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Chemoreception in marine organisms
Book reviews
387
scales,and the important topic of surgesis given a brief treatment. The chapter on hydraulic works deals with the hydraulics of such structures from inlets for power-station cooling systemsto the distribution of the warmer output water, and alsothe considerationsin the dispersalof sewagefrom underwater outlets. The two volumes should be a useful reference source of factual information for anyone concerned with practical work in shallow coastalwaters. They would, however, have been improved with an author index and a comprehensivelisting of the nomenclature used.It is a pity that the author hasbeen let down by less-than-accuratespelling and proof reading, even to the extent of mis-spelling the author’s own name on one occasion(that one must have hurt); the reviewer is still wondering how an angle can fear to tread. However, one cannot expect almost a quarter of a million words to be immaculate. The author has put a great deal of effort into compiling thesebooks; for a long time to comethey will be looked upon as a useful compilation of relevant information by anyone interestedin coastsand shallowwater. L. DRAPER
Chemoreception
in Marine Organisms
Edited by P. T. Grant and A. M. Mackie Academic Press, London
1974,
xi $ 295pp.
46 Figures,
k7.40
A multi-author work needs to be analysed on two levels. On the one hand each of the contributions must be judged in isolation, though bearing in mind its context within the whole. On the other hand the work must be consideredin its entirety, with regard to its merits of inclusion and omission, its balance and its continuity. The former task is the more straightforward, though not necessarilythe easieron that account. The latter is more complex, and the rigour with which it is prosecuted will depend upon the nature of the subject. A definitive account of a well establishedtopic demandshigh standardsof coherence and completeness,but in a study of a new and rapidly evolving field thesedesirablecharacteristics must be of necessityeschewedin somemeasurein the interests of topicality. The book reviewed here is clearly within the secondof these categories,and must be judged by the more generouscriteria appropriate to it. The first chapter by Laverack on the structure and function of chemosensorycells is a very sound introduction and it reviews concisely the state of our knowledge, or more accurately perhaps,of our ignorance.For it soontranspiresthat really we know nothing yet of what happenswhen a stimulator-y molecule reachesthe surface of a sensory cell. This chapter is essentialreading for all involved in or embarking upon a chemosensorystudy and because these will be drawn from so many disciplines, it would have done better to assumeless knowledge on the part of the reader. Thus Table I deservesa Figure to explain the various fine structures listed and even with their captions the Figures are not all easily understood by the uninitiated. The abiding messagewithin the chapter is one of warning: the variable responseof receptor cellsto similar stimuli, the CNS modulation of receptor sensitivity and the synergistic effect of stimulantsall indicate pitfalls for the unwary, whether they be electrophysiologistsor whole-animal behaviourists. The secondchapter by Bardach and Villars is on the chemical sensesof fishes. It commenceswith a fairly detailed account of the structure of the chemosensoryorgans,which are
388
Book reviews
clearly demarcated as either olfactory or gustatory. There is then a brief section on the responses of theseorgansand to finish a longish sectionon the behavioural patterns associated with chemoreception.This sumsup the current state of our knowledge, with a fair understanding of both receptor morphology and the ultimate behaviour, but with little comprehension of how the environment, through its action upon the former, mediatesthe latter. Several interesting points emerge. First, there is the distinct separation of olfactory and gustatory function, which is not automatically to be anticipated in aquatic organisms. Admittedly there is some common ground in that certain stimulants can activate both systems,but generally they maintain their distinction. Second, it is shown that whereas the role of olfaction in the alerting phase of feeding behaviour is well documented, the methods of locating food sourcesby chemosensorymeans are still far from understood. Finally olfaction proves important in social and reproductive behaviour, which is rather unexpected in view of the more familiar visually moderated displays and reactions of fish and this promisesto be a fertile field for future study. The next chapter is the first of three dealing with different facets of invertebrate chemoreception and in it the editors cover interspeciesand intraspecieschemoreceptionby marine invertebrates. The larger portion is devoted to interspecific behaviour such as escape reactions, defencesecretionsand host finding. There is a rather encyclopaedic list of examples, with detailsof severalof the chemicalsinvolved. There follows an all too brief review of intraspecific chemical communication, which is a pity as these reactions are probably of greater overall biological significancethan the more spectacularinterspecific ones. This no doubt reflects how little work has been done here and showsit to be another important subject for deeper investigation. A notable omissionfrom this and succeedingchapters is any general account of invertebrate chemoreceptors.Admittedly their diversity precludes a concisetreatment like that given to fish in chapter z, but they should not have been totally ignored and could have been included at the expenseof lessrelevant material elsewhere. Chapter 4, by Lenhoff, is entitled ‘Chemoreception in aquatic invertebrates with special emphasison the feeding behaviour of Coelenterates’. The first part is a general review of food stimulants in invertebrates and it complementsthe previous chapter from which this topic was deliberately omitted. The remainder dealswith feeding in Hydra and severalother coelenterates,showinghow certain chemicals,notably glutathione, trigger specific responses. This is covered in rather more detail than is appropriate to the context. However, it ends with a stimulating discussionof the relationship of the glutathione reaction to olfactory, gustatory and hormonal mechanismsand points out the essentialsimilarity of all three and the difficulty of differentiating them in simpler organisms. The final chapter, by Crisp, is the longest and surveys its chosentopic excellently. It must be pointed out, however, that only the final 30 pagesof this 78 pagechapter are strictly relevant to the subject of chemoreception, the remainder completing a comprehensive review of all the known factors influencing the settlement of marine invertebrate larvae. As such it is valuable in its own right and will be of interest to many workers not directly concerned with chemical stimuli. The section on chemoreceptionshows how far this type of work has progressedwith larval settlement, for from Table 4 it is seenthat experimental evidence for chemicalsubstrate attractivenesshas been obtained for a variety of phyla. The accountsof the isolation of chemical attractants give a valuable insight into the methodsand results of these studies and incidentally show what felicitous organismsbarnacles have proved to be for such investigations.The mechanismof chemoreceptionis shown to depend upon contact recognition of non-diffusable material adsorbed on the substrate, a ‘tactile chemical sense’differing from the normal conceptionsof both taste and smell.
Book reviews
389
Despite the few shortcomings mentioned earlier, this is a very useful book as a whole, bringing together as it does accounts of these diverse yet related topics, each written by experts in these rapidly evolving fields. It offers an informative and stimulating melange which should be read by workers in any branch of marine chemosensorystudies. A clear picture is given of those aspectsin which appreciableadvanceshave already been made,and attention is drawn to someof the fields urgently in need of further study. Notable amongst the latter are the action of stimulatory moleculesat the receptor site, and the whole subject of intra-specific chemical communication. Ii. G. HARTNOLL
Marine Algae of the West Coast of Florida Clinton J. Dawes Univksity
of Miami
Press I974,
xci
+ 201 I@,,
8I5.00
In recent years there hasbeen published a proliferation of regional manualson marine algae. Some of them are mere pamphlets for use of amateursseekingnamesfor specimenspicked up on the beachor seenthrough a face mask. Someother manualshave beencomprehensive. This is an example of such a manual and is certainly designedto be used asa textbook in the local area, aswell as a guide for the amateur. The flora covered here is that found on the west coast of Florida between Cedar Key in the north to Cape Roman0 in the south, including speciesfound 70 miles offshore. The greatest stressis on Tampa Bay and vicinity. The emphasishere is both taxonomic and ecological.The introductory chapter explains the physical characteristics of the marine habitats of the area. A brief discussionof the characteristics of an alga and then a delineation of the characteristics of the four main macroalgaldivisions. There are a few points in this sectionthat seemto me to be inaccurate or incorrect usageof terms. The author claimsthat the blue-green algae‘must be considered to be bacteria’. The two groups certainly have characters in common, but this is a moot point and is by no meansuniversally accepted. Heterocysts are said to be ‘empty’. Recent work seemsto point out that they are not empty cellsand are probably the seatof nitrogenfixation. Under Phaeophyta he states they have stems, roots and leaves. What should be stated here is that certain structures are leaf-like, stem-like and root-like. These are not true structures asfound in higher plants. In referenceto using color to identify reds and browns, the author claimsthat if in doubt, put them in hot water. He statesthat the reds will become green but not the browns. This is a very poor criterion, for Fucus and Laminaria will become brilliant green in hot water. Figure 13 showsa trichome of Hydrocoleum lyngbyaceum with a characteristic ‘tuft of hair at the tip cell’. Long ago these ‘tufts’ have been shown to be epiphytes, either bacteria or diatomsand are not part of the algal cell. These epiphytes can attach here, since there is no sheath material being produced by this end cell, which would prevent attachment. These inaccuraciescertainly do not detract from the book’s value, but should be corrected if future editions are planned. Adequate keys are included, first for the main divisions and then for the algal speciesin each division. As far as I can determine thesekeys are quite satisfactory.
