Determinants of the increased CO<Subscript>2</Subscript> emission and adaption strategy in Chinese energy-intensive industry

Climate change has not only brought about many natural hazards but also threaten the sustainable development of industry. This study is to investigate the adaptive implications for energy-intensive industries of China in response to climate change impacts. For this purpose, a deep and comprehensive analysis on the change of CO₂ emission for 6 energy-intensive sectors is explored over the period of 2000–2007. A Log-Mean Divisia Index based on time series is also introduced in our study to identify the key factors toward the change of CO₂ emission. It is shown that there were 146.1 million metric tons carbon increased in energy-intensive industries from 2000 to 2007. And the excessive growth of industrial output and increasingly fossil-intensive energy consumption structure were the main driving forces for the increased CO₂ emission. Nevertheless, energy intensity change and declining emission coefficient of electricity played negative role in the growing trend of CO₂ emission. On the basis of these four determinants (namely industrial output, energy intensity, fuel mix effect, and emission coefficient), it is suggested that both economic motives and technologically feasible approaches should be implemented to control the scale of excessive productions and improve energy efficiency toward the energy-intensive industries. And more importantly, strengthening energy-intensive sectors’ awareness of climate change adaptation should be given stronger emphasis as long-term work with the help of some propaganda campaigns for instance.     

Does the Agulhas Current amplify global temperatures during super‐interglacials?

Future projections of climate suggest our planet is moving into a ‘super‐interglacial’. Here we report a global synthesis of ice, marine and terrestrial data from a recent palaeoclimate equivalent, the Last Interglacial (ca. 130–116 ka ago). Our analysis suggests global temperatures were on average ～1.5°C higher than today (relative to the AD 1961–1990 period). Intriguingly, we identify several Indian Ocean Last Interglacial sequences that suggest persistent early warming, consistent with leakage of warm, saline waters from the Agulhas Current into the Atlantic, intensifying meridional ocean circulation and increasing global temperatures. This mechanism may have played a significant positive feedback role during super‐interglacials and could become increasingly important in the future. These results provide an important insight into a future 2°C climate stabilisation scenario. Copyright © 2010 John Wiley & Sons, Ltd.     

Spatial Patterns and Predictors of Drift Algal Subsidy in Deep Subtidal Environments

The movement of resource subsidies across natural systems can have important effects on recipient communities and has emerged as a key research area in ecology. Detrital subsidies are critical in marine ecosystems where communities are reliant on external sources of primary production, yet few studies have quantified the spatial extent of drift algae at coastal scales. Using observations of the seafloor (up to 140 m depth) from tow-camera surveys along 145 km of Nova Scotia coast, and bathymetric data of this region, we created the first predictive map of drift subsidy in a marine ecosystem. We used a random forest model to generate our predictions, which correctly classified 95 % of observations into a presence or absence of drift. Distance from source, slope, and bathymetric position index (elevation relative to surrounding landscape) was the main predictor variables of the occurrence of drift. Drift algae occurred across a range of benthic habitats within our study area, but most frequently within 1.4 km of the coast on flat bottoms or in regions with zero or negative bathymetric position index. Such areas were coincident with seafloor depressions and flat low-energy habitats. Repeated observations at some locations indicated that areas with steep slopes or large curvature tended to have variable patterns of drift compared to areas with little or no slope or curvature. We predict that deep subtidal environments receiving drift subsidy will be impacted by the declines in kelp biomass projected for this region (and others) due to changes in ocean climate.     

Early Silurian ‘algal meadows’ of Anticosti Island,eastern Canada: an analogue to modern sea grass meadows?

In modern marine ecosystems, sea‐grass and chlorophyte meadows play an important ecological role by serving as a carbon sink. Despite their generally limited areal distribution, the high productivity of sea‐grass meadows makes them an efficient assimilator of CO₂. During the early Palaeozoic, complex life was virtually confined to the marine environment, with algae being one of the common carbon‐fixers, alongside abundant calcifying cyanobacteria, rhodophytes, chlorophytes and charophytes, as well as non‐skeletal dinoflagellates and acritarchs. Fossil and molecular data indicate that marine thallophytic algae first appeared in the Early Proterozoic and became widespread in the Palaeozoic, although their fossil record is sporadic because of their soft‐bodied nature; in the absence of angiosperm sea grass and mangroves and poorly understood phytoplankton biomass, thallophytic algae were probably major primary producers. In this article, we suggest that thallophytic algae may have played a significant role as a carbon sink in the Early Silurian, analogous to modern sea‐grass meadows or kelp forests, based on the well‐preserved Early Silurian thallophytic algal meadow from Anticosti Island, eastern Canada.     

