Urban coral reefs: Degradation and resilience of hard coral assemblages in coastal cities of East and Southeast Asia

© 2018 The Author(s) Given predicted increases in urbanization in tropical and subtropical regions, understanding the processes shaping urban coral reefs may be essential for anticipating future conservation challenges. We used a case study approach to identify unifying patterns of urban coral reefs and clarify the effects of urbanization on hard coral assemblages. Data were compiled from 11 cities throughout East and Southeast Asia, with particular focus on Singapore, Jakarta, Hong Kong, and Naha (Okinawa). Our review highlights several key characteristics of urban coral reefs, including “reef compression” (a decline in bathymetric range with increasing turbidity and decreasing water clarity over time and relative to shore), dominance by domed coral growth forms and low reef complexity, variable city-specific inshore-offshore gradients, early declines in coral cover with recent fluctuating periods of acute impacts and rapid recovery, and colonization of urban infrastructure by hard corals. We present hypotheses for urban reef community dynamics and discuss potential of ecological engineering for corals in urban areas

Rotational motion of pentane in the flat γ-cages of zeolite KFI

The orientation distribution and confined rotational motion of n-pentane in the oblate ¿ cages of zeolite KFI is computed by use of MD simulation. Pentane is preferably oriented with its end-to-end vector in the x and y direction perpendicular to the C4 symmetry axis of the cage. For comparison with a previous NMR study (Zorine et al.; J. Phys. Chem. B 2004, 108, 5600), the orientational autocorrelation function (OACF) of the C1C2C3 bi-sector is obtained from the simulations between 125 and 450 K, and decomposed into three exponential components. The slowest component follows the Arrhenius law with an activation energy of 13 kJ mol-1 and corresponds well to the effective rotation correlation times obtained from NMR relaxation above 200 K. MD trajectory analysis suggests that this component reflects gauche-trans conformation changes within the cage. According to our present findings, rotation of trans-trans pentane about the cage symmetry axis, which was previously proposed as the source for NMR relaxation, is actually too fast. Based on the OACF analysis, the non-Arrhenius behavior observed in the mentioned NMR study is now explained by a simultaneous increase of the correlation time and relative amplitude of the slowest OACF component versus inverse temperature