: on Earth, it is water.
  • An element with ease to form stable compounds: on Earth, it is carbon.
  • A source of energy: on Earth, it is the Sun.

We are looking for planets or satellites with these characteristics, although other possibilities such as liquid methane (in the case of Titan, a satellite of Saturn), ethane, sulfuric acid, ammonia or acetic acid as solvent are being considered. Life-based on other elements such as silicon, it is a recurring topic in science fiction stories.

Artistic representation of Titan’s methane lakes. Credit: Steven Hobbs

WHAT IS NEEDED TO SUSTAIN LIFE?

The celestial body has to fulfill a series of characteristics so that life can be sustained:

  • An abundance of chemical elements such as carbon, hydrogen, oxygen, and nitrogen to form organic compounds.
  • The planet/satellite has to be within the habitability area of its star (orbiting at a distance that allows a temperature suitable for life).
planet, star, habitable zone
Habitability area (green) according to the temperature of the star. Red: too hot, blue: too cold. Source: NASA / Kepler / D Mission. Berry
  • A source of energy enough to maintain the temperature and allow the formation of complex molecules.
  • An appropriate gravity to keep an atmosphere and not crush the living beings of the planet.
  • A magnetic field to divert the radiation incompatible with life.
The Earth’s magnetic field protects life from the solar wind. Source: ESA

In our Solar System, the candidates that possibly fulfill these characteristics are Mars, Europe and Ganymede (satellites of Jupiter), Enceladus and Titan (satellites of Saturn) and Triton (satellite of Neptune).

WHY CARBON?

Living beings are formed by cells, and if we reduce the scale, by molecules, and atoms (like all matter). Why is life-based on carbon?

In fact, in the constitution of organisms 26 elements are involved, but 95% of living matter consists of carbon (C), hydrogen (H), nitrogen (N), oxygen (O), phosphorus (P) and sulfur (S). We can imagine them as the “bricks of life”: by combining these building blocks, we can obtain complex organisms. These bricks can be joined to others by covalent bonds. Metaphorically, atoms can be imagined as spheres with hands which can be grasped by other hands. For example, the main energy source molecule for all living things is ATP (Adenosine triphosphate, C10H16N5O13P3).

enlaces químcos, moléculas, sulphur, phosphorus, hidrogen, oxigen, carbon, nitrogen, chemical bond
Schematic representation of carbon, hydrogen, oxygen, nitrogen and phosphorus atoms and their valences (possible bonds). Own production based on figure 6.3 of “Life in space” (see references)

The candidate element to sustain life would have to be an abundant element able to form a great amount of bonds with itself and with other elements. The 5 most abundant elements in the universe:

  • Helium: does not form compounds
  • Hydrogen and oxygen: they have 1 and 2 hands: they can only form very simple compounds
  • Nitrogen: can bind to 3 atoms, but no chains of several nitrogen atoms are known.
  • Carbon: it has 4 hands so it can be strongly bonded to other carbons with single, double, or triple bonds. This allows it to form long chains and three-dimensional structures and can still join to other atoms. This versatility allows constructing molecules chemically active and complex, just the complexity that makes life possible.
DNA chemical structure, double helix
DNA chemical structure where we can see the importance of carbon bonding to form rings and chains. Source

Could there be life in another place based on a different atom?

ALTERNATIVES TO CARBON

SILICON EXTRATERRESTRIALS

Since establishing 4 links is so useful, silicon is the first candidate for biologists and science fiction writers, even if it is not as abundant as carbon. Silicon (Si) can also form 4 bonds and is abundant on rocky planets like Earth, but …

