Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i

Particulate Biogenic Silica

Particle Filtration
FTP View Data
To assist in the interpretation of the data, it can be displayed using the Hawaii Ocean Time-series Data Organization & Graphical System (HOT-DOGS©).

Analytical Method

Samples for elemental analyses of Particulate biogenic silica (PSi) were collected into 4L polyethylene carboys; filtered through 47 mm polycarbonate filter holders; onto 47 mm polycarbonate, membrane filters; and placed into 50 ml polypropylene centrifuge tubes. Time course subsamples (1.5, 3, 4.5, 6.5 and 24 hours) were measured colorimetrically to distinguish Lithogenic-Si from Biogenic-Si (DeMaster, 1981). The average field variability between duplicate analyses during 2015 are presented in the Table below.


PSi
Cruise mean CV
(%)
mean SD
(nmol/l)
N
269 10.3 1.718 2
270 47.2 5.993 2
271 33.3 7.022 2
272 14.2 2.298 2
273 10.8 1.499 2
274 16.5 3.348 2
275 18.7 4.052 2
277 8.0 1.648 2
278 8.4 2.871 2
279 18.9 2.326 2
Mean 18.6 3.278 10

Results

Particulate biogenic silica (PSi) concetrations in the surface ocean over the last 19 years of the program are shown in Figure 68 and Figure 69. PSi typically ranges from < 5 to about 25 nmol kg-1 in the upper 100 m of the water column. During the summer months in 1998, 2000 and 2005, PSi increased dramatically in the upper 50 m of the water. This feature appears associated with a large bloom of diatomes, as evidenced from the sharp increases in fucoxanthin (Figure 48)