Few biogeographic studies of dinoflagellate cysts include the near-shore estuarine environment. We determine the effect of estuary type, biogeography, and water quality on the spatial distribution of organic-walled dinoflagellate cysts from the Northeast USA (Maine to Delaware) and Canada (Prince Edward Island). A total of 69 surface sediment samples were collected from 27 estuaries, from sites with surface salinities >20. Dinoflagellate cysts were examined microscopically and compared to environmental parameters using multivariate ordination techniques. The spatial distribution of cyst taxa reflects biogeographic provinces established by other marine organisms, with Cape Cod separating the northern Acadian Province from the southern Virginian Province. Species such as Lingulodinium machaerophorum and Polysphaeridinium zoharyi were found almost exclusively in the Virginian Province, while others such as Dubridinium spp. and Islandinium? cezare were more abundant in the Acadian Province. Tidal range, sea surface temperature (SST), and sea surface salinity (SSS) are statistically significant parameters influencing cyst assemblages. Samples from the same type of estuary cluster together in canonical correspondence analysis when the estuaries are within the same biogeographic province. The large geographic extent of this study, encompassing four main estuary types (riverine, lagoon, coastal embayment, and fjord), allowed us to determine that the type of estuary has an important influence on cyst assemblages. Due to greater seasonal variations in SSTs and SSSs in estuaries compared to the open ocean, cyst assemblages show distinct latitudinal trends. The estuarine context is important for understanding present-day species distribution, the factors controlling them, and to better predict how they may change in the future.
Bibliographical noteFunding Information:
The Natural Science and Engineering Research Council of Canada (NSERC), the Canadian Association of Palynology (CAP), and the Geological Society of America (GSA) provided partial funding for this research through student research awards to AMP. This research was partially supported by NSERC Discovery grants to VP and GLC, respectively, NSERC CREATE (Collaborative Research and Training Experience) to MRSC, WATER (Watershed and Aquatics Training in Environmental Research) program to MRSC, and the Canadian Watershed Research Consortium to MRSC. We would to thank all those who provided information or water quality data from estuaries in this study: Alison Branco (Peconic Estuary Program, SCDHS South Shore Bays Water Quality), Barbara Warren (Salem Sound Coastwatch), Brad Hubeny (Salem State University ? Geological Sciences), Ron Huber (Friends of Penobscot Bay), Christopher Deacutis (RIDEM Div. of Fish and Wildlife, Narragansett Bay Water Quality Monitoring Network), Jane Disney (Frenchman Bay Partners), Kevin Brinson (Delaware Environmental Observing System), Peter Milholland (Friends of Casco Bay Citizen Stewards Water Quality Monitoring Program), Tony Williams (Buzzards Bay Coalition), Bebe Moulton (Friends of Blue Hill Bay), Mark Tedesco (EPA), William Hastback (NYSDEC ? Bureau of Marine Resources), Matthew Sclafani (Cornell University), Pierce Rafferty (Henry L. Ferguson Museum), Warren Prell (Brown University, Dept. of Geological Sciences). Chris Pickerell (Marine Program Director, Cornell), Jaime Vaudrey (University of Connecticut), Provincetown Center for Coastal Studies, Blue Hill Bay Coastal Monitoring Program ? Marine Environmental Research Institute, and the many citizen scientists that are part of these organizations who volunteer their time to collect water quality measurements. The US grain size used in this article was produced by the U.S. Environmental Protection Agency through its Environmental Monitoring and Assessment Program (EMAP). Jingyi Zhang and Artur Plis (McGill University) and Maureen Soon (University of British Columbia) are thanked for preparing and completing the biogenic silica analysis. The associate editor and two anonymous reviewers are thanked for their constructive comments that helped improve this manuscript.
- Coastal waters
- Prince Edward Island
- estuary type
- northeast USA
- water quality