  • The Si-Si bond is quite weak. In an aqueous medium, life based on silicon would not be sustained for a long time as many compounds dissolve in it, although it could be possible in another medium, such as liquid nitrogen (Bains, W.).
  • It is very reactive. Silane, for example (one silicon atom bonded to 4 hydrogens) spontaneously ignites at room temperature.
  • It is solid at most temperatures. Although it can easily form structures with oxygen (silica or silicon dioxide), the result is almost always a mineral (quartz): too simple and only reacts molten at 1000ºC.
  • It does not form chains or networks with itself, due to its greater size compared to carbon. Sometimes it forms long chains with oxygen (silicones), that perhaps could be joined to other groups to form complex molecules. The alien of the movie Alien has silicone tissues. The beings formed by silicones would be more resistant, which leads to speculate what kind of extreme conditions they could withstand.
Horta, a silicon-based form of life featured in the science fiction series Star Trek. Source

NITROGEN AND PHOSPHORUS EXTRATERRESTRIALS

Let’s look at some characteristics of nitrogen and phosphorus:

  • Nitrogen: can only form 3 bonds with other molecules and is poorly reactive.
  • Phosphorus: its bonds are weak and multiple bonds uncommon, although it can form long chains. But it is too reactive.

By combining the two, stable molecules could be obtained, but the beings based on nitrogen and phosphorus would have other problems: the nitrogen compounds, from which they would have to feed, are not abundant in planets and the biological cycle would not be energetically favorable.

BORON, SULFUR AND ARSENIC EXTRATERRESTRIALS

The most unlikely biochemistries could be based on these elements:

  • Boron: can form long chains and bind to other elements such as nitrogen, hydrogen or carbon
  • Sulfur: can form long chains, but because of its size is highly reactive and unstable.
  • Arsenic: is too large to form stable compounds, although its chemical properties are similar to those of phosphorus.

In 2010, the journal Science published a scientific research in which researchers claimed to have discovered a bacterium (GFAJ-1) capable of living only in arsenic, lethal to any living being. It broke the paradigm of biology by not using phosphorus (remember ATP and DNA structure) and opened up new study lines for astrobiology. In 2012, two independent investigations refuted the theory of researcher Felisa Wolfe-Simon and his team. Phosphorus remains essential for organisms to live and develop on Earth.

GFAJ-1 bacterium. Source

At the moment, these hypothetical biochemistries are nothing more than speculations, so astrobiologists are still looking for carbon-based life, although we already know that science never ceases to amaze us. Although we could identify life based on other elements if we ever find extraterrestrial life (or vice versa) the revolution will be so great that it won’t matter if they are carbon-based beings.

REFERENCES

 

MIREIA QUEROL ALL YOU NEED IS BIOLOGY

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Technology to the rescue of data

The purpose of this article is to show a general vision of the main problems of the traditional sampling techniques and the actual situation and advantages that the modern methods offer. More specific examples will be given in future articles in order to explain the running and some studies that have been using these new techniques.

THE PROBLEM

In science is very important to have a good quality data in order to develop any study and not being criticized by editors and REVISORS of the SCIENTIFIC MAGAZINES. Frequency, number, type and sampling sensors are just the first ones of a long list of important factors that you need to have in mind when planning the sampling of your study. There is no magic trick, each study is different and requires number and sampling frequency… different, specific and optimum.

When you are trying to discover the marine mysteries the problems just get bigger, the accessibility is much more limited than in the terrestrial habitats and you cannot go sampling every time you desire, some days maritime weather conditions difficult sampling and, often, you are forced to cancel it, leaving an important data gap. Traditional sampling methods, even their evolution among the years, requires the presence in situ of the scientist, nowadays we are not using a simple thermometer anymore but a complex CTD that provide a much more precision in multitude of different parameters (depending on the sensors attached at the CTD), at the same time and at the desired depth, but we always need a ship, for going at the selected coordinates, and some operators for raising and lowering the sensor. Moreover, biological sampling traditional techniques (trawling and longlines, among many other fishing arts, as well as direct observations via scuba diving) present another huge problem: they are very invasive methods, not just for the species itself but, many times like with bottom trawling method, for the environment, furthermore, the animals captured usually die during the manipulation process. Notice that, for being invasive methods (nets, ships, scuba divers,…), the correct study of the animals normal behaviour is affected, due to the response of the fish towards these invasive presence.

