Timber harvesting results in persistent deficits in summer streamflow

by Steve Lundeberg, Oregon State University

Credit: Oregon State University

Summer streamflow in industrial tree plantations harvested on 40- to 50-year rotations was 50% lower than in century-old forests, data from the long-term Alsea Watershed Study in the Oregon Coast Range showed.

The research, led by Oregon State University's Catalina Segura, is an important step toward understanding how intensively managed plantations might influence water supplies originating in forests and downstream aquatic ecosystems, especially as the planet becomes warmer and drier.

"Industrial plantation forestry is expanding around the globe and that's raising concerns about the long-term effects the plantations might be having on water, especially in dry years," Segura said.

Findings were published in the Journal of Hydrology.

Running through southern Benton and Lincoln counties in Oregon, the Alsea River empties into the Pacific Ocean at Waldport and supports runs of chinook and coho salmon as well as steelhead and cutthroat trout.

The Alsea watershed has a rich research history dating back six decades; in the 1960s, it was the site of one of the first comprehensive studies of the effects of forest harvesting on water quality and fish habitat in the nation.

Those research results provided evidence for standards included in the landmark 1971 Oregon Forest Practices Act, among the first such laws in the United States to set rules to protect streams from the impacts of timber harvesting.

In the current study, Segura and collaborators looked at 27 years of streamflow data to compare the effects of historic and contemporary forestry practices on summer streamflow in three sites within the Alsea watershed: Flynn Creek, Deer Creek and Needle Branch.

Flynn Creek, 210 hectares in size, was designated a U.S. Forest Service Research Natural Area in 1975 and has been left undisturbed; 60% to 70% of its canopy is red alder and big-leaf maple, and the rest is Douglas-fir that regenerated following a 19th century fire.

Deer Creek is 311 hectares and has been historically used to study how road building and extensive forest management affect water quality. Three 25-hectare areas (25% of the total watershed area) in the Deer Creek watershed were clear-cut in 1966 (buffer areas near streams were left uncut). Over the last 30 years the watershed has been harvested again via intermittent thinning and clear-cutting.

Needle Branch, 75 hectares, has been used for examining how watersheds are affected by contemporary logging practices compared to historical practices—the 1960s and earlier. The entire watershed was clear-cut between 1956 and 1966. Eighty-two percent of that happened in 1966, with no trees left along the stream. It was 100% harvested again from 2009 to 2014 using contemporary methods, including retention of riparian vegetation near the stream.

Together, streamflow data from Needle Branch, Deer Creek and Flynn Creek enabled the scientists to determine forestry practices' effects on how much water was flowing in the streams.

After the mature forests were harvested in 1966, streamflow increased for seven years, then began to decline as the Douglas-fir seedlings grew, eventually falling below pre-harvest streamflow levels.

Compared to mature forests, daily streamflow from 40- to 53-year-old plantations was 25% lower overall and 50% lower during summer months, when there is minimal precipitation in the Coast Range.

The harvesting of the plantations didn't lead to much of an increase in streamflow. The likely reason: high evapotranspiration from replanted Douglas-firs and other rapidly regenerating vegetation, and from the vegetation in the riparian buffer.

Evapotranspiration is the sum of the water that reaches the atmosphere through evaporation and transpiration—the process that moves water throughout a plant from its roots to its leaves.

"Results of this study indicated that 40- to 50-year rotations of Douglas-fir plantations can produce persistent, large, summer low-flow deficits," Segura said. "While the clear-cutting of these plantations, with retention of riparian buffers, increased daily streamflow slightly, streamflow did not return to where it was before the harvesting of those mature forests, which apparently do not use as much water."

The findings, together with other regional studies, indicate that the magnitude of summer streamflow deficits is related to the proportion of watershed area in young (30- to 50-year-old) plantations, Segura said. Comparatively little is known, she added, about the specifics regarding how evapotranspiration levels change as a tree ages or how much it varies with changes in forest structure as the forest matures.

