Climate researchers correct faulty rainfall predictions for China’s breadbasket

Peer-Reviewed Publication

INSTITUTE OF ATMOSPHERIC PHYSICS, CHINESE ACADEMY OF SCIENCES

 

IMAGE: FARMERS ARE TRANSPLANTING RICE IN A PADDY FIELD IN HEILONGJIANG PROVINCE, NORTHEAST CHINA IN SPRING. view more 

CREDIT: XIANLI YANG

Climate models had until recently not been performing very well predicting variation in the spring rainfall over northeast China, home to some of the country’s main cereal production. This uncertainty potentially puts the food security of the country—and even the world—at risk. Researchers have however now identified the problem: a previously unidentified major shift that occurred in the mid-1980s in atmospheric flows from the North Atlantic as a result of a weakening jet stream.

Their findings are reported in a paper published in the journal Advances in Atmospheric Sciences on August 12.

Northeast China, including Heilongjiang province—the country's largest grain producer—is one of the country's major breadbaskets. The area's agriculture is key to the nation's basic food self-sufficiency. And sowing season comes in the spring there. As a result, any changes that might be caused by global warming to springtime precipitation in the region will be vital to understand in order to ensure food security for the 1.4 billion people who make the country their home. And if China's ability to feed itself is threatened, so is that of the rest of the world.

Unfortunately, up until now, climate models have not done a very good job of simulating variability in spring rainfall over northeast China—which also includes the provinces of Jilin, Liaoning, and eastern Inner Mongolia—compared to how well they perform for other areas.

“It had long been thought that the sea-surface temperature over North Atlantic Ocean were closely related to springtime precipitation in northeast China,” said Zhiwei Zhu, lead author of the paper and researcher with the Key Laboratory of Meteorological Disaster at Nanjing University of Information Science and Technology. “But this was too crude an understanding, and seasonal predictions for the northeast China have just been completely off compared to how well models perform seasonal predictions for the rest of the country.”

It may seem far-fetched that sea-surface temperature in the North Atlantic can affect spring rains as far away as northeast China, but such long-distance production of anomalies taking place thousands of kilometers away—termed ‘teleconnections’ by climate scientists and oceanographers—are common both in the atmosphere and the ocean.

An example of such teleconnections are Rossby waves, also called planetary waves, westerly winds that flow in very large wavy patterns meandering from south to north and back again. Rossby waves form as a result of the rotation of the Earth and contribute to the transfer of heat from the tropics to the poles and of cold air to the tropics. A succession of these waves is called a wave train.

“But our predictions based off these teleconnections were somehow wrong,” added Professor Zhu.

In order to better come to grips with what was happening in the northeast China, the researchers produced a fresh analysis considering average monthly precipitation data from gauge stations throughout China and monthly average sea-surface temperatures taken by the US National Oceanic and Atmospheric Administration (NOAA) over a sixty-year period (1961–2020).

They found that there had been a major change in the atmospheric teleconnections between the tropical North Atlantic and northeast Chinese spring rainfall in that time.

Until the mid-1980s, spring rains in the Chinese northeast had been linked to a Rossby wave train that propagated along the westerly jet stream and were coupled to extratropical (mid-latitude) North Atlantic sea surface temperature, not tropical sea-surface temperatures.

Then, in the mid-eighties, there was an abrupt shift, and ever since, northeast Chinese spring rains have been linked to a completely different Rossby wave train that propagate along a great circle route (the shortest route between two points on the surface of a sphere) that is coupled with tropical North Atlantic sea-surface temperatures.

As the atmospheric teleconnections have shifted, so have any anomalous sea-surface temperatures associated with them, and thus altering the origins of the northeast Chinese spring rains.

In essence, they found that the linkage between northeast China spring rainfall and North Atlantic regional sea-surface temperature is unstable, not permanent as had earlier been thought.

This alternating of Rossby wave trains has in turn been caused by a weakening over the decades of the westerly jet stream—narrow bands of strong winds in the upper atmosphere—over North America (Climate scientists have hypothesized that the jet stream may gradually weaken as a result of global warming).