Investigating the Functional Role of an Artificial Reef Within an Estuarine Seascape: a Case Study of Yellowfin Bream (<Emphasis Type="Italic">Acanthopagrus australis</Emphasis>)

Estuaries contain mosaic habitats which support fish across different life stages. Artificial reefs represent a form of habitat enhancement which can provide additional structure for fishes and improve fishing opportunities, but the role of artificial reefs within the broader estuarine seascape has not been extensively studied. We used a VEMCO Positioning System (VPS) to monitor the fine-scale movements of yellowfin bream (Acanthopagrus australis, referred to as Bream), an estuarine predator and important recreational species. Fish were implanted with acoustic tags with accelerometer sensors (to measure relative fish activity), and their movements monitored on an artificial reef and adjacent habitats. Elevated activity patterns during crepuscular periods indicated that foraging was likely occurring over a large seagrass bed adjacent to the artificial reef system. Alternatively, lower activity was observed when fish were on the artificial reef, which may reflect the role of this habitat as a refuge, or that alternative foraging strategies were being employed. All fish exhibited a high degree of fidelity to the artificial reef on which they were tagged, and there was minimal movement among other reef groups within the array. There was extensive overlap in space use contours for smaller fish on the seagrass edge, but no overlap for larger fish that also tended to forage further afield. These findings have implications for the way in which artificial reefs support fish production, especially the importance of connectivity with other key habitats within the estuarine seascape.     

Organic petrography and geochemistry of inertinite-rich mudstones, Jakobsstigen Formation, Upper Jurassic, northeast Greenland: Indications of forest fires and variations in relative sea-level

The lower-middle Oxfordian Jakobsstigen Formation, Wollaston Forland, northeast Greenland, consists mainly of stacked coarsening-upward successions of offshore to shoreface heteroliths, sandstone and rare foreshore sandstones. The units are separated by thin, laterally extensive sheets of terrigenous carbonaceous mudstones, which have been subjected to organic petrographic and geochemical studies. The mudstones are thermally immature, with maturities corresponding to R₀ in the range 0.35–0.50%. The mudstones contain very high proportions of allochthonous inertinite, subordinate huminite, char and negligible proportions of liptinite. Inertinite reflectance distributions are markedly bimodal, with maxima at approximately 1.73 and 4.91% R_m. Both pyrolysis yields and solvent extract yields are low. The distributions of n-alkanes are markedly light-end skewed and show a pronounced predominance of even-numbered compounds in the lower carbon number range. Biomarker-distributions feature a dominance of C₂₉-steranes, slight enhancement of extended hopanes and αββ-steranes, low proportion of tricyclic triterpanes and very low hopane/sterane ratios. Sedimentological, organic petrographical and geochemical evidence suggests that the regular alternation between marine and terrestrial depositional environments during deposition of the Jakobsstigen Formation was related to low-amplitude, high-frequency changes in relative sea-level and local climate. The mudstones were deposited during early rise of relative sea-level in shallow, flat-bottomed lakes or lagoons on a broad coastal plain. The lakes acted as traps for fine elastic sediment and for predominantly windborne inertinite, generated by wildfires in the hinterland. High rates of evaporation rendered the lakes mildly saline, hampering their colonization by vegetation other than cyanobacteria and halophilic microorganisms. Similarly, saline porewaters excluded higher plant vegetation from emergent areas. Upon continued rise of the relative sea-level, the lakes were gradually flooded and their deposits became covered by sandy shallow marine sediments. The larger areas covered by shallow marine waters during periods of high relative sea-level led to a more humid local climate and to lower frequency of wildfires. During falling relative sea-level, the marine deposits were eroded and partially removed and the cycle subsequently repeated upon renewed rise in relative sea-level. Hence, minor changes in relative sea-level gave rise to the regular alternation of two vastly different depositional environments, as well as to marked variations in local climate.     