"We need to improve our understanding of tree water use at the stand or forest level and how that changes as forests age," she said. "We also need to continue to maintain our long-term studies as much as we can. The only way we found out what we learned here is because we had the long-term data."Global analysis of streamflow response to forest management

---

More information: Catalina Segura et al. Long-term effects of forest harvesting on summer low flow deficits in the Coast Range of Oregon, Journal of Hydrology (2020). DOI: 10.1016/j.jhydrol.2020.124749

Natural solutions to the climate crisis? One-quarter is all down to Earth

by Zhang Nannan, Chinese Academy of Sciences

Agroforestry systems play a critical role in natural climate solutions. Credit: KIB

Joint research conducted by the Nature Conservancy and the Kunming Institute of Botany, Chinese Academy of Sciences, calculated the carbon-storing power of global soils and showcased approaches like agroforestry designed to capitalise on untapped potential.

A critical, nature-based approach to mitigating climate change has been right at our feet all along, according to a new study reporting that soil represents up 25% of the total global potential for natural climate solutions (NCS) – approaches that absorb CO2 from the atmosphere and lock it into landscapes, including forests, croplands and peatlands.

Representing the first time soil's total global potential for carbon-mitigation across forests, wetlands, agriculture and grasslands together has been cataloged, the study provides a timely reminder not to neglect the power of soils and the many benefits these ecosystems can deliver for climate, wildlife and agriculture.

Published in the journal Nature Sustainability, the study is titled "The role of soil carbon in natural climate solutions." the research also argues that a lack of clarity to date regarding the full scale of this opportunity and how to best capitalize on it has restricted investment.

Lead author Dr. Deborah Bossio, the Nature Conservancy's lead soil scientist, says, "While momentum continues to build behind the role nature can play in the global response to climate change, soils have historically enjoyed less of the limelight as a natural climate solution compared with, say, forests or mangroves. Our study is designed to redress this situation by highlighting the full carbon-mitigation potential of soils across a range of landscapes, but also—crucially—exploring practical mechanisms that already exist for accelerating the uptake of these comparatively untapped approaches, including their integration into burgeoning carbon markets. This is particularly important for agriculture sector, for which more effective management of soils represents the single biggest contribution this industry can make towards mitigating climate change."

Co-author Dr. Robert Zomer of the KIB/CAS says, "Soils and improved soil management have a tremendous potential to store carbon. Agroforestry, and more generally just including more trees in the agricultural landscape, has been shown to be one of the most important approaches to increasing soil organic carbon with substantial global mitigation potential. In addition, highlighting the complimentary beneficial impacts available from improved agricultural production practices aimed at improving soil health, both the increased on-farm bio-diversity and livelihood diversification can enhance farm and ecosystem resilience."

Demonstrating that soil carbon represents up to 25% of total global NCS potential, the paper also estimated that 40% of this potential will be delivered by protecting existing soil carbon reserves, while 60% will come from rebuilding stocks depleted by practices such as over-intensive arable agriculture and the draining of peatlands.

Breaking these data down further, the researchers also showed the share of total NCS potential that soil represents across various, climate-critical landscapes—from a relatively diminutive 9% of forest mitigation potential, through 47% for agricultural lands and grasslands, right up to 72% of total carbon sequestration potential in wetland landscapes.

The study also showed that agroforestry systems can have significant positive impacts on soil organic carbon across specific geographies. Moreover, the majority of other soil carbon pathways tend to be "no regrets" practices that deliver soil fertility, climate resilience and provide other ecosystem services alongside climate mitigation.

"We already know that nature has a powerful role in mitigating runaway climate change," said Prof. XU Jianchu from KIB/CAS, who was not associated with the study. "This study showed the NCS provide pathways for sustainable development that have both climate mitigation and livelihood improvement potential. It is essential that soil health become a central pillar of agricultural production, not just for climate mitigation, but also for both environmental and food security."Restore soil to absorb billions of tonnes of carbon: study

---

More information: D. A. Bossio et al. The role of soil carbon in natural climate solutions, Nature Sustainability (2020). DOI: 10.1038/s41893-020-0491-z

Journal information: Nature Sustainability 

Researchers reveal lignin protection mechanism in forest soils

by Zhang Nannan, Chinese Academy of Sciences

Credit: CC0 Public Domain

Over the course of forest succession, both components of plant residues and the structure of soil microbial communities play important roles in affecting soil aggregates, and thus the sequestration and stability of soil organic carbon. However, up till now there is still a lack of holistic understanding of the interactions among root turnover, microbial community composition, chemical composition of plant residues and different sized soil aggregates.

