The association between algae organisms and environmental factors in Hai-tan Strait of Fujian, China

Abstract

27 points were surveyed, and then algae and seawater samples were collected in Hai-tan Strait. The correlation on HAB (harmful algae blooms) species and environmental factors were studied. Water temperature (T) and salinity (S) ranging from 11.9 °C to 27.8 °C and 20.4 to 33.7 in the year, respectively. Dissolved inorganic nitrogen (DIN) in surface water ranged from 0.098 to 0.776 mg·L−1, PO4-P ranged from 0.0016 to 0.0729 mg·L−1. And Eutrophication index (E) ranged from 0.03 to 13.8, varied different. 102 species of algae belonging to 4 classes and 52 genera were identified. The diversity was increasingly from winter to summer, decreasingly from summer to autumn, highest in summer. 49 species of red tide organisms were found in Hai-tan Strait, main two classes were Bacillariophyta and Pyrrophyta. Ceratium tripos and Noctiluca scintillans were dominant species in spring, Skeletonema costatum was common, and was also mainly HABs dominant species in summer, autumn and winter. Pearson correlation and Canonical correspondence analysis (CCA) showed that environment factors had significant correlation with dominance HABs species in different extent, and the ordination result was that S(Salinity) > T(Temperature) > pH > E(Eutrophication index) > DO(dissolved oxygen) > DIN > PO4-P. Prorocentrum donghaiense, Skeletonema costatum, Noctiluca scintillans and Karenia mikimotoi caused many times red tide in 2011 to 2016. However, Prorocentrum donghaiense and Karenia mikimotoi cell density was low in survey year. North of the strait and east coast of the southern strait were sensitive sea area of red tide. The work highlights for the first time ecological characteristic of HAB was studied in Hai-tan Strait. Further, the data and results of this study will help us to improve efficiency for controlling HAB. Even, it is worthwhile to the management and response to the red tide disaster. Ordination result can also be a good indicator of ecological risk.