This research focuses on residents' perceptions of personal benefits from tourism, identifying not only the relationships between personal benefits from tourism and residents' attitudes toward tourism but also the nature of benefits associated with tourism. The study was conducted in a small rural community where tourism is still at its emerging stage. It was found that residents' perceptions of personal benefits from tourism were closely associated with their attitudes toward tourism in a positive direction. The significant contribution of this study falls on the recognition of noneconomic perspective of tourism benefits for residents in a community where tourism has not yet explicitly emerged. In particular, the data lend support for social exchange theory and improve its understanding in tourism investigations.

Abstract. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are useful molecular indicators for organic carbon (OC) sources and the paleoenvironment. Their application in marine environments, however, is complicated because of a mixed terrestrial and marine source. Here, we examined brGDGTs in sediments from the Mariana Trench, the deepest ocean without significant terrestrial influence. Our result shows a strong predominance of hexamethylated 6-methyl brGDGT (IIIa′) (73.40±2.39 % of total brGDGTs) and an absence of 5-methyl brGDGTs, different from previously reported soils and marine sediments that comprised both 5-methyl and 6-methyl brGDGTs. This unique feature, combined with high δ13COC (-19.82±0.25 %), low OC∕TN ratio (6.72±0.84), low branched and isoprenoid tetraether (BIT) index (0.03±0.01), and high acyclic hexa- ∕ pentamethylated brGDGT ratio (7.13±0.98), support that brGDGTs in the Mariana Trench sediments are autochthonous rather than terrestrial products. The compiling of literature data shows that the enhanced fractional abundance of hexamethylated 6-methyl brGDGTs is a common phenomenon in continental margins when the marine influence was intensified. The cross plot of acyclic hexa- ∕ pentamethylated brGDGT ratio and fractional abundance of brGDGT IIIa′ provide a novel approach to distinguish terrestrial and marine-derived brGDGTs.

Black carbon is ubiquitous in the marine environment. However, whether it accumulates in the deepest ocean region, the hadal zone, is unknown. Here we measure the concentration and carbon isotopes (δ13C and Δ14C) of black carbon and total organic carbon in sediments from six hadal trenches. Black carbon constituted 10% of trench total organic carbon, and its δ13C and Δ14C were more negative than those of total organic carbon, suggesting that the black carbon was predominantly derived from terrestrial C3 plants and fossil fuels. The contribution of fossil carbon to the black carbon pool was spatially heterogeneous, which could be related to differences in the distance to landmass, land cover and socioeconomic development. Globally, we estimate a black carbon burial rate of 1.0 ± 0.5 Tg yr−1 in the hadal zone, which is seven-fold higher than the global ocean average per unit area. We propose that the hadal zone is an important, but overlooked, sink of black carbon in the ocean.

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