Feng Yue, Zhang Junhui and other researchers from the Forest Boundary Ecology Group of the Institute of Applied Ecology (IAE), Chinese Academy of Sciences, together with Prof. Han Shijie at Henan University, quantified lignin phenol composition, concentrations and oxidation levels in macroaggregates, microaggregates and silt–clay fractions in soils at five successional stages of the mixed broadleaf–Korean pine (Pinus koraiensis) forests in the Changbai Mountains.

The researchers also measured root biomass and turnover, and microbial biomass, etc. By analyzing data they collected, the researchers explored the mechanism affecting the protection of soil aggregates on plant-derived organic matter during the succession of the type of forest.

As a result, large macroaggregates (2-8 mm) accounted for 45.17—59.87% of the bulk soil dry weight and comprised 40.22—60.89% of soil organic carbon (SOC) in the stands of pioneer forests. There were higher proportion of small macroaggregates (0.25-2 mm) and SOC but lower lignin content and oxidation levels in the bulk soil and aggregates in the mature stands compared to other forest stands.

They found the highest soil carbon and lignin concentrations and that the silt-clay fractions sequestrated 56.18% of SOC and up to 84.17% of the lignin content in the 239 years old forest stands.

The study showed that, along with forest succession and the changes in plant residue chemistry, fine root and microbial biomass, SOC sequestration and lignin protection shifted from large aggregates to small particles of silt-clay fractions. This may lead to the long-term accumulation of SOC in late successional forests.

In conclusion, by quantifying lignin, the researchers of this study revealed the relationship between carbon sequestration in soil aggregates and carbon input from plant residues over the course of vegetation development.

This study has been published in Soil Science Society of America Journal with the title "Variation in soil lignin protection mechanisms in five successional gradients of mixed broadleaf-pine forests."New findings in plant root and fungal interaction help to resolve the complexity of soil carbon cycling

---

More information: Yue Feng et al. Variation in soil lignin protection mechanisms in five successional gradients of mixed broadleaf–pine forests, Soil Science Society of America Journal (2020). DOI: 10.1002/saj2.20032

Major advances in our understanding of New World Morning Glories

THEY ARE NOT A WEED THEY ARE A PSYCHOACTIVE DRUG

by Pensoft Publishers

Sweet potato (Ipomoea batatas) growing as a weed in a waste ground, San Ramon, Peru. Credit: Robert Scotland

A major advance in revealing the unknown plant diversity on planet Earth is made with a new monograph, published in the open-access, peer-reviewed journal PhytoKeys. The global-wide study, conducted by researchers at the University of Oxford, lists details about each of the 425 New World species in the largest genus within the family of morning glories, thanks to an all-round approach combining standard, modern and new-generation identification techniques.


The family of morning glories, also known as bindweeds, whose scientific name is Convolvulaceae, includes prominent members like the sweet potato and ornamental plants such as the moonflower and the blue dawn flower. In fact, one of the key conclusions, made in the present work, is that within this plant group there are many other species, besides the sweet potato, that evolved storage roots long before modern humans appeared on Earth. Furthermore, most of those are yet to be evaluated for economic purposes.

To make their findings, the research team of John Wood, Dr. Pablo Muñoz Rodríguez, Bethany R.M. Williams and Prof Robert Scotland applied the "foundation monograph" concept that they had developed for similarly diverse and globally distributed, yet largely understudied groups. Usually, such groups with hundreds of species have never been surveyed across their entire geographical range, which in turn results in the existence of many overlooked new species or species wrongly named.

As a result, the monograph adds six new to science species and establishes nine new subspecies, previously recognised as either distinct species or varieties. The publication also cites all countries where any of those 425 morning glories occurs. In order to provide detailed knowledge about their identities and ecologies, the authors also produced over 200 illustrative figures: both line drawings and photos.

Professor Robert Scotland with the evolutionary tree of the studied genus -- Ipomoea. The study involved DNA sequencing of 2,000 specimens. Credit: John Baker

John Wood of the Oxford team members collects plants in Bolivia. Credit: BRM Williams

In their study, the scientists also investigate poorly known phenomena concerning the genus. For instance, the majority of the plants appear to originate from two very large centres, from where they must have consequently radiated: the Parana region of South America and the Caribbean Islands. Today, however, a considerable amount of those species can be found all around the globe. Interestingly, the team also notes a strong trend for individual species or clades (separate species with a common ancestor) to inhabit disjunct localities at comparable latitudes on either side of the tropics in North America and South America, but not the Equator.

