Pollinators are a key component of global biodiversity, providing vital ecosystem services to crops and wild plants. There is clear evidence of recent declines in both wild and domesticated pollinators, and parallel declines in the plants that rely upon them. Here we describe the nature and extent of reported declines, and review the potential drivers of pollinator loss, including habitat loss and fragmentation, agrochemicals, pathogens, alien species, climate change and the interactions between them. Pollinator declines can result in loss of pollination services which have important negative ecological and economic impacts that could significantly affect the maintenance of wild plant diversity, wider ecosystem stability, crop production, food security and human welfare.

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Global pollinator declines: trends, impacts and drivers.

Climate change 2014 - Synthesis Report

Viruses exist wherever life is found. They are a major cause of mortality, a driver of global geochemical cycles and a reservoir of the greatest genetic diversity on Earth. In the oceans, viruses probably infect all living things, from bacteria to whales. They affect the form of available nutrients and the termination of algal blooms. Viruses can move between marine and terrestrial reservoirs, raising the spectre of emerging pathogens. Our understanding of the effect of viruses on global systems and processes continues to unfold, overthrowing the idea that viruses and virus-mediated processes are sidebars to global processes.

Viruses in the sea

A census of the biomass on Earth is key for understanding the structure and dynamics of the biosphere. However, a global, quantitative view of how the biomass of different taxa compare with one another is still lacking. Here, we assemble the overall biomass composition of the biosphere, establishing a census of the ≈550 gigatons of carbon (Gt C) of biomass distributed among all of the kingdoms of life. We find that the kingdoms of life concentrate at different locations on the planet; plants (≈450 Gt C, the dominant kingdom) are primarily terrestrial, whereas animals (≈2 Gt C) are mainly marine, and bacteria (≈70 Gt C) and archaea (≈7 Gt C) are predominantly located in deep subsurface environments. We show that terrestrial biomass is about two orders of magnitude higher than marine biomass and estimate a total of ≈6 Gt C of marine biota, doubling the previous estimated quantity. Our analysis reveals that the global marine biomass pyramid contains more consumers than producers, thus increasing the scope of previous observations on inverse food pyramids. Finally, we highlight that the mass of humans is an order of magnitude higher than that of all wild mammals combined and report the historical impact of humanity on the global biomass of prominent taxa, including mammals, fish, and plants.

https://www.pnas.org/content/pnas/115/25/6506.full.pdf

The biomass distribution on Earth

Home PURPOSE OF THE CENTER: To develop the center to address state-of-the-art research, create innovating educational programs, and support technology transfers using commercially viable results to assist the Army Research Laboratory to develop the next generation Future Combat System in the telecommunications sector that assures prevention of perceived threats, and Non Line of Sight/Beyond Line of Sight lethal support.

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Bacteria and archaea dominate the biomass of benthic deep-sea ecosystems at all latitudes, playing a crucial role in global biogeochemical cycles, but their macroscale patterns and macroecological drivers are still largely unknown. We show the results of the most extensive field study conducted so far to investigate patterns and drivers of the distribution and structure of benthic prokaryote assemblages from 228 samples collected at latitudes comprising 34°N to 79°N, and from ca. 400- to 5570-m depth. We provide evidence that, in deep-sea ecosystems, benthic bacterial and archaeal abundances significantly increase from middle to high latitudes, with patterns more pronounced for archaea, and particularly for Marine Group I Thaumarchaeota. Our results also reveal that different microbial components show varying sensitivities to changes in temperature conditions and food supply. We conclude that climate change will primarily affect deep-sea benthic archaea, with important consequences on global biogeochemical cycles, particularly at high latitudes.

https://advances.sciencemag.org/content/advances/2/4/e1500961.full.pdf

Macroecological drivers of archaea and bacteria in benthic deep-sea ecosystems

Benthic deep-sea environments are the largest ecosystem on Earth, covering ∼65% of the Earth surface. Microbes inhabiting this huge biome at all water depths represent the most abundant biological components and a relevant portion of the biomass of the biosphere, and play a crucial role in global biogeochemical cycles. Increasing evidence suggests that global climate changes are affecting also deep-sea ecosystems, both directly (causing shifts in bottom-water temperature, oxygen concentration and pH) and indirectly (through changes in surface oceans' productivity and in the consequent export of organic matter to the seafloor). However, the responses of the benthic deep-sea biota to such shifts remain largely unknown. This applies particularly to deep-sea microbes, which include bacteria, archaea, microeukaryotes and their viruses. Understanding the potential impacts of global change on the benthic deep-sea microbial assemblages and the consequences on the functioning of the ocean interior is a priority to better forecast the potential consequences at global scale. Here we explore the potential changes in the benthic deep-sea microbiology expected in the coming decades using case studies on specific systems used as test models.

Potential impact of global climate change on benthic deep-sea microbes.

