No abstract

Ocean warming can modify the phytoplankton biomass on decadal scales. Significant increases in sea surface temperature (SST) and rainfall in the northwest of Australia over recent decades are attributed to climate change. Here, we used four biomarker proxies (TEX86 index, long‐chain n‐alkanes, brassicasterol, and dinosterol) to reconstruct approximately 60‐year variations of SST, terrestrial input, and diatom and dinoflagellate biomass in the coastal waters of the remote Kimberley region. The results showed that the most significant increases in SST and terrestrial input occurred since 1997, accompanied by an abrupt increase in diatom and dinoflagellate biomasses. Compared with the results before 1997, the average TEX86H temperature during 1997–2011 increased approximately 1°C, rainfall increased 248.2 mm, brassicasterol and dinosterol contents increased 8.5 and 1.7 times. Principal component analysis indicated that the warming SST played a more important role in the phytoplankton increase than increased rainfall and river discharge.

No abstract

No abstract

The Holocene environment evolution in the East China Sea (ECS) is characterized by the gradual establishment and strengthening of its shelf circulation system, but knowledge about temperature responses in temporal and spatial scales is limited due to the lack of continuous high-resolution records. Here, we compare ′ U K 37 and TEX 86 temperature records for three cores from the ECS shelf, which provide the temporal and spatial patterns of Holocene temperature structure variations. These temperature records revealed broadly consistent temporal trends with three intervals characterized by two distinct shifts. During the early Holocene (10.0-6.0 ka), the modern-type circulation system was not established, which resulted in strong water column stratification; and the higher sea surface temperature (SST) might be associated with the Holocene Thermal Maximum (HTM). The interval of 6.0 to 1.0/2.0 ka displayed a weaker stratification caused by the intrusion of the Yellow Sea Warm Current (YSWC) and the initiation of the circulation system. A decreasing SST trend was related to the formation of the cold eddy generated by the circulation system in the ECS. During 1.0/2.0 to 0 ka, temperatures were characterized by much weaker stratification and an abrupt decrease of SST caused by the enhanced circulation system and stronger cold eddy, respectively. Thus, the temperature structure in the shelf of ECS was closely related with circulation system changes during the mid-late Holocene, which was most likely driven by the intrusion of Kuroshio Current (KC). The significant asynchrony of temperature decreases in the three locations during the late Holocene was likely caused by the gradual expansion of the ECS cold eddy area.