ALBERT

Description: The effects of hydrostatic pressure and dissolved oxygen concentration on oxygen consumption rates were examined in the mesopelagic, vertically migrating squid Histioteuthis heteropsis from southern California offshore waters. Elevated hydrostatic pressure (to 136 atm) had no significant effects on oxygen consumption rates at 5°C. Lox oxygen concentrations (〈0.5 ml O2 liter -1) depressed rates of oxygen consumption. These findings suggest that biosis may be necessary to supply the total nergy needs of this species at daytime depths in the oxygen minumum layer off southern California.

Description: Climate change will increase both average temperatures and extreme summer temperatures. Analyses of the fitness consequences of climate change have generally omitted negative fitness and population declines associated with heat stress. Here, we examine how seasonal and interannual temperature variability will impact fitness shifts of ectotherms from the past (1961–1990) to future (2071–2100), by modelling thermal performance curves (TPCs) for insect species across latitudes. In temperate regions, climate change increased the length of the growing season (increasing fitness) and increased the frequency of heat stress (decreasing fitness). Consequently, species at mid-latitudes (20–40°) showed pronounced but heterogeneous responses to climate change. Fitness decreases for these species were accompanied by greater interannual variation in fitness. An alternative TPC model and a larger data set gave qualitatively similar results. How close maximum summer temperatures are to the critical thermal maximum of a species – the thermal buffer – is a good predictor of the change in mean fitness expected under climate change. Thermal buffers will decrease to near or below zero by 2100 for many tropical and mid-latitude species. Our forecasts suggest that mid-latitude species will be particularly susceptible to heat stress associated with climate change due to temperature variation

Description: Fluvial processes dominate sediment flux from most cold environments and as such are particularly sensitive to environmental change. However, these systems demonstrate high variability in flow and sediment transfer rates in both the short and long-term which presents specific problems for establishing integrated sediment flux studies. The objective of this paper is to briefly review the nature of fluvial and floodplain sediment sources in cold environments and to make recommendations on the measurement of fluvial sediment fluxes from these sources to sinks. The paper outlines a framework for examining fluvial sediment fluxes in cold environments including: sources of sediment in glacial and periglacial environments; techniques for measuring fluvial sediment transfers; and methods for measuring contemporary deposition in lacustrine sediment sinks. Within this framework, we stress that it is particularly important to provide consistency in methods for monitoring sediment flux and to adopt appropriate sampling frequencies. We recommend that the most appropriate methods for establishing integrated sediment flux studies in these cold environments are: repeat surveys and terrestrial laser scanning of valley and slope sediment stores on a monthly – daily frequency; weekly-daily sediment budgeting of bedload transfer using rapid resurvey methods; hourly or better time series of suspended and solute transport using data logger acquisition systems; and monitoring of lacustrine sedimentation using sediment accumulation sensors and/or weekly-daily estimates from passive sediment traps. Application of the proposed integrated framework will improve our understanding of sediment flux in cold environments and allow us to better assess the sensitivity of cold environments to environmental change within the context of contemporary and past sediment flux.

Description: Abstract Aims Bacterially induced calcium carbonate precipitation from various isolates was investigated aiming at developing an environmentally friendly technique for ornamental stone protection and restoration. Methods and Results Microorganisms isolated from stone samples and identified using 16S rDNA and biochemical tests promoted calcium carbonate precipitation in solid and novel liquid growth media. Biomineral morphology was studied on marble samples with scanning electron microscopy. Most isolates demonstrated specimen weight increase, covering partially or even completely the marble surfaces mainly with vaterite. The conditions under which vaterite precipitated and its stability throughout the experimental runs are presented. Conclusions A growth medium that facilitated bacterial growth of different species and promoted biomineralization was formulated. Most isolates induced biomineralization of CaCO3. Microorganisms may actually be a milestone in the investigation of vaterite formation facilitating our understanding of geomicrobiological interactions. Pseudomonas, Pantoea and Cupriavidus strains could be candidates for bio‐consolidation of ornamental stone protection. Significance and Impact of the Study Characterization of biomineralization capacity of different bacterial species improves understanding of the bacterially induced mineralization processes and enriches the list of candidates for bio‐restoration applications. Knowledge of biomineral morphology assists in differentiating mineral from biologically induced precipitates.