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Organic carbon patterns and budgets in the Long Island Sound estuary
Author(s) -
Vlahos Penny,
Whitney Michael M.
Publication year - 2017
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.1002/lno.10638
Subject(s) - estuary , environmental science , total organic carbon , oceanography , continental shelf , heterotroph , autotroph , hydrology (agriculture) , primary production , geology , ecology , biology , ecosystem , paleontology , geotechnical engineering , bacteria
A multi‐year observational time series was evaluated across the 150 km central axis of the U.S. east coast's Long Island Sound (LIS) estuary, in three distinct regions. Fluxes were calculated at the boundaries of the regions using observations coupled to a hydrodynamic model and applied to a mass balance to assess organic carbon (OC) export from LIS. For all years, during stratified summer periods, LIS was a net exporter of OC to the continental shelf. LIS annual net carbon export however, varied with river flow. The heterotrophic or autotrophic nature of LIS also shifted inter‐annually. During the mass balance analysis period (2009–2012), LIS ranged between net OC import from the continental shelf and heterotrophy in the lowest river flow year (2012) and net export of OC and autotrophy in the highest flow year (2011). Analysis suggests that LIS switches from net OC import to export when the annual river inputs exceed 19 km 3 yr −1 . Applying these thresholds to the annual river flow record suggests that net import occurred in 15% of the last 20 years and that LIS usually is a net exporter of OC (85%). Annually averaged LIS carbon export values based on river flow conditions over the last 20 yr are estimated at 56 ± 64 × 10 6 kg yr −1 . Analysis also suggests that LIS shifts from net heterotrophic to net autotrophic when annual river flow exceeds 26 km 3 yr −1 (35% of the last 20 yr). Net heterotrophic conditions are most common, representing 65% of the last 20 yr.