Housekeeping in the Hydrosphere: Microbial Cooking, Cleaning, and Control under Stress

Who’s cooking, who’s cleaning, and who’s got the remote control within the waters blanketing Earth? Anatomically tiny, numerically dominant microbes are the crucial “homemakers” of the watery household. Phytoplankton’s culinary abilities enable them to create food by absorbing sunlight to fix carbon and release oxygen, making microbial autotrophs top-chefs in the aquatic kitchen. However, they are not the only bioengineers that balance this complex household. Ubiquitous heterotrophic microbes including prokaryotic bacteria and archaea (both “bacteria” henceforth), eukaryotic protists, and viruses, recycle organic matter and make inorganic nutrients available to primary producers. Grazing protists compete with viruses for bacterial biomass, whereas mixotrophic protists produce new organic matter as well as consume microbial biomass. When viruses press remote-control buttons, by modifying host genomes or lysing them, the outcome can reverberate throughout the microbial community and beyond. Despite recognition of the vital role of microbes in biosphere housekeeping, impacts of anthropogenic stressors and climate change on their biodiversity, evolution, and ecological function remain poorly understood. How trillions of the smallest organisms in Earth’s largest ecosystem respond will be hugely consequential. By making the study of ecology personal, the “housekeeping” perspective can provide better insights into changing ecosystem structure and function at all scales.

Download Full-text

Investigations on the role of dissolved organic matter in determining ecosystem structure and function: the plankton and photoheterotrophy

10.2172/5044724 ◽

1975 ◽

Author(s):

K McKinley

Keyword(s):

Organic Matter ◽

Dissolved Organic Matter ◽

Structure And Function ◽

Ecosystem Structure ◽

And Function ◽

Ecosystem Structure And Function

Download Full-text

The effects of modern war and military activities on biodiversity and the environment

Environmental Reviews ◽

10.1139/er-2015-0039 ◽

2015 ◽

Vol 23 (4) ◽

pp. 443-460 ◽

Cited By ~ 46

Author(s):

Michael J. Lawrence ◽

Holly L.J. Stemberger ◽

Aaron J. Zolderdo ◽

Daniel P. Struthers ◽

Steven J. Cooke

Keyword(s):

Military Training ◽

Structure And Function ◽

Aquatic Systems ◽

Ecosystem Structure ◽

Population Declines ◽

Exclusion Zone ◽

Negative Effects ◽

And Function ◽

Ecosystem Structure And Function ◽

Modern War

War is an ever-present force that has the potential to alter the biosphere. Here we review the potential consequences of modern war and military activities on ecosystem structure and function. We focus on the effects of direct conflict, nuclear weapons, military training, and military produced contaminants. Overall, the aforementioned activities were found to have overwhelmingly negative effects on ecosystem structure and function. Dramatic habitat alteration, environmental pollution, and disturbance contributed to population declines and biodiversity losses arising from both acute and chronic effects in both terrestrial and aquatic systems. In some instances, even in the face of massive alterations to ecosystem structure, recovery was possible. Interestingly, military activity was beneficial under specific conditions, such as when an exclusion zone was generated that generally resulted in population increases and (or) population recovery; an observation noted in both terrestrial and aquatic systems. Additionally, military technological advances (e.g., GPS technology, drone technology, biotelemetry) have provided conservation scientists with novel tools for research. Because of the challenges associated with conducting research in areas with military activities (e.g., restricted access, hazardous conditions), information pertaining to military impacts on the environment are relatively scarce and are often studied years after military activities have ceased and with no knowledge of baseline conditions. Additional research would help to elucidate the environmental consequences (positive and negative) and thus reveal opportunities for mitigating negative effects while informing the development of optimal strategies for rehabilitation and recovery.

Download Full-text

Environmental ecology: The impacts of pollution and other stresses on ecosystem structure and function

Ecological Economics ◽

10.1016/0921-8009(91)90028-d ◽

1991 ◽

Vol 4 (2) ◽

pp. 168-169

Author(s):

Nils Kautsky

Keyword(s):

Structure And Function ◽

Ecosystem Structure ◽

And Function ◽

Ecosystem Structure And Function

Download Full-text

Netrin-1 in Atherosclerosis: Relationship between Human Macrophage Intracellular Levels and In Vivo Plaque Morphology

Biomedicines ◽

10.3390/biomedicines9020168 ◽

2021 ◽

Vol 9 (2) ◽

pp. 168

Author(s):

Susanna Fiorelli ◽

Nicola Cosentino ◽

Benedetta Porro ◽

Franco Fabbiocchi ◽

Giampaolo Niccoli ◽

...

Keyword(s):

Progressive Increase ◽

Human Macrophage ◽

Plaque Morphology ◽

Artery Disease ◽

Atherosclerotic Process ◽

And Function ◽

And Control ◽

Macrophage Accumulation

Netrin-1 is a laminin-like protein that plays a pivotal role in cell migration and, according to the site of its release, exerts both pro and anti-atherosclerotic functions. Macrophages, key cells in atherosclerosis, are heterogeneous in morphology and function and different subpopulations may support plaque progression, stabilization, and/or regression. Netrin-1 was evaluated in plasma and, together with its receptor UNC5b, in both spindle and round monocyte-derived macrophages (MDMs) morphotypes from coronary artery disease (CAD) patients and control subjects. In CAD patients, plaque features were detected in vivo by optical coherence tomography. CAD patients had lower plasma Netrin-1 levels and a higher MDMs expression of both protein and its receptor compared to controls. Specifically, a progressive increase in Netrin-1 and UNC5b was evidenced going from controls to stable angina (SA) and acute myocardial infarction (AMI) patients. Of note, spindle MDMs of AMI showed a marked increase of both Netrin-1 and its receptor compared to spindle MDMs of controls. UNC5b expression is always higher in spindle compared to round MDMs, regardless of the subgroup. Finally, CAD patients with higher intracellular Netrin-1 levels showed greater intraplaque macrophage accumulation in vivo. Our findings support the role of Netrin-1 and UNC5b in the atherosclerotic process.

Download Full-text

Experimental warming differentially affects vegetative and reproductive phenology of tundra plants

Nature Communications ◽

10.1038/s41467-021-23841-2 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Courtney G. Collins ◽

Sarah C. Elmendorf ◽

Robert D. Hollister ◽

Greg H. R. Henry ◽

Karin Clark ◽

...

Keyword(s):

Growing Season ◽

Plant Phenology ◽

Reproductive Phenology ◽

Ecosystem Structure ◽

Experimental Warming ◽

Growing Seasons ◽

Tundra Ecosystem ◽

Phenological Shifts ◽

And Function ◽

Ecosystem Structure And Function

AbstractRapid climate warming is altering Arctic and alpine tundra ecosystem structure and function, including shifts in plant phenology. While the advancement of green up and flowering are well-documented, it remains unclear whether all phenophases, particularly those later in the season, will shift in unison or respond divergently to warming. Here, we present the largest synthesis to our knowledge of experimental warming effects on tundra plant phenology from the International Tundra Experiment. We examine the effect of warming on a suite of season-wide plant phenophases. Results challenge the expectation that all phenophases will advance in unison to warming. Instead, we find that experimental warming caused: (1) larger phenological shifts in reproductive versus vegetative phenophases and (2) advanced reproductive phenophases and green up but delayed leaf senescence which translated to a lengthening of the growing season by approximately 3%. Patterns were consistent across sites, plant species and over time. The advancement of reproductive seasons and lengthening of growing seasons may have significant consequences for trophic interactions and ecosystem function across the tundra.

Download Full-text