全球海洋硅循环及研究中面临的主要挑战

海洋硅循环是海洋生物地球化学循环的关键过程之一,对调控全球二氧化碳浓度、海洋酸碱度和多种元素(氮、磷、铁、铝等)的循环具有重要作用。在当今气候变化和人类活动影响日益增强的背景下,硅循环与“生物泵”及碳循环的紧密联系,是其成为地球科学领域研究热点的主要原因。海洋中硅的外部来源主要为河流、地下水、大气沉降、海底玄武岩风化作用和海底热液输送5个途径,在全球气温变暖趋势的影响下,极地冰川融化成为高纬度海域不可忽视的硅源。生物硅在沉积物中的埋藏、硅质海绵和生物硅的反风化作用是重要的海洋硅移除过程。海洋硅循环过程复杂,受生物(生物吸收、降解)、物理(吸附、溶解)和化学(矿化分解和反风化作用)多重因素的影响,针对海洋硅循环关键过程的研究有助于综合评估海洋硅的“源-汇”和收支。本文总结了海洋硅循环的主要过程及海洋硅的收支,根据国际和国内研究现状讨论了当前海洋硅循环研究中面临的主要问题和挑战。现有研究成果显示,海洋硅的外源输入和输出通量比以往的评估分别增加了2.4和2.2倍。在短时间尺度内(<8 ka),全球海洋中硅的收支大致平衡,海洋硅循环基本处于稳定状态。气候变化和人类活动导致河流输送至陆架边缘海的硅通量发生变化,可能影响硅藻等海洋浮游植物种群结构,是未来海洋硅循环研究需要关注的问题之一。陆架边缘海较高沉积速率和强烈的反风化作用提高了该区域生物硅的埋藏效率,准确评估该区域生物硅的埋藏通量仍是亟须解决的难题。目前的研究评估了全球海洋浮游硅藻、硅质海绵以及放射虫生产力,而海洋底栖硅藻生产力的贡献受到忽视,未来需要关注底栖硅藻对生物硅的贡献及其在海洋硅的生物地球化学过程中的作用。     

Single-crystal Raman spectra of YAlO<Subscript>3</Subscript> and GdAlO<Subscript>3</Subscript>: comparison to several orthorhombic ABO<Subscript>3</Subscript> perovskites

Room-temperature-polarized single-crystal Raman spectra have been measured for both GdAlO₃ and YAlO₃. Both aluminates crystallize in the orthorhombic (Pbnm) perovskite structure. Of the 24 possible Raman modes in 4 symmetries, 20 and 17 modes were observed for gadolinium and yttrium aluminates, respectively. Comparisons of the Raman spectra of these two aluminates to those of 28 other orthorhombic ABO₃ perovskites revealed remarkably similar spectral patterns, regardless of chemistry or valency of the cations. Closer examination of the effect of mass, valencies, and size of the cations on the Raman spectra versus composition revealed that for the observed modes, the A cation plays the dominant role in determining the Raman shift. In particular, the one to two lowest energy modes in each symmetry are determined by cation mass and valency no matter what the chemistry. For some perovskites with common A cations, higher energy modes were also strikingly similar. In particular, the calcium perovskites had almost all A_g modes at the same energies despite the greatly varying B cations. The second to the lowest mode in A_g and B_1g depended only on A cation mass for all perovskites. The volume plays a minor role throughout but is hard to separate from mass effects because the most massive cations are also the largest. However, if the B-cation is common, for example, aluminates or ferrites, the volume has a minor effect on the higher energy modes. These trends were not observed for all perovskites. Notable exceptions were found if a perovskite is near a phase transition or metastable, as found for three manganites. The effect of increased valency of the A cation from 2–4 to 3–3 perovskites expresses itself as relatively larger Raman shifts for the lowest energy modes. Analog studies of MgSiO₃ perovskites should be undertaken with only 2–4 perovskites. The increased understanding for the mode distributions of perovskites allows for better estimates of their thermodynamic properties through vibrational modeling.     

