The above research states that seagrass needs 15-25% surface irradiance
(energy from the sun) which is noted to be a high light requirement
compared to the needs of other marine growth. The effects of
human
activities within the Indian River Lagoon affected the seagrass
growth. The most significant of these are the fluctuation of
salinity, water runoff, dredging and chemical pollutants. Sea grass
is used as an indicator to the estuary's health condition. If the sea
grass is diminishing then the water is unwell.
“A
lagoon-wide seagrass monitoring program led by scientists from the
St. Johns River Water Management District is responsible for
monitoring long-term trends in IRL seagrass population status,
health, and coverage trends. Data from this program and associated
water quality monitoring programs indicates that the amount of light
reaching the benthic habitat is the primary factor limiting seagrass
coverage in the lagoon. Water column turbidity, chlorophyll a
concentration, and color are the principal determinants of water
clarity in the lagoon, with turbidity being by far the most
important” (Christian and Shang 2003). and
http://www.sms.si.edu/irlspec/IRL_seagrasstrends.htm
Smithsonian Marine Station at Fort Pierce.
My
scientific efforts will show how much turbidity and for how long does
the increased turbidity linger due to maintenance dredging in the
Brevard County section of IRL. Also, noting how much light is needed
for the seagrass to survive. In the past week I have contacted the
Army Corp of Engineers and was informed of the scheduled maintenance
dredging occurring at this time in Brevard. My projected plan is to
test the turbidity very near the dredging site. I will then return
for samples every two weeks until the water clears or my lab time has
ended with a decreased level records.
Valerie--this sounds like a good plan. First--does this mean you now know exactly where the dredging will occur? Second--your every-two-weeks sampling plan might be too far apart. If you an, you should likely sample twice or once a week. I know this involves quite a bit of travel. Make sure you also document the environmental conditions e.g., wind speed and direction especially since wind/waves can resuspend sediments and contribute to turbidity. Otherwise--good job. Please keep us posted!!
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