387
scales,and the important topic of surgesis given a brief treatment. The chapter on hydraulic works deals with the hydraulics of such structures from inlets for power-station cooling systemsto the distribution of the warmer output water, and alsothe considerationsin the dispersalof sewagefrom underwater outlets. The two volumes should be a useful reference source of factual information for anyone concerned with practical work in shallow coastalwaters. They would, however, have been improved with an author index and a comprehensivelisting of the nomenclature used.It is a pity that the author hasbeen let down by less-than-accuratespelling and proof reading, even to the extent of mis-spelling the author’s own name on one occasion(that one must have hurt); the reviewer is still wondering how an angle can fear to tread. However, one cannot expect almost a quarter of a million words to be immaculate. The author has put a great deal of effort into compiling thesebooks; for a long time to comethey will be looked upon as a useful compilation of relevant information by anyone interestedin coastsand shallowwater. L. DRAPER
Chemoreception
in Marine Organisms
Edited by P. T. Grant and A. M. Mackie Academic Press, London
1974,
xi $ 295pp.
46 Figures,
k7.40
A multi-author work needs to be analysed on two levels. On the one hand each of the contributions must be judged in isolation, though bearing in mind its context within the whole. On the other hand the work must be consideredin its entirety, with regard to its merits of inclusion and omission, its balance and its continuity. The former task is the more straightforward, though not necessarilythe easieron that account. The latter is more complex, and the rigour with which it is prosecuted will depend upon the nature of the subject. A definitive account of a well establishedtopic demandshigh standardsof coherence and completeness,but in a study of a new and rapidly evolving field thesedesirablecharacteristics must be of necessityeschewedin somemeasurein the interests of topicality. The book reviewed here is clearly within the secondof these categories,and must be judged by the more generouscriteria appropriate to it. The first chapter by Laverack on the structure and function of chemosensorycells is a very sound introduction and it reviews concisely the state of our knowledge, or more accurately perhaps,of our ignorance.For it soontranspiresthat really we know nothing yet of what happenswhen a stimulator-y molecule reachesthe surface of a sensory cell. This chapter is essentialreading for all involved in or embarking upon a chemosensorystudy and because these will be drawn from so many disciplines, it would have done better to assumeless knowledge on the part of the reader. Thus Table I deservesa Figure to explain the various fine structures listed and even with their captions the Figures are not all easily understood by the uninitiated. The abiding messagewithin the chapter is one of warning: the variable responseof receptor cellsto similar stimuli, the CNS modulation of receptor sensitivity and the synergistic effect of stimulantsall indicate pitfalls for the unwary, whether they be electrophysiologistsor whole-animal behaviourists. The secondchapter by Bardach and Villars is on the chemical sensesof fishes. It commenceswith a fairly detailed account of the structure of the chemosensoryorgans,which are
388
Book reviews
clearly demarcated as either olfactory or gustatory. There is then a brief section on the responses of theseorgansand to finish a longish sectionon the behavioural patterns associated with chemoreception.This sumsup the current state of our knowledge, with a fair understanding of both receptor morphology and the ultimate behaviour, but with little comprehension of how the environment, through its action upon the former, mediatesthe latter. Several interesting points emerge. First, there is the distinct separation of olfactory and gustatory function, which is not automatically to be anticipated in aquatic organisms. Admittedly there is some common ground in that certain stimulants can activate both systems,but generally they maintain their distinction. Second, it is shown that whereas the role of olfaction in the alerting phase of feeding behaviour is well documented, the methods of locating food sourcesby chemosensorymeans are still far from understood. Finally olfaction proves important in social and reproductive behaviour, which is rather unexpected in view of the more familiar visually moderated displays and reactions of fish and this promisesto be a fertile field for future study. The next chapter is the first of three dealing with different facets of invertebrate chemoreception and in it the editors cover interspeciesand intraspecieschemoreceptionby marine invertebrates. The larger portion is devoted to interspecific behaviour such as escape reactions, defencesecretionsand host finding. There is a rather encyclopaedic list of examples, with detailsof severalof the chemicalsinvolved. There follows an all too brief review of intraspecific chemical communication, which is a pity as these reactions are probably of greater overall biological significancethan the more spectacularinterspecific ones. This no doubt reflects how little work has been done here and showsit to be another important subject for deeper investigation. A notable omissionfrom this and succeedingchapters is any general account of