Moving forward, climate scientists need to pay close attention to such decadal shifts, the researchers say, in order to produce better predictions of climate variation for northeast China and perhaps even the whole of northeast Asia in the spring.

Having identified the cause of the of the faulty climate predictions for the region, the researchers now intend to develop a better, decadal-varying seasonal prediction model covering a century-long period.

 

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JOURNAL

Advances in Atmospheric Sciences

DOI

10.1007/s00376-022-2024-3 

ARTICLE TITLE

Alternation of the Atmospheric Teleconnections Associated with the Northeast China Spring Rainfall during a Recent 60-Year Period

ARTICLE PUBLICATION DATE

12-Aug-2022

Circular economy to boost the 2030 agenda for sustainable development

Peer-Reviewed Publication

TSINGHUA UNIVERSITY PRESS

 

IMAGE: THE IMAGE ABOVE SHOWS A COMPARISON BETWEEN LINEAR AND CIRCULAR ECONOMY MODELS. AS THE NAME SUGGESTS, THE RESOURCE GOES THROUGH A TAKE-MAKE-CONSUME-DISPOSE SEQUENCE LINEARLY TO FINALLY PRODUCE A LARGER AMOUNT OF WASTE MATERIAL IN A LINEAR ECONOMY. ON THE OTHER HAND, IN CIRCULAR ECONOMY, THE RESOURCE CYCLES THROUGH THE PRODUCTION LOOP WITH LESSER WASTE AS WELL AS SOME USEFUL BIPRODUCTS, WHICH IS WELL IN TUNE WITH THE ASPIRATIONS OF MANY SDGS. view more 

CREDIT: CIRCULAR ECONOMY, TSINGHUA UNIVERSITY PRESS.

Circular economy is a brilliant concept that has found its way not only in elevating various aspects of our lives but also in solidifying future plans and goals for a sustainable society. In that sense, it also has high potential in achieving United Nations 2030 agenda for sustainable development goals (SDGs) that was adopted in 2015 with the motive of “transforming our world”. It has been recognized composedly by the local and the national governments alike, as well as by mainstream private sectors that aim to achieve the UN agenda for SDGs.

A paper describing circular economy as a vital enabler for the sustainable use of resources for achieving the UN agenda for SDGs appeared in the journal Circular Economy on June 17, 2022 (https://doi.org/10.1016/j.cec.2022.100001). In this article, Khajuria and co-authors focused on the promotion of circular economy arguing its significance in attaining SDGs under the United Nations agenda that aims on shifting the world onto a sustainable and resilient development path leaving no one behind. The authors review some distinctive case studies concerning the promotion of circular economy and their implementation aimed toward the SDGs and discuss some key points on the current standing and possible future directions in diverse scenarios.

 

In order to meet sustainable development goals, circular economy (with a “made-to-be-made-again” policy) represents a fundamental alternative to the linear economic model (with a “take-make-consume-dispose” policy) that is restorative to maintain the utility of products, components, and materials, and to retain their values. The main challenge is to minimize the need for new inputs of material and energy while reducing the environmental pressure linked to resource extraction, emissions, and waste. The circular economy model offers a new chance for innovation and integration among natural ecosystems, businesses model, public-private-partnership, our daily lives, society, and waste management. The image above shows a comparison between linear and circular economy models. As the name suggests, the resource goes through a take-make-consume-dispose sequence linearly to finally produce a larger amount of waste material in a linear economy. On the other hand, in circular economy, the resource cycles through the production loop with lesser waste as well as some useful biproducts, which is well in tune with the aspirations of many SDGs.

