NRE dynamics Flashcards
What is chl-a an indicator of?
phytoplankton biomass
True or False: the NRE experiencing increased hurricane frequency since the mid-1990s
True for 1995-2011 (Paerl et al. 2014), though there has been a decrease in recent years, possibly due to the development of an El Nino
What major phytoplankton group is most abundant in moderate flow waters?
diatoms
What major phytoplankton groups are most abundant in low flow waters? (2)
dinoflaggelates, cyanobacteria
What major phytoplankton groups are most abundant in high flow waters? (2)
cryptophytes and chlorophytes
The NRE is preliminar _________ limited
nitrogen
High FW discharge after a storm event can lead to high ________ and low _______ and residence times.
flushing
chl-a/biomass
____________ ______________ ultimately controls longitudinal transport and residence time.
freshwater discharge
Where does the chl-a max form?
Where residence time increases in coincidence with adequate nutrient supplies (these are often correlated in the NRE)
River morphology is also important– often formes at the bend in the estuary
How does a drought/storm event affect the location of the chl-a?
Drought– less FW flushing, moves chl-a max upstream
Storm– more FW flushing, moves chl-a max downstream
What is the average residency time in the Neuse?
2-3 months
69 days in Sept, 81 days in Oct according to Paerl et al. 2006
How might a large storm event affect residence time in the estuary
Drastically decreases (from months to ~a week in 1999)
Why do we see elevated chl-a after a hurricane?
Caused by fertilization of downstream waters caused by increased FW discharge
When were P inputs banned in the NRE watershed?
1980s
Did the P ban have any effect on N concentrations?
NO; may have actually promoted N-enrichment downstreeam
FW is __ limited.
PO4
SW is __ limited.
NO3
Salinity is a function of ______, _______, and _______ in the NRE
precipitation; flow, wind-driven mixing
What are the nutrient-related characteristics of site 30 in the NRE?
upper NRE, where most nutrients are delivered but have short residence times due to the morphology of the estuary
What are the nutrient-related characteristics of the middle NRE (sites 70 and 120)?
Where chl-a concentration is highest due to widening (increased res times); also see stratification here often
Where is the USGS streamflow gauging station used in Hans’ studies?
Near Kinston, 20km upstream of Streetsferry Bridge in New Bern
What phytoplankton group tends to be most abundant in the summer months (according to Valdes-Weaver et al. 2006)?
Cyanobacteria
True or false: Low flow rates cause phytoplankton advection downstream.
False; HIGH flow rates cause phytoplankton advection downstream
Why is tidal amplitude in the NRE so low?
Barrier islands; get low tidal amplitude through small inlets
Is there any seasonal signal to FW flow in the NRE?
Yes, weak seasonality w/ higher flows in the late winter/early spring
When is the NRE N-limited?
In the late spring through fall, when primary productivity is high
What is the average residence time in the Neuse?
> 1 month
Why is it important that avg residence time>phytoplankton generation time?
Allows phytoplankton biomass to accumulate
What is the formulat for residence time?
T = v/q
Where v = the capacity/volume of the system and q = the flow/discharge rate
What paper looked at Vibrio/phytoplankton in the NRE in 2004?
Hsieh et al. 2007
What was the general relationship of Vibrio and chlorophyll a shown by Hsieh et al. 2007?
Vibrio and chlorophyll a both increased moving downstream; however, past the salt front Vibrio alone increased and chlorophyll a began to decline
In Hsieh et al. 2007 what was the relationship between Vibrio and DOC? Salinity?
both positive
What paper saw an increase in Vibrio during storm events in the Neuse?
Wetz et al. 2008 (relative increase compared to the concentrations predicted by temperature/salinity models
Where is the weather station used to monitor wind in the NRE?
New Bern airport
Which paper looked at sediment/water column transport of Vibrio and FIB?
Fries et al. 2008
