did you do to. turn it back to the roots again men of. the church family from somalia live around the world and one of them needed urgent assistance. a family starts october 18th on d w. welcome to your weekly dose of science be on tomorrow today. our journey in the footsteps of alexander from humble continues to the orinoco river and south america. in the neighboring amazon basin huge fires are raging but not all blazes are necessarily bad for the environment. climate change isn't just affecting the rain forest how can we future proof our woodlands in other regions.

but 1st to tortoises and turtles a fascinating bunch giant colomba goes tortoises can weigh up to $300.00 kilos sadly many species of these reptiles are in decline only 3 yangtze giant soft shell turtles are thought to still exist and that's even though a lot of these creatures have a very long life spans some live more than 200 years and was somewhat time valentine wanted to know more. how do you see to all those find their way back to their place of birth. look ahead to the toes are globetrotters following ocean currents they can travel more than 100 kilometers a day with their aerodynamic shape them paddle like feet they are in bursts able to exceed speeds of 25 kilometers an hour. they have to come up to breathe every. hours because they have lungs not gills and they go ashore to lay their eggs

. every few years a female sea turtle returns to the beach where she herself hatched digs a hole and deposits a clutch of around $100.00 eggs in it. then she leaves the nest and returns to the sea. after a few weeks the babies hatch and follow a light source such as moonlight reflected on the water to reach the ocean. then later return as adults is known as natal homing. but how do sea turtles find their way back from flowers and of kilometers away. one theory is that they navigate by sensing our planet's magnetic field and using it as a g.p.s. system of sorts. a long term study in eastern florida show

that the pattern of nesting places a lot ahead sea turtles moved in tandem with subtle shifts in the earth's magnetic field lines. but is a home beach necessarily a safe one unfortunately not god knows them crows steal the eggs right out of the nest once the baby turtles reach the sea hungry crabs and official wake them. tourism also upsets the delicate cycle of egg laying and hatching only one in a 1000 hatchlings is likely to survive to adulthood. so why do sea turtles go back to that birth place to nest one hypothesis is that the females assume they'll find favorable conditions if they return to the beach where they themselves were hatched the logic being if it worked for me why shouldn't it work for my office. brain.

everything is interconnected the ideas of visionary german researcher and explorer alexander from humboldt continue to influence us today born 250 years ago on september 4th 769 he traveled the world in search of new experiences and insights he recorded his 5 year journey in central and south america in his diary luckily he invented a waterproof ink so his writings even survived a shipwreck on the orinoco and we can still read them today. the last in our series retracing alexander from humboldt footsteps takes us to one of the longest rivers in south america the orinoco.

when i came to fear stan i was 19 years old and it was in may sing to see all these forests and suddenly you can see the whole thing jumping on the water and i fall in love with it which is all. so i decided to put my life to study the dolphin on the system one of the other enough.

this trembling of the air this solitude this wild expanse of the river transports the traveler into adventurous nature. this was our exeunt front on both describe the orinoco river. on his research expedition he spent 2 and a half months following the mighty waterway documenting its every twist and turn. for the explorers from europe the endless wilderness on land and in the water was a source of continuous wonder and unexpected dangers. nobody back

home expected to return alive from his or a no go expedition. now if you want to be an expedition the scientists make baby research. and you know now you know they have they basically meant to do that and not the trouble from the rub to the continent if you knowledge about these so we we have a lot of things to learn to steal from home will then endurance they bash on the grill city and i think this guy's an example for us to put some goals and go behind them. biologist for an undertow he go as a research camp here it's the base for the international expeditions he leads across the entire river network.