GEOTRACES - An international study of the global marine biogeochemical cycles of trace elements and their isotopes

Trace elements serve important roles as regulators of ocean processes including marine ecosystem dynamics and carbon cycling. The role of iron, for instance, is well known as a limiting micronutrient in the surface ocean. Several other trace elements also play crucial roles in ecosystem function and their supply therefore controls the structure, and possibly the productivity, of marine ecosystems. Understanding the biogeochemical cycling of these micronutrients requires knowledge of their diverse sources and sinks, as well as their transport and chemical form in the ocean.Much of what is known about past ocean conditions, and therefore about the processes driving global climate change, is derived from trace-element and isotope patterns recorded in marine deposits. Reading the geochemical information archived in marine sediments informs us about past changes in fundamental ocean conditions such as temperature, salinity, pH, carbon chemistry, ocean circulation and biological productivity. These records provide our principal source of information about the ocean's role in past climate change. Understanding this role offers unique insights into the future consequences of global change.The cycle of many trace elements and isotopes has been significantly impacted by human activity. Some of these are harmful to the natural and human environment due to their toxicity and/or radioactivity. Understanding the processes that control the transport and fate of these contaminants is an important aspect of protecting the ocean environment. Such understanding requires accurate knowledge of the natural biogeochemical cycling of these elements so that changes due to human activity can be put in context.Despite the recognised importance of understanding the geochemical cycles of trace elements and isotopes, limited knowledge of their sources and sinks in the ocean and the rates and mechanisms governing their internal cycling, constrains their application to illuminating the problems outlined above. Marine geochemists are poised to make significant progress in trace-element biogeochemistry. Advances in clean sampling protocols and analytical techniques provide unprecedented capability for high-density sampling and measurement of a wide range of trace elements and isotopes which can be combined with new modelling strategies that have evolved from the World Ocean Circulation Experiment (WOCE) and Joint Global Ocean Flux Study (JGOFS) programmes. A major new international research programme, GEOTRACES, has now been developed as a result of community input to study the global marine biogeochemical cycles of trace elements and their isotopes. Here, we describe this programme and its rationale.     

Atomistic model of diopside-K-jadeite (CaMgSi<Subscript>2</Subscript>O<Subscript>6</Subscript>-KAlSi<Subscript>2</Subscript>O<Subscript>6</Subscript>) solid solution

Atomistic model was proposed to describe the thermodynamics of mixing in the diopside-K-jadeite solid solution (CaMgSi₂O6-KAlSi₂O₆). The simulations were based on minimization of the lattice energies of 800 structures within a 2 × 2 × 4 supercell of C2/c diopside with the compositions between CaMgSi₂O₆ and KAlSi₂O₆ and with variable degrees of order/disorder in the arrangement of Ca/K cations in M2 site and Mg/Al in Ml site. The energy minimization was performed with the help of a force-field model. The results of the calculations were used to define a generalized Ising model, which included 37 pair interaction parameters. Isotherms of the enthalpy of mixing within the range of 273–2023 K were calculated with a Monte Carlo algorithm, while the Gibbs free energies of mixing were obtained by thermodynamic integration of the enthalpies of mixing. The calculated T-X diagram for the system CaMgSi₂O₆-KAlSi₂O₆ at temperatures below 1000 K shows several miscibility gaps, which are separated by intervals of stability of intermediate ordered compounds. At temperatures above 1000 K a homogeneous solid solution is formed. The standard thermodynamic properties of K-jadeite (KAlSi₂O₆) evaluated from quantum mechanical calculations were used to determine location of several mineral reactions with the participation of the diopside-K-jadeite solid solution. The results of the simulations suggest that the low content of KalSi₂O₆ in natural clinopyroxenes is not related to crystal chemical factors preventing isomorphism, but is determined by relatively high standard enthalpy of this end member.     

