摘要:

ABSTRACTNew productivity data are given for 62 macroalgal species from 6 intertidal habitats spanning a latitudinal range of nearly twelve degrees on the Pacific Coast of south‐western North America. Our data, utilizing a functional‐form group approach, support an hypothesis relating morphological forms to photosynthetic performances. Specifically, the Sheet‐Group showed the highest productivity (mean apparent net photo synthetic performance = 5.16 mg C · g−1· h−1) with a reduction of ca. two‐fold between each of the following four groups: Filamentous‐Group (2.47), Coarsely Branched‐Group (1.30), Thick Leathery‐Group (0.76) and Jointed Calcareous‐Group (0.45). The Crustose‐Group had by far the lowest mean net productivity being only 0.07 mg C · g−1· h−1. The‐functional‐form group approach is a promising tool for predicting the outcome of productivity‐related ecological and evolutionary processes without being restricted temporal

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03188.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTHomothallic sexual reproduction inChlamydomonas monoicaStrehlow culminated in the formation of mature, chloroform‐resistant zygospores (zygotes) in clonal culture. Early in the zygote maturation process, a distinctive “primary zygote wall” was released into the culture medium where it remained stable for at least several days. This wall appeared as a rigid, darkly‐outlined, and often multilayered structure, as viewed by phase contrast microscopy. From a sample, of 2500 individual clones isolated after ethyl methanesulfonate mutagenesis, five maturation‐defective strains(zym)produced abnormal zygotes which failed to release a primary zygote wall, failed to develop the normal reticulate zygospore wall, and disintegrated within five days. These strains were utilized to identify additional mutants which were sexually competent, but self‐sterile (het). Mixed cultures of thezymandhetmutant strains were found to contain numerous, fully‐matured, chloroform‐resistant zygospores and discarded primary zygote walls. In combination, the two types of mutants provided a useful system for the selective recovery of heterozygous zygospores, thus facilitating genetic studies on a homothall

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03189.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTConcentrates of the picoplankton (0.2–2.0 μm) sized fraction from the euphotic zone of estuarine and oceanic waters were examined by transmission electron microscopy. In addition to the numerous phototrophic procaryotes (chroococcoid cyanobacteria) previously reported, small phototrophic eucaryotes were observed in 20 of 25 samples examined.Micromonas pusilla(Butcher) Manton and Parks, a 1 × 1.5 μm flagellate, was abundant in estuarine samples in summer. Similar sized cells of non‐flagellated chlorophytes, eitherNannochlorisNaumann orChlorellaBeijerinck, were observed sporadically in many samples. The most ubiquitous microalga was a scaled, non‐flagellated prasinophyte that occurred at 9 of 15 different locations on 15 of 20 sampling dates in water samples from Iceland to the Caribbean Sea, This tiny alga (0.5 to 1.0 μm in diam.) is probably the smallest known photo‐trophic eucaryote and has not heretofore been described. Enrichment cultures using conventional techniques on several cruises yielded only theChlorella‐type of green alga, as well as numerous isolates of unicellular chroococcoid

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03190.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe marine brown algaFucus spiralisL. and the red algaGoniotrichum alsidii(Zanard) increase their growth upon the, addition of SeO32‐or SeO42‐when cultivated axenically in the artificial seawater ASP6 F2. In the concentration range 1 · 10−10‐1 · 10−7M there are two optima, one at 3.3 · 10−10M and another at 3.3 · 10−8M. α‐To‐copherol, often administered together with selenium to mammals suffering from selenium deficiency, gives no additive effect with selenium, but α‐tocopherol in the concentration range 1 × 10−7‐1 × 10−6M does influence the morphology of theFucusplants. Organic

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03191.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe, effects of ice onAscophyllum nodosum(L.) Le Jolis within the Great Bay Estuary System of New Hampshire‐Maine, U.S.A. were assessed during the winter of 1980–81. Approximately 50% of the plants late fall standing crop, or an estimated 136 tonnes dry weight, was removed by ice‐rafting. Pieces ofAscophyllumremoved averaged 22 cm in length, 15 g in fresh weight and generally represented 2–3 years of growth. Although the winter of 1980–81 wax somewhat extreme, a similar pruning process probably occurs each year contributing to the characteristic bushy habit of attached inner estuarine plants.Ascophyllumfragments rafted in ice and deposited into salt marshes are suggested as a major source of the, ecadscorpioides(Hornema