The monograph exemplifies the immense value of natural history collections. Even though the researchers have conducted fieldwork, most of their research is based on herbarium specimens. They have even managed to apply DNA sequencing to specimens over 100 years old. The publication also provides detailed information about the characteristics, distribution and ecology of all the species. It is illustrated with over 200 figures, both line drawings and photos.

"A major challenge in monographing these groups is the size of the task given the number of species, their global distribution and extensive synonymy, the large and increasing number of specimens, the numerous and dispersed herbaria where specimens are housed and an extensive, scattered and often obscure literature," comment the scientists.

"Unlike traditional taxonomic approaches, the 'foundation monograph' relies on a combination of standard techniques with the use of online digital images and molecular sequence data. Thereby, the scientists are able to focus on species-level taxonomic problems across the entire distribution range of individual species," they explained.What's the story, morning glory? Taxonomy, evolution and sweet potatoes

More information: Pablo Muñoz-Rodríguez et al, A taxonomic monograph of Ipomoea integrated across phylogenetic scales, Nature Plants (2019). DOI: 10.1038/s41477-019-0535-4

Telecommuting could curb the coronavirus epidemic

by Mohja Rhoads and Fynnwin Prager, The Conversation MARCH 17, 2020

Credit: CC0 Public Domain

Recent surveys from both the National Household Transportation Survey and the Bureau of Labor Statistics indicate that around 29% of the United States workforce has the option to work at home, and around 15% usually does so.

Working from home pays a double dividend during a pandemic. First, it can help to limit the spread of the highly contagious coronavirus. This supports organizations' efforts to limit travel and major public events, and more assertive efforts by governments in badly affected regions to restrict population movement altogether.

Restricting travel and canceling events have substantial costs at a time when businesses are already dealing with absences due to illnesses. Allowing people to work from home can help cut some of these losses.

There are many jobs that can be conducted only at a place of work. For example, a dentist can perform a root canal only at an office, a bus driver must drive a bus and a longshoreman must travel to a port.

However, recent advances in digital technologies, software and networks have made working from home much easier. Now many can conduct all or a portion of their work at home, and the data show that some workers from all occupations and industries work from home at some point during the week. What this means is that even the most physical of industries have some jobs or portions of jobs that can be conducted remotely, even if part-time.

Researchers estimate that at least 50% of the workforce has a job that is compatible with working at home for a portion of the week, such as those in sales, legal, media and military occupations. This workforce could contribute to the economy and limit their exposure to the coronavirus.

The limited uptake of working at home has more to do with managerial resistance than the type of work itself. When organizations come together and government provides the necessary resources, flexible workplace strategies have been successful in helping ease traffic during major events such as the 1984 Los Angeles Olympics and maintaining government services during catastrophic weather events such as Snowmageddon in 2010

Provided by The Conversation 

Coronavirus could spark a revolution in working from home. Are we ready?

by Libby Sander, The Conversation

A dedicated home office is a key strategy to work from home successfully. Credit: Shutterstock

Imagine your employer asking you to work from home until further notice.

As COVID-19 continues to spread, this seems an increasingly likely scenario. "Everyone who can work from home should work from home," said Harvard epidemiologist William Hanage this week.

In China and neighboring countries, millions are doing so for the first time.

In the United States, companies readying staff to work remotely include Twitter, Apple, Microsoft, Amazon and JP Morgan.

This week, NASA's Ames Research Center in California joined them and declared a mandatory telework policy after an employee tested positive to COVID-19. NASA sites across the country have been testing their work-from-home capabilities.

In Dublin last week, Google sent 8,000 workers home for a day to trial an extended remote-work scenario after one employee came down with flu-like symptoms.

In Australia, Clayton Utz, Cisco and Vodafone temporarily closed offices last week as a precautionary measure.

The likelihood of extended workplace shutdowns seems increasingly likely. So what do we know about the pros and cons of working from home?