Separation of H<Subscript>2</Subscript>S from CH<Subscript>4</Subscript> by polymeric membranes at different H<Subscript>2</Subscript>S concentrations

In this work, permeation of mixed gases H₂S/CH₄ through commercial polyphenylene oxide (PPO) hollow fiber and poly (ester urethane) urea (PEUU) flat membranes was studied at pressures of 345–689 kPa, at ambient temperature and at 313.15 K. Various H₂S concentrations of about 100–5000 ppm in CH₄ binary synthetic gas mixtures as well as a real natural gas sample obtained from a gas refinery containing 0.3360 mol.% H₂S (equivalent to 3360 ppm) were tested. It was observed that the permeance of components was affected by the balance between competitive sorption and plasticization effects. Separation factors of H₂S/CH₄ were in the range of 1.3–2.9, 1.8–3.1 and 2.2–4.3 at pressures of 345, 517 and 689 kPa, respectively. In the range of 101–5008 ppm of H₂S in CH₄, the effect of temperature on the separation factor was nearly negligible; however, permeances of both components of the mixtures increased with temperature. Additionally, the results obtained by PEUU membrane indicated that it was a better choice for hydrogen sulfide separation from H₂S/CH₄ mixtures than PPO. For PPO membrane, removal of hydrogen sulfide from high-concentration (up to 5008 ppm) binary mixtures of H₂S/CH₄ was compared with that of low concentration (as low as 101 ppm) through PPO. At concentrations of 101–968 ppm, plasticization was dominant compared with the competitive sorption, while for the H₂S feed concentrations of 3048 ppm, the competitive sorption effect was dominant. For H₂S concentration of 5008 ppm, the balance between these two effects played an important role for explanation of its trend.     

On CO<Subscript>2</Subscript> fluid flow and heat transfer behavior in the subsurface,following leakage from a geologic storage reservoir

Geologic storage of CO₂ is expected to produce plumes of large areal extent, and some leakage may occur along fractures, fault zones, or improperly plugged pre-existing wellbores. A review of physical and chemical processes accompanying leakage suggests a potential for self-enhancement. The numerical simulations presented here confirm this expectation, but reveal self-limiting features as well. It seems unlikely that CO₂ leakage could trigger a high-energy run-away discharge, a so-called “pneumatic eruption,” but present understanding is insufficient to rule out this possibility. The most promising avenue for increasing understanding of CO₂ leakage behavior is the study of natural analogues.     

Magnetic properties and neutron diffraction study of two manganese sulfosalts: monoclinic MnSb<Subscript>2</Subscript>S<Subscript>4</Subscript> and benavidesite (MnPb<Subscript>4</Subscript>Sb<Subscript>6</Subscript>S<Subscript>14</Subscript>)

Mn²⁺Sb₂S₄, a monoclinic dimorph of clerite, and benavidesite (Mn²⁺Pb₄Sb₆S₁₄) show well-individualized single chains of manganese atoms in octahedral coordination. Their magnetic structures are presented and compared with those of iron derivatives, berthierite (Fe²⁺Sb₂S₄) and jamesonite (Fe²⁺Pb₄Sb₆S₁₄). Within chains, interactions are antiferromagnetic. Like berthierite, MnSb₂S₄ shows a spiral magnetic structure with an incommensurate 1D propagation vector [0, 0.369, 0], unchanged with temperature. In berthierite, the interactions between identical chains are antiferromagnetic, whereas in MnSb₂S₄ interactions between chains are ferromagnetic along c-axis. Below 6 K, jamesonite and benavidesite have commensurate magnetic structures with the same propagation vector [0.5, 0, 0]: jamesonite is a canted ferromagnet and iron magnetic moments are mainly oriented along the a-axis, whereas for benavidesite, no angle of canting is detected, and manganese magnetic moments are oriented along b-axis. Below 30 K, for both compounds, one-dimensional magnetic ordering or correlations are visible in the neutron diagrams and persist down to 1.4 K.     

First-principles-based calculations of the CaCO<Subscript>3</Subscript>–MgCO<Subscript>3</Subscript> and CdCO<Subscript>3</Subscript>–MgCO<Subscript>3</Subscript> subsolidus phase diagrams

 Planewave pseudopotential calculations of supercell total energies were used as bases for first-principles calculations of the CaCO₃–MgCO₃ and CdCO₃–MgCO₃ phase diagrams. Calculated phase diagrams are in qualitative to semiquantitative agreement with experiment. Two unobserved phases, Cd₃Mg (CO₃)₄ and CdMg₃(CO₃)₄, are predicted. No new phases are predicted in the CaCO₃–MgCO₃ system, but a low-lying metastable Ca₃Mg(CO₃)₄ state, analogous to the Cd₃Mg(CO₃)₄ phase is predicted. All of the predicted lowest-lying metastable states, except for huntite CaMg₃(CO₃)₄, have dolomite-related structures, i.e. they are layer structures in which A _m B _n cation layers lie perpendicular to the rhombohedral [111] vector. Received: 6 May 2002 / Accepted: 23 October 2002 Acknowledgements This work was partially supported by NSF contract DMR-0080766 and NIST.     

