摘要:

Abstract.Growth ofPosidonia oceanica(L.) DELILE was studied in a natural stand in 4 m depth at Ischia (Gulf of Naples). Renewal and growth of leaves was continuous throughout the year but showed strong seasonal modulation. The major factor for individual leaf growth as well as for the seasonal aspects of the entire foliage is seasonal modulation of leaf appearance rather than of leaf growth. Leaf area index varied between 2 nm2m‐2in autumn and 6 m2m‐2in late summer. Annual production is estimated to be 613 g dw m‐2for leaf blades, 54 g dw m‐2for leaf sheaths, and 27 g dw m‐2for rhizomes. Rhizome production is highly different between the primary and the secondary growth axis (274 versus 30 mg dw ‐shoot‐1y‐1respectively) in plagiotrope growth. Both foliage and rhizome growth are positively correlated

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1984.tb00128.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.Organic substances are suspected to influence the unpredictable, episodic blooms which characterize the planktonic pennate diatomAsterionella glacialisin certain coastal waters. Experiments to test its general responsiveness to organic enrichments in terms of growth rate and colony formation were carried out. An axenic clone was grown at 10° C, 0.039 l min‐1,12:12 LD cycle in Guillard'sf/2 medium enriched with eight different organic substances. Growth rates in organically‐enriched media during exponential phase usually exceeded those in f/2 medium alone. Cell yields after 12 days in media enriched with glycyl‐glycin and trypticase + yeast extract were significantly greater than in the other treatments. Longer chain lengths accompanied organic enrichment, notably with trypticase + yeast extract and 100ppm soil extract. These results suggest thatAsterionella glacialisis positively responsive to elevated levels of certain organic substances. A potential effect of organic substance ‐ trace metal ‐ silica interactions on colony‐size

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1984.tb00129.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.MarineAscomycetes, BasidiomycetesandDeuteromyceteswere collected in tropical and subtropical regions (Australia, Belize, Fiji, Hawaii, Marshall Islands, Mexico, New Zealand, Palau, Thailand), and the known range of distribution for these fungi was extended. Exclusively tropical are 27 taxa, 9 are probably restricted to the tropics also, and 11 are cosmopolitan. Distribution maps are given for 5 taxa. New species (4), varieties (3), and combinations (2) ofAscomycetesare proposed, and keys to the taxa ofHalosarpheiaandLulworthiaare presented. Most of the species are decomposers of mangrove parts or of detritus in sandy beaches. Nine new host plants were found. MarineAscomyceteswere discovered for the first time living in shells of foraminifera.

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1984.tb00130.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Abstract.In the first decisive study of color‐change in brittlestars, four Caribbean species,Ophiocoma echinata, 0. paucigranulata, O. pumila,andO. wendtiare reported to change color from day to night. Color‐change is most striking inO. wendti,which is dark brown during the day, and is banded gray and black from dusk to dawn. The transformation occurs over a 3 to 4 hour period and is effected by chromatorphores which appear to respond to illumination, independently of the central nervous system. Color‐change may also be mediated by an endogenous rhythm.Ophiocoma wendtiis more responsive to light than the other 3 species tested. It reacts to lower levels of illumination at night than during the day, exhibiting negative phototaxis in moonlight as well as in sunlight. I suggest that color‐change may expose (or shield) photosensitive tissues that control the brittlestar's detection of shaded fissures in the reef. Thereby, chromatophore activity may be connected with the brittlestar's chief defense from predators, the ability to detect shadow and escape into darkened crevices. Although experiments to date with predacious fish are equivocal. the color patterns ofOphiocomaspecies mav provide protective cam

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1984.tb00131.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0173-9565    

DOI:10.1111/j.1439-0485.1984.tb00132.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY