Seasonal changes in lipid content and composition in the benthic amphipods Monoporeia affinis and Pontoporeia femorata

Abstract

Seasonal variation in lipid content and composition was studied in deposit-feeding amphipods from a Baltic archipelago. In Monoporeia afinis, which is more active and has a higher respiration rate, lipid levels were low in winter and early spring, rose to 27% of the dry mass in late summer, then declined in autumn. In Pontoporeia femorata, which regulates its oxygen consumption, lipid levels were 20-23% of the dry mass. In October, maturing male P. fimorata had a significantly lower lipid content than females. Triacylglyccrol and phospholipid accounted for -90% of lipids. Phospholipid dominated in M. afinis in March, but triacylglycerol accumulated and became the main lipid after the spring bloom. Triacylglycerol was always the main lipid in P. femorata, but also accumulated after the spring diatom bloom. Both species seem to assimilate and store food resources from the diatom bloom. The higher feeding rate of M. afinis may explain its greater accumulation of lipid. Lower metabolic costs in P. femorata may allow it to maintain steady lipid levels for most of the year.

Population dynamics, response to sedimentation and role in benthic metabolism of the amphipod Monoporeia affinis in an open-sea area of the northern Baltic Sea

“…This indicates that densitydependent control of Monoporeia affinis population size through competition for food (Sarvala 1986, Maximov 1997, especially as such competition reduces recruitment success, is a valid hypothesis for explaining the interannual variations in this amphipod population. Corroborating this interpretation, the negative effect of a high density, and of the presence of older generations, on the survival and growth of the young-of-theyear of M. affinis has been experimentally demonstrated by Hill (1992).…”

The fate of diatom carbon within a freshwater benthic community-a microcosm study

“…Jonasson 1972;Kajak 1988) and lipid dynamics (e.g. Gardner et al 1985;Hill et al 1992). Moreover, interannual variation in the magnitude of diatom input to profundal communities may strongly affect macroinvertebrate life histories (Johnson and Wiederholm 1992).…”

Effects of warming and shifts of pelagic food web structure on benthic productivity in a coastal marine system

“…due to environmental change, may have drastic effects on the benthic community. The differences in amphipod response between treatments were greater in terms of weight than in terms of area and demonstrate the ability of amphipods to respond to differences in food source in terms of weight and lipid gain, as reported by Hill et al (1992). The amphipods had the ability to respond to the higher primary production in the A-webs after the light acclimatisation period.…”

“…If the gonads remain unfertilized, they will degenerate and the females will die, resulting in a lost generation. In addition, it has been suggested that M. affinis needs to reach a threshold size (Leonardsson et al 1988) or achieve a threshold lipid ratio of at least 20% to be able to reproduce (Hill et al 1992).…”

“…If the gonads remain unfertilized, they will degenerate and the females will die, resulting in a lost generation. In addition, it has been suggested that M. affinis needs to reach a threshold size (Leonardsson et al 1988) or achieve a threshold lipid ratio of at least 20% to be able to reproduce (Hill et al 1992).Results from this study indicate that in a future climate perspective, the occurence of smaller phytoplankton species and increased importance of bacterial production, leading to decreased transport of C to benthos and reduced food quality, may have an additive negative effect on benthic productivity in areas such as the northern Baltic Sea.Acknowledgements. This study was supported by grants from the Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning to A.A. (No.…”