Under controlled experimental conditions, release rates of organic matter were estimated for five species of Barents Sea macrophytes and for thirteen species of Black Sea macrophytes. The release rates of different species from the Barents Sea were bctwccn 0.9 and 2.9 mg of organic matter per gram (dry wt) of plants per hour (mg g-l hr-") in March and between 1.7 and 9.8 mg 6-l hr-' in June. The release rates of different species from the Black Sea were between 1.25 and 6.1 mg g-l hrzL in fast growing plants and bctwccn 0.5 and 1.6 mg 8-l hr-' in slowly growing plants. Approximate quantities of total dissolved organic matter rclcased per year have been calculated to bc about 39% of gross production in brown algae, about 38% in red algae, and about 23% in green algae. The rest of the organic matter was released during decomposition of that part of standing stock not consumed by herbivorous animals. About 30% of gross production may be released in this way. Thus, the total flow of dissolved organic matter from seaweeds during growth and after death may be as much as 70% of their gross production. The ecological significance of external organic mctabolitcs rclcased in the surrounding water is discussed. 'A paper on this subject by J. McN. Sieburth will appear in the J. Exp. Mar, Biol. Ecol., 3. 2 The authors are very indeb,ted to Dr. J. D. 1-I. Strickland for his valuable and cordial help in retranslating the paper into contemporary American-English from our Russian-English,

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For Ascophyllum nodosum, Fucus vesiculosus, Fucus inflatus and Rhodymenia palmata in the Barents Sea a quantitative description isgiven of the relationship between length (L) and weight (W) ofthe thallus, and for/4. nodosum also between weight (W) and age (7"). The weight of the thallus has also been related to the intensity of two physiological functions -photosynthesis (/*,·) and the consumption of organic substances (P0) dissolved in the water. According to the value of linear growth per unit of weight and the intensity of P,·, the different species form the series: Rhodymenia palmata > Fucus inflatus > Fucus vesiculosus > Ascophyllum nodosum, From the W-T relationship a lag phase ("early youth"), a logarithmic phase ("youth"), and the beginning of a stationary phase ("maturity") have been disclosed in the ontogenesis of A. nodosum. It has been shown that the photosynthesis and Organotrophy of the thallus diminish with the increase of its weight. This dependence is approximated by a power equation, which parameters have been determined. In two species A. nodosum and F. vesiculosus the weight {HO ratios of tissues of different age (t) have been determined. On the basis of these data, stages of youth, maturity and senescence of tissues have been determined in A. nodosum. The comparison of the w-t curves of A. nodosum and F. vesiculosus shows that a different strategy of thallus formation is innerem in them.The knowledge of functional morphology of higher organisms -especially animals -has developed very purposefully and successfully. At the same time the functional morphology of marine plants has been represented by investigations which, even if numerous, are uncoordinated, and no purposeful development of such research has been observed äs yet. Marine marcrophytes, however, with their perennial, usuaUy veiy ramified thalli and strongly expressed basic function (photosynthesis) could doubtlessly provide a wealth of data for the comparison of form and function. In our opinion one of the main causes for the lagging of functional morphology of marine macrophytes depends on the absence of a quantitative approach, a systematic measurement of at least the principal morphological parameters ofthe thallus -length and weight. If such measurements were paralleled by simultaneous measurements of physiological functions, primarily photosynthesis, the functional morphology of marine plants would be given the necessary foundation. An analysis of the literature devoted to marine macrophytes shows that even for the best studied species ofthe northern seas, asA nodosum, (Baardseth 1970), despite a relatively great variety of Information, very littie quantitative data are available on growth and relationship of morphological and physiological characters. The aim of this work is to make a morpho-physiological anaJysis of the thalli of two species of macrophytes ocurring in masses ~ Ascophyllum nodosum and Fucus vesiculosus. We have less data on the third species studied -Fucus inflatus.

The hierarchical structure of the thallus of the brown alga Cystoseira barbata from the Black Sea and the relationship between the structure and apparent photosynthesis were studied. The thalli were selected for measurements in different months of the year from three regions of the Crimean shore. The morphological analysis was successively carried out at several levels of the thallus's structure: at the level of axes of different orders, at the level of separate branches, morphological divisions (sum of the main branches, sum of the adventitious branches, the stem) and the whole thallus. The following parameters were measured and calculated for all levels: weight, water content, ash, organic carbon and chlorophylls and c in biomass, surface area, relative surface area, relative (specific) and total photosynthesis (evaluated by the radioactive carbon method). Proceeding from the axial analysis, the authors suggest an example of the determination of morphological and physiological parameters of the whole thallus at the age of 2.5 years.Results of the measurements and calculations revealed that properties of the axes of different orders are essentially different. Properties of the axes of different orders, their number and proportion are in their turn responsible for the properties of the higher levels of the organization of the thallus (branches, divisions, whole thalli). Besides, the axial analysis provides knowledge on the morphophysiological condition of the plant and allows to calculate the carbon flow through the thallus and the population. The axial analysis enables to evaluate the effect of contamination on a certain species and its population. Methodological aspects of the axial analysis are also discussed.In the previous work (Khailov 1979) the structure of the Cystoseira thallus and its transformation in ontogenesis were described in terms of the main and the adventitious branches. However, branches are complex and variable per se. It was formerly shown that their carbon exchange with the environment is determined by the ratio of more elementary structures of different age . The axes of different orders are elementary structures which cannot be subdivided any further. So in the present work we have carried out the axial analysis of the main and the adventitious branches.