The document presents an overview of oceanographic instruments, detailing their definitions and specific types such as the Secchi disc, Stempel’s pipette, remote sensing technologies, underwater photography, and scuba apparatus. Each instrument is described with its purpose, functionality, and relevant applications in oceanography. Additionally, the document provides references for further information related to the topics discussed.

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PRESENTED BY:
VISHAKHA CHODANKAR
ROLL NO: 03
OCEANOGRAPHIC INSTRUMENTS

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DEFINITION
Oceanographic instruments are devices that allows for the
measurement of one or more properties of seawater in situ.
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TOPICS TO BE COVERED
Secchi disc
Stempel’s pipette
Remote sensing and satellite imaging
Underwater photography
SCUBA apparatus

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SECCHI DISC
• Created by Angelo Secchi - 1865.
• It is a plain white or black & white, circular disc
• About 30 cm(12 in) in diameter
• Used to measure water transparency or turbidity in
water bodies.
• The disc is mounted on a pole or line and
lowered slowly down in the water .
• The depth at which the disc is no longer visible
is measured – Secchi depth.
• It is related to water turbidity.
How to use?

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 Correlates the visibility of the disc from surface to the Euphotic depth.

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STEMPEL’S PIPETTE
• Stempel’s pipette is used for collecting samples
of zooplanktons.
• It is an easy and quick method for sub-sampling
plankton samples.
• Each spool takes the same size sample time
after time.
• Sometimes called as aliquot samplers.

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REMOTE SENSING AND SATELLITE IMAGING
• Remote sensing is the acquisition of information about an object or phenomenon without making
physical contact with the object
• Remote sensing is used in numerous fields, including geography, land surveying and most Earth science
disciplines (for example, hydrology, ecology, meteorology, oceanography, glaciology, geology)

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HOW DOES IT WORK?
• Satellite imagery is a special case of digital
photography.
• Radiation bands in the electromagnetic
spectrum that are reflected from the Earth’s
surface back into space can be collected by
satellite sensors and stored digitally as
pixels.
• The most common electromagnetic bands for
satellite imagery are visible light, near infrared
radiation (NIR), infrared radiation (IR), and
ultraviolet radiation (UV).

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• Some satellites collect only the radiation that that is reflected from the surface of the earth.
(Passive)
• Other satellites like JASON, emit radiation at 13.6 GHz and 5.3GHz and measure the time it takes
for the “round trip”. (Active)
• Active satellites measure elevation and are used to generate topography.
Sensor ranges-
• Visible Spectrum- full color digital photography
• Infrared- “heat”
• Near-Infrared- vegetation
• Mid-Infrared- soils
• Ultraviolet- clouds and snow cover

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ADVANTAGES
• Remote sensing makes it possible to collect data of dangerous or inaccessible
areas.
• Remote sensing applications include monitoring deforestation in areas such
as the Amazon Basin, glacial features in Arctic and Antarctic regions,
and depth sounding of coastal and ocean depths.
• It provides researchers with enough information to monitor trends such as El
Niño and other natural long and short term phenomena.
• Remote sensing also replaces costly and slow data collection on the
ground, ensuring in the process that areas or objects are not disturbed.

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UNDERWATER
PHOTOGRAPHY
• Underwater photography is the process of
taking photographs while under water.
• It is usually done while scuba diving.
• But can be done while diving on surface
supply
• Snorkeling
• Swimming
• From a submersible or remotely operated
underwater vehicle
• From automated cameras lowered from the
surface.
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• Successful underwater imaging is usually done with
specialized equipment and techniques.
• Animals such as fish and marine mammals are
common subjects.
• But photographers also pursue shipwrecks,
submerged cave systems, underwater
"landscapes", invertebrates, seaweeds, geological
features, and portraits of fellow divers.

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• Lighting –
• The primary obstacle faced by underwater photographers
is the loss of color and contrast when submerged to any
significant depth.
• The water is seldom optimally clear, and the dissolved
and suspended matter can reduce visibility
• Equipment –
• Waterproof digital cameras
• The first amphibious camera was the Calypso,
reintroduced as the Nikonos in 1963. Nikon ended the
Nikonos series in 2001
• Sea and Sea USA made the Motor Marine III, an
amphibious range-finder camera for 35mm film.
• Cameras made for dry work can also work underwater,
protected by add-on housings, which are made for point
and shoot cameras.
• Compact cameras with full exposure controls, and single
lens reflex cameras (SLRs).
• Use wide-angle lenses or macro lenses.

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• Underwater flash –
• The use of a flash or strobe is often regarded
as the most difficult aspect of underwater
photography.
• Generally, the flash should be used to
supplement the overall exposure and to restore
lost color, not as the primary light source
• Split images –
• A composition that includes roughly half above
the surface and half underwater, with both in
focus.
• popular in recreational scuba magazines.
• David Doubilet a National
Geographic photographer was one of the
pioneers of the traditional technique
• Applications –
• Artistic photography
• Records of the environment for personal and
scientific purposes

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SCUBA APPARATUS
• A scuba set is a breathing apparatus carried entirely by an underwater diver.
• Scuba is an acronym for self-contained underwater breathing apparatus.
• Provides the diver with breathing gas at the ambient pressure.

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REFERENCES
• Websites –
• http://www.coastalwiki.org/wiki/Oceanographic_instrument
• https://www.nalms.org/secchidipin/monitoring-methods/the-secchi-disk/what-is-a-
secchi-disk/
• https://en.wikipedia.org/wiki/Secchi_disk
• https://en.wikipedia.org/wiki/Remote_sensing#Satellites
• https://en.wikipedia.org/wiki/Scuba_set#Hazards_and_safety
• https://en.wikipedia.org/wiki/Underwater_photography
• Satellite imagery and remote sensing ppt – by D. Whitaker

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THANK YOU