Time series of Raw DNA metabarcoding sequences from the Isfjorden Adventfjorden (IsA) marine time series, run by the University Centre in Svalbard (UNIS) from December 2011 until present. The IsA time series (https://www.unis.no/project/isa/) is a model system to study seasonal dynamics, interannual variability and long term changes in a high-Arctic marine ecosystem impacted by Atlantic water inflow.

Samples have been taken once every week in 2012, once every two weeks in 2013 and once every month since 2014 until 2019. Sea water samples collected with the help of niskin bottles were first pre-filtered using a 10 μm mesh, and further filtered using a 0.45 μm filter. Organisms in the size range 10-0.45 μm were further studied.

DNA was extracted using the DNeasy Plant Mini Kit, using the manufacturer´s protocol with some modifications. DNA extracts with concentration above 1 ng/µl were sent for high-throughput 300 bp paired-end Illumina MiSeq sequencing to amplify the V4 region of the nuclear 18s rRNA gene using primers TAReuk454FWD1 (CCAGCASCYGCGGTAATTCC) and TAReukREV3 (ACTTTCGTTCTTGATYRATGA) at the Integrated Microbiome Resource (IMR), Dalhousie, Canada.

The dataset contains sequences that can easily be used in the DADA2 pipeline, which generates an OTU, TAX, ENVT table in a phyloseq object (https://benjjneb.github.io/dada2/tutorial.html).

The data is organized into distinct folders corresponding to the different dates or time points when the samples were sent. For instance, the samples from 2011 to 2017 were sent collectively, while those from 2018 and 2019 were sent separately.

An explanatory text file has been included with the dataset. This file provides details about each sample, including the depth from which it was obtained and the date it was collected. The file also contains breaks, that distinguish the folders and and the files within.

Folders labelled "Weak/failed" are samples that did not work due to lower DNA concentrations, and hence have not been included in the txt file.

Example, Sample name -> 1_S97_L001_R1_001.fastq.gz The sample name before the first underscore is described in the txt file. Taken from Folder -> 2011-17 Is sample taken from 28-01-2015, at a depth of 25m.