Variability of the nutrient stream near Kuroshio's origin

Area of Science:

• Oceanography
• Marine Biology
• Biogeochemistry

Background:

• The Kuroshio Current, known as the
• Black Stream,
• is a major Pacific Ocean current.
• It appears black due to low nutrient levels in surface waters.
• Nutrient concentrations increase with depth, forming a nutrient stream below the euphotic zone.

Purpose of the Study:

• To investigate the poorly studied nutrient stream within the Kuroshio Current.
• To identify different modes of the nutrient stream off SE Taiwan.
• To assess changes in nutrient transport and their impact on productivity.

Main Methods:

• Analysis of oceanographic data to identify nutrient stream structures.
• Observation of subsurface water transport and nutrient flux.
• Comparison of nutrient stream modes and their spatial distribution.

Main Results:

• Three distinct modes of the Kuroshio nutrient stream were identified off SE Taiwan.
• Northward nutrient transport has increased since 2015, linked to a rise in subsurface water transport since 2013.
• The nutrient stream supports high productivity in the East China Sea and Kuroshio Extension.

Conclusions:

• The Kuroshio nutrient stream plays a critical role in supporting marine ecosystems and fisheries.
• Understanding its structure and dynamics is crucial for predicting productivity changes.
• The observed increase in nutrient transport suggests a potential shift in the Kuroshio Current's biogeochemical functioning.