This article discusses several innovative circular economy solutions to waste including specific 3Rs policies and practices in some fast-developing countries including Bangladesh, China, Guyana, Thailand, and the Philippines. It compiles and discusses several distinctive ideas and visions considered during a special session held at the 16th International Conference on Waste Management and Technology, where several policymakers, engineers, researchers, and experts in the field of waste management from around the world exchanged opinions and shared knowledge on critical solutions and pathways to achieve multiple SDGs. The lead author, Anupam Khajuria, a researcher at the United Nations Centre for Regional Development, Japan, underlines – “3R has a central role in enhancing resource efficiency and creating a circular economy that enables society to maximize the economic return on limited resources”. The circular economy goes beyond recycling and is based on a restorative industrial system focused to treat waste as a resource. The implementation of a circular economy is specifically based on both resource efficiency and eco-efficiency, and it helps to move toward a green and sustainable economy. Khajuria explains that business models based on circular economy represent the decoupling of economic growth from resource consumption that boosts economic growth and product lifetime through repair, reuse, and ultimately recycling. “The unsustainable use of resources generates vast amounts of waste that may lead to serious environmental consequences including extreme climate changes”, articulates Khajuria. Managing waste in the most efficient and environment-friendly manner is therefore of great importance for the future. Khajuria further adds – “Technological innovations grounded on circular economy approach have been proven to be highly efficient for reducing the amount of final waste, for decreasing the use of virgin natural resources, as well as for increasing production efficiency that leads to a quality life concerning environmental health, right in tune with the UN agenda for SDGs”. According to Khajuria, the transition of sustainable waste management to circular economy utilizes the potential of waste by increasing recycling and reuse of waste material and aims to have a climate-neutral waste activity that helps to improve its economic balance.

It is evident that circular economy provides new opportunities and has positive effects on the UN SDGs, particularly, SDG 12 relates to responsible consumption and production. The circular economy offers a solution to address the issue of waste management in developing countries that can lead to maximizing the designed solution of the product as well as alleviate several issues such as poverty, hunger, and gender and social inequality. This also means that circular economy model can add various opportunities for a sustainable economy such as creating new jobs, green public procurement, technology transfer of frontier technology including the fourth industrial revolution (4IR) and artificial intelligence (AI), and implementation of digital and transferable knowledge.

“Since circular economy approach is based on recycling and reusing the waste material in a circular manner by extracting maximum benefits from the natural resources, it saves the environment from excessive toxic waste and from unnecessary resource extraction, and at the same time, increases the end product. However, despite several potential environmental and economic benefits of circular economy concept, the current pace of transformation is not adequate, and more efficient strategic approaches are necessary to accelerate this process”, explains Prabhat Verma, a co-author and a professor at Osaka University, Japan.

This article also debates that there are a number of circular economy options, including Nature-based Solutions (NbS) that can facilitate the transition to a circular economy and support the sustainable management of the environment, with a reduced carbon footprint. NbS offer opportunities to evaluate present growth trajectories holistically to balance and regenerate the embedded natural and human capital. The circular economy approach provides the necessary framework and conditions that could be leveraged to attract investments for NbS. Finally, it recognizes that various stakeholders, including governments, research institutes, and private enterprises are promoting and accelerating circular economy waste management solutions that require innovative technologies and management methods. Active collaboration of various stakeholders with their respective expertise would certainly bring in some phenomenon changes in the current situation and will accelerate the transition towards circular economy to meet the UN 2030 agenda for SDGs.

 

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About Circular Economy

 

Circular Economy is an international journal serving as a sharing and communication platform for novel contributions and outcomes on innovative techniques, systematic analysis, and policy tools of global, regional, national, local, and industrial park's waste management system to improve the reduce, reuse, recycle, and disposal of waste in a sustainable way.

Circular Economy is a fully open access journal. It is co-published by Tsinghua University Press and Elsevier, and academically supported by the School of Environment, Tsinghua University, and the Circular Economy Branch, Chinese Society for Environmental Sciences. At its discretion, Tsinghua University Press will pay the Open Access Fee for all published papers from 2022 to 2024.

 

About Tsinghua University Press

 

Established in 1980, belonging to Tsinghua University, Tsinghua University Press (TUP) is a leading comprehensive higher education and professional publisher in China. Committed to building a top-level global cultural brand, after 41 years of development, TUP has established an outstanding managerial system and enterprise structure, and delivered multimedia and multi-dimensional publications covering books, audio, video, electronic products, journals and digital publications. In addition, TUP actively carries out its strategic transformation from educational publishing to content development and service for teaching & learning and was named First-class National Publisher for achieving remarkable results.