Adsorption of H<Subscript>2</Subscript>O,NH<Subscript>3</Subscript> and C<Subscript>6</Subscript>H<Subscript>6</Subscript> on alkali metal cations in internal surface of mordenite and in external surface of smectite: a DFT study

Adsorption of H₂O, NH₃ and C₆H₆ on H- and alkali metal-exchanged structures of mordenite and on corresponding cations on the smectite layer is investigated by ab initio density-functional calculations. Proton or an alkali metal cation compensates one Al/Si framework substitution and resides in the extra-framework position of zeolite or above flat smectite layer close to the Al/Si substitution. Pronounced similarities between zeolite and smectite are observed in changes of the adsorption energies and location of the external cation with changing character of the external cation. Calculated adsorption energies exhibit the following trend: E(NH₃) > E(H₂O) > E(C₆H₆). Because of looser contact with the framework, zeolitic cations are stronger adsorption centers and calculated adsorption energies of zeolites are by ~20–30% larger than cations of smectites. The highest adsorption energy is calculated for H-exchanged structures and down the group of alkali metal cations a decrease of the adsorption energy is observed. Deviations from the smooth variation of the adsorption energy are caused by: (1) formation of strong hydrogen bonds in H-exchanged structures, (2) adsorption induced migration of the external Li⁺ cation, and (3) steric hindrances of the flat C₆H₆ molecule adsorbed on the cation in the cage of zeolite.     

XMCD at Fe L<Subscript>2,3</Subscript> edges,Fe and S K edges on Fe<Subscript>7</Subscript>S<Subscript>8</Subscript>

Pyrrhotite (Fe₇S₈) is a natural iron sulphide that can participate in rock magnetisation. Its electronic structure is not yet surely described. X-ray magnetic circular dichroism (XMCD) at Fe L_2,3 edges on Fe₇S₈, coupled with multiplet calculations, shows that iron is present only as Fe²⁺ in this magnetic iron sulphide. It reveals a strong magnetic orbital moment. XMCD at Fe and S K edges shows the quite strong polarization of both Fe and S in Fe₇S₈.     

Local Habitat Influences on Feeding and Respiration of the Intertidal Mussels <Emphasis Type="Italic">Perumytilus purpuratus</Emphasis> Exposed to Increased <Emphasis Type="Italic">p</Emphasis>CO<Subscript>2</Subscript> Levels

Coastal ecosystems are exposed to changes in physical-chemical properties, such as those occurring in upwelling and freshwater-influenced areas. In these areas, inorganic carbon can influence seawater properties that may affect organisms and populations inhabiting benthic habitats such as the intertidal mussel Perumytilus purpuratus. Feeding and metabolic responses were measured in adult mussels from two geographic regions (central and southern Chile) and two local habitats (river-influenced and non-river-influenced) and three pCO₂ levels (380, 750, and 1200 μatm pCO₂ in seawater). The feeding rates of mussels tend to increase at high pCO₂ levels in seawater; however this response was variable across regions and local habitats. In contrast, there was no difference in the respiratory rate of mussels between geographic areas, but there was a significant reduction of oxygen consumption at intermediate and high levels of pCO_2. The results indicate that river-influenced organisms compensate for reductions in metabolic cost at elevated pCO₂ levels by having their energy demands met, in contrast with non-river-influenced organisms. The lack of regional-scale variability in the physiological performance of mussels may indicate physiological homogeneity across populations and thus potential for local adaptation. However, the local-scale influences of river- and non-river-influenced habitats may counterbalance this regional response promoting intra-population variability and phenotypic plasticity in P. purpuratus. The plasticity may be an important mechanism that allows mussels to confront the challenges of projected ocean acidification scenarios.     

