Bacterioneuston may play a key role in water-air exchange of gases and in processing organic matter and pollutants that accumulate at the sea-surface microlayer (SML). However, the phylogenetic diversity of bacterioneuston has been poorly characterized. We analyzed 24 samples each from the SML and underlying water (UW) at three sites in the Ria de Aveiro estuary, Portugal. Cultivation and culture-independent techniques were used to compare bacterioneuston and bacterioplankton. Culturable heterotrophic bacteria were enriched in the SML. The culturable community was dominated by Psychrobacter and Acinetobacter. The presence of high numbers of Psychrobacter was a notable result. Differences were confined to a few genera overrepresented in UW samples (Kocuria, Agrococcus and Vibrio). 16S rDNA DGGE profiles were highly stable in terms of number and position of bands between sampling sites and dates but cluster analysis revealed a slight tendency for grouping according to sampled layer. SML-specific DGGE bands affiliated with Actinobacteria, Cyanobacteria, Gammaproteobacteria and Bacteroidetes. Low similarity between nucleotide sequences of DGGE-bands and previously reported sequences suggest the occurrence of SML-specific populations. Enrichment of SML for Pseudomonas and Aeromonas was questioned and the diversity of both communities was analyzed. Consistent differences between SML and UW aeromonads communities were not identified. In terms of Pseudomonas, a culturable operational taxonomic unit was consistently overrepresented within SML samples. Taken together, our results indicate that the similarity between SML and UW communities depends on spatial and temporal factors.
Objective
Authors have recently suggested that difficult temperament in infancy may be associated with rapid weight gain, but none of the previous studies actually report associations between temperament and feeding as a response to infant distress. The purpose of the present study was to examine whether greater infant difficulty elicits more feeding, which in turn leads to more rapid weight gain in early infancy.
Methods
Mother-infant pairs (N=154) were visited at 3- and 6-months in their homes. Besides anthropometric measures, mothers kept a 24-hour diary of their infants’ sleep, cry, and feed patterns, and answered questions regarding feeding and infant difficultness.
Results
Feeding occurred as a response to nearly half (48%) of the crying intervals recorded, though it more often occurred in the absence of crying (83%). Mothers were most likely to report holding or rocking their infant as the first strategy they would employ if their baby fussed or cried. A regression analysis that included crying, feeding, weaning, sleep and infant weight revealed maternal reports of numbers of feeds per day as the only variable that predicted weight gain from 3-6 months.
Conclusion
Infant crying is often followed by feeding, and more frequent feeding may promote more rapid weight gain. However, feeding frequency in the first few months appears to be more a matter of maternal discretion than a yoked response to temperamental difficulty. This does not preclude the possibility that overfeeding in later infancy could be tied to temperamental difficulty and subsequently related to overweight in early childhood.
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