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GCE III - Key Finding in 2019

    The importance of lateral transport in southeastern estuaries

    Richards (2018) synthesized data from a series of hydrographic surveys and monitoring instruments to characterize water flow in the South Atlantic Bight (SAB). He found that along-shelf flows are controlled by winds whereas cross-shelf flows are controlled by a combination of along-shore wind stress and freshwater discharge. The study confirmed the importance of lateral transport from estuaries onto the shelf, with strong evidence for freshwater intrusion during spring when discharge from the Altamaha River is high (Fig. 1). These results were in agreement with model output generated by FVCOM (Wang et al. 2017), and demonstrate that the hydrodynamic model can be used to examine dynamical responses in the system. These observations also provide support for the ideas put forth by Di Iorio and Castelao (2013) regarding the potential for intra-estuarine connectivity, as offshore transport near from the Altamaha was associated with onshore transport into Sapelo Sound. These findings show that the complicated system of connected channels and marsh complexes found in the SAB facilitate lateral transport and prolong the residence time of estuarine water, with implications for nutrient dynamics and other processes.


    Fig. 1 Freshwater intrusion upon the GA shelf during the months of April and July, 2014. This mapping is a result of CTD casts across 8 transects spanning the shelf adjacent to the GCE LTER domain. From Richards 2018.


This material is based upon work supported by the National Science Foundation under grants OCE-9982133, OCE-0620959, OCE-1237140 and OCE-1832178. Any opinions, findings, conclusions, or recommendations expressed in the material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.