Spatial and Temporal Distribution Characteristics of Red Tide in Ningde Coastal Waters From 2010 to 2020

Abstract

In order to analyze the spatio-temporal distribution and species characteristics of red tide in the coastal waters of Ningde, all red tide events occurred in this study area were collected from 2010 to 2020. The important conclusions were as follows: Firstly, a total of 16 red tides occurred in Ningde coastal waters, with an annual average of 1.5 times in the past 11 years. The total area of red tides was as high as 1468 km2, with an annual average of 133.5 km2. The duration of red tides was 169 days, with an annual average of 15.4 days. Secondly, red tide occurred from April to June, with a high frequency in May. Thirdly, red tide species included dinoflagellates and diatoms. In terms of frequency and area of red tide, Prorocentrum donghaiense ranked first, followed by Karenia mikimotoi, and the last one was Skeletonema costatum. Fourthly, in terms of spatial distribution, the locations with the highest frequency of red tide and the longest duration were in Funing Bay and its surrounding waters (Zone A), while the largest area of red tide was scattered in Sansha outer Bay (Zone D), and the largest number of red tide species was located in Sansha inner Bay (Zone C). Fifthly, there were four times of toxic red tides caused by Karenia mikimotoi, mainly concentrated in the waters around Xiapu coastal waters. Appropriate temperature and salinity, rich nutrients and good weather were the prerequisite conditions for the formation of red tide of Karenia mikimotoi.

Keywords

• red tide
• spatial-temporal distribution
• diatoms
• dinoflagellates
• karenia mikimotoi
• ningde coastal waters