Pharmaceutical residues in aquatic environment and water remediation by TiO<Subscript>2</Subscript> heterogeneous photocatalysis: a review

The occurrence of pharmaceutical compounds in the natural water sources has been reported as early as in the year 1980. Until now, the presence of pharmaceutical compounds in the aquatic environment has been frequently reported in the literature. Moreover, increasing evidence suggests that these contaminants have posed a threat to both humans and ecosystems. In this regard, the present review paper seeks to offer an overview of this environmental issue of pharmaceutical pollution where the subject matters to be reviewed include the effects, sources and mitigation strategies of pharmaceuticals in the aquatic environment. Besides, a review of the fundamentals and mechanisms of heterogeneous photocatalysis technology is also presented in this paper. Heterogeneous photocatalysis is a rapidly expanding technology which has been extensively investigated and applied in wastewater treatment for the remediation of persistent pollutants such as pharmaceutical compounds during the last decade. Furthermore, the ideal photocatalyst titanium dioxide (TiO₂), which can collaborate and perform well in the photocatalysis treatment process, is also discussed. The advantages and limitations associated with the application of this treatment method are summarized and discussed in details. Finally, this review paper focuses on the future trend of the photocatalysis technology and identifies the barriers and lacking parts which need to be resolved in the near future.     

Diel Aquatic CO<Subscript>2</Subscript> System Dynamics of a Bermudian Mangrove Environment

Mangrove ecosystems play an important, but understudied, role in the cycling of carbon in tropical and subtropical coastal ocean environments. In the present study, we examined the diel dynamics of seawater carbon dioxide (CO₂) and dissolved oxygen (DO) for a mangrove-dominated marine ecosystem (Mangrove Bay) and an adjacent intracoastal waterway (Ferry Reach) on the island of Bermuda. Spatial and temporal trends in seawater carbonate chemistry and associated variables were assessed from direct measurements of dissolved inorganic carbon, total alkalinity, dissolved oxygen (DO), temperature, and salinity. Diel pCO₂ variability was interpolated across hourly wind speed measurements to determine variability in daily CO₂ fluxes for the month of October 2007 in Bermuda. From these observations, we estimated rates of net sea to air CO₂ exchange for these two coastal ecosystems at 59.8 ± 17.3 in Mangrove Bay and 5.5 ± 1.3 mmol m⁻² d⁻¹ in Ferry Reach. These results highlight the potential for large differences in carbonate system functioning and sea-air CO₂ flux in adjacent coastal environments. In addition, observation of large diel variability in CO₂ system parameters (e.g., mean pCO₂: 390–2,841 μatm; mean pH_T: 8.05–7.34) underscores the need for careful consideration of diel cycles in long-term sampling regimes and flux estimates.     

Settlement-Size Larval Red Drum (<Emphasis Type="Italic">Sciaenops ocellatus</Emphasis>) Respond to Estuarine Chemical Cues

Planktonic larvae combine directed swimming and functional sensory systems to locate benthic habitats. Some adult marine fishes use chemical cues for orientation to specific habitats, but olfactory function for estuarine fish larvae has received little research attention. This laboratory study quantified behavioral responses of red drum (Sciaenops ocellatus) larvae to estuarine chemical cues to examine the role of water chemistry as an orientation cue for locating or remaining in settlement habitat. Spontaneous activity (kinesis) was measured for pre-settlement-size larvae exposed to artificial sea water (as a negative control) and one of six treatments (sterilized sea water, sea water from a channel at ebb tide, sea water from a channel at flood tide, sea water from seagrass habitat, tannic acid dissolved in sterilized sea water, or lignin dissolved in sterilized sea water). Larvae that reached a size of competency to settle (approximately 10 mm standard length) swam faster when exposed to lignin dissolved in sterilized sea water than in other treatments; smaller larvae showed no response. Olfactory preference (taxis) was tested using a paired-choice experiment. Settlement-size larvae preferred water from seagrass beds to artificial sea water. The observed chemokinesis and chemotaxis in response to lignin dissolved in sterilized sea water and sea water from a seagrass bed demonstrate that red drum larvae can distinguish and respond to different water masses and suggest that chemical stimuli from seagrass settlement habitat may aid in orientation and movement to or retention in suitable settlement sites.