摘要:

Few workers have used enclosures specifically to study interactions between zoo‐plankton and cyanobacteria. Differences among studies in enclosure size, nutrient level, plankton abundance and species composition, presence or absence of fish, and length of experiments make generalisations difficult. Zooplankton had no direct effect on the growth of ungrazed cyanobacteria(Anabaena flos‐aquae, Aphanizomenon flos‐aquae, largeMicrocystiscolonies) in short‐term (<5 days) and long‐term (> 1 month) enclosure studies. When large cyanobacteria were abundant, someDaphniaspp. snowed reduced reproduction and development. When large grazers were abundant they suppressed the growth of edible, colonial cyanobacteria (Aphanizomenon elenkinii, smallMicrocystiscolonies). By altering the ambient light and nutrient environment, large zooplankton may suppress cyanobacteria; evidence for the importance of grazers in promoting cyanobacterial dominance by removing competing phytoplankton species is equivocal. Zooplankton may suppress nitrogen fixation by cyanobacteria through ammonia excretion and may promote a change in dominance from diatoms to cyanobacteria through recycling phosphorus but not silicon.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516243

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

Laboratory studies on cyanobacteria‐zooplankton interactions have largely focused on the inadequacy of cyanobacteria as a food source. Some features of cyanobacteria can be regarded as anti‐herbivore defences. Large colonies ofAphanizomenon, AnabaenaandMicrocystiscannot be handled by zooplankton, but do not interfere seriously with the filtering process. Small colonies and filaments, however, may cause severe inhibition of the feeding process by mechanical interference. This reduces zooplankton growth, reproduction, and survival. Copepods, rotifers, andBosminaare less affected by mechanical disturbance than cladocerans. If ingested, some cyanobacteria may be poorly digested or may not provide essential nutrients. Some cyanobacteria are reported to be toxic to zooplankton. Several strains ofMicrocystisproduce an endotoxin, but the amount of toxin produced differs among strains and with the condition ofMicrocystis. Zooplankton encountering toxic cells cease feeding. Some evidence of an extra‐cellular herbivore deterrent was found forAnabaena. Thus, cyanobacteria may either be individually protected or may create an environment that is unfavourable for efficient grazers (e.g.,Daphnia).

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516244

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

One hundred and four taxa of planktonic cyanobacteria (blue‐green algae) have been recorded from New Zealand lakes: 32 belong to the Chroococcales, 72 to the Nostocales. None of the taxa is endemic to New Zealand; most (if not all) are cosmopolitan. On average, more taxa have been reported from North Island (7.8 ± 6.7,N= 69) than South Island lakes (3.3 ± 3.9,N= 59). This difference is attributable, in part, to the large proportion of glacial lakes in the South Island, which are commonly poor in plant nutrients and possess sparse phytoplankton populations. Many of the taxa show a strong preference for eutrophic conditions. Notable exceptions areAnabaena affinisandGomphosphaeria lacustris, which occur in a large proportion of mesotrophic (48%) and oligotrophic lakes (43%), respectively. Taxa which are often abundant and frequently responsible for conspicuous water‐blooms areMicrocystis aeruginosa, Anabaena circinalis, A. flos‐aquaeandA. spiroides. The limited population data available indicate a high level of interannual variability in the timing, magnitude, and duration of cyanobacterial blooms in New Zealand lakes.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516245

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

摘要:

A small volume of experimental work with cyanobacteria in New Zealand has been produced through the last two decades. Except for some studies with geothermal organisms biased to New Zealand conditions, most work has followed the world‐wide trends in cyanobacterial research. There has been some emphasis on N2‐fixing species, but symbiotic relationships, metabolic kinetics, nutrient and other environmental factors promoting ecological dominance, and toxicity have been investigated.

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516246

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516247

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516248

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516249

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516250

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516251

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor

ISSN:0028-8330    

DOI:10.1080/00288330.1987.9516252

出版商:Taylor & Francis Group    

年代:1987

数据来源: Taylor