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JOURNAL

Circular Economy

DOI

10.1016/j.cec.2022.100001 

ARTICLE TITLE

Accelerating circular economy solutions to achieve the 2030 agenda for sustainable development goals

Social and communication skills co-evolve

The more complex the social group in lemurs, the more signals the animals use to communicate

Peer-Reviewed Publication

DEUTSCHES PRIMATENZENTRUM (DPZ)/GERMAN PRIMATE CENTER

 

IMAGE: THE MORE COMPLEX THE SOCIAL SYSTEM IS IN LEMURS, THE MORE SIGNALS THE ANIMALS USE TO COMMUNICATE. view more 

CREDIT: CHRIS SCHLOEGL

Living together in groups entails constant interactions between individuals. Individuals need to permanently assess the behavior of others and to respond flexibly to it. Primates and other animals regulate and coordinate their interactions predominantly by vocal, visual, tactile, and olfactory signals. However, it is unclear what social or ecological factors influence the number of signals and the evolution of the various signaling modalities. One hypothesis holds that more complex signals have evolved in pair- or group-living species to regulate their more diverse social interactions. To investigate these relationships, Claudia Fichtel and Peter Kappeler, researchers in the Behavioral Ecology and Sociobiology Unit at the German Primate Center - Leibniz Institute for Primate Research, investigated which factors may explain the diversity of vocal, visual, and olfactory signaling repertoires in different lemur species. They were able to show that lemurs living in larger groups with correspondingly more complex social systems also have more complex communication systems in all three modalities. The size of the signaling repertoire could not be attributed to specific environmental factors, nor was it associated with body size or brain size (Philosophical Transactions B).

To regulate and coordinate interactions animals have to communicate. The lemurs of Madagascar communicate in different modalities and exhibit the major forms of social organization: they live either solitary, in pairs, or in groups. In addition, the activity patterns of the more than 120 known species vary. There are diurnal and nocturnal species, as well as species that are active day and night. "Because lemurs have evolved in isolation from other primates for more than 50 million years, they provide an excellent opportunity to identify fundamental principles in the coevolution of social and communicative traits," explains Peter Kappeler.

The vocal repertoire of lemurs is about as large as that of other monkey species. Lemurs also use vocalizations to signal their dominance status, resolve conflicts, signal their emotional state to others, maintain group cohesion, coordinate group movements, or defend territories. In addition, olfactory communication is prominent in lemurs. They have specialized glands on their genitalia, chest, hands or head, and their secretions are applied to trees, but also to conspecifics. Lemurs also use gestures or facial expressions to regulate social relationships. As, for example, submission in rank disputes is indicated by visual signals in some species but vocal signals in others, it is important to investigate the extent of the signaling repertoire in all modalities to understand whether increasing social complexity has facilitated the evolution of communicative complexity. The study showed that lemurs living in larger groups also evolved more vocal, visual, and olfactory signals. From this, the researchers concluded that communicative abilities have diversified in parallel with increasing social complexity. In addition, Fichtel and Kappeler were able to show that social complexity probably evolved first during evolution, followed by communicative complexity. Variation in other factors, such as habitat characteristics, activity patterns, or the number of lemur species existing in the same habitat, did not explain the evolution of more extensive communicative repertoires. Similarly, there was neither a relationship between vocal and visual repertoire size and brain size, nor between the number of scent glands or scent signals and body size of the lemur species.

"Our study shows that the complexity of vocal, olfactory, and visual communication in lemurs has coevolved with the complexity of the social system, but not with socio-ecological factors, such as the type of habitat or the number of other species in the same range," Claudia Fichtel concludes.

CAPTION

Verreaux's Sifakas foraging in Kirindy Forest in Madagascar. The more complex the social system is in lemurs, the more signals the animals use to communicate.

CREDIT

Claudia Fichtel/Deutsches Primatenzentrum

DOI

10.1098/rstb.2021.0297 

METHOD OF RESEARCH

Literature review

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Coevolution of social and communicative complexity in lemurs

ARTICLE PUBLICATION DATE

8-Aug-2022

Museum collections indicate bees increasingly stressed by changes in climate over the past 100 years

by Natural History Museum

Credit: CC0 Public Domain

Scientists from Imperial College London and the Natural History Museum today published two concurrent papers analyzing UK bumblebee populations.