NEW TECHNOLOGIES

Recently, new different revolutionary sampling methods (Autonomous Underwater Vehicle and Cabled Underwater Observatory) have been implanted in order to reduce the above-mentioned problems. In the two given examples we find a set of sensors, adaptable to the desired study, installed in a small space. While AUV allow an automatic, or remote control, movement towards exact coordinates and, in some cases, are able to send the collected data via satellite, submarine observatories are fixed at the seabed becoming just one more element of the environment and producing no perturbation in the normal behaviour of the animals. Due to the connection via cable they can receive permanently energetic supplying without relying on the batteries duration, and send the collected data at real time. Therefore, the new technologies allow us to increase sampling frequency since the dependency on the climate conditions become much less important unlike the above-mentioned case of the scuba divers. However, the disturbance does not decrease when working with AUV, as well as the complications in studying animal behaviour.

Guanay2, the AUV designed by the technological group SARTI-UPC. Image: SARTI-UPC.
Guanay2, the AUV designed by the technological group SARTI-UPC. Image: SARTI-UPC.

UNDERWATER OBSERVATORIES

Cabled underwater observatories are slowly colonizing the coast around the world either forming big networks or individual observatories.

Nowadays, the more powerful observatories are the Canadian VENUS and NEPTUNE, both of them managed by the Ocean Networks Canada.  The first one was deployed on the 2006 and consists of 3 nodes placed between 100 and 300 meters deep in the Salish Sea, British Columbia, Canada. In addition to its function of studying the oceanographic phenomena it was also used as a test site of what would be its bigger brother, the NEPTUNE. This second network is working since 2009 and consist of 6 nodes and multitude of different sensors distributed on the oceanic profile of the Vancouver Isle west coast, from 23 to 2660 meters deep. For being placed over the fault produced due the interaction between the Juan de Fuca the Nord-American tectonic plate, it is an important observatory for the study of the plate tectonic forces.

NEPTUNE nodes distribution.
NEPTUNE nodes distribution. Autor: NEPTUNE (Creative Commons)

In Europe, we are not lagging behind, the EMSO (European Multidisciplinary Seafloor and Water Column Observatory) has grouped the isolated observatories, either underwater platforms or pelagic buoys, with the objective of forming a multidisciplinary network at European level.

OBSEA

One of the members of this European network is placed in the Catalan Coast, the OBSEA. The OBSEA platform (Western Mediterranean Expandable SEAfloor OBservatory) is a cabled video platform located at 20m depth, 5 km off Vilanova i la Geltrú. It was designed, deployed and managed by the technologic group SARTI from the UPC (Universitat Politècnica de Catalunya), conceived as a platform capable of supporting many different sensors in order to monitor different oceanographic parameters (such as temperature, salinity, seismic waves, tides heigh,…), and is also an instrumentation test site within the EMSO. The observatory is equipped with two video cameras, one fixed and the other with a 360º rotation angle, which can acquire digital images of the environment surrounding the OBSEA and everyone can check those live images from the OBSEA website.

OBSEA platform. Image: SARTI-UPC.
OBSEA platform. Image: SARTI-UPC.

New sampling methods help the researches to get a lot of good quality data for achieving a better understanding of the oceans. Sometimes however, the sampling frequency is so high that the amount of data produced is bigger than can be processed and we have to develop new software capable of working with big volume of data and help us in their manipulation and interpretation.

REFERENCES

  • 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.
  • Ona E and Godø OR (1990). Fish reaction to trawling noise: the significance for trawl sampling. Rapports et Procès-Verbaux des Réunions. vol. 189, pp: 159-166.
  • Stoner AW, Ryer CH, Parker SJ, Auster PJ and Wakefield WW (2008). Evaluating the role of fish behavior in surveys conducted with underwater vehicles. Canadian Journal of Fisheries and Aquatic Science. vol. 65, pp: 1230-1243.
  • Thrush SF and Dayton PK (2002). Disturbance to Marine Benthic Habitats by Trawling and Dredging: Implications for Marine Biology.Annual Reviews of Ecology and Systematics. vol. 33, pp: 449-473.
  • OBSEA
  • OCEAN NETWORKS CANADA
  • SARTI-UPC
  • Wikipedia NEPTUNE

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La tecnología al rescate de los datos

En este artículo se pretende dar una visión general de las principales problemáticas que presentan las técnicas tradicionales de obtención de datos y la situación actual y ventajas que ofrecen los métodos más modernos. En artículos futuros se darán ejemplos más concretos para explicar el funcionamiento y los estudios que se desarrollan con estas nuevas técnicas.

