Sampling results from Station 1 ( 1974-2008 ) show a median TP concentration of 6.4 parts per billion ( ppb ), a mean secchi disk transparency of, and a mean Chl-a concentration of 1.2 ppb.
32.
During this period, 11 years of secchi disk transparency data, 7 years of total phosphorus ( TP ) data, 2 years of chlorophyll-a ( Chl-a ) data, and 5 years of dissolved oxygen ( DO ) data has been collected.
33.
During this period, 16 years of secchi disk transparency data, 17 years of total phosphorus ( TP ) data, 16 years of chlorophyll-a ( Chl-a ) data, and 14 years of dissolved oxygen ( DO ) data have been collected.
34.
Water quality monitoring data has been collected since 1974, including 29 years of secchi disk transparencies, 23 years of total phosphorus ( TP ) data, 20 years of chlorophyll-a ( Chl-a ) data and 7 years of dissolved oxygen ( DO ) profiles.
35.
The water of the Weddell Sea is about 1400 m deep at its deepest point; it is exceptionally clear ( the Secchi disk visibility reading at 80 metres recorded in the Weddell Sea on 13 October 1986 was the deepest ever, at the theoretical maximum in absolutely pure water ).
36.
The Secchi disk readings do not provide an exact measure of transparency, as there can be errors because of the sun's glare on the water, or one person may see the disk at one depth, but another person with better eyesight may see it at a greater depth.
37.
Some of the tools used to evaluate a beach in the field include : dye ball water tracer for measuring currents such as longshore and especially dangerous rip and tidal currents, Secchi disk for measuring water clarity and visibility, a Brunton compass / clinometer to determine beach slope, field sieve set to determine sand grain size, and a hand lens for mineralogical identification.
38.
First, to determine the transparency / turbidity in reservoirs, Whipple modified the original all-white Secchi disk to & a disc about 8 inches in diameter, divided into quadrants painted alternately black and white like the target of a level-rod & The black and white Secchi disk is the standard disk currently used in limnology investigations and marine water quality studies.
39.
First, to determine the transparency / turbidity in reservoirs, Whipple modified the original all-white Secchi disk to & a disc about 8 inches in diameter, divided into quadrants painted alternately black and white like the target of a level-rod & The black and white Secchi disk is the standard disk currently used in limnology investigations and marine water quality studies.
