sand
278
sand particles of sediment in the 64 !lm to 2 mm size fraction. It is usually
assumed to be of siliceous composition unless otherwise qualified (e.g.,
"coral sand"). --7grain size.
sandspit --7spit.
sand wave --7megaripple.
sapropel aquatic ooze or sludge composed of plant remains, desintegrated in an
anaerobic environment in swamps or on the bottom of shallow lakes and seas.
It contains more hydrocarbon than peat. It may be a source material natural
gas.
saprotrophs (syn. saprophages) heterotrophic organisms, chiefly bacteria and
fungi, which feed on dead organic matter.
Sarcodina --7Rhizopoda.
Sarcomastigophora --7Protoloa.
satellite oceanography is remote sensing of the ocean by means of satellite-borne
instruments. By means of passive remote sensing in the infrared wave bands
the sea surface temperature distribution is measured routinely. By measuring the reflectance of visible light, the distribution of chlorophyll, suspended matter and Gelbstoff in the surface waters can be obtained. Active remote sensing
in the microwave bands is used to measure wave heights and wave spectra,
surface winds, and also the height of the sea surface. For all these remotesensing techniques from satellites an accurate correction for the atmospheric influence on the radiation is needed. However, the presence of clouds is
prohibitive for the use of visible light and infrared radiation in satellite
oceanography. The satellites used are in part operational weather satellites,
but satellites are also launched with dedicated oceanographic missions. Both
geostationary and polar-orbit satellites have oceanographic applications.
scanning electron microscope (SEM) is used for the study of very small particles. It
can reach a higher resolution than the light microscope, because it uses an
image-forming radiation with much shorter wavelength than visible light.
With the SEM, particles of ca. 6 nm can be distinguished. With a narrow
electron beam the surface of an object is scanned and after interaction with
the material, low-energy electrons escape from the sample. These secondary
electrons are used to construct an image which depicts the sample surface
with mainly topographic information. Other electrons and photons escaping from deeper layers in the sample can - after each has been collected with
specific detectors - give information on the chemical composition of the
278
sand particles of sediment in the 64 !lm to 2 mm size fraction. It is usually
assumed to be of siliceous composition unless otherwise qualified (e.g.,
"coral sand"). --7grain size.
sandspit --7spit.
sand wave --7megaripple.
sapropel aquatic ooze or sludge composed of plant remains, desintegrated in an
anaerobic environment in swamps or on the bottom of shallow lakes and seas.
It contains more hydrocarbon than peat. It may be a source material natural
gas.
saprotrophs (syn. saprophages) heterotrophic organisms, chiefly bacteria and
fungi, which feed on dead organic matter.
Sarcodina --7Rhizopoda.
Sarcomastigophora --7Protoloa.
satellite oceanography is remote sensing of the ocean by means of satellite-borne
instruments. By means of passive remote sensing in the infrared wave bands
the sea surface temperature distribution is measured routinely. By measuring the reflectance of visible light, the distribution of chlorophyll, suspended matter and Gelbstoff in the surface waters can be obtained. Active remote sensing
in the microwave bands is used to measure wave heights and wave spectra,
surface winds, and also the height of the sea surface. For all these remotesensing techniques from satellites an accurate correction for the atmospheric influence on the radiation is needed. However, the presence of clouds is
prohibitive for the use of visible light and infrared radiation in satellite
oceanography. The satellites used are in part operational weather satellites,
but satellites are also launched with dedicated oceanographic missions. Both
geostationary and polar-orbit satellites have oceanographic applications.
scanning electron microscope (SEM) is used for the study of very small particles. It
can reach a higher resolution than the light microscope, because it uses an
image-forming radiation with much shorter wavelength than visible light.
With the SEM, particles of ca. 6 nm can be distinguished. With a narrow
electron beam the surface of an object is scanned and after interaction with
the material, low-energy electrons escape from the sample. These secondary
electrons are used to construct an image which depicts the sample surface
with mainly topographic information. Other electrons and photons escaping from deeper layers in the sample can - after each has been collected with
specific detectors - give information on the chemical composition of the