Geofluids

Research Article

Understanding the Compositional Variability of the Major Components of Hydrothermal Plumes in the Okinawa Trough

Table 1

Physical properties and major component compositions of hydrothermal plume water columns in the middle and southern Okinawa Trough.


	Iheya North		Clam		Yonaguni Knoll IV		Tangyin		Average seawater
	Average	Range	Average	Range	Average	Range	Average	Range	Average seawater

Current velocity (m s⁻¹)	–	–	0.139 ()	0.008–0.500	0.457 ()	0.079–0.820	0.235 ()	0.016–0.963	–
Salinity	34.4 ()	34.2–34.8	34.4 ()	34.3–34.8	34.4 ()	34.3–34.8	34.4 ()	34.4–34.8	35.0
Temperature (°C)	8.19 ()	4.14–23.3	6.09 ()	3.80–21.3	5.89 ()	3.88–23.8	6.12 ()	3.90–24.3	–
Turbidity (FTU)	0.048 ()	0.024–0.398	0.065 ()	0.025–0.302	0.182 ()	0.043–0.459	0.183 ()	0.031–0.372	–
Oxygen (ml l⁻¹)	2.43 ()	1.56–4.90	1.96 ()	1.52–4.93	1.87 ()	1.48–4.32	1.88 ()	1.46–4.32	–
pH, 25°C	7.79 ()	7.55–8.05	7.80 ()	7.53–8.14	7.71 ()	7.65–7.98	7.75 ()	7.56–7.98	7.8
Potential density (kg m⁻³)	26.6 ()	23.6–27.3	27.0 ()	24.3–27.4	27.0 ()	23.5–27.4	27.0 ()	23.3–27.4	–
B³⁺	0.378 ()	0.330–0.448	0.395 ()	0.354–0.526	0.483 ()	0.452–0.534	0.388 ()	0.375–0.406	0.412
Na⁺	494 ()	459–549	500 ()	462–534	499 ()	463–526	489 ()	458–520	470
Mg²⁺	54.1 ()	50.9–57.9	54.1 ()	51.8–56.3	53.3 ()	52.0–54.5	53.1 ()	51.1–55.7	53.1
Total S	28.6 ()	26.9–30.6	28.9 ()	27.9–30.3	28.1 ()	27.0–29.4	27.7 ()	27.1–28.7	28.2
K⁺	10.3 ()	9.70–11.2	10.4 ()	9.90–10.9	10.6 ()	10.2–11.2	10.5 ()	9.77–11.0	10.0
Ca²⁺	10.0 ()	9.02–11.0	10.2 ()	9.81–11.0	10.0 ()	9.56–10.6	9.87 ()	9.47–10.5	10.3
Mn²⁺	–	–	0.007 ()	0.001–0.037	0.017 ()	0.001–0.065	–	–	0.007
Sr²⁺	84.9 ()	73.2–99.1	86.5 ()	78.9–97.4	89.5 ()	84.1–94.6	87.0 ()	84.2–91.4	92.4
Cl^-	570 ()	547–611	575 ()	562–591	576 ()	568–585	578 ()	568–594	546
F^-	0.710 ()	0.639–0.818	0.704 ()	0.603–0.768	0.668 ()	0.604–0.845	0.691 ()	0.612–0.775	0.684
	27.3 ()	26.1–29.5	27.6 ()	26.7–28.3	27.4 ()	26.8–27.9	27.6 ()	26.8–28.1	28.2

Unit mmol kg⁻¹ for B, Na, Mg, Total S, K, Ca, Cl^-, , , F^-, Br^-, and ; μmol kg⁻¹ for Mn and Sr. “–”: no data. Average seawater data from Turekian [50] and Millero [4].