covering an area of almost 1000000 square kilometers the basin is one of the largest ecosystems in south america scientists come here to study it's astonishing diversity of species both in the river itself and in the forests that line at. the base an area that is home to 250 different species of mammals and over 100 reptiles finding the animals is no easy task for the researchers many of the creatures are nocturnal and move territory several times a year. if baker across the need of our own grew up here. he sets up cameras in the forest fitted with motion sensors that are to study the behavior of the animals over a period of months. when it has come at them but then we can install these camera

traps at various heights and this camera records everything that happens here up to a height of 40 or 50 centimeters it enables us to record larger animals such as jaguars tapirs and copy barbarous well now leave the camera here for at least 3 months in. a few kilometers upstream they are no go squeezes its way through a maze of cataracts. the arch waters rapids are an ecosystem in their own right nutritious algae grow on the rugged. granite rocks a feast for the fish that pass through here. over

a 1000 different species live in the waters of the orinoco and many of them exclusive to the river. be a bit but you know this place is dangerous you know that if it if you don't know the river well you could overturn and drowned in the rapids you know what you had that a young man drowned over there recently in a good one i thought that would be like that. but a gallon oh yes i've been fishing here for 40 years my father used to bring you here when i was a kid but i mean i wanted to teach my son but he's lost interest in fishing don't get me oh no no no no they would go any but. for centuries people here lived off the riches of the orinoco to this day there are still families that move from shore

to shore many of them from venezuela they settle wherever there are currently the most fish to catch but the ecosystem here is out of balance increasing river traffic and dam construction have had a disruptive effect on the natural course of the are you know. we as a human we need to change your own minds and take care of these places the rivers are unprotected in most countries you protect sometimes the land but the water they are jus examples in latin america of government say ok listen let's protect the rivers and and and we keep all of the ecosystems or a livelihood of many people are the rivers when we need help to reverse for healthy people and for healthy biodiversity. increasingly human activities are encroaching on the rivers ecosystems this

prompted for an under trujillo to buy land here a few years ago and turn it into a reserve. planting danimal species are able to gradually recover here protected from deforestation poaching and environmental pollution. if they are long term. they come flakes in a very well day with the leaves on the bottom. and if you don't know. if they are a lot of time they're under water in a bay shallow water and they could be pests with death. and dying. in the water looking for the play or the fish by.

extensive conservation zones help to ensure that a growing number of animals returned to the riverside areas as footage from the camera traps confirms each of the animals has its own individual pattern enabling the researchers to come and track their behavior. one major success for the reserve is the return of the jaguar to the rain forest the big cats are going under threat due to the loss of their habitat to make way for crop and livestock farming you think it will be coming. then they are not the only species to are found a new home in the reserve. it

was in questions about the day of the eco system for everything everything in good conditions but now no trouble because everything happening so quickly now they get a vision of the. fast so if. you lose the species and we need to do something like these prevent conservation and to support as well the national parks. of animal sounds on the orinoco led to sleepless nights for home board but also to a pioneering concept the animal world faces a constant struggle in which species numbers are constrained by mutual competition . no more than 2 centuries later there equilibrium has been disturbed the

animal's biggest enemy today is a 2 legged species. during his travels along the orinoco. humboldt also confirmed that there was a link between the orinoco and amazon river systems the rio de. on his journey through the rain forest he wrote you find yourself in a new world in wild and untamed nature nowadays there are few places left on this planet undisturbed by human activity. devastating fires have been raging in the amazon rain forest for weeks such huge blazes are unusual here. through the high humidity and the lush vegetation usually prevent flames from spreading but in the past few years things have changed the world's largest rain

forest has become more vulnerable to drought due to climate change. many of the current fires were caused by humans. loggers use fire to clear underbrush and dried indigenous people from their land. farmers set blazes to gain land for their cattle and to grow crops but the soil itself isn't all that fertile it's the intact forest ecosystem that so efficiently recycles nutrients the amazon is a reservoir for 150 gigatons of carbon dioxide and now the fires are releasing huge amounts of c o 2 into the atmosphere. astronaut luca parmitano observed the forest fires in the amazon from the international space station and photographed the thick smoke trails. these red dots give an impression of the number of fires burning on

a single day their impact on the rain forest is devastating in comparison the problem in southern africa seems far worse. than the blazes seen here are for the most part savannah fire. grasslands need the flames to renew themselves old grass burns fertilizing the soil and making way for new growth . on facebook we asked you to tell us what you think about forest fires have you ever been affected by one. k.p. pandy from india writes fire is a good servant if it's controlled but a bad master if it's beyond control forest fires and global climate change are a vicious circle global communities need to break this cycle by promoting renewable energy technologies and reducing deforestation and forest degradation. from ecuador

