Systematic, continental scale temporal monitoring of marine pelagic microbiota by the Australian Marine Microbial Biodiversity Initiative

Sustained observations of microbial dynamics are rare, especially in southern hemisphere waters. The Australian Marine Microbial Biodiversity Initiative (AMMBI) provides methodologically standardized, continental scale, temporal phylogenetic amplicon sequencing data describing Bacteria, Archaea and microbial Eukarya assemblages. Sequence data is linked to extensive physical, biological and chemical oceanographic contextual information. Samples are collected monthly to seasonally from multiple depths at seven sites: Darwin Harbour (Northern Territory), Yongala (Queensland), North Stradbroke Island (Queensland), Port Hacking (New South Wales), Maria Island (Tasmania), Kangaroo Island (South Australia), Rottnest Island (Western Australia). These sites span ~30° of latitude and ~38° longitude, range from tropical to cold temperate zones, and are influenced by both local and globally significant oceanographic and climatic features. All sequence datasets are provided in both raw and processed fashion. Currently 952 samples are publically available for bacteria and archaea which include 88,951,761 bacterial (72,435 unique) and 70,463,079 archaeal (24,205 unique) 16 S rRNA v1-3 gene sequences, and 388 samples are available for eukaryotes which include 39,801,050 (78,463 unique) 18 S rRNA v4 gene sequences

Ecological boundaries constrain pro- and eukaryotic richness: from the ice edge to the equator in the Pacific Ocean

Marine microbes along with micro eukaryotes are key regulators of oceanic biogeochemical pathways. Here we present a high-resolution (every 0.5° latitude) dataset describing microbial pro- and eukaryotic diversity, in the surface and just below the thermocline, along a 7000km transect from 66° S at the Antarctic ice edge to the equator in the South Pacific Ocean. The transect, conducted in Austral winter, covered key oceanographic features including crossing of the polar front (PF), the subtropical front (STF) and the equatorial upwelling region. Our data indicate that temperature does not determine patterns of marine microbial richness, complementing the global model data from Ladau, et al. (2013). Rather, NH4⁺ nanoplankton and primary productivity were the main drivers for archaeal and bacterial richness. Eukaryote richness was highest in the least productive ocean region, the tropical oligotrophic province. We also observed a novel diversity pattern in the South Pacific Ocean; a regional increase in archaeal and bacterial diversity between 10° S and the equator. Our data showed that the mean latitudinal ranges of archaea and bacteria decreased with latitude, thereby not confirming the Rapoport's rule. We show that permanent oceanographic features, such as the STF and the equatorial upwelling can have a significant influence on pro- and eukaryotic richness