https://www.um.edu.mt/library/oar/handle/123456789/37464 2026-07-20T00:36:15Z https://www.um.edu.mt/library/oar/handle/123456789/37621 Title: On the biology of some rice-field weeds in Sardinia : Cotula and Heteranthera Authors: Marchioni Ortu, A.; De Martis, B. Abstract: The biology and ecology of Cotula coronopifolia L. (Compositae), Heteranthera rotundifolia (Kunth) Griseb. and Heteranthera reniformis Ruiz & Pavon (Ponte- deriaceae), three new weeds naturalized in rice-fields of central-southern Sardinia, are described. Attention is focussed on the degree of propagation of these "taxa", as a consequence of their suitability for the environmental conditions of Sardinian rice- fields, where it seems that marked convergences exist with regard to the original habitat of these species. 1989-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/37585 Title: Airborne pollens analysis in Cagliari (south Sardinia) : observations on Ailanthus altissima (Miller) Swingle,Casuarina equisetifolia J .R. & G. Foster and Schinus molle L. Authors: Ballero, Mauro Abstract: In this paper the phenological and airborne pollens dispersal data of Casuarina equisetijolia J .R. & G. Foster, Ailanthus altissima (Miller) Swingle and Schinusmolle L., three exotic species widely used for street planting, are examined. The findings have enabled a detailed identification of the phenological stages and to determine the amount of airborne pollens of each species, resulting in a better understanding of their biorhythms and of their pathogenic role. 1989-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/37580 Title: CENTRO : volume 1 : issue 4 Editors: Axiak, Victor Abstract: Tale of contents: 1/ AGIUS, C., JACCARINI, V. - A survey of the nitrate and phosphate levels of inshore marine waters from Malta (Central Mediterranean) -- 2/ MARCHIONI ORTU, A., DeMARTIS, B. - On the biology of some rice-field weeds in Sardinia: Cotula and Heteranthera -- 3/ FRILIGOS, N. - Preliminary Chemical and Hydrological Observations in the Ionian Sea -- 4/ BALLERO, M. - Airborne pollens analysis in Cagliari (South Sardinia): observations on Ailanthus altissima (Millar) Swingle, Casuarina equisetifolia J .R. & G. Foster and Schimus molle L. -- 5/ BAZZANTI, M., FERRARA, O., MASTRANTUOMO, L. - Composition and structure of planktonic and benthic communities as a basic information in fishpond culture -- 6/ GRAMENTZ, D. - Marine Turtles in the Central Mediterranean Sea 1989-01-01T00:00:00Z https://www.um.edu.mt/library/oar/handle/123456789/37579 Title: A survey of the nitrate and phosphate levels of inshore marine waters from Malta (Central Mediterranean) Authors: Agius, C.; Jaccarini, Victor Abstract: The nitrate and phosphate levels were monitored over a one-year period in three inshore localities in Malta. There were recorded no seasonal variations in nutrient levels at Marsaxlokk bay. At Mistra bay a slight decrease in nitrate-nitrogen was recorded during the autumn and winter periods. At both these locations, how- ever the nitrate-nitrogen was generally below llJig-atil and phosphate-phosphorus al- ways less than 0.2 /J1.g-atll. The values are typical of most areas in the Mediterranean. The concentrations of nutrients at Rinella creek were consistently manifold higher and peaked during the winter months. This, very probably, reflects the combined effects of organic pollution and rainfall on this very enclosed creek. Occasionally, short-lived high levels of nitrates were recorded at Marsaxlokk and Mistra bays. These seem to originate from agitation of bottom sediments. 1989-01-01T00:00:00Z