How common is working from home?

Perhaps not as common as you might think.

In Australia many companies now offer flexible work arrangements, but that doesn't necessarily mean employees can work from home. Even those permitted to work from home may only be allowed to do so on a limited basis.

As the list of tech companies mentioned may indicate, it is easier to do a job from home if you need only an internet connection and a telephone line.

In building a case for the national broadband network in 2010, Australia's Gillard government set a target of 10% of the workforce teleworking half the time. This was up from an estimated 6% of employedAustralians having some form of regular teleworking arrangement.

Consultancy Access Economics predicted this could save A$1.4 billion to A$1.9 billion a year—about A$1.27 billion of that being the time and cost savings of avoided travel.

Teleworking has many benefits

Governments since Gillard's have been less focused on the idea, to the the extent we lack reliable contemporary statistics for telework in Australia.

But with increased commuting times, caring responsibilities and the stress of modern workplaces, the research says most employees highly value being able to work from home. In fact, a 2017 US study found employees valued the option at about 8% of their wages.

Research has also highlighted benefits including increased productivity, rated by both the employees and supervisors. One study showed a 13% increase in performance for employees working from home.

Part of this may be due to an increased ability to focus and less distraction. My research shows employees who can't focus to complete their work are less likely to perform well.

Working from home usually means employees have greater autonomy over how they do their work, including the hours and conditions of their work, and how they manage their lives and other responsibilities. These benefits of teleworking have been shown to lead to greater job satisfaction, lower absenteesim and turnover, increased commitment to the organization and, importantly, reductions in stress associated with work.

Work-from-home arrangements may also give organizations access to a greater talent pool.

But there are downsides as well

That said, there are challenges associated with working from home that organizations and individuals often do not plan well for.

Studies have shown working from home for extended periods can leave employees feeling socially and professionally isolated.

When we work from home, we have fewer opportunities to interact and acquire information, which may explain why remote workers can feel less confident than their office-based counterparts.

This reduction in interaction and knowledge sharing is a key barrier to the take-up of working from home.

According to a meta-analysis of 46 studies involving more than 12,000 employees, working from home more than 2.5 days a week could negatively affect relationships with coworkers as well as knowledge transfer.

Further, resentment could arise if teleworking was not widely available.

Employees who work from home have also perceived negative consequences for their career. Out of sight can sometimes be out of mind. Research published last month, however, suggests telecommuters are promoted as much as office-based colleagues.

Another significant issue is maintaining boundaries with home life. It can be hard to switch off, particularly when we don't have a dedicated home office. Telecommuters often work longer hours, with 48% of employees increasing their work hours in one study.

How can we make it work?

organizations can increase the success of working from home. Regular communication, particularly using video conferencing, can help ensure tasks are coordinated, knowledge is transferred, and social and professional isolation is reduced.

For organizations used to managing based on visibility and presence, letting go of traditional ideas of how to manage and focusing on outputs will be required.

If schools are also closed, employers will need to be sensitive to the challenges employees face working from home with children to care for and online schooling to incorporate.

Finally, employees need to establish boundaries between work and home life. Being able to switch off at the end of the day is important for both physical and mental health.

With no end in sight to COVID-19, many businesses are developing or implementing work-from-home policies to ensure business continuity. If employees and employers can get the balance right and enjoy the benefits of well-planned telework, this coronavirus outbreak could prove to be the tipping point for remote work arrangements to become the norm.

Facebook shuts London, Singapore offices after coronavirus case

This article is republished from The Conversation under a Creative Commons license. Read the original article. This article is republished from The Conversation under a Creative Commons license. Read the original article.

Fast reconnection in turbulent media

by Lazarian (Cesra), Community of European Solar Radio Astronomers

VELIKOVSKY AND MY PHYSICS PROF (A VELIKOVSKIAN) SAID THE SUN IS ELECTROMAGNETIC ENERGY WERE CORRECT

Vorticity of flow in the turbulent reconnection region (X is along the reversing components of magnetic field, Y is perpendicular to the current layer). The measured spectrum corresponds to the expectations of the MHD turbulent theory. No plasmoids is seen for the 3D steady state magnetic reconnection. Credit: Lazarian et al, 2020