Numerous submarine canyons around the world are preferential conduits for episodic dense shelf water cascading (DSWC), which quickly modifies physical and chemical ambient conditions while transporting large amounts of material towards the base of slope and basin. Observations conducted during the last 20 yr in the Lacaze-Duthiers and Cap de Creus canyons (Gulf of Lion, NW Mediterranean Sea) report several intense DSWC events. The effects of DSWC on deep-sea ecosystems are almost unknown. To investigate the effects of these episodic events, we analysed changes in the meiofaunal biodiversity inside and outside the canyon. Sediment samples were collected at depths varying from ca. 1000 to > 2100 m in May 2004 (before a major event), April 2005 (during a major cascading event) and in October 2005, August 2006, April 2008 and April 2009 (after a major event). We report here that the late winter–early spring 2005 cascading led to a reduction of the organic matter contents in canyon floor sediments down to 1800 m depth, whereas surface sediments at about 2200 m depth showed an increase. Our findings suggest that the nutritional material removed from the shallower continental shelf, canyon floor and flanks, and also the adjacent open slope was rapidly transported to the deep margin. During the cascading event the meiofaunal abundance and biodiversity in the studied deep-sea sediments were significantly lower than after the event. Benthic assemblages during the cascading were significantly different from those in all other sampling periods in both the canyon and deep margin. After only six months from the cessation of the cascading, benthic assemblages in the impacted sediments were again similar to those observed in other sampling periods, thus illustrating a quick recovery. Since the present climate change is expected to increase the intensity and frequency of these episodic events, we anticipate that they will increasingly affect benthic bathyal ecosystems, which may eventually challenge their resilience.

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Major consequences of an intense dense shelf water cascading event on deep-sea benthic trophic conditions and meiofaunal biodiversity

The deep-ocean interior contains the majority of microbes present on Earth. Most deep-sea microbes are concentrated in surface sediments, with abundances up to 4 orders of magnitude higher, per unit of volume, than in highly productive waters of the photic zone. To date, it has been shown that prokaryotic biomass largely dominates over all other biotic components, but the relative importance of Bacteria, Archaea and viruses to the global benthic biomass has not yet been quantified. Here, we report that the microbial abundance in the top 50 cm of deep-sea sediments of the world oceans is on the order of 1.5 ± 0.4 × 1029. This is largely represented by viruses (9.8 ± 2.5 × 1028), followed by Bacteria (3.5 ± 0.9 × 1028 cells) and Archaea (1.4 ± 0.4 × 1028 cells). The overall biomass in the top 50 cm of the deep-sea sediments is 1.7 ± 0.4 Pg C, largely represented by bacterial biomass (ca. 78%), followed by archaeal biomass (ca. 21%) and viruses (<1%). The bathymetric patterns of abundance and biomass of the 3 microbial components show differences: abundance and biomass of Bacteria decrease with increasing water depth, whereas those of Archaea and viruses remain constant. These results support the hypothesis that the role of Archaea and viruses could be more relevant in the deepest part of the ocean floor.

https://www.int-res.com/articles/ame_oa/a075p081.pdf

Towards a better quantitative assessment of the relevance of deep-sea viruses, Bacteria and Archaea in the functioning of the ocean seafloor

To investigate the role of viruses in extracellular DNA production through cell lysis, we selected two systems where viruses are expected to be the main component controlling prokaryote dynamics. These systems include anoxic subsuperficial coastal sediments and water and sediments of two deep-hypersaline anoxic basins (i.e., DHABs) of the eastern Mediterranean. Viral production was high in both places. Viruses were responsible for 10– 60% of prokaryote mortality in anoxic sediments and up to 100% in deep-anoxic waters. The daily contribution of DNA released by viral lysis to the total extracellular DNA pool was 2–11% in anoxic sediments and more than 100% in the brines of both deep-sea basins. Extracellular DNA released by viral infection was rapidly degraded by deoxyribonucleases (DNases), which were also high in permanently anoxic conditions. Overall, our data suggest that DNA released by viral lysis, because of its high lability and fast turnover, may represent an important mechanism of trophic supply for prokaryotes, particularly in systems characterized by limited availability of external trophic sources. Extracellular DNA is a constituent of both dissolved and particulate organic matter pools (DOM and POM) in all aquatic ecosystems, including a soluble fraction represented by naked free DNA and a nonsoluble fraction made up of

https://aslopubs.onlinelibrary.wiley.com/doi/pdf/10.4319/lo.2007.52.2.0508

Cinzia Corinaldesi

Papers

Macroecological drivers of archaea and bacteria in benthic deep-sea ecosystems

Potential impact of global climate change on benthic deep-sea microbes.

Major consequences of an intense dense shelf water cascading event on deep-sea benthic trophic conditions and meiofaunal biodiversity

Towards a better quantitative assessment of the relevance of deep-sea viruses, Bacteria and Archaea in the functioning of the ocean seafloor

Viral infection plays a key role in extracellular DNA dynamics in marine anoxic systems