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03192.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe colonial matrices of the volvocacean algae were examined for the presence of sulfated and carboxylated polysaccharides. These results were compared to a similar examination of the single‐celledChlamydomonas reinhardtiiDang. The colonial algae examined werePandorina morumBory,Eudorina elegansEhr.,Platydorina caudataKofoid,Pleodorina californicaShaw,Pleodorina illinoisensisKofoid andVolvox carterivar.nagariensisIyengar. Alcian blue staining of whole colonies at pH 0.5 and 2.5 showed evidence for the presence of both sulfated and carboxylated polysaccharides in the extracellular matrix. Quantitative measurement of alcian blue bound to solubilized matrices supported the in vivo results. There was a trend toward an increase in sulfated polysaccharides in the more evolutionary advanced forms with the exception ofPleodorina.This trend was readily seen in the sulfate: carboxyl ratios:Pandorina morum—0.4,Eudorina elegans—1.0,Platydorina caudata—2.1 andVolvox carteri—2.2. The acidic nature of thePleodorinamatrix with a sulfate: carboxyl ratio of 0.2 appeared to be more like that ofPandorinarather than that of the more advan

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03193.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTInternal nitrogen pools in thalli ofGracilaria tikvahiaeMcLachlan were examined in three experiments as a function of total nitrogen content of the thallus, nitrogen deprivation, and nitrogen resupply. Amino acids and proteins appeared to form the major nitrogen storage pools inG. tikvahiae, while DNA appeared to be relatively unimportant in this regard. Inorganic nitrogen in the forms of NH4+and NO3−was found in the thalli; however, its contribution to the total nitrogen, pools was small. Within the protein pool, the phycoerythrin pigments appear important as a source of nitrogen when thalli are initially becoming nitrogen limited. In general, there was an inverse relationship between the levels of nitrogen and the carbohydrate content of the algal thall

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03194.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTGrowth and pigment concentrations of the, estuarine dinoflagellate,Prorocentrum mariae‐lebouriae(Parke and Ballantine) comb. nov., were measured in cultures grown in white, blue, green and red radiation at three different irradiances. White irradiances (400–800 nm) were 13.4, 4.0 and 1.8 W · m−2with photon flux densities of 58.7 ± 3.5, 17.4 ± 0.6 and 7.8 ± 0.3 μM quanta · m−2· s−1, respectively. All other spectral qualities had the same photon flux densities. Concentrations of chlorophyllaand chlorophyllcwere inversely related to irradiance. A decrease of 7‐ to 8‐fold in photon flux density resulted in a 2‐fold increase in chlorophyllaandcand a 1.6‐ to 2.4‐fold increase in both peridinin and total carotenoid concentrations. Cells grown in green light contained 22 to 32% more peridinin per cell and exhibited 10 to 16% higher peridinin to chlorophyllaratios than cells grown in white light. Growth decreased as a function of irradiance in white, green and red light grown cells but was the same at all blue light irradiances. Maximum growth rates occurred at 8 μM quanta · m−2· s−1in blue light, while in red and white light maximum growth rates occurred at considerably higher photon flux densities (24 to 32 μM quanta · m−2· s−1). The fastest growth rates occurred in blue and red radiation. White radiation producing maximum growth was only as effective as red and blue light when the photon flux density in either the red or blue portion of the white light spectrum was equivalent to that of a red or of blue light treatment which produced maximum growth rates. These differences in growth and pigmentation indicate thatP. mariae‐lebouriaeresponds to th

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03195.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe non‐photosynthetic phagotrophic dinoflagellate,Gymnodinium fungiformeAnissimova, ingests prey cytoplasm through a highly extensible structure called the peduncle. Although the peduncle is not observable whenG. fungiformeis swimming, it protrudes 8–12 μm from the sulcal‐angular vicinity of the cell during feeding, and is approximately 3.3 μm wide when the cytoplasm of its prey is flowing through it. A circular‐oval ring of overlapping microtubules, the ‘microtubular basket’ may be seen in transmission electron microscope sections ofG. fungiformeand it is inferred that this structure is a cross section of a retracted peduncle. The microtubular basket‐peduncle complex is discussed in relation to similar structures in other dinoflagellates and to the tentacle of the suctorian ciliates which have a homologous i

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03196.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY

摘要:

ABSTRACTThe relative importance of respiration and organic carbon release to the efficiency of carbon specific growth ofSkeletonema costatum(Grev.) Clave was evaluated over a light range from 1500–15 μE · m−2· s−1. Net growth efficiency ranged from 0.45–0.69 with a maximum at 130 μE · m−2· s−1. Respiration was 93% or more of the variations in growth efficiency. Organic carbon release ranged from 0–7% of gross production and increased with light intensity. Carbon specific particulate production was a hyperbolic function of incident light intensity and was related exponentially to particulate carbon production per unit chlorophylla.Full sunlight conditions, 1500 μE · m−2· s−1, did not induce photoinhibition of gross production. Variations in the efficiency of growth ofS. costatumwere minimized over a wide range of light intensities mainly because of variations in cellular pigments which permitted the efficient utilization of available light energy, and a reduction in the losses of carbon which increases the growth rate, possibly as a consequence of the recycling of respi

ISSN:0022-3646    

DOI:10.1111/j.1529-8817.1982.tb03197.x

出版商:Blackwell Publishing Ltd    

年代:1982

数据来源: WILEY