Chlorophyll a distribution and size structure across contrasting water masses of the southwest Pacific Ocean

Here we present physico-chemical and biological data collected during 12 research cruises conducted in SW Pacific waters east of Aotearoa New Zealand between 2009 and 2017. Nutrient and chla samples were collected mainly with Niskin bottles deployed with a Seabird 9plus CTD rosette. A small fraction of the data presented were sampled also from manually deployed Niskin bottles and the RV Tangaroa Underway Flow-Through System (TUFTS) system equipped with temperature, salinity and fluorescence sensors. The dataset includes measurements of temperature, salinity, oxygen and transmissivity obtained with a Seabird 9plus; inorganic nutrients (dissolved reactive phosphorus, dissolved reactive silica, nitrate + nitrite); total chlorophyll a (chla) filtered onto GFF filter, size fractionated chla (0.2, 2, 20 microns) obtained by sequential filtration of seawater through 20, 2 and 0.2 micron polycarbonate filters; and derived mixed-layer depth estimated following temperature and density criteria. The depth of the euphotic zone included was calculated from chla concentration following the approach described in Maritorena and Morel, 2001 (doi:10.1029/2000jc000319). These data were used to provide oceanographic context to DNA metabarcoding analysis of 18S rRNA V4 region that was carried out on DNA samples collected in parallel to nutrient and chla samples. The study resulting from this analysis has been submitted to Progress in Oceanography.