Interactions between Karlodinium veneficum and Prorocentrum donghaiense from the East China Sea

Abstract

The dinoflagellate Prorocentrum donghaiense is a dominant harmful algal bloom (HAB) species on the East China Sea (ECS) coast. The co-occurrence of Karlodinium veneficum with P. donghaiense is often observed and can later develop into dense blooms. However, the role of K. veneficum in P. donghaiense population dynamics is unknown. In the current study, three K. veneficum (GM1, GM2, and GM3) strains were isolated from the ECS with one (GM1) from a mixed, dense bloom of P. donghaiense and other HAB species. All three isolates had identical ITS sequences that were concordant with the species designation. Unique karlotoxin congeners were isolated from one strain (GM2). The sterol compositions of P. donghaiense and K. veneficum were consistent with sensitivity to karlotoxin in the former and insensitivity in the latter. Additional experimentation showed that: (1)in monocultures, higher growth rate of P. donghaiense than K. veneficum is observed in nutrient-enriched and nutrient-depleted media. In co-cultures, the growth of P. donghaiense is inhibited; (2) feeding on P. donghaiense by K. veneficum is clearly demonstrated by fluorescent dye tracking; and (3) the isolated karlotoxin is lethal to P. donghaiense in a concentration-dependent manner. From these studies we propose that K. veneficum may play a negative role in P. donghaiense bloom maintenance and that P. donghaiense may in turn be a bloom initiator as a prey item for K. veneficum.

The Globalization of Cultural Eutrophication in the Coastal Ocean: Causes and Consequences

“…Particularly, large scale blooms (covering an area > 1,000 km 2 ) have been recorded every year since 1998, and the dinoflagellate Prorocentrum donghaiense has become the recurrent bloom species for more than 10 years (Li et al, 2014;Lu et al, 2014). Blooms of other potentially toxic dinoflagellates (Karodinium veneficum, Karenia mikimotoi, K. veneficum, Alexandrium tamarense, A. catenella, and Heterosigma akashiwo) have also been observed (Lu et al, 2014;Zhou et al, 2015;Wang Y.-F. et al, 2018). Toxic dinoflagellate blooms have resulted in millions of dollars of lost fish landings (Tang et al, 2006;Zhou et al, 2008;Li et al, 2014;Mackey et al, 2017;Glibert et al, 2018;Chen et al, 2019).…”

Two new karlotoxins found in Karlodinium veneficum (strain GM2) from the East China Sea

“…The dinoflagellate Karlodinium veneficum strain GM2 (NMB jah047-1 in Microalgae Collection in Ningbo University) was originally isolated from a seawater sample collected in Yushan, East China Sea (ECS), in June 2006 (Zhou et al, 2015). The strain was previously under the taxonomic synonym ‘ Karlodinium micrum ’.…”

“…Instead of forming single-species bloom, K. veneficum frequently co-occurred with other harmful algae, such as Karenia mikimotoi and Prorocentrum donghaiense , as an ECS red tide (Zhou et al, 2008), however, whether this species is endemic or was imported by ballast water is still unknown. In our previous study, K. veneficum may terminate P. donghaiense blooms through grazing, and initiate its own subsequent blooms in ECS (Zhou et al, 2015). That the toxic strain GM2 from ECS may produce unique karlotoxin congeners was revealed by LC/MS data (Zhou et al, 2015).…”

“…In our previous study, K. veneficum may terminate P. donghaiense blooms through grazing, and initiate its own subsequent blooms in ECS (Zhou et al, 2015). That the toxic strain GM2 from ECS may produce unique karlotoxin congeners was revealed by LC/MS data (Zhou et al, 2015). The structure of karlotoxin from ECS strains has not yet been characterized.…”

Biogenic Silica and Organic Carbon Records in Zhoushan Coastal Sea over the Past One Hundred Years and Their Environmental Indications

“…It has been proven that there was a serious eutrophication in the ZCS during the past four decades due to human activities in the drainage basin and artificial aquaculture activities in offshore areas [1][2][3][4]. The frequency of occurrence of red tide in this area has also significantly increased since 1980s, accompanied with an increasing trend of harmful algal blooming [5][6][7][8][9]. Although many studies have proven that illumination, water temperature, and nutrients are important factors that influence algae growth [10,11], it is necessary to study whether overloading nutrients and changes of nutrient ratio are a key cause of changes in the dominant algal species of red tides in the ZCS during the past four decades associated with changes of illumination and water temperature [12,13].…”