Problemática

En el mundo científico disponer de unos buenos datos tiene una vital importancia para poder desarrollar cualquier estudio sin que sea duramente criticado por editores y revisores de las revistas científicas. La frecuencia, tamaño, tipo y aparatos de medida son solo los primeros de una larga lista de factores que se tienen que tener en cuenta cuando planeas la recogida de datos de tu estudio. No existe ningún tipo de fórmula mágica, pues cada estudio es distinto a los otros y necesitará un tamaño y frecuencia de muestreo,… distinto, ajustado y óptimo.

Cuándo nos disponemos a descubrir los misterios del mundo marino el tema se complica aún más, pues su accesibilidad es bastante más limitada que el mundo terrestre y no se pueden obtener muestras siempre que uno quiere, en días con condiciones marítimas adversas el muestreo se puede complicar y, en muchos casos, cancelar, dejando un vacío de datos importante. Los métodos de estudio tradicional, aunque han evolucionado mucho a lo largo de los años, requieren una presencia in situ del investigador o técnico en el momento de tomar las medidas, actualmente hemos pasado de utilizar un simple termómetro a un complejo CTD que nos permite medir con mucha precisión multitud de parámetros distintos (según los aparatos de medida asociados a él), al mismo momento y a la profundidad deseada, pero siempre necesitaremos un barco que nos lleve a las coordenadas escogidas y unos operarios que bajen y suban el aparato. Además, las técnicas tradicionales de obtención de datos biológicos (arrastre y palangre, entre otras artes de pesca, así como observaciones subacuáticas directas realizadas por submarinistas) presentan otro gran inconveniente: se trata de técnicas altamente invasivas, no sólo para las mismas especies sino, en algunos casos cómo la pesca de arrastre, para el propio medio físico, además en muchos casos los animales capturados mueren durante el proceso de medidas. Cabe añadir que, por el hecho de ser métodos invasivos (redes, barcos, submarinistas,…), se dificulta el estudio del comportamiento normal de los individuos, pues los peces reaccionan delante de ésta presencia invasiva.

Nuevas tecnologías

En los últimos años se han incorporado diferentes métodos de muestreo totalmente revolucionarios (Autonomous Underwater Vehicles y Observatorios submarinos cableados entre otros) para tratar de reducir estos inconvenientes.  En los dos ejemplos mencionados encontramos un conjunto de sensores de medida, hasta cierto punto adaptable al tipo de estudio realizado, concentrados en un espacio muy reducido. Mientras que los AUV permiten un desplazamiento automático o con control remoto hasta las coordenadas exactas y, en algunos casos, un retorno de los datos vía satélite, los observatorios submarinos mantienen un punto de muestro fijo en el fondo marino y, a la larga, será un elemento más del medio y no producirá una perturbación en el comportamiento natural de las comunidades. Además, al estar conectados vía cable a tierra pueden recibir alimentación eléctrica de forma permanente y sin estar condicionados por la duración de las baterías y enviar los datos que recogen continuamente. Así pues las nuevas tecnologías nos han permitido aumentar la frecuencia de la toma de datos, pues ya no hay una dependencia de las condiciones climáticas cómo en el caso del muestreo por submarinismo, aun así el carácter invasivo se mantiene con los AUV, así como la dificultad de un estudio de comportamiento mencionada anteriormente.

Guanay2, el AUV diseñado por el grupo de investigación SARTI-UPC. Fotografía: SARTI-UPC.
Guanay2, el AUV diseñado por el grupo de investigación SARTI-UPC. Fotografía: SARTI-UPC.

