The effects of a high magnesium-to-calcium ratio on the egg-laying rate of an aquatic planorbid snail,<i>Biomphalaria pfeifferi</i>

Harrison, A. D.; Nduku, W. K.; Hooper, A. S. C.

doi:10.1080/00034983.1966.11686407

Cited by 28 publications

(12 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…One possible explanation for the high conductivity in Lake Manyame and Bhiri Dam is that they both receive water from the Great Dyke , a unique geological feature consisting of mafic and ultramafic rocks such as norite, pyroxenite and serpentine (Worst, 1960). The streams originating on the dyke have an unusually high concentration of magnesium (Harrison et al, 1966) and this might explain the high conductivity of the 2 lower impoundments. The bioassays with Selenastrum capricornutum showed that productivity in Lake Chivero, as in the study by Robarts and Southall (1977), is limited by light rather than by any nutrient.…”

Section: Discussionmentioning

confidence: 99%

Nutrient limitation of phytoplankton in five impoundments on the Manyame River, Zimbabwe

Tendaupenyu¹

2012

WSA

View full text Add to dashboard Cite

Nutrient limitation was investigated in the Manyame lakes, namely, Harava Dam, Seke Dam, Lake Chivero, Lake Manyame and Bhiri Dam, during 2004-05. Selenestrum capricornutum was used as the test organism in one group of bioassays and the lakes' natural phytoplankton population in the other. Nitrogen was indicated to be the primary limiting nutrient in Harava Dam, Seke Dam and Lake Manyame. Phosphorus was found to be the primary limiting nutrient in Bhiri Dam while no nutrient was indicated to be limiting the growth of phytoplankton in Lake Chivero; instead, light was implicated to be limiting the growth of phytoplankton. Harava Dam and Seke Dam showed signs of enrichment, relative to 1977, attributed to sewage discharge from expanding urban settlements in Ruwa and surrounding areas. Lake Chivero has remained much the same in the last 30 years and was indicated to be acting as a nutrient trap, since the dams downstream of it were not found to be as eutrophic. Lake Manyame, Seke Dam and Harava Dam were concluded to be mesotrophic, Bhiri Dam oligotrophic and Lake Chivero eutrophic.

show abstract

Section: Discussionmentioning

confidence: 99%

Nutrient limitation of phytoplankton in five impoundments on the Manyame River, Zimbabwe

Tendaupenyu¹

2012

WSA

View full text Add to dashboard Cite

show abstract

“…However, in the present study, none of the individual chemical constituents in the water samples examined exceeded the tolerance range for B. pfeifferi snails: water temperatures measured in the morning as well as the maximum temperatures in the afternoon lay within the favourable range (Appleton 1978), water conductivites were above the critical value (Polderman et al 1985) and calcium concentrations were at least 2 1 / 2 times higher than the minimum value of 5 mg/l Ca 2+ (Williams 1970a, b). The magnesium/calcium ratios were low and never exceeded 0.8, and were therefore unlikely to have had a negative impact on the egg production of B. pfeifferi (Harrison et al 1966). The highest sodium/calcium ratio was recorded at site D but its value, 1.38, was below the critical value of 2.4 (Schutte & Frank 1964).…”

Section: Discussionmentioning

confidence: 99%

“…However, Bulinus globosus was found to be more tolerant of low calcium concentrations, both in field studies (Williams 1970a) and in experimental investigations (Williams 1970b). High magnesium/calcium ratios were found to have a negative impact on the egg production of B. pfeifferi (Harrison et al 1966). Water with a sodium/calcium ratio exceeding 2.4 affected snail densities and B. pfeifferi was found very rarely in such conditions (Schutte & Frank 1964).…”

mentioning

confidence: 99%

Evaluation of Chemical and Physical-morphological Factors as Potential Determinants of Biomphalaria pfeifferi (Krauss, 1848) Distribution

Utzinger¹,

Mayombana²,

Mez³

et al. 1997

Mem. Inst. Oswaldo Cruz

View full text Add to dashboard Cite

show abstract

“…Porém, segundo Leveque e col. 6 , "B. glabatra suporte d'autant mieux les fortes teneurs en Magnesium que le rapport Mg/ Ca est faible. L'effet inhibiteur n'apparait qu'à une valeur de ce rapport d'environ 30.…”

Section: A) B Glabrata B) H Duryiunclassified

Ação inibidora de termofosfato magnesiano sobre a fecundidade de planorbídeos e seu possível significado no controle da esquistossomose mansoni

Milward-de-Andrade

Torga

1981

Rev. Saúde Pública

View full text Add to dashboard Cite

. F. Ação inibidora de termofosfato magnesiano sobre a fecundidade de planorbídeos e seu possível significado no controle da esquistossomose mansoni. Rev. Saúde públ., S, Paulo, 15:59-71, 1981. RESUMO:A eficácia de termofosfato magnesiano (fertilizante e corretivo do solo) na alimentação de planorbídeos, em laboratório, foi testada ao longo de cinco semanas, verificando-se o crescimento da concha de populações experimentais de Bimphalaria glabrata (Say, 1818) e Helisoma duryi (Wetherby, 1879). Reversamente observou-se que aquele produto mineral bloqueou a oviposição de ambas as espécies, a partir da segunda semana do experimento, quando proporcionado, isoladamente ou associado, a latoso ou a folhas de alface. Em conseqüência, supõe-se que sua ampla utilização nas novas áreas de cultivo, obtidas através de métodos modernos de irrigação, poderá, adicionalmente -ao ser carreado pelas chuvas, para ecossistemas lênticos ou lóticos -reduzir as populações pioneiras de diferentes espécies de Bimphalaria constituindo-se útil meio de controle da esquistossomose mansoni, em zonas rurais. Ademais, poderá ser eficaz no controle dos hospedeiros intermediários de Schistosoma mansoni que, usualmente, se estabelecem em lagoas de criação de peixes -cuja multiplicação, em áreas tropicais, vem sendo incentivada, quer como atividade econômica alternativa para o pequeno proprietário rural quer como exigência de necessidade nutricional das comunidades humanas mais pobres. Supõe-se, ainda, que o material testado poderá controlar populações de limneídeos, hospedeiros intermediários de Fasciola hepatica. São sugeridos testes de campo que possam efetivamente comprovar a hipótese levantada, e também estudos destinados ao conhecimento do mecanismo de ação do elemento magnésio no bloqueio da fertilidade de moluscos. Salienta-se a necessidade de pesquisas especiais sobre o efeito de diferentes concentrações de magnésio em ovos e formas juvenís de planorbídeos, bem como sobre miracídios e cercárias (intra-caramujos e livre-natantes) de trematódeos.

show abstract

The effects of a high magnesium-to-calcium ratio on the egg-laying rate of an aquatic planorbid snail,Biomphalaria pfeifferi

Cited by 28 publications

References 0 publications

Nutrient limitation of phytoplankton in five impoundments on the Manyame River, Zimbabwe

Nutrient limitation of phytoplankton in five impoundments on the Manyame River, Zimbabwe

Evaluation of Chemical and Physical-morphological Factors as Potential Determinants of Biomphalaria pfeifferi (Krauss, 1848) Distribution

Ação inibidora de termofosfato magnesiano sobre a fecundidade de planorbídeos e seu possível significado no controle da esquistossomose mansoni

Contact Info

Product

Resources

About