Solar flares, similar to many other astrophysical energetic processes, are related to magnetic reconnection. During these events magnetic energy is transferred from other forms of energy, mostly heat and energetic particles. Traditionally, the goal of various models of magnetic reconnection was to explain the rate of this energy transfer. However, the flares are just one of the processes that involve magnetic reconnection. If one imagines any complex motion in a highly conducting medium, the magnetic field, which is assumed to be frozen into the fluid as a result of the famous Alfven (1942) theorem, should create intersections of "knots" that have to arrest the motion of the fluid, unless the magnetic reconnection is fast. Turbulent motions, that are ubiquitous for high Reynolds number astrophysical fluids, present a typical example of such complex fluid motions.

The analytical theory presented in Lazarian & Vishniac (1999, henceforth LV99) testify that 3-D MHD turbulence can make the magnetic reconnection fast, solving problems related both to flares and to explaining the dynamics of turbulent flows. The numerical difficulties associated with the simulations of reconnection within 3-D turbulent flows impeded the progress of testing of the predictions of the turbulent reconnection theory. As a result, models that required only 2-D numerical simulations, i.e. the plasmoid reconnection (Loreiro et al 2007), became widely used and compared with observations. The situation has changed recently as higher resolution numerical simulations became available making testing of 3-D reconnection feasible.

A recent review in Lazarian et al. (2019, henceforth LX19) summarizes the theoretical, numerical and observational progress achieved in the field of 3-D turbulent reconnection. Numerical simulations of the scale 2048x8982x2048 are illustrated in Figure 1. The large scale of the simulations is required to have the outflow thick enough to get it turbulent. Those simulations testify that in 3-D the growth rate of the plasmoid instability is significantly less than of the Kelvin-Hemholtz instability of the outflow. Therefore, in 3-D the magnetic reconnection mediated by plasmoids can be expected only at the initial stage of the reconnection, before the turbulent outflow is formed.

For a given level of turbulence, the numerical simulations show the rate of reconnection that is expected from the LV99 theory. As for flares involving reconnection, they have a natural explanation within the turbulent reconnection model. According to the model, the level of magnetic reconnection increases with the level of turbulence. The increase of the matter outflow increases the level of the turbulence and this, in turn, increases further the reconnection rate. This is a runaway process.

One of the most dramatic predictions of the turbulent reconnection theory is the flux freezing violation in turbulent fluids, the effect that was also successfully demonstrated numerically.

The role of the plasma effects is a hotly debated issue in the literature with simulations that account for plasma effects usually showing reconnection rates faster than those in MHD limit. In LX19 theoretical arguments on the decreasing importance of the plasma effects with the increase of the length of the turbulent reconnection region are supported by numerical simulations. The PIC simulations presented in the review provide results that are consistent with those obtained with MHD simulations.

LX19 contains a list of observations that support the turbulent reconnection theory. Those include both solar observations, solar wind measurements, data on the Parker spiral, etc.

Due to the progress of 3-D numerical simulations, the model of turbulent reconnection has demonstrated its validity. The model has a set of predictions that can be tested observationally. Studies of solar reconnection, see Chitta & Lazarian (2019), provide a good way to test the predictions of the turbulent reconnection theory.Mix master: Modeling magnetic reconnection in partially ionized plasma

---

More information: Based on a recent paper Lazarian et al, Physics of Plasmas, 2020: DOI: doi.org/10.1063/1.5110603

Dams in the upper Mekong River modify nutrient bioavailability downstream

by Science China Press

Dams stimulate phytoplankton production and modify nutrient export downstream in the Lancang-Mekong River Credit: Science China Press

The number of hydropower dams has increased dramatically in the last 100 years for energy supply, climate change mitigation, and economic development. However, recent studies have overwhelmingly stressed the negative consequences of dam construction. Notably, it is commonly assumed that reservoirs retain nutrients, and this nutrient reduction significantly reduces primary productivity, fishery catches and food security downstream. Such perception largely hampers electricity supply and even sustainable socio-economic development in many developing regions such as the Congo and lower Mekong basins.

