Four short sediment cores were collected to explore the impacts of bay scallop farming on the composition and accumulation of sedimentary organic matter (SOM). The results revealed that SOM was mainly composed of relatively easily biodegradable substances as evidenced by the high contribution rate of biopolymeric carbon (77.8–94.4%). The sediment accumulation rate in the scallop farming area (SFA) was 28.6% higher than that in the non-scallop farming area (NSFA). The total organic carbon (TOC) and total nitrogen (TN) burial fluxes in the SFA were 33.1 and 36.6% higher than those in the NSFA, respectively. A rough estimate showed that the burial fluxes of TOC, TN, scallop-derived OC, and marine algal-derived OC in the ~150 km² SFA could increase by 1.08, 0.11, 0.39, and 0.68 g m⁻² yr⁻¹, respectively, with annual scallop production increasing 10⁴ t. This study highlights the significant effects of scallop farming on the biogeochemistry of SOM in coastal waters, which provides a direct reference for future research on the carbon cycle in shellfish culture areas.

The central part of the Zhangjiakou area is occupied by the Yanshan orogenic basin. A large number of piedmont faults developed over time, controlling the exposure of geothermal anomalies. The fluid chemistry characteristics and their influence on the heat generation mechanism of the medium- and low-temperature convective geothermal field in the area are not fully understood. In this study, the geothermal fluid was sampled and tested, and the hydrogeological background conditions were analyzed. The results show that the sulfate in geothermal fluid originates from the dissolution of gypsum or H₂S oxidation in deep magma. The geothermal fluid in the faulted basin flows upward after deep circulation and interacts with shallow groundwater. The main source of geothermal fluid is atmospheric precipitation. The temperature of the hot reservoir is between 82 °C and 121 °C, and the depth of geothermal water circulation is more than 3200 m. It can be seen that the geothermal resources in this area are formed by the long-term contact of residual magma, geothermal heating and mechanical heating of neotectonic movement after atmospheric precipitation recharge.