Fungal and Bacterial Diversity Patterns of Two Diversity Levels Retrieved From a Late Decaying Fagus sylvatica Under Two Temperature Regimes

Environmental fluctuations are a common occurrence in an ecosystem, which have an impact on organismic diversity and associated ecosystem services. The aim of this study was to investigate how a natural and a species richness-reduced wood decaying community diversity were capable of decomposing Fagus sylvatica dead wood under a constant and a fluctuating temperature regime. Therefore, microcosms with both diversity levels (natural and species richness-reduced) were prepared and incubated for 8 weeks under both temperature regimes. Relative wood mass loss, wood pH, carbon dioxide, and methane emissions, as well as fungal and bacterial community compositions in terms of Simpson‘s diversity, richness and evenness were investigated. Community interaction patterns and co-occurrence networks were calculated. Community composition was affected by temperature regime and natural diversity caused significantly higher mass loss than richness-reduced diversity. In contrast, richness-reduced diversity increased wood pH. The bacterial community composition was less affected by richness reduction and temperature regimes than the fungal community composition. Microbial interaction patterns showed more mutual exclusions in richness-reduced compared to natural diversity as the reduction mainly reduced abundant fungal species and disintegrated previous interaction patterns. Microbial communities reassembled in richness-reduced diversity with a focus on nitrate reducing and dinitrogen-fixing bacteria as connectors in the network, indicating their high relevance to reestablish ecosystem functions. Therefore, a stochastic richness reduction was followed by functional trait based reassembly to recover previous ecosystem productivity. © Copyright © 2021 Muszynski, Maurer, Henjes, Horn and Noll

Emission of CO2 and CH4 From 13 Deadwood Tree Species Is Linked to Tree Species Identity and Management Intensity in Forest and Grassland Habitats

Deadwood is an important component of the global carbon cycle, and its decomposition releases carbon dioxide (CO2) and methane (CH4) into the atmosphere. However, the main drivers of these greenhouse gas emissions from deadwood are not well understood. We investigated drivers that govern the CO2 and CH4 emission rates of 793 deadwood specimens from 13 different tree species, which were exposed on 27 forest and 38 grassland plots at Schorfheide-Chorin (Germany) for one year. Tree species identity was an important driver for emissions of both gases, whereas habitat type and management intensity were only important for CO2 emission rate. CO2 emission rates were positively linked to mass loss and were one-third higher in forest compared to grassland habitats. The wood traits organic extractives, lignin, and sulfur content were negatively associated with CO2 emission rates, whereas carbon, nitrogen, and magnesium content showed the opposite effect. Among climate variables, air humidity in forest and soil moisture in grassland habitats positively affected CO2 emission rates. CH4 emission rates showed a negative relationship with increasing wood density exposed in both habitat types but were positively related to tree species with higher sulfur contents. Taken together, CO2 emission rates from deadwood were well predicted by wood traits, management intensity and climatic variables, whereas CH4 emission rates were less well predictable and were influenced only by wood traits that differed from those of CO2 emissions. Our results provide a deeper insight into the mineralization processes of deadwood and should be considered in further carbon cycle assessments.ISSN:0886-6236ISSN:1944-922

Drivers of deadwood decay of 13 temperate tree species are similar between forest and grassland habitats

Deadwood provides an important carbon source in forests and wooded ecosystems and, accordingly, forest management strategies discuss the enrichment of deadwood amount and diversity by different tree species. To investigate the decomposition processes of enriched deadwood, we simultaneously placed 3,669 size-standardized and gamma sterilized wood specimens of 13 tree species (Populus tremula, Tilia cordata, Prunus avium, Betula pendula, Carpinus betulus, Fraxinus excelsior, Quercus robur, Fagus sylvatica, Acer platanoides, Larix decidua, Pinus sylvestris, Picea abies, and Pseudotsuga menziesii) at a total of 300 forest and grassland plots in three regions in Germany covering large gradients of management intensity and environmental conditions. After 1 year, mass loss was calculated and its relationship with wood traits and environmental conditions was assessed to determine the most important factors. Mass loss was overall higher in forest compared to grassland habitats, with wood traits as the most important driver, followed by region and environmental factors related to microclimate. However, management intensity was less relevant to explain the mass loss in both habitats. Our results suggest that decomposition of enriched deadwood, even after removal of endophytes, is influenced by the same drivers (positively by moisture and abundance of macronutrients, negatively by lignin and phenol concentration) as naturally occurring wood. Furthermore, due to the immense and standardized experimental setting, our study contributes to a better understanding of the important drivers of mass loss in different tree species and thus provides the basis for predictions of the carbon cycle in a changing world.ISSN:2624-893