Observatorios submarinos

Los observatorios cableados están colonizando poco a poco las costas de nuestro planeta, ya sea en forma de grandes redes de observatorios submarinos o de observatorios aislados.

Las redes de observatorios más potentes actualmente son las canadienses VENUS y NEPTUNE, las dos gestionada a través de la  Ocean Networks Canada. La primera fue instalada el año 2006 y consta de 3 nodos observatorios situados entre 100 y 300 metros de profundidad en el mar de Salish, Columbia Británica, al suroeste de Canadá. Además de su función de estudio de los fenómenos oceanográficos de la zona se utilizó cómo banco de pruebas del que seriía su hermano mayor, el NEPTUNE. Esta segunda red de observatorios está en funcionamiento desde el año 2009 y cuenta con 6 nodos observatorios y multitud de sensores de medida distribuidos al largo del perfil oceánico de la costa oeste de la isla de Vancouver, de los 23 a los 2660 metros de profundidad. Por el hecho de estar distribuida por la zona que conforma la falla entre las placas tectónicas Juan de Fuca y la Norteamericana hacen que sea una estación de observación clave en el estudio de las placas tectónicas in situ y de sus efectos.

Distribución de los nodos del observatorio NEPTUNE de Canadá.
Distribución de los nodos del observatorio NEPTUNE de Canadá. Autor: NEPTUNE (Creative Commons).

En Europa tampoco nos quedamos atrás, la EMSO (European Multidisciplinary Seafloor and Water Column Observatory) ha agrupado el conjunto de observatorios aislados, tanto plataformas submarinas como boyas pelágicas, para formar una red multidisciplinar a nivel europeo.

OBSEA

Uno de los observatorios miembros de esta red europea se encuentra situada en la costa catalana, el OBSEA. La plataforma OBSEA (Western Mediterranean Expandable SEAfloor OBservatory) es un observatorio submarino situada a 5 kilómetros de la costa de Vilanova i la Geltrú a 20 metros de profundidad que está conectado, mediante un cable mixto de energía y comunicaciones, con la base terrestre. Está diseñado, instalado y gestionado por el grupo tecnológico SARTI de la UPC (Universitat Politècnica de Catalunya), concebido inicialmente como una plataforma en la cual se pudiesen conectar multitud de diferentes sensores para medir diferentes parámetros ambientales (temperatura, salinidad, movimientos sísmicos, altura de las olas,…) y, además, sirve como banco de pruebas de la EMSO para sensores destinados a otros observatorios. Unos de los aparatos que hay instalados son 2 videocámaras, una de eje fijo y la otra con un eje de rotación de 360º, que nos permiten ver a través de la página web de la plataforma la comunidad de peces que habita en el medio.

Observatorio OBSEA. Fotografía: SARTI-UPC.
Observatorio OBSEA. Fotografía: SARTI-UPC.

Los nuevos métodos de muestreo, pues, nos ayudan a los investigadores a recoger una gran cantidad buenos datos con el fin de entender mejor el mar que nos rodea. Aun así, algunas veces la frecuencia de recogida es tan elevada que se generan más datos de los que se pueden procesar y se tienen que desarrollar, paralelamente a los sensores que registran los datos, software informático capaz de trabajar con estos volúmenes de datos tan grandes, y que ayude a su manejo e interpretación.

Referències

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.

Ona E and Godø OR (1990). Fish reaction to trawling noise: the significance for trawl sampling. Rapports et Procès-Verbaux des Réunions. vol. 189, pp: 159-166.

Stoner AW, Ryer CH, Parker SJ, Auster PJ and Wakefield WW (2008). Evaluating the role of fish behavior in surveys conducted with underwater vehicles. Canadian Journal of Fisheries and Aquatic Science. vol. 65, pp: 1230-1243.

Thrush SF and Dayton PK (2002). Disturbance to Marine Benthic Habitats by Trawling and Dredging: Implications for Marine Biology.Annual Reviews of Ecology and Systematics. vol. 33, pp: 449-473.