The first investigated the morphology (body shapes) of bee specimens dating back to 1900. Using digital images, the group first investigated the asymmetry in bumblebee wings as an indicator of stress. High asymmetry (very differently shaped right and left wings) indicates the bees experienced stress during development—an external factor that affected their normal growth.

Studying four UK bumblebee species, the group found evidence for stress getting higher as the century progressed from its lowest point around 1925. Further analysis showed that each bee species displayed a consistently higher proxy of stress in the latter half of the century.

Learning from the past to predict the future

By taking the climate conditions during the year of collection—namely annual mean temperature and annual rainfall—the team found that in hotter and wetter years bees showed higher wing asymmetry. The study is published today in the Journal of Animal Ecology.

Author Aoife Cantwell-Jones, from the Department of Life Sciences (Silwood Park) at Imperial, says that "by using a proxy of stress visible on the bee's external anatomy and caused by stress during development just days or weeks before, we can look to more accurately track factors placing populations under pressure through historic space and time."

Author Dr. Andres Arce, now at the University of Suffolk, stated that their "goal is to better understand responses to specific environmental factors and learn from the past to predict the future. We hope to be able to forecast where and when bumblebees will be most at risk and target effective conservation action."

Senior author Dr. Richard Gill, from the Department of Life Sciences (Silwood Park) at Imperial, says that "with hotter and wetter conditions predicted to place bumblebees under higher stress, the fact these conditions will become more frequent under climate change means bumblebees may be in for a rough time over the 21st century."

DNA from single legs

As well as measuring the wing shapes of bees, in a second parallel study the team successfully sequenced the genomes of over a hundred bumblebee museum specimens dating back more than 130 years. In a pioneering advance, ancient DNA methods typically used for studying wooly mammoths and ancient humans, were for the first time used on an insect population.

Scientists from the Natural History Museum and the Earlham Institute quantified DNA preservation using just a single bee leg from each of the bees studied. From these developments, published today in Methods in Ecology & Evolution, the researchers can now look to determine how the reported stress may lead to genetic diversity loss.

In conjunction with providing a new reference genome, the team will now use this data to study how bee genomes have changed over time, gaining an understanding of how whole populations have adapted—or not—to changing environments.

The value of museum collections

Focusing on bumblebee collections, the team worked with curators from the Natural History Museum London, National Museums Scotland, Oxford University Museum of Natural History, World Museum Liverpool, and Tullie House Museum Carlisle.

Author Dr. Victoria Mullin, from the Natural History Museum, say that "museum insect collections offer an unparalleled opportunity to directly study how the genomes of populations and species have been affected by environmental changes through time. However, they are a finite resource and understanding how best to utilize them for genetic studies is important."

Senior author Professor Ian Barnes, from the Natural History Museum, says that "one of the main problems with museum collections is that the quality of DNA can be very variable, making it difficult to predict which type of analyses we should do. We now have a much better idea about DNA preservation in insect collections, which is a massive boost to our ongoing work to understand the history and future of insect populations."

Dr. Gill concluded that "these studies showcase the value of leveraging museums specimens to go back in time and unlock the past's secrets. But what we have done is just the beginning, and by continuing our work with these vital public collections and collaborating with curators we can only discover more.

"This work was part of a Natural Environment Research Council-funded project and could not have been achieved without the commitment, hard work, and diligence of the museum curators, and our other collaborators. We are also grateful to BBSRC funds in supporting the generation of the bumblebee reference genome."Britain's butterflies are getting bigger as the climate changes

More information: Aoife Cantwell-Jones, et al, Signatures of increasing environmental stress in bumblebee wings over the past century: Insights from museum specimens, Journal of Animal Ecology (2022). doi.org/10.1111/1365-2656.13788

Victoria Mullin et al, First large-scale quantification study of DNA preservation in insects from natural history collections using genome-wide sequencing, Methods in Ecology & Evolution (2022). doi.org/10.1111/2041-210X.13945