However, solid scientific support for the widespread belief that dams retain nutrients is usually lacking, because monitoring programs gathering data to establish how nutrient fluxes and phytoplankton production have changed after dam construction are rare. A new article by Qiuwen Chen and his research group at Nanjing Hydraulic Research Institute, China, together with Prof. Jef Huisman from the University of Amsterdam and Prof. Stephen C Maberly from UK Centre for Ecology & Hydrology now provides extensive monitoring data for the upper Mekong River. Their data reveal some surprising new insights.

Contrary to expectation, their study shows that a cascade of reservoirs along the upper Mekong River increased downstream bioavailability of nitrogen and phosphorus. The core mechanism is the synergic effect of increased hydraulic residence time and the development of hypoxic conditions due to stratification and organic matter accumulation. The lack of oxygen results in release of nutrients from the sediment and subsequent accumulation of ammonium and phosphorus in the deeper water layers of the reservoir, which enhances the concentration of dissolved nutrients released downstream from the base of the reservoirs.

Moreover, the longer residence time in the reservoirs strongly increased phytoplankton production, with a shift in species composition from diatoms upstream to green algae in the downstream reservoirs.

Upstream dams are regularly blamed for nutrient retention and consequently the collapse of primary productivity and fisheries, and even human rights of subsistence in the lower Mekong River. This work implies that the fishery decline in the lower Mekong River might be caused by other factors such as over-fishing, habitat modification, disruption of fish migration by dam construction or water quality deterioration from local sources, rather than a reduction in nutrient availability or primary productivity induced by the cascade dams upstream.

This novel perspective on the globally important issue emphasizes the need for dedicated monitoring of the environmental impacts of hydropower dams on nutrient cycling and primary production. The findings are of great significance not only for science, but also for sustainable social-economic development along the Mekong River and other transboundary rivers worldwide.

Thais spike China-led plan to dredge Mekong river

---

More information: Qiuwen Chen et al, Hydropower reservoirs on the upper Mekong River modify nutrient bioavailability downstream, National Science Review (2020). DOI: 10.1093/nsr/nwaa026

COVID-19 Edition - LabourNEWS Mar. 20, 2020

During this time of a global health pandemic, we want to stay in touch and share our continued work with you. Below you will find releases from the AFL, as well as, resources to help navigate supports being made available. News Labour's Response Plan for Alberta This week, Premier Kenney rammed through a budget that will result in job losses and further cuts. We are facing a global health pandemic while also suffering from a massive drop in the price of oil. At a time like this, Albertans need our government to step up with support, not step on us with austerity. Yesterday, Alberta labour leaders unanimously supported an 8-point response plan for during this crisis. Taken together, we think our suggestions will help us "flatten the curve" of infection; fortify our health care system; and ward off the collapse of our economy. See Labour's response and proposed approach here. Lack of Surge Capacity As we watch communities around the globe grapple with COVID-19's effects on their health care systems, questions arise about whether Alberta is prepared to handle this health crisis. We are raising the alarm that we do not have adequate resources in place for a surge of patients and we are calling on Premier Kenney to immediately act to address capacity by opening more acute care and intensive care hospital beds. Read our release on a lack in surge capacity here. Kenney Must Provide Paid Sick Leave Albertans need certainty and support during the pandemic caused by COVID-19. If we want Albertans to follow the advice of public health officials and stay home when their sick, they need to know that they will still be paid. Since the beginning of the COVID-19 pandemic, we have been publicly demanding just that. Last week, Premier Kenney recognized this issue and announced that he would provide Albertans with paid sick leave, BUT unfortunately, this week, he backtracked and announced he would ensure workers have access to unpaid sick leave. We think that the Premier misleading Albertans during a crisis is unacceptable. The Premier needs to act now to fix this, which is why it's an important part of labour's 8-point response plan. Resources Alberta Government COVID-19 Resource: https://www.alberta.ca/coronavirus-info-for-albertans.aspx Alberta Health: Help in Tough Times Resource: https://www.albertahealthservices.ca/amh/Page16759.aspx Government of Canada COVID-19 Programs and Support: https://www.canada.ca/en/department-finance/news/2020/03/canadas-covid-19-economic-response-plan-support-for-canadians-and-businesses.html Take Action Follow Us Online Please follow us on Facebook and Twitter for more regular updates as issues unfold. We encourage you to share relevant information with your networks.

Alberta Federation of Labour 10408 124 St, #300, Edmonton, AB T5N 1R5, Canada