Examples of Philips XL30 Field Emission SEM applications

Scanning electron image of Braarudosphaera bigelowii, a unicellular planktonic alga
Braarudosphaera bigelowii, a unicellular planktonic alga with calcareous exoskeleton

The specimen was sampled off the Portuguese continental margin by J. Young and C. Koch as part of a project comparing modern and Late Quaternary coccolithophore assemblages off northwest Europe and their reaction to rapid climate changes over the 100,000 years. 

The cell is only 15 microns across. The high resolution of the XL30 makes it exceptionally suitable for imaging minute organisms such as this.

XL30 images are high resolution allowing magnification on selected areas to view detail - such as the lamella structure of the plates as shown above on the right.

Scanning electron image of the rapheless valve of the diatom species Achnanthes angustata Greville
Rapheless valve of the diatom species Achnanthes angustata Greville

All diatoms have two valves. These are usually more or less the same but in Achnanthes one valve has a raphe - a slit down the centre, whilst the other lacks this. The one that lacks the raphe is shown here. It is shown at a higher magnification on the right.

Most of the type specimens for this genus are in the Natural History Museum. The one shown here is in the Greville collection, one of our early prizes. It was collected in Chiba, Japan. 

In collaboration with Ken Toyoda, a PhD student from Japan, we are conducting research on a revision of the genus Achnanthes. 

Scanning electron microscope image of airborne particulate from the smelter town of Karabash, Russia
Airborne particulate from the smelter town of Karabash, Russia

The particulate was collected onto a 0.45 micron pore size filter using air pump apparatus. The particulate is mainly less than 1 micron in diameter and is therefore respirable, potentially inhaled into the deep regions of the lung. 

Elemental analysis of the material using the JEOL 5900LV analytical scanning electron microscope revealed that the particulates consist mainly of oxides and sulphates containing lead, zinc and cadmium. Sequential extraction studies of the material showed that the metals are present in a relatively soluble form. Inhalation of the particulate is therefore likely to pose a severe risk to human health.

The research was part of the MinUrals project.

Scanning electron microscope image of a coccolithophore, Acanthoica quattrospina
Coccoliths of the coccolithophore, Acanthoica quattrospina

The image highlights the structural complexity of the individual coccoliths - the circular plates. Each coccolith is only about 1.5 thousandths of a millimeter across but they are formed of an intricate set of cycles of interlocking calcite crystals.

The image has been artificially coloured by computer.

Scanning electron microscope image of the common coccolithophore, Emiliania huxleyi
Coccolithophore, Emiliania huxleyi

Emiliania huxleyi is the most common coccolithophore and one of the most ubiquitous organisms on Earth.

It occurs throughout the world's oceans - from sub-arctic to equatorial latitudes and from coastal to mid-ocean environments, and is present in nearly every plankton sample taken. 

It is particulary abundant at temperate latitudes and frequently forms blooms in the North Atlantic and North Sea with a few million cells per litre. The vast numbers of coccoliths in these blooms gives the water a milky colour and they have been extensively mapped by satellites.

The image has been artificially coloured by computer.