title: Maternal transfer and sublethal immune system effects of brevetoxin exposure in nesting loggerhead sea turtles (Caretta caretta) from western Florida.
abstract: Blooms of Karenia brevis (also called red tides) occur almost annually in the Gulf of Mexico. The health effects of the neurotoxins (i.e., brevetoxins) produced by this toxic dinoflagellate on marine turtles are poorly understood. Florida's Gulf Coast represents an important foraging and nesting area for a number of marine turtle species. Most studies investigating brevetoxin exposure in marine turtles thus far focus on dead and/or stranded individuals and rarely examine the effects in apparently "healthy" free-ranging individuals. From May-July 2014, one year after the last red tide bloom, we collected blood from nesting loggerhead sea turtles (Caretta caretta) on Casey Key, Florida USA. These organisms show both strong nesting and foraging site fidelity. The plasma was analyzed for brevetoxin concentrations in addition to a number of health and immune-related parameters in an effort to establish sublethal effects of this toxin. Lastly, from July-September 2014, we collected unhatched eggs and liver and yolk sacs from dead-in-nest hatchlings from nests laid by the sampled females and tested these samples for brevetoxin concentrations to determine maternal transfer and effects on reproductive success. Using a competitive enzyme-linked immunosorbent assay (ELISA), all plasma samples from nesting females tested positive for brevetoxin (reported as ng brevetoxin-3[PbTx-3] equivalents [eq]/mL) exposure (2.1-26.7ng PbTx-3eq/mL). Additionally, 100% of livers (1.4-13.3ng PbTx-3eq/mL) and yolk sacs (1.7-6.6ng PbTx-3eq/mL) from dead-in-nest hatchlings and 70% of eggs (<1.0-24.4ng PbTx-3eq/mL) tested positive for brevetoxin exposure with the ELISA. We found that plasma brevetoxin concentrations determined by an ELISA in nesting females positively correlated with gamma-globulins, indicating a potential for immunomodulation as a result of brevetoxin exposure. While the sample sizes were small, we also found that plasma brevetoxin concentrations determined by an ELISA in nesting females significantly correlated with liver brevetoxin concentrations of dead-in-nest hatchlings and that brevetoxins could be related to a decreased reproductive success in this species. This study suggests that brevetoxins can still elicit negative effects on marine life long after a bloom has dissipated. These results improve our understanding of maternal transfer and sublethal effects of brevetoxin exposure in marine turtles.
authors.affiliation: Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA. Electronic address: jperrault@usfsp.edu.
authors.forename: Justin R
authors.initials: JR
authors.lastname: Perrault
authors.affiliation: Department of Chemistry and Biochemistry, Middlebury College, 14 Old Chapel Road, Middlebury, VT 05753, USA. Electronic address: kbauman@ucsd.edu.
authors.forename: Katherine D
authors.initials: KD
authors.lastname: Bauman
authors.affiliation: College of Arts and Sciences, University of South Florida Sarasota-Manatee, 8350 North Tamiami Trail, Sarasota, FL 34243, USA. Electronic address: taylorgreenan@gmail.com.
authors.forename: Taylor M
authors.initials: TM
authors.lastname: Greenan
authors.affiliation: Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA. Electronic address: pcblum@mote.org.
authors.forename: Patricia C
authors.initials: PC
authors.lastname: Blum
authors.affiliation: Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA. Electronic address: mhenry@mote.org.
authors.forename: Michael S
authors.initials: MS
authors.lastname: Henry
authors.affiliation: Marine Immunology Program, Mote Marine Laboratory, 1600 Ken Thompson Parkway, Sarasota, FL 34236, USA. Electronic address: cjwalsh@mote.org.
authors.forename: Catherine J
authors.initials: CJ
authors.lastname: Walsh
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid; D004141:Dinoflagellida / Q000378:metabolism; D004625:Embryo, Nonmammalian / Q000187:drug effects / Q000378:metabolism; D004781:Environmental Exposure; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005431:Florida; D057097:Harmful Algal Bloom; D007113:Immunity, Innate / Q000187:drug effects; D008387:Marine Toxins / Q000032:analysis / Q000097:blood / Q000633:toxicity*; D010063:Ovum / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects; D035964:Oxocins / Q000032:analysis / Q000097:blood / Q000633:toxicity*; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D012098:Reproduction / Q000187:drug effects*; D053719:Tandem Mass Spectrometry; D014426:Turtles / Q000254:growth & development / Q000378:metabolism*; D014873:Water Pollutants / Q000633:toxicity*; D015017:Yolk Sac / Q000378:metabolism; D000095702:Polyether Toxins
chemical_list: D008387:Marine Toxins; D035964:Oxocins; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; D014873:Water Pollutants; C546612:brevetoxin 3; D000095702:Polyether Toxins
keywords: Brevetoxin; Eggs; Gulf of Mexico; Hatchling; Immune system; Liver; Marine turtle