Influence of temporally varying weatherability on CO₂-climate coupling and ecosystem change in the late Paleozoic

Earth's penultimate icehouse period, the late Paleozoic ice age (LPIA), was a time of dynamic glaciation and repeated ecosystem perturbation, which was under conditions of substantial variability in atmospheric pCO2 and O2. Improved constraints on the evolution of atmospheric pCO2 and O2∕CO2 ratios during the LPIA and its subsequent demise to permanent greenhouse conditions are crucial for better understanding the nature of linkages between atmospheric composition, climate, and ecosystem perturbation during this time. We present a new and age-recalibrated pCO2 reconstruction for a 40 Myr interval (∼313 to 273 Ma) of the late Paleozoic that (1) confirms a previously hypothesized strong CO2–glaciation linkage, (2) documents synchroneity between major pCO2 and O2∕CO2 changes and compositional turnovers in terrestrial and marine ecosystems, (3) lends support for a modeled progressive decrease in the CO2 threshold for initiation of continental ice sheets during the LPIA, and (4) indicates a likely role of CO2 and O2∕CO2 thresholds in floral ecologic turnovers. Modeling of the relative role of CO2 sinks and sources active during the LPIA and its demise on steady-state pCO2 using an intermediate-complexity climate–carbon cycle model (GEOCLIM) and comparison to the new multi-proxy CO2 record provides new insight into the relative influences of the uplift of the Central Pangean Mountains, intensifying aridification, and increasing mafic rock to granite rock ratio of outcropping rocks on the global efficiency of CO2 consumption and secular change in steady-state pCO2 through the late Paleozoic.

Resilience of plankton trophic structure to an eddy-stimulated diatom bloom in the North Pacific Subtropical Gyre

We investigated the response of an open-ocean plankton food web to a major ecosystem perturbation event, the Hawaiian lee cyclonic eddy Opal, using compound-specific isotopic analyses of amino acids (CSIA-AA) of individual zooplankton taxa. We hypothesized that the massive diatom bloom that characterized Opal would lead to a shorter food chain. Using CSIA-AA, we differentiated trophic position (TP) changes that arose from altered transfers through protistan microzooplankton, versus metazoan carnivory, and assessed the variability at the base of the food web. Contrary to expectation, zooplankton TPs were higher in the eddy than in ambient control waters (up to 0.8 trophic level), particularly for suspension feeders close to the food-web base. Most of the effect was due to increased trophic transfers through protistan consumers, indicating a general shift up, not down, of grazing and remineralization in the microbial food web. Eucalanus sp., which was 15-fold more abundant inside compared to outside of the eddy, was the only taxon observed to be a true herbivore (TP = 2.0), consistent with a high phenylalanine (Phe) δ15N value indicating feeding on nitrate-fueled diatoms in the lower euphotic zone. Oncaea sp., an aggregate-associated copepod, had the largest (1.5) TP difference, and lowest Phe δ15N, suggesting that detrital particles were local hot spots of enhanced microbial activity. Rapid growth rates and trophic flexibility of protistan microzooplankton apparently allow the microbial community to reorganize to bloom perturbations, as microzooplankton remain the primary phytoplankton grazers—despite the dominance of large diatoms—and are heavily preyed on by the mesozooplankton.

Influence of temporally varying weatherability on CO₂–climate coupling and ecosystem change in the late Paleozoic

Earth's penultimate icehouse, the Late Paleozoic Ice Age (LPIA), was a time of dynamic glaciation and repeated ecosystem perturbation, under conditions of substantial variability in atmospheric pCO2 and O2. Improved constraints on the evolution of atmospheric pCO2 and O2 : CO2 during the LPIA and its subsequent demise to permanent greenhouse conditions is crucial for better understanding the nature of linkages between atmospheric composition, climate, and ecosystem perturbation during this time. We present a new and age-recalibrated pCO2 reconstruction for a 40-Myr interval (~313 to 273 Ma) of the late Paleozoic that (1) confirms a previously hypothesized strong CO2-glaciation linkage, (2) documents synchroneity between major pCO2 and O2 : CO2 changes and compositional turnovers in terrestrial and marine ecosystems, (3) lends support for a modeled progressive decrease in the CO2 threshold for initiation of continental ice sheets during the LPIA, and (4) indicates a likely role of CO2 and O2 : CO2 thresholds in floral ecologic turnovers. Modeling of the relative role of CO2 sinks and sources, active during the LPIA and its demise, on steady-state pCO2 using an intermediate complexity climate-C cycle model (GEOCLIM) and comparison to the new multi-proxy CO2 record provides new insight into the relative influences of the uplift of the Central Pangaean Mountains, intensifying aridification, and increasing mafic rock to-granite rock ratio of outcropping rocks on the global efficiency of CO2 consumption and secular change in steady-state pCO2 through the late Paleozoic.

Survival of Pseudomonas putida for Biodiesel Blend (B20) in Soil Bioremediation

The commercialization of biodiesel and their diesel blends in many countries can cause environmental pollution due to their spillage. This study aims to investigate the survival of Pseudomonas putida in soil contaminated with biodiesel/diesel blends (B20). The spillage simulation of B20 was conducted at laboratory scale for 24 days of incubation time. The experimental results show that contamination of biodiesel/diesel blends into the soil induced a reduction in growth of Pseudomonas putida. The growth of Pseudomonas putida was measured high in control compared to B20 sample. Soil microorganisms as well as Pseudomonas putida are very sensitive to any ecosystem perturbation therefore this study could notably serves as necessary information in soil bioremediation.

Survival of Pseudomonas putida for Biodiesel Blend (B5) in Soil Bioremediation

The soil-contaminated areas can be cleaned-up by the emerging science and technology of bioremediation. This study aims to investigate the survival of Pseudomonas putida (P. putida) as biodegradable agent in soil contaminated with biodiesel/diesel blends (B5). The spillage simulation of B5 was conducted at laboratory scale for 24 days of treatment. The results show that contamination of biodiesel/diesel blends in soil induced a reduction growth of P. putida. The growth of P. putida was measured high in control compared to B5 sample proved the inhibitory effect has occurred. Nevertheless, the P. putida colonies counts for sample B5 were persisted high until the end of treatment period at 5.0 x106 CFU/ml. P. putida is very sensitive to any ecosystem perturbation therefore this study notably serves as necessary information and potentially exploits as a useful oil-soil biodegradable agent in soil bioremediation.

Ecological Stability during the Late Paleozoic Cold Interval

Ecosystem Stability and taxonomic stasis are the opposite aspect in the history of life from ecosystem perturbation and reorganization, or extinction and origination. Naturally, change is more exciting than stasis, and change also is more useful in many ways as, for instance, in the development of biostratigraphic frameworks. Paleontological preference for geologically rapid change has gone so far that a fast evolving group of organisms has been used to create an orthostratigraphy (Orthochronologie of Schindewolf, 1950), which is claimed to be the “real” biostratigraphy. By implication, all other taxonomic groups are relegated to a secondary status of merely delivering “parastratigraphies,” which may be useful (locally or regionally), but are not the “real thing.” Ammonites, conodonts, foraminifera, and a few other taxa hold the distinction of being the “chosen” taxa, and it should be self-evident that only marine organisms qualify for this role. On the other hand, organisms on land always have been known to demonstrate coarser stratigraphic resolution. By implication, they might be more prone to ecosystem and taxonomic stasis over the long run. This, in itself, is an important observation.