Ammonia oxidizers in the sea-surface microlayer of a coastal marine inlet

Abstract

Planktonic archaea are thought to play an important role in ammonia oxidation in marine environments. Data on the distribution, abundance, and diversity of ammonia oxidizers in the coastal sea-surface microlayer (SML) are lacking, despite previous reports of high abundance of Thaumarchaeota in the SML of estuaries and freshwater lakes. Here, we failed to detect the presence of ammonia-oxidizing bacteria in any of our samples taken from a semi-enclosed marine inlet in Japan. Therefore, we shifted our focus to examine the archaeal community composition as well as the Thaumarchaeota marine group I (MG-I) and ammonia monooxygenase subunit A (amoA) gene copy numbers and composition in the SML and corresponding underlying water (UW, 20 cm). amoA gene copy numbers obtained by quantitative PCR were consistent with the typical values observed in the surface waters of oceanic and coastal environments where nitrification activity has been detected, but the copy numbers were two- to three-fold less than those reported from the surface layers and UW of high mountain lakes. Both amoA and MG-I 16S rRNA gene copy numbers were significantly negatively correlated with chlorophyll-a and transparent exopolymer particle concentrations in the SML. Communities of archaea and ammonia-oxidizing archaea in SML samples collected during low wind conditions (≤5 m s–1) differed the most from those in UW samples, whereas the communities in SML samples collected during high wind conditions were similar to the UW communities. In the SML, low ratios of amoA to MG-I 16S rRNA genes were observed, implying that most of the SML Thaumarchaeota lacked amoA. To our knowledge, our results provide the first comparison of ammonia-oxidizing communities in the coastal SML with those in the UW.

Ecogenomics reveals distinctive viral-bacterial communities in the surface microlayer of a natural surface slick

“…The SML has been considered an "extreme" habitat influenced by high solar radiation, wind-wave interaction, accumulation of pollutants, sudden changes in temperature and salinity, contact to rainfall and depositions from the atmosphere, among other parameters [3][4][5][6][7][8]. While abundance, diversity and function of eukaryotes, bacteria, and archaea [9][10][11][12] have been studied in the SML, little is known about residing viruses (reviewed by Rahlff [13]). This is particularly true for the SML within natural surface slicks.…”

Phylotype resolved spatial variation and association patterns of planktonic Thaumarchaeota in eastern Chinese marginal seas

“…As a consequence, the thaumarchaeotal community compositions were similar in SML and surface water. Also, little effect of SML on archaeal communities has been observed in other coastal sites (Cunliffe et al 2009 ; Wong et al 2018 ), suggesting that the SML environment is less favorable to archaea than to bacteria (Cunliffe et al 2009 ).…”

“…Considering the higher concentration of inorganic nutrients (e.g., ammonia), we hypothesized that the SML may have selected differential thaumarchaeotal communities and nitrification activity compared to that of the surface water. However, the diversity and distribution pattern of Thaumarchaeota in marine SML remains largely unknown (Wong et al 2018 ).…”

Using Pollution Index to determine water quality in Banda Aceh waters, Indonesia

“…The existence of a floating cage around station 1 and the water flow connected to the aquaculture area was thought to contribute to the high levels of ammonia in the surrounding areas. Intensive aquaculture with high stocking density and high feeding frequency encourages sewage accumulation very quickly (Wong et al, 2018).…”