OBSEA

OCEAN NETWORKS CANADA

SARTI-UPC

Wikipedia NEPTUNE

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La tecnologia al rescat de les dades

En aquest article es pretén donar una visó general de les principals problemàtiques que presenten les tècniques tradicionals d’obtenció de dades i la situació actual i els avantatges que ofereixen els mètodes més moderns. En articles futurs es donaran exemples més concrets per explicar el funcionament i els estudis que es duen a terme amb aquestes noves tècniques.

Problemàtica

En el món científic disposar d’unes bones dades és de vital importància per poder dur a terme qualsevol estudi sense i que no sigui durament criticat per editors i revisors de les revistes científiques. La freqüència, mida, tipus i aparells de mesura són només els primers d’una llarga llista de factors que has de tenir en compte alhora de plantejar la presa de dades del teu estudi. No existeix cap tipus de fórmula màgica, doncs cada estudi és diferent i requerirà una mida i freqüència mostral,… diferent, ajustat i òptim.

Quan ens disposem a descobrir els misteris del món marí el tema es complica encara més, doncs la seva accessibilitat és força més limitada que el món terrestre i no es poden prendre mostres sempre que un vol, en dies amb condicions marítimes adverses el mostreig es pot complicar i, en molts casos, cancel·lar, deixant un buit de dades important. Els mètodes d’estudi tradicionals, tot i que han evolucionat molt al llarg dels anys, requereixen una presència in situ de l’investigador o tècnic alhora de prendre les mesures, actualment hem passat d’utilitzar un simple termòmetre a un complex CTD que ens permet mesurar amb molta precisió multitud de paràmetres  diferents (segons els aparells de mesura associats a aquest), al mateix moment i a la profunditat que desitgem, però sempre necessitarem un vaixell que ens porti a les coordenades escollides i uns operaris que baixin i pugin l’aparell. A més a més, les tècniques tradicionals de presa de dades biològiques (l’arrossegament i palangres, entre d’altres arts de pesca, així com observacions subaquàtiques directes realitzades per submarinistes) presenten un altre gran inconvenient: són tècniques altament invasives, no només per les espècies en concret sinó, en alguns casos com la pesca d’arrossegament, per el propi medi físic, a més en molts casos els animals capturats moren durant el procés de mesures. Cal afegir que, per tractar-se de mètodes invasius (xarxes, vaixells, submarinistes,…), es dificulta l’estudi del comportament normal dels individus, doncs els peixos reaccionen envers aquesta presència invasiva.

Noves tecnologies

En els darrers anys s’han incorporat diferents mètodes de mostreig totalment revolucionaris (Autonomous Underwater Vehicle i Observatoris submarins cablejats entre d’altres) per tal de reduir aquests inconvenients. En els dos exemples esmentats trobem un conjunt d’aparells de mesura, fins a certa mesura adaptable al tipus d’estudi desitjat, concentrats en un espai molt reduït. Mentre que els AUV permeten un desplaçament automàtic o amb control remot fins a les coordenades exactes i, en alguns casos, un retorn de les dades via satèl·lit, els observatoris submarins ens mantenen un punt de mostreig fix al fons marí i, a la llarga, serà un element més del medi i no produirà una pertorbació en el comportament natural de les comunitats. A més, a l’estar connectats via cable a terra poden rebre alimentació elèctrica de forma permanent sense estar condicionats per la duració de les bateries, i enviar les dades que recullen contínuament. Així doncs aquestes noves tecnologies han permès augmentar la freqüència de la presa de mostres, doncs ja no hi ha una dependència de les condicions climàtiques com en cas de la observació fent submarinisme, tot i això el caràcter invasiu es manté amb els AUV, així com la dificultat d’un estudi de comportament esmentada anteriorment.

Guanay2, l'AUV dissenyat pel grup de recerca SARTI-UPC.
Guanay2, l’AUV dissenyat pel grup de recerca SARTI-UPC. Fotografia: SARTI-UPC.

Observatoris submarins

Els observatoris submarins cablejats estan colonitzant poc a poc les costes del nostre planeta ja sigui en forma de grans xarxes d’observatoris submarins o d’observatoris aïllats.