invertebrate chemoreceptors.Admittedly their diversity precludes a concisetreatment like that given to fish in chapter z, but they should not have been totally ignored and could have been included at the expenseof lessrelevant material elsewhere. Chapter 4, by Lenhoff, is entitled ‘Chemoreception in aquatic invertebrates with special emphasison the feeding behaviour of Coelenterates’. The first part is a general review of food stimulants in invertebrates and it complementsthe previous chapter from which this topic was deliberately omitted. The remainder dealswith feeding in Hydra and severalother coelenterates,showinghow certain chemicals,notably glutathione, trigger specific responses. This is covered in rather more detail than is appropriate to the context. However, it ends with a stimulating discussionof the relationship of the glutathione reaction to olfactory, gustatory and hormonal mechanismsand points out the essentialsimilarity of all three and the difficulty of differentiating them in simpler organisms. The final chapter, by Crisp, is the longest and surveys its chosentopic excellently. It must be pointed out, however, that only the final 30 pagesof this 78 pagechapter are strictly relevant to the subject of chemoreception, the remainder completing a comprehensive review of all the known factors influencing the settlement of marine invertebrate larvae. As such it is valuable in its own right and will be of interest to many workers not directly concerned with chemical stimuli. The section on chemoreceptionshows how far this type of work has progressedwith larval settlement, for from Table 4 it is seenthat experimental evidence for chemicalsubstrate attractivenesshas been obtained for a variety of phyla. The accountsof the isolation of chemical attractants give a valuable insight into the methodsand results of these studies and incidentally show what felicitous organismsbarnacles have proved to be for such investigations.The mechanismof chemoreceptionis shown to depend upon contact recognition of non-diffusable material adsorbed on the substrate, a ‘tactile chemical sense’differing from the normal conceptionsof both taste and smell.
Book reviews
389
Despite the few shortcomings mentioned earlier, this is a very useful book as a whole, bringing together as it does accounts of these diverse yet related topics, each written by experts in these rapidly evolving fields. It offers an informative and stimulating melange which should be read by workers in any branch of marine chemosensorystudies. A clear picture is given of those aspectsin which appreciableadvanceshave already been made,and attention is drawn to someof the fields urgently in need of further study. Notable amongst the latter are the action of stimulatory moleculesat the receptor site, and the whole subject of intra-specific chemical communication. Ii. G. HARTNOLL
Marine Algae of the West Coast of Florida Clinton J. Dawes Univksity
of Miami
Press I974,
xci
+ 201 I@,,
8I5.00
In recent years there hasbeen published a proliferation of regional manualson marine algae. Some of them are mere pamphlets for use of amateursseekingnamesfor specimenspicked up on the beachor seenthrough a face mask. Someother manualshave beencomprehensive. This is an example of such a manual and is certainly designedto be used asa textbook in the local area, aswell as a guide for the amateur. The flora covered here is that found on the west coast of Florida between Cedar Key in the north to Cape Roman0 in the south, including speciesfound 70 miles offshore. The greatest stressis on Tampa Bay and vicinity. The emphasishere is both taxonomic and ecological.The introductory chapter explains the physical characteristics of the marine habitats of the area. A brief discussionof the characteristics of an alga and then a delineation of the characteristics of the four main macroalgaldivisions. There are a few points in this sectionthat seemto me to be inaccurate or incorrect usageof terms. The author claimsthat the blue-green algae‘must be considered to be bacteria’. The two groups certainly have characters in common, but this is a moot point and is by no meansuniversally accepted. Heterocysts are said to be ‘empty’. Recent work seemsto point out that they are not empty cellsand are probably the seatof nitrogenfixation. Under Phaeophyta he states they have stems, roots and leaves. What should be stated here is that certain structures are leaf-like, stem-like and root-like. These are not true structures asfound in higher plants. In referenceto using color to identify reds and browns, the author claimsthat if in doubt, put them in hot water. He statesthat the reds will become green but not the browns. This is a very poor criterion, for Fucus and Laminaria will become brilliant green in hot water. Figure 13 showsa trichome of Hydrocoleum lyngbyaceum with a characteristic ‘tuft of hair at the tip cell’. Long ago these ‘tufts’ have been shown to be epiphytes, either bacteria or diatomsand are not part of the algal cell. These epiphytes can attach here, since there is no sheath material being produced by this end cell, which would prevent attachment. These inaccuraciescertainly do not detract from the book’s value, but should be corrected if future editions are planned. Adequate keys are included, first for the main divisions and then for the algal speciesin each division. As far as I can determine thesekeys are quite satisfactory.