Journal information: Journal of Animal Ecology 

Provided by Natural History Museum 

Modern pesticides damage the brain of bees so they can't move in a straight line

Impaired 'optomotor' response could lower ability of exposed bees to forage and pollinate flowers

Peer-Reviewed Publication

FRONTIERS

 

VIDEO: HONEYBEES ARE SUSPENDED ON TOP OF A TRACKING BALL, WHICH REGISTERS THEIR WALKING MOTIONS IN REAL TIME AND SENDS THESE TO A COMPUTER FOR ANALYSIS. view more 

CREDIT: RH PARKINSON, C FECHER, AND JR GRAY

The challenge to let people walk back and forth in a straight line isn't just used by police to test if drivers are intoxicated: it's also used by neurologists to diagnose neurological disorders like ataxia, where parts of the brain that coordinate movement are impaired. Now, researchers use an insect version of this challenge to show for the first time that modern pesticides damage the nervous system of honeybees so that it becomes hard for them to walk in a straight line. The results are published in Frontiers in Insect Science.

"Here we show that commonly used insecticides like sulfoxaflor and the neonicotinoid imidacloprid can profoundly impair the visually guided behavior of honeybees. Our results are reason for concern because the ability of bees to respond appropriately to visual information is crucial for their flight and navigation, and thus their survival," said lead author Dr Rachel H Parkinson, currently a scientist at the University of Oxford.

The results add to what the Food and Agriculture Organization of the United Nations and the World Health Organization have called the "rapidly growing body of evidence [which] strongly suggests that the existing levels of environmental contamination [from neonicotinoid pesticides] are causing large-scale adverse effects on bees and other beneficial insects".

Optomotor response keeps insects in line

Insects have an innate 'optomotor response', which lets them orient themselves back onto a straight trajectory when they threaten to steer off-course while walking or flying. Parkinson and colleagues challenged the optomotor response of walking honeybees to respond accurately and timely to videos of vertical bars that moved from left to right, or vice versa, across two screens in front of them. This 'tricks' the bee into assuming that she has suddenly been blown off-course and needs to perform a corrective turn to return to a straight path. A healthy optomotor response will then instruct the bee's motor system to orient back to an illusory straight line mid-way between the optic flow from right and left.

The researchers compared the efficiency of the optomotor response between four groups of wild-caught forager honeybees, with between 22 and 28 bees tested per group: each had been allowed to drink unlimited 1.5 molar sucrose solution over five days, either pure or contaminated with 50 ppb (parts per billion) imidacloprid, 50 ppb sulfoxaflor, or 25 ppb imidacloprid and 25 ppb sulfoxaflor simultaneously.

Optomotor response worse after exposure to pesticides

All bees were less good at responding to the simulated optic flow when the bars were narrow or moving slowly (ie, seemingly far away) than when they were wide or moving fast (ie, seemingly close by). But for any width and speed, the bees who had ingested the pesticides performed poorly compared to control bees. For example, they turned quickly in one direction only and didn't respond to changes in the direction of movement of the bars, or showed a lack of turning responses. The asymmetry between left and right turns was at least 2.4 times greater for pesticide-exposed bees than for control bees.

Minor brain damage

The researchers also show with molecular techniques that pesticide-exposed bees tended to have elevated proportion of dead cells in parts of the brain's optic lobes, important for processing visual input. Likewise, key genes for detoxification were dysregulated after exposure. But these changes were relatively weak and highly variable across bees, and unlikely to be the sole explanation for the observed strong impairment of the optomotor response.

"Neonicotinoid and sulfoximine insecticides activate neurons in the insect brain and are not always recycled fast enough to prevent toxicity. The effects we observed could be due to a type of rewiring in the brain: to prevent neural damage by reducing the sensitivity of neurons to these compounds," said Parkinson.

Parkinson looked ahead: "To fully understand the risk of these insecticides to bees, we need to explore whether the effects we observed in walking bees occur in freely flying bees as well. The major concern is that – if bees are unable to overcome any impairment while flying – there could be profound negative effects on their ability to forage, navigate, and pollinate wildflowers and crops."

