Spatial and temporal aspects of Gyrodinium galatheanum in Chesapeake Bay: distribution and mixotrophy

Abstract

Abstract. Gyrodinium galatheanum (Braarud) Taylor 1995 is a common bloom-forming, potentially toxic photosynthetic dinoflagellate in Chesapeake Bay, USA. Abundance of this dinoflagellate achieved densities >4 ϫ 10 3 cells ml -1 in the mid-and upper Bay during late spring and early summer of 1995 and 1996. Ingestion of cryptophytes by this dinoflagellate was detected in most samples collected from the Bay. During late spring and early summer, mean number of ingested cryptophytes per G.galatheanum was as high as 0.46 for dinoflagellate populations located in surface waters of the mid-and upper Bay where dissolved inorganic phosphorus was low. Observations on the distribution of G.galatheanum in Chesapeake Bay show that populations of this dinoflagellate were usually restricted to waters with salinities ranging from 7 to 18 psu, seasonally progressed up the estuary, and usually co-occurred with cryptophytes. Correlation analysis indicates that abundance of G.galatheanum and incidence of feeding was negatively correlated with dissolved inorganic phosphorus, and that incidence of feeding was positively correlated with abundance of cryptophyte prey. These results indicate that G.galatheanum is an important component of the Chesapeake Bay phytoplankton during the spring and summer. Our results suggest that the phagotrophic capability possessed by this phototrophic dinoflagellate may contribute to its success in a varying-resource environment like Chesapeake Bay.

Feeding in the mixotrophic dinoflagellate Ceratium furca is influenced by intracellular nutrient concentrations

“…In many primarily photosynthetic dinoflagellates, feeding also seems to be related to inorganic nutrient concentrations. In Chesapeake Bay, ingestion of ciliates by Ceratium furca and of cryptophytes by Gyrodinium galatheanum increased with decreasing inorganic P concentrations (Li et al 2000a,b, Smalley & Coats 2002, whereas Prorocentrum minimum contained a greater number of food vacuoles at higher NH 4 concentrations (Stoecker et al 1997).…”

“…Feeding by field populations of Ceratium furca and G. galatheanum showed a similar relationship with inorganic nutrient ratios and was positively correlated with inorganic N:P ratios (Li et al 2000b, Smalley & Coats 2002). These observations suggest that nutrient ratios, rather than absolute nutrient concentrations, may play a role in regulating phagotrophy in these mixotrophs (Raven 1997, Stoecker et al 1997, Li et al 2000a,b, Smalley & Coats 2002.…”

Feeding mechanism, prey specificity and growth in light and dark of the plastidic dinoflagellate Karlodinium armiger

“…they are mixotrophic (Li et al 1999, De Salas et al 2005. The best known species is K. veneficum (synonym: K. micrum), which has been extensively studied in the field and the laboratory (Nielsen 1996, Li et al 1999, 2000a, 2000b, Adolf et al 2006a. Without addition of food, K. veneficum may grow in the light at fairly low rates (0.25 to 0.5 d ) with cryptophytes as food.…”

Blooms of Dinoflagellate Mixotrophs in a Lower Chesapeake Bay Tributary: Carbon and Nitrogen Uptake over Diurnal, Seasonal, and Interannual Timescales

“…In a study of Alexandrium catenella, Collos et al (2013) found that only 47% of the C demand was met by bicarbonate uptake and the remainder was made up through grazing. While we did not examine mixotrophic grazing in this study, many of the dinoflagellates that dominated the algal community in this study are known to graze (Li et al 2000;Jeong et al 2004Jeong et al , 2005aJeong et al , b, 2015. Early studies suggested that algal heterotrophy was a response to low ambient nutrient concentrations (Stoecker et al 1997, Fan et al 2003, Stoecker and Gustafson 2003; however, more recently, algal mixotrophy has been found to be common in eutrophic environments (Adolf et al 2008.…”