Species composition of extant coccolithophores including twenty six new records from the southwest Pacific near New Zealand

摘要

Background Coccolithophores are one of the major components of marine phytoplankton and also one of the most prominent members of haptophyte algae. Studies of the extant coccolithophores started more than half a century ago in New Zealand waters, and with two exceptions, were limited to only a few relatively small areas close to shore. In this study the diversity of these ‘calcium carbonate scale-producers’ were updated from specimens collected in oceanic waters around the wider region of New Zealand. Methods Water samples collected from 156 stations on 10 voyages between 2009 and 2011 were filtered through Nuclepore polycarbonate membrane filters. Coccolithophores retained on these filters were identified using scanning electron microscopy. Results A total of 46 extant coccolithophore taxa were identified from 160 samples collected around New Zealand. The total number of coccolithophore taxa identified was greatest to the east (46), intermediate to the west (15) and least to the northeast and south (4 each) of New Zealand. These coccolithophores were classified into seven families in the four orders, with three families in incertae sedis , and one in a nannolith family. Forty two taxa were heterococcolithophores and four were holococcolithophopres. Conclusion Approximately 57?% of the extant coccolithophores recorded were first-time records for the region. Even though Syracosphaera taxa generally occurred at low frequencies, they were the largest group and made up c. 31?% of all extant coccolithophores recorded in this study. Our findings provide updated information on the species composition and biogeography of coccolithophores in the southwest Pacific near New Zealand.