Les xarxes d’observatoris més potents actualment són les canadenques VENUS i NEPTUNE, ambdues gestionades a través de la Ocean Networks Canada. La primera va ser instal·lada l’any 2006 i consta de 3 nodes observatoris situats entre 100 i 300 metres de profunditat al mar de Salish, Columbia Britànica, al sud-oest de Canadà. A més de la seva funció d’estudi dels fenòmens oceanogràfics de la zona es va utilitzar com a banc de proves del que seria el seu germà gran, el NEPTUNE. Aquesta segona xarxa d’observatoris està en funcionament des de l’any 2009 i compta amb 6 nodes observatoris i multitud d’aparells de mesura distribuïts al llarg del perfil oceànic de la costa oest de l’illa de Vancouver, dels 23 als 2660 metres de profunditat. Pel fet d’estar distribuïda per la zona que conforma la falla entre les plaques tectòniques Juan de Fuca i la Nord Americana fan que sigui una estació d’observació clau en l’estudi de les plaques tectòniques in situ i dels seus afectes.

Distribució dels nodes de l'observatori NEPTUNE de Canadà.
Distribució dels nodes de l’observatori NEPTUNE de Canadà. Autor: NEPTUNE (Creative Commons)

A Europa, però, no ens quedem enrere, la EMSO (European Multidisciplinary Seafloor and Water Column Observatory) ha agrupat el conjunt d’observatoris aïllats, tant plataformes submarines com boies pelàgiques, per formar una xarxa multidisciplinar a nivell europeu.

OBSEA

Un dels observatoris membres d’aquesta xarxa europea es troba situat a la costa catalana, l’OBSEA. La plataforma OBSEA (Western Mediterranean Expandable SEAfloor OBservatory) és un observatori submarí situat a 5km de la costa de Vilanova i la Geltrú a 20 metres de profunditat que està connectat, mitjançant un cable mixt d’energia i comunicacions, amb la base terrestre. Està dissenyat, instal·lat i gestionat pel grup tecnològic SARTI de la UPC (Universitat Politècnica de Catalunya), concebut inicialment com una plataforma a la qual s’hi poden endollar multitud de diferents aparells per mesurar diferents paràmetres ambientals (temperatura, salinitat, moviments sísmics, alçada de les onades,…) i que, a més, serveix de banc de proves de la EMSO per sensors destinats a altres observatoris. Uns d’aquests aparells que hi ha instal·lats són dues videocàmeres, una de fixe i l’altre amb un eix de rotació de 360º que ens permeten veure a través de la pàgina web de la plataforma la comunitat de peixos que habita en aquell medi.

Observatori OBSEA.
Observatori OBSEA. Fotografia: SARTI-UPC.

Els nous mètodes de mostreig, doncs, ens ajuden als investigadors a recollir una gran quantitat de bones dades per tal de poder entendre millor el mar que ens envolta. De vegades però, la freqüència de recollida és tan elevada que es generen més dades de les que es poden processar i s’han de desenvolupar, paral·lelament als aparells que registren les dades, software informàtic capaç de treballar amb aquests volums de dades tan grans, i que ajudi a la seva manipulació i interpretació.

Referències

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.

Ona E and Godø OR (1990). Fish reaction to trawling noise: the significance for trawl sampling. Rapports et Procès-Verbaux des Réunions. vol. 189, pp: 159-166.

Stoner AW, Ryer CH, Parker SJ, Auster PJ and Wakefield WW (2008). Evaluating the role of fish behavior in surveys conducted with underwater vehicles. Canadian Journal of Fisheries and Aquatic Science. vol. 65, pp: 1230-1243.

Thrush SF and Dayton PK (2002). Disturbance to Marine Benthic Habitats by Trawling and Dredging: Implications for Marine Biology. Annual Reviews of Ecology and Systematics. vol. 33, pp: 449-473.

OBSEA

OCEAN NETWORKS CANADA

SARTI-UPC

Wikipedia NEPTUNE

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