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MEMS in MarineScience

Abhinaw

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Need for sensors in marinescience

Sensing in marine environment maybe done for various

reasons :

Oil exploration and related applications

Global weather predictions

Monitor water quality for any contamination

Measure parameters detrimental to the health ofstructures in the sea ( like oil rigs and ships )

Stud of a uatic lants and animals

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Parameters monitored inmarine science

Temperature,

pressure, light

transmission,

tidal and current

velocity

Plant pigments

Dissolvedgases(like oxygen),pH, metals,pesticides

Seabed

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Why measure these quantitiesafter all ?

Water temperature effects a lot of processesdirectly viz.

Solubility of substances in water

Feeding and reproduction of aquatic organisms

Also, waters ability to hold dissolved oxygendecreases as water temperature increases. Now,this is really crucial for aquatic life !!

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Importance of measuring

light penetration Indicates algal growth

Indicates presence of silt in estuaries(confluence of river and the sea).

Sediments if present in water in largeamounts

May block sunlight to submerged plants

Can carry pesticides and other pollutants

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Where are these MEMS

devices attached ?

http://www.oceanor.no/images/oc-buoys.gif

The MEMS devices, inmarine

sensing maybe attachedto:

Ships

Floating devices (buoys)

in the sea

Fixed sea structures (likeoil rigs)

Sea bed using links

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AUV ( Autonomous underwatervehicle )

AUVs are unmannedunderwater vehicles forreal time monitoring in theoceans.

AUVs can be equipped withLab on a Chip, a set ofsensors developed on asingle chip, using MEMS.

These Lab on a Chipdevices can sense a largenumber of chemicalpollutants simultaneously.

AUV

http://isis2.admin.usf.edu/ur/usfmagazine/spring02/rip1.html

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MEMS in oil exploration and relatedapplications

To find potential oilreserves

To detect oil leakage from

pipelines

In cases of unfortunate oilspills

MEMS sensors can help to

sense information aboutthe ocean currents.

Using this it is possible topredict how far the oil slickwill be transported.

This information can aid inclean up.

http://www.spiderstaging.com/rigging/images/offshore_oil.jpg

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Finding potential oil and gasreserves

MEMS geophones and accelerometerscan sense the vibrations sent up from theearths belly.

An array of MEMS geophones are planted

over a wide area on the seabed.

Vibrations are intentionally produced onthe ground surface using sometechniques.

The MEMS devices measure the reflectionof these waves from different layers inthe earths belly.

These readings are then used to create a

MEMS Accelerometer

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Role of MEMS in coastal weathermonitoring

MEMS sensors can provide vital information aboutwave pressure, temperature, tidal and currentvelocity (using devices like the MEMS Dopplercurrent profiler).

The information obtained can be used to developmaps indicating the distribution of theseparameters throughout the ocean.

These maps can provide accurate data, regardingany imminent sea storms, tsunamis (large seawaves caused due to large scale movementsinside the earths surface).

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Hydrophones ))))

Just as microphones collect sounds in air, hydrophones

are small devices that detect sounds in water.

The sources of sounds in water maybe ships,earthquakes, waves or marine animals.

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Digital mammal tags

These are tiny devicesattached to animalslike whales, sharks,dolphins etc..

Provides vital dataabout the animal andits surroundings

A tag houses

Pressure sensor(s)

Temperaturesensor(s)

Hydrophone (soundsensor

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MEMS in marine militaryoperations

An array of MEMS sensors spread on the ocean floor coulddetect the presence of enemy submarines.

MEMS sensors (pressure sensors, accelerometers etc.) are

being used in anti-torpedo weapons on submarines andships.

MEMS sensors in torpedoes are responsible for

Detonating the torpedo at the right time Hittin the tar et in a crowded environment

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Challenges for MEMS sensors

in marine environment Complex nature of marine environment

Fouling of sensor surfaces

Selecting one out of several species

Should be able to detect extremely lowlevels of chemical concentrations

Resist drifting along with the currents

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Future of MEMS in marinescience

MEMS promises to be an effective technique ofproducing marine sensors of high quality, at lower

costs.

The use of fiber optics in marine science offersseveral avenues in fabrication and packaging of

sensors.

The use of sensor dust in the oceans in the comingyears, would be the best that this technology couldoffer.

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Thanks for

Listenin