Dissolved methane in the Chukchi Sea during 2017-2020

Methane (CH4) is one of the important greenhouse gases. CH4 dry mole fractions in the atmosphere have increased continuously since the onset of the industrial revolution, contributing to more than 20% of the anthropogenic radiative forcing in the lower atmosphere since 1750. In addition, the ice-covered parts of the Arctic are now known to be a reservoir of organic carbon, suggesting that the coastal areas in the Arctic may be a neglected but essential component of the global CH4 budget.

Seawater samples for CH4 analysis were collected onboard R/V “Xuelong 1”, “Xuelong 2”, and “Xiangyanghong 3” during the 8-11th Chinese Arctic Research Expedition (CHINARE) to the Chukchi Sea during 2017-2020.

1. Equipment:

Name gas chromatography

Model: Agilent 7890A

Method: purge-and-trap

Calibration: CH4:N2 mixtures, China Institute of Metrology

2 Sampling and analysis

The samples were collected with a rosette water sampler equipped with Niskin bottles. Briefly, seawater was transferred to biochemical-oxygen-demand bottles (one for each depth), which were stored in the dark at 4 °C after adding 180 μL of saturated HgCl2.

3 Location

The Chukchi Sea.