CAPTION

The bee's optomotor response is tested by showing videos of horizontally

 moving vertical bars to her on two screens, creating the illusion of optic flow.

CREDIT

RH Parkinson, C Fecher, and JR Gray

JOURNAL

Frontiers in Insect Science

DOI

10.3389/finsc.2022.936826 

METHOD OF RESEARCH

Experimental study

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Chronic exposure to insecticides impairs honeybee optomotor behavior

ARTICLE PUBLICATION DATE

17-Aug-2022

http://www.rachelcarson.org/SilentSpring.aspx

Silent Spring - Rachel Carson 

Carson's passionate concern in Silent Spring is with the future of the planet and all life on Earth. She calls for humans to act responsibly, carefully, and as ...

https://theanarchistlibrary.org/library/lewis-herber-murray-bookchin-our-synthetic-environment

Our Synthetic Environment | The Anarchist Library 

Source: http://www.revoltlib.com/anarchism/our-synthetic-environment/view.php. Notes: Lewis Herber is the psuedonym of Murray Bookchin.

Sea secrets surface in the Great Australian Bight

New twist in oceanic upwellings in famed feeding ground

Peer-Reviewed Publication

FLINDERS UNIVERSITY

Oceanographers have discovered more about why the eastern Great Australian Bight supports a year-round abundance of marine predators, including different whale species and white sharks which attract cage divers and filmmakers inspired by the Hollywood blockbuster Jaws. 

For the first time, experts from Flinders University and the South Australian Research and Development Institute (SARDI) have described substantial subsurface phytoplankton layers deep beneath the eastern part of the Bight – which serves to support the rich marine biodiversity even when the surface phytoplankton blooms disappear at certain times of the upwelling season.   

“To conserve this important region, and prepare for climate change, we need to further understand these systems and food sources,” says Flinders University researcher Alex Shute, the first author of a new study in Continental Shelf Research. 

“To understand this, we explored year-to-year variations of phytoplankton layers in the region using satellite data in conjunction with water-column data from the Integrated Marine Observing System (IMOS).” 

To their surprise the IMOS data uncovered a ‘missing link’ of layers of substantial subsurface phytoplankton at water depths of 30m to 70m – undetected by even satellite imagery until now.  

The seasonal upwelling of nutrient-rich water fuels the production of phytoplankton, which Flinders University oceanographer Associate Professor Jochen Kaempf and colleagues have studied for almost 20 years.  

Known as the Great Southern Australian Coastal Upwelling System (GSACUS), it is one of Australia’s most productive marine ecosystems – attracting large marine mammals including whales, seals and sealions, as well as valuable fish populations such as the southern bluefin tuna. 

Associate Professor Kaempf says this new study highlights how the marine food chain survives even in years when the surface phytoplankton upwelling doesn’t occur. 

‘’Our observation of subsurface phytoplankton layers is the missing key explaining the high productivity of the region.  

"This study demonstrates how little we actually know about the functioning of marine ecosystems, and how important real field observations are,’’ adds Associate Professor Kaempf, who is president of the Australian Meteorological and Oceanographic Society (AMOS), Adelaide Division.  

The research was funded by a Flinders University Climate Seed Grant entitled “Climate-change impacts on upwelling in the eastern Great Australian Bight.”  

SARDI is the research arm of SA Primary Industries and Regions (PIRSA).  

The article, Variability of surface and subsurface phytoplankton blooms in a seasonal coastal upwelling system (2022), by A Shute, L Kämpf, M Doubell, AR Rodriguez, L Möller, R Baring and M Newman, has been published in Continental Shelf Research. DOI: 10.1016/j.csr.2022.104832. 

