Elucidating terrestrial nutrient sources to a coastal lagoon, Chincoteague Bay, Maryland, USA (Page 1)  
location map

Elucidating terrestrial nutrient sources to a coastal lagoon, Chincoteague Bay, Maryland, USA

Long-term non-linear ecosystem-scale changes in water quality and biotic communities in coastal lagoons have been associated with intensification of anthropogenic pressures. In light of incipient changes in Johnson Bay (an embayment of Chincoteague Bay, Maryland-Virginia, USA), examination of nitrogen sources was conducted through synoptic water quality monitoring, stable nitrogen isotope signatures (deltaN-15) of in situ bioindicators, and denitrification estimates. These data were placed in the context of long-term and broader spatial analyses. Despite various watershed protection efforts, multiyear summer time studies (2004-2007) suggested that high levels of terrestrially derived nutrients still enter Johnson Bay. Total nitrogen concentrations in Johnson Bay were 132% the concentrations in the broader Chincoteague Bay during the late 1970s (mean 2004-2007 was 40.0 - 73.2 µM). Comparing total nitrogen concentrations in Johnson Bay to St. Martin River (consistently the most eutrophic region of these coastal bays), Johnson Bay has increased from 62.5% to 82.5% of the concentrations in St. Martin River during the late 1970s. Though specific sources of nitrogen inputs have not yet been definitively identified, the long-term increase in total nitrogen concentrations occurred despite increased and continued conservation and protection measures. We suggest that investigating nutrient sources can reveal potentially ineffective nutrient policies and that this knowledge can be applied towards other coastal lagoons.

Keywords: coastal lagoons, nitrogen, anthropogenic factors, water quality, land use, Maryland, Chincoteague Bay

Author(s)Fertig BM, O’Neil JM, Beckert KA, Cain CJ, Needham DM, Carruthers TJB, and Dennison WC
IAN Author(s)Ben Fertig, Kris Beckert, Tim Carruthers, Bill Dennison
PublisherAcademic Press Inc Elsevier Science
Journal / BookEstuarine, Coastal And Shelf Science 116: 1-10
TypePaper | Journal Article
Location(s)Chincoteague Bay
Number of Pages10
Link https://doi.org/10.1016/j.ecss.2012.08.013