TY - JOUR 
A1 - Pérez Ruzafa, Ángel
AU - Gilabert Cervera, Francisco Javier
AU - Gutiérrez Ortega, José Miguel
AU - Fernández Alías, Alfredo
AU - Marcos Diego, Concepción
AU - Sabah, Saleh
T1 - Evidence of a planktonic food web response to changes in nutrient input dynamics in the Mar Menor coastal lagoon, Spain
Y1 - 2002
SN - 1573-5117
UR - http://hdl.handle.net/10317/10346
AB - Nutrient input dynamics in the Mar Menor coastal lagoon has recently changed as a consequence of changes in agricultural practises. An interannual comparison of the environmental variables and the planktonic biomass size-spectra was performed between 1988 and 1997. While nitrate concentration was low in 1988, the values in 1997 increased considerably. Since 1995, two alloctonous jellyfish species (Rhyzostoma pulmo and Cotylorhiza tuberculata) occurred in large numbers in summer time and reached peak abundance in summer of 1997. The size-spectra analysis comparison revealed that, in spite of changes in nutrient input that stimulated the growth of larger phytoplankton cells, there were no significant differences in the spectra slope which followed a similar seasonal trend in both years. However, the plankton biovolume considered under the size range compared (between 2 and 1000 µm diameter) was, paradoxically, always lower in 1997. Given that there were higher nutrient levels in 1997, this finding suggest a strong top-down control mechanism of size structure. Gut contents of jellyfishes showed their preference for large diatoms, tintinnids, veliger larvae and copepods, corroborating that size structure in these assemblages can be subject to top-down control. The implication of these results is that the feeding activities of large gelatinous zooplankton (jellyfishes) may play an important role controlling the consequences of eutrophication within the Mar Menor coastal lagoon.
KW - Coastal lagoon
KW - Eutrophication
KW - Pelagic food web
KW - Top-down control
KW - Jellyfish
KW - Size biomass-spectra
KW - Ecologíal
KW - 2417.05 Biología Marina
KW - 2508.05 Hidrobiología
LA - eng
PB - Kluwer Academic Publishers
ER -