Observation of the microfauna of the deep-sea benthos using light and scanning electron microscopy

1973 ◽  
Vol 20 (4) ◽  
pp. 413-417 ◽  
Author(s):  
Bryan R. Burnett
2007 ◽  
Vol 87 (6) ◽  
pp. 1721-1726 ◽  
Author(s):  
Les Watling

Deep water cladorhizids are now generally thought to be carnivorous. While the methods of prey capture have been established for species of Asbestopluma, and perhaps Chondrocladia, information is sparse for species of Cladorhiza. The external morphology of the deep-sea Alaskan species, Cladorhiza corona, was examined immediately after collection, and then again later using scanning electron microscopy (SEM). All sponges examined had captured, and in most cases, fully encased, prey items which for the most part consisted of planktonic copepods. The hypothesis of this paper is that the primary process of prey capture is by means of a sticky substance and that prey stick to the sponge on contact. The abundant cladorhizid anisochelae do not seem to be arranged in a manner such that they can be used for prey capture as has been seen in Asbestopluma. Digestion of the prey occurs in a temporary cavity created by migrating sponge cells. Within this cavity lipid from the copepod is liberated, then absorbed and transported to the central part of the sponge. It is not known how much of the remaining tissue of the copepod is digested. Copepods have very high lipid content so their capture would provide the sponge with abundant energy from each prey item. The sponges seem to have their highest density in areas where bottom flow and migrating copepod numbers are both high.


Author(s):  
Caterina Longo ◽  
Francesco Mastrototaro ◽  
Giuseppe Corriero

Thirty species of sponges (29 Demospongiae, 1 Hexactinellida) have been recorded in association with a white coral bank situated off Cape S. Maria di Leuca (southern Italy) at depths ranging from 430 to 1160 metres. Notwithstanding the occurrence of clearly eurybathic species, two depth-dependent sponge groups can be identified along the bathymetric gradient. Two species, Geodia nodastrella and Plocamiopsis signata, are reported for the first time from the Mediterranean Sea. The sponge assemblage shows a higher affinity with the fauna from the Boreal region, with very low number of Mediterranean endemic species. Systematic notes concerning the poorly known and intriguing species, studied using scanning electron microscopy analysis, are reported.


Author(s):  
L.J. Walley

The morphology of the setae, on the mouthparts and the cirri of 33 barnacle species, was investigated by scanning electron microscopy. The species examined were selected from a range of pedunculate and balanomorph families living in a variety of habitats from the littoral zone to deep-sea vents. It was found that the setae could be divided into five groups: simple, denticulate, setulate, plumo-denticulate and aesthetascs. The categories were subdivided resulting in 43 setal types being recognized. Balanomorph cirripedes were found to have a greater variety of setae than pedunculates. Setulate setae on the cirri, and specialized setae on the mandibular palps and the first maxillae tended to be associated with the development of the balanomorph form. Setal type was correlated with taxonomy, whether based on shell structure and soft body morphology or DNA analysis, but with some anomalies which deserve further investigation. The problems of reconciling the proposed cirripede setal categories with those described in the Decapoda are discussed.


Author(s):  
J. G. Colman ◽  
P. A. Tyler ◽  
J. D. Gage

The larval shell morphology of 14 species of neogastropod from the Rockall Trough, N.E. Atlantic has been examined using scanning electron microscopy. Mode of development has been interpreted from protoconch size and morphological features, from the ratio of protoconch diameter to number of larval whorls and by comparisons with confamilial or congeneric shallow-water neogastropods in which development is known. Eight species have non-planktotrophic and 6 have planktotrophic development. Food availability and feeding strategy are important factors in the development of the two different reproductive strategies in the deep sea.


2015 ◽  
Vol 95 (7) ◽  
pp. 1389-1394 ◽  
Author(s):  
Joana R. Xavier ◽  
Inês Tojeira ◽  
Rob W.M. Van Soest

Hexactinellids or glass sponges constitute a predominantly deep-sea sponge group typically occurring at bathyal and abyssal depths. Some species form dense populations along the European and African continental slope but the distribution and extent of these populations remains ill known and the driving factors behind their occurrence poorly understood. Here we report an aggregation of the hexactinellid sponge Poliopogon amadou Thomson, 1878 at ~2700 m depth on the Great Meteor seamount, a large seamount located southern of the Azores archipelago. A description of the species, along with scanning electron microscopy of its spicules, is provided.


Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.


Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.


Author(s):  
Nakazo Watari ◽  
Yasuaki Hotta ◽  
Yoshio Mabuchi

It is very useful if we can observe the identical cell elements within the same sections by light microscopy (LM), transmission electron microscopy (TEM) and/or scanning electron microscopy (SEM) sequentially, because, the cell fine structure can not be indicated by LM, while the color is; on the other hand, the cell fine structure can be very easily observed by EM, although its color properties may not. However, there is one problem in that LM requires thick sections of over 1 μm, while EM needs very thin sections of under 100 nm. Recently, we have developed a new method to observe the same cell elements within the same plastic sections using both light and transmission (conventional or high-voltage) electron microscopes.In this paper, we have developed two new observation methods for the identical cell elements within the same sections, both plastic-embedded and paraffin-embedded, using light microscopy, transmission electron microscopy and/or scanning electron microscopy (Fig. 1).


Author(s):  
Ronald H. Bradley ◽  
R. S. Berk ◽  
L. D. Hazlett

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.


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