Estuarine Subaqueous Soil Temperature

Abstract

Most biological and chemical processes related to soil function and formation are temperature dependent. To begin understanding soil temperature in estuarine subaqueous soils, this parameter was investigated in two shallow coastal lagoons in southern New England. Temperature loggers were placed in the soil at two depths (25 and 50 cm) on three subaqueous soil‐landscape types. Soil temperatures were compared among soil‐landscape types, and relative to overlying water temperature, ambient air temperature, and a tidal marsh soil. Subaqueous soil temperature varied slightly among soil‐landscape types, and appears to be primarily influenced by water temperature and depth. Mean annual water temperatures (11.5–12.4°C) were within 1°C of the associated soil temperatures regardless of water depth suggesting that mean annual water temperature would serve as an excellent surrogate for mean annual soil temperature. Soil temperatures at the 50‐cm depth showed less fluctuation than temperatures measured at 25 cm from the soil–water column interface. Mean annual soil temperatures measured at 50 cm were 12.3 and 12.6°C in washover fan and lagoon bottom soils, respectively. Subaqueous soil temperatures were noticeably warmer than the tidal marsh soil. Differences between mean summer and mean winter soil temperatures were >10°C. Thus, these subaqueous soils classify within the mesic soil temperature regime; similar to subaerial soils of southern New England.