Strategies of property developers in the context of carbon tax.

China needs to guide property developers in actively reducing emissions to reach carbon emission reduction targets and respond to global climate change. A carbon tax is an important policy tool. Still, to establish successful rules to steer property developers' reasonable carbon emission reduction behavior, we must first explore property developers' decision-making mechanisms. This study develops an emission reduction and price game model for property developers under the constraint of a carbon tax. It then applies reverse order induction and optimization methods to identify the game equilibrium solution for property developers. Using the game equilibria, we explore the carbon tax mechanism on emission reduction and property developer pricing strategies. We can derive the following conclusions if the carbon tax policy is not implemented: 1.House prices are related to the substitutability of the two types of competitive property developers. 2.The greater the substitutability, the greater the cost of emission reduction paid by consumers. 3.The game equilibrium carbon emission intensity is the average carbon emission intensity of the housing business. In the situation of enacting a carbon tax, we arrive at the following conclusions: 1.The profits of real estate developers who do not have the advantage of emission reduction continue to decline with the increase of carbon tax. 2. For real estate developers who have the advantage of decreasing emissions, profits declined initially and then increased as the carbon tax rate increased, and only when the carbon tax rate reaches Tm1* can they fully leverage the cost advantage and obtain ever-increasing profits. 3.Low tax rates should be adopted by the government at the start of the implementation of the carbon tax policy to provide a buffer time for real estate developers who do not have the advantage of emission reduction costs.

A global assessment of the mixed layer in coastal sediments and implications for carbon storage.

The sediment-water interface in the coastal ocean is a highly dynamic zone controlling biogeochemical fluxes of greenhouse gases, nutrients, and metals. Processes in the sediment mixed layer (SML) control the transfer and reactivity of both particulate and dissolved matter in coastal interfaces. Here we map the global distribution of the coastal SML based on excess 210Pb (210Pbex) profiles and then use a neural network model to upscale these observations. We show that highly dynamic regions such as large estuaries have thicker SMLs than most oceanic sediments. Organic carbon preservation and SMLs are inversely related as mixing stimulates oxidation in sediments which enhances organic matter decomposition. Sites with SML thickness >60 cm usually have lower organic carbon accumulation rates (<50 g C m-2 yr-1) and total organic carbon/specific surface area ratios (<0.4 mg m-2). Our global scale observations reveal that reworking can accelerate organic matter degradation and reduce carbon storage in coastal sediments.

Sedimentary phosphorus cycling and budget in the seasonally hypoxic coastal area of Changjiang Estuary.

Anthropogenic activities have greatly accelerated phosphorus (P) inputs from land to coastal seas. The increased P inputs from major rivers can cause adjacent coastal areas to experience seasonal hypoxia with the enhancing coastal eutrophication, which can subsequently increase P cycling and alter long term preservation. Analysis of sediment core measurements including SEDEX P speciation coupled with diagenetic kinetic models were performed on two cores in the coastal area under the Changjiang river plume, that experiences seasonal hypoxia. It was found that the benthic flux of dissolved reactive phosphate (DRP) in the Changjiang Estuary (CJE) was higher than that of adjacent areas of the Chinese coastal shelf. Sedimentary phosphorus transformations of Fe-bound P and organic P resulted in the in-situ formation of authigenic P (probably apatite), which was the major form of reactive P buried in the sediment. P burial efficiency (PBE) was lower than that of the oxic Chinese shelf but higher than that of other seasonally hypoxic areas in the world away from major river inputs. An exponential relationship between PBE and bottom water dissolved oxygen was developed, which suggested a positive feedback mechanism of increased hypoxia increasing P recycling, and hence intensifying eutrophication. The relatively high input of sediment including detrital P from the adjacent major river can explain many of the observed differences in P cycling from other seasonally hypoxic areas.

Distribution and budget of biogenic silica in the Yangtze Estuary and its adjacent sea.

Field investigations of the Yangtze Estuary and its adjacent sea were carried out from July to August 2011. The distribution, source, transportation and transformation of biogenic silica (BSi) in suspended particulate matter (SPM) and core sediments were comprehensively investigated; dissolved silica (DSi) in pore water was also analyzed in this work. The budgets of reactive silica (RSi) and BSi in the East China Sea (ECS) were initially constructed on the basis of the above survey. The results indicated that the BSi distribution in this area was mainly affected by the input of the Yangtze River and Taiwan Warm Current, which was significantly correlated with SPM. The RSi flux input by rivers accounts for 17.6% of the total source of RSi in the ECS. Thus, these findings combined with the horizontal distribution of BSi in the Yangtze Estuary and its adjacent sea indicate that riverine input has a profound influence on the primary production of diatoms in the euphotic zone. Submarine groundwater exchange accounts for 22.3% of the DSi input, especially in the upwelling region, which will directly affect the euphotic nutrient structure. The DSi benthic flux from pore water to upper water exceeds riverine input by 3-fold, accounting for 11.5% of primary production in the ECS, which can alleviate the Si limiting effect caused by the decrease in DSi flux from the Yangtze runoff in recent years. Approximately 75.5% of BSi is dissolved and re-engaged in the ECS silicon cycle in the settlement process.