Aerobic anoxygenic phototrophs of the Adriatic Sea

Abstract

Aerobic anoxygenic phototrophs are a newly discovered member of the bacterial community in the Adriatic Sea. During the last seven years, when we started to study these organisms, we have collected a considerable number of samples from different environments, from the coast, the estuary, and the open sea. Here we have compiled data from 34 georeferenced study sites from four studies that summarize all that is known about aerobic anoxygenic phototrophs and examine the spatial and vertical distribution and environmental factors affecting this community in the Adriatic Sea. We found horizontal and vertical influences on AAP distribution, mainly salinity, nitrates, chlorophyll a, ammonium, temperature, and soluble reactive phosphorus. Much is known about their ecology in the Adriatic, and with a new survey underway, we will expand our knowledge of their community composition and their role in carbon flux to higher trophic levels.

Ecology of aerobic anoxygenic phototrophs on a fine-scale taxonomic resolution in Adriatic Sea unravelled by unsupervised neural network

“…Nevertheless, a high average salinity (38.35) combined with a temperature greater than 16 °C associated with the highest concentrations of nitrites, silicates and Chl a negatively affected AAP diversity (BMU 5). In contrast to previous studies [ 5 , 24 ], there was neither a clear nor a linear relationship between Chl a (coupled with cyanobacterial abundance peaks), and the abundance of AAPs in our order- and genus-level models.…”

“…As for the absolute abundances, the average values of 1.427 ± 0.754 × 10 4 cells mL −1 correspond to those previously reported for the central Adriatic. However, the range of 0.30 × 10 4 to 3.41 × 10 4 cells mL −1 was narrower in our study, compared to studies that sampled Adriatic estuaries [ 22 – 24 ]. The average relative abundance of AAPs was 3.862% ± 2.266% of total prokaryotes (minimum of 0.548%, maximum of 10.258%), which is comparable to previous results from the Adriatic [ 22 , 23 ] and the Mediterranean [ 4 , 18 , 57 ], as well as the Global Ocean Sampling Expedition [ 41 ].…”

“…Subsequent studies based on one-year sampling along the trophic gradient described their spatial and vertical distribution with maximum abundances reported in late winter (April) [ 23 ]. A recent review article collected seven years of data from 34 sites to gain insights into their distribution and controlling environmental factors in the Adriatic Sea [ 24 ].…”