The Significance and Challenges of Monocyte Impairment: For the Ill Patient and the Surgeon

Background: Trauma, major elective surgery, and overt sepsis can lead to a cascade of immunological change. A subset of these patients will have a degree of immune suppression that leads to hyporesponsive innate defenses, increasing the risk of infective co-morbidity and death. This article is an overview of monocyte impairment in the high-risk surgical patient. Specifically, our primary focus is on observations made pertaining to monocyte function and pathophysiological mechanisms underpinning this impairment. Clinical factors influencing monocyte function are also discussed. Methods: A Pubmed search was conducted to review aspects of monocyte impairment in the surgical patient. Search terms included “monocyte impairment,” “immunoparalysis,” and “endotoxin tolerance” cross-referenced against terms including “trauma,” “major surgery,” and “sepsis.” Results: Findings revealed a broad variety of monocyte defects reported in surgical patients. They ranged from altered cytokine responses, particularly ex vivo TNF-α production, to impaired antigen presentation such as depressed HLA-DR expression. The latter is the most commonly described marker of secondary infection and death. Studies of underlying mechanisms have commonly utilized a model of endotoxin tolerance with in vitro monocytes, revealing a complex array of dysregulated pathways. For our purposes, endotoxin tolerance and monocyte impairment are sufficiently similar entities to permit further study as a single subject. In the high risk patient, microRNAs (also referred to as miRNA or miR) are emerging as potential biomarkers that may modify such pathways. Creation of a reliable impaired human monocyte model could be important to all such considerations. Conclusion: Impairment of monocyte function continues to be predictive of nosocomial infection, multi-organ failure, and death in some surgical patients. However, the optimal marker that could identify a patient as high risk early enough, and whether it might guide potential therapy, still is yet to be proven

A Core Outcome Measurement Set for Pediatric Critical Care

Objectives: To identify a PICU Core Outcome Measurement Set (PICU COMS), a set of measures that can be used to evaluate the PICU Core Outcome Set (PICU COS) domains in PICU patients and their families. Design: A modified Delphi consensus process. Setting: Four webinars attended by PICU physicians and nurses, pediatric surgeons, rehabilitation physicians, and scientists with expertise in PICU clinical care or research (n = 35). Attendees were from eight countries and convened from the Pediatric Acute Lung Injury and Sepsis Investigators Pediatric Outcomes STudies after PICU Investigators and the Eunice Kennedy Shriver National Institute of Child Health and Human Development Collaborative Pediatric Critical Care Research Network PICU COS Investigators. Subjects: Measures to assess outcome domains of the PICU COS are as follows: cognitive, emotional, overall (including health-related quality of life), physical, and family health. Measures evaluating social health were also considered. Interventions: None. Measurements and Main Results: Measures were classified as general or additional based on generalizability across PICU populations, feasibility, and relevance to specific COS domains. Measures with high consensus, defined as 80% agreement for inclusion, were selected for the PICU COMS. Among 140 candidate measures, 24 were delineated as general (broadly applicable) and, of these, 10 achieved consensus for inclusion in the COMS (7 patient-oriented and 3 family-oriented). Six of the seven patient measures were applicable to the broadest range of patients, diagnoses, and developmental abilities. All were validated in pediatric populations and have normative pediatric data. Twenty additional measures focusing on specific populations or in-depth evaluation of a COS subdomain also met consensus for inclusion as COMS additional measures. Conclusions: The PICU COMS delineates measures to evaluate domains in the PICU COS and facilitates comparability across future research studies to characterize PICU survivorship and enable interventional studies to target long-term outcomes after critical illness.</p