  

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JOURNAL

Continental Shelf Research

DOI

10.1016/j.csr.2022.104832 

METHOD OF RESEARCH

Data/statistical analysis

SUBJECT OF RESEARCH

Not applicable

ARTICLE TITLE

Variability of surface and subsurface phytoplankton blooms in a seasonal coastal upwelling system

ARTICLE PUBLICATION DATE

16-Aug-2022

Living together: how two different species of dolphins coexist in Australia

New study highlights the importance of prey and habitat diversity

Peer-Reviewed Publication

FLINDERS UNIVERSITY

 

IMAGE: AN AUSTRALIAN SNUBFIN (ORCAELLA HEINSOHNI) DOLPHIN view more 

CREDIT: PHOTO COURTESY GUIDO PARRA VERGARA

New research by Flinders University scientists sheds new light on the reasons why two species of dolphins coexist in the northern Australian waters.  

Australian snubfin (Orcaella heinsohni) and humpback (Sousa sahulensis) dolphins live in sympatry throughout most of their range, primarily in shallow (less than 30m deep) tropical/subtropical coastal waters from southern New Guinea across northern Australia.

“A major challenge in ecology and conservation is to understand the means by which species coexist as this is the basis of biodiversity,” says Associate Professor Guido Parra Vergara, lead author of the research published in the journal Ecology and Evolution. 

“If we are to understand the effects of global change on marine mammal biodiversity, and how we can maintain assemblages of coexisting species, we need to understand their patterns of co-occurrence; the biological significance of their interactions, and the mechanisms underlying their coexistence.”  

Ecological niche theory predicts the coexistence of closely related species is promoted by resource partitioning in space and time. Understanding how different species of marine mammals such as dolphins co-exist is particularly challenging due to their size, high mobility, longevity, and the fact that they spend most of their time underwater.  

Ecologically, both species are similar. Each occur in small populations of typically fewer than 150 individuals, show a high degree of overlap in space use, have similar patterns of habitat use and behavioural activities according to space and time, and are recorded frequently in mixed species groups.  

Thus, segregation into exclusive ranges in space and time, and difference in habitat use and behavior patterns, do not seem to fully explain their coexistence. 

To compare stable isotope ratios of carbon and nitrogen in their skin, researchers collected skin samples from live Australian snubfin and humpback dolphins along the east coast of Queensland.  

Differences in carbon isotope ratios are passed up the food web to consumers, providing a quantifiable estimate of habitat and resource use. In contrast, nitrogen isotope ratios increase at each trophic level with top predators having higher nitrogen isotope values compared to lower trophic levels. 

The results of the isotope analysis suggest that while both dolphin species feed at similar trophic levels, have substantial dietary overlap and rely on similar basal food resources, there are subtle differences in their habitat use and prey selection that may promote the coexistence of Australian snubfin and humpback dolphins.  

Snubfin dolphins forage on a wider diversity of prey, while humpback dolphins forage on a wider range of habitats.  

This information elucidates some of the mechanisms of coexistence between these ecologically similar dolphin species and highlights the importance of prey and habitat diversity for the conservation of dolphin communities. 

“Food diversity and abundance and habitat heterogeneity are key factors promoting the coexistence of these two dolphin species, and pressure from overfishing and pollution that could reduce prey abundance and diversity or deteriorate their habitat quality could affect the future of such dolphin co-existence,” says Associate Professor Parra Vergara. 

“Because dolphins play important roles in maintaining the structure and function of marine communities and ecosystems, any pressures on their food and habitat resources need to be considered when planning future multi-species conservation.” 

The research - Isotopic niche overlap between sympatric Australian snubfin and humpback dolphins, by Guido Parra Vergara, Zachary Wojtkowiak, Katharina Peters and Daniele Cagnazzi - has been published in the journal Ecology and Evolution. https://doi.org/10.1002/ece3.8937 

   

CAPTION

Australian humpback (Sousa sahulensis) dolphin

CREDIT

Photo courtesy Guido J Parra Vergara (Flinders University

CAPTION

To compare stable isotope ratios of carbon and nitrogen in dolphins, Flinders University researchers collected skin samples from live Australian snubfin and humpback dolphins along the east coast of Queensland.

CREDIT

Cetacean Ecology, Behaviour and Evolution Lab, Flinders University

JOURNAL

Ecology and Evolution

METHOD OF RESEARCH

Survey

SUBJECT OF RESEARCH

Animals

ARTICLE TITLE

Isotopic niche overlap between sympatric Australian snubfin and humpback dolphins