COMBINED EFFECTS OF MACRONUTRIENTS AND METALS ON THE ADRIATIC GREEN ALGA ULVA RIGIDA C.AG

• Published in: Journal of phycology Vol. 36; no. s3; p. 50
• Main Authors: Munda, I. M., Veber, M.
• Format: Journal Article
• Language: English
• Published: Boston, MA, USA Blackwell Science Inc 01-12-2000
• Subjects: Brackish; Chlorophyta; Marine; Ulva rigida; MED, Adriatic Sea
• ISSN: 0022-3646; 1529-8817
• DOI: 10.1046/j.1529-8817.1999.00001-149.x

The ephemeral green alga Ulva rigida C. Ag. is common in polluted and eutrophicated sites of the northern Adriatic. Its tolerance and responses to the combined effects of excess macronutrients (nitrates, phosphates) and metals (Mn, Co, Zn) that are essential micronutrients were studied in vitro regarding growth expressions, survival, elemental composition (N, C, P), and metal accumulation. Plants belonging to vernal/estival and autumnal populations were compared. Excess nutrients were applied together with the single metals. Nitrate and phosphate were used separately and in a dual combination. In control samples that lacked metals, it was obvious that plants belonging to vernal and estival populations grew better in phosphate than in nitrate enriched media and that the opposite was true for autumnal plants. The presence of metals altered the responses of U. rigida to excess nutrients. In some of the samples a relationship between Mn accumulation and growth was indicated, Mn promoting growth. Metal accumulation was greater in the autumnal than in the vernal and estival plants, being the highest for Mn and lowest for Zn. A comparison between experimental series of different duration revealed that the metal accumulation increases time‐dependently for Mn and Co. The N and P content of the plants followed the nutrient enrichment of the media. Autumnal plants accumulated more N and P than vernal and estival ones. It was obvious that the presence of metals influences the nitrogen uptake of U. rigida, in the sequence Mn‐Co‐Zn. The presence of Mn promotes nitrogen uptake and that of Zn is inhibitory.