Hi all,
We finally got some rain in the basin on 26 May that sent river flows to nearly twice their seasonal norm. On May 31, the estuary was still really salty though. The salt wedge was upstream of New Bern and bottom water at New Bern (station 30) was ~ 10. Surface salinity at the mouth of the estuary was ~20. Water temperatures ranged from low 20s C in the bottom waters to nearly 30 C at the surface. The strong temperature gradient reinforced the vertical density gradient caused by salinity. Surface to bottom salinity differences ranged from about 10 upstream to 2 at the mouth. Hypoxic bottom water conditions were observed from the tip of the salt wedge at station 30 downstream to station 160. A subsurface zone of elevated chlorophyll (~40 ug/L) occurred at ~ 1 m depth at station 50. Microscopic observation of station 50 surface water indicated the phytoplankton community was dominated by small centric diatoms and cryptophytes. Generally, both small centric diatoms and cryptophytes are highly edible fuel for the estuarine food web. Elevated turbidity (15-20 NTU) at the freshwater head of the estuary is indicative of the elevated discharge conditions.
-Nathan
