A role of vertical mixing on nutrient supply into the subsurface chlorophyll maximum in the shelf region of the East China Sea

Keunjong Lee, Takeshi Matsuno, Takahiro Endo, Joji Ishizaka, Yuanli Zhu, Shigenobu Takeda, Chiho Sukigara

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

In summer, Changjiang Diluted Water (CDW) expands over the shelf region of the northern East China Sea. Dilution of the low salinity water could be caused by vertical mixing through the halocline. Vertical mixing through the pycnocline can transport not only saline water, but also high nutrient water from deeper layers to the surface euphotic zone. It is therefore very important to quantitatively evaluate the vertical mixing to understand the process of primary production in the CDW region. We conducted extensive measurements in the region during the period 2009–2011. Detailed investigations of the relative relationship between the subsurface chlorophyll maximum (SCM) and the nitracline suggested that there were two patterns relating to the N/P ratio. Comparing the depths of the nitracline and SCM, it was found that the SCM was usually located from 20 to 40 m and just above the nitracline, where the N/P ratio within the nitracline was below 15, whereas it was located from 10 to 30 m and within the nitracline, where the N/P ratio was above 20. The large value of the N/P ratio in the latter case suggests the influence of CDW. Turbulence measurements showed that the vertical flux of nutrients with vertical mixing was large (small) where the N/P ratio was small (large). A comparison with a time series of primary production revealed a consistency with the pattern of snapshot measurements, suggesting that the nutrient supply from the lower layer contributes considerably to the maintenance of SCM.

Original languageEnglish
Pages (from-to)139-150
Number of pages12
JournalContinental Shelf Research
Volume143
DOIs
Publication statusPublished - Jul 1 2017
Externally publishedYes

Fingerprint

East China Sea
vertical mixing
chlorophyll
nutrient
nutrients
water
primary production
euphotic zone
water salinity
halocline
saline water
pycnocline
time series analysis
dilution
turbulence
China
sea
summer
time series

All Science Journal Classification (ASJC) codes

  • Oceanography
  • Aquatic Science
  • Geology

Cite this

A role of vertical mixing on nutrient supply into the subsurface chlorophyll maximum in the shelf region of the East China Sea. / Lee, Keunjong; Matsuno, Takeshi; Endo, Takahiro; Ishizaka, Joji; Zhu, Yuanli; Takeda, Shigenobu; Sukigara, Chiho.

In: Continental Shelf Research, Vol. 143, 01.07.2017, p. 139-150.

Research output: Contribution to journalArticle

Lee, Keunjong ; Matsuno, Takeshi ; Endo, Takahiro ; Ishizaka, Joji ; Zhu, Yuanli ; Takeda, Shigenobu ; Sukigara, Chiho. / A role of vertical mixing on nutrient supply into the subsurface chlorophyll maximum in the shelf region of the East China Sea. In: Continental Shelf Research. 2017 ; Vol. 143. pp. 139-150.
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