posts the fires in the amazon are nothing compared to the 1000 time bigger devastation the forest has undergone over the past 40 years the fire is the desperate cry of a jungle that has been mutilated by the interests of multi-millionaires and a few government beneficiaries it has turned the eyes of the world to the rain forest before she disappears. and putra from indonesia urges let's start a movement everyone should plant at least one tree if it's chopped down will plant a new one. thanks for your comments. there are more than $4000000000.00 hectares of forest worldwide they cover 30 to 40 percent of the earth's surface. the most densely forested countries are russia brazil canada the us and china more than half of the planet's woodlands are located

there but for decades forests have been disappearing at an alarming rate climate change pasts and fire do less damage than humans who continue to flee are foreigners to create farmland. and that's even though forests can help prevent mudslides and stop soil erosion. forests protect. carbon dioxide around 10 tons per hectare of land and they produce oxygen for us to brief their home to 80 percent of all land animal and plant species the trees collect huge quantities of water whatever reaches the forest floor is stored there or is filtered as it seeps away. forests can cool the air in cities by up to 80 degree celsius acting like a huge air conditioning system but not every species of tree has the same cooling properties. in the future what types of best stand up to climate

change. this to city was woodland next to an old spruce plantation has a special function to help combat climate change. but will it really outperform the spruces. researchers in austria using these devices to study the spruce and maple trees. they want to know if one of the 2 woodlands remains cool in the summer how much particulate matter the trees fell to from the air and how well they grow during the hot dry summer up to now a little data like this has been collected. these sensors measure the temperature. and analyzes the data so far he has no concrete findings but he has developed a hypothesis. much deeper roots trees to. dry weather

like we've got this summer the roots can tap more water from the ground and draper as the water on the surface of the layers and thereby effectively cooling. effect of cooling. that makes the decision as far as a better economic system. ending area and communities benefit from the fresh air and cool air. for more than 40 years ranger has been concerned with devising the best kind of woodland to cope with hot and dry summers. here and of area in southern germany the bark beetle has destroyed vast swathes of spruce trees. now you can paddle as restructuring the woodland into his colleagues or planting wild fruit trees deciduous trees indigenous to the forest. clean water we need healthy air with low levels of particulates and we need protection against

erosion. and every forest should provide that so we have to manage your woodlands well and take care of. his idea is to plant particular types of forests for particular functions the 1st is the energy forest fast growing poplars that can be used in the local wood chip power plant for heating and electricity. stefan vic cop a would energy expert is examining how much biomass can be produced by poplar trees . they'll still produce shoots from their roots or stumps after they're felled that's why one tree can be harvested several times each sector of poplar forest can produce the equivalent of around 5000 liters of heating oil per year the trees also cleanse the atmosphere absorb greenhouse gases and help ensure clean drinking water . point 2 meters that's

a fair amount for an 11 year old tree. 50 percent of germany's energy is used to produce heat and ward is ideal for that purpose we can burn it with a very high yield support for. the scientists are researching how much we. and how much of bach the popular generated and how much energy can be produced from it in the ideal case only the wood would be used for power generation the bark produces more fine particulate the researchers are working on new harvesting methods leaving the park behind in the forest along with the leaves to rot and feed the soil with nutrients. back in the climate protection forest which planted 25 years ago the researchers are still comparing the deciduous and spruce forests. as examining whether the trees grew during the hot summer months 1st he looks at the maple tree.

or curve you see circumference measuring it. shows expanded by 15 millimeters 45 millimeters in diameter. and how well did the spruce grow. more than one millimeter in diameter much. after. until now heat was regarded as the crucial factor in determining a tree's growth here in germany but more and more attention is switching to the importance of water following recent heat waves trees can grow only when they get enough water. and only then can the forest in turn help make rain as they grow trees release water vapor through their leaves. sense.

as a cloud see water vapor is the posited on the tappings creating raindrops and rain . without the water vapor would needlessly evaporate into the atmosphere. findings show that the city was forests. hope with a lot of dry summer months better than the old spruce forests. i hope we can turn things around in time and we need to futureproof our forests so they can keep providing us with fresh air and clean water. if our old one is right why are great but if they. do you have a science question that you've always wanted and say it we're happy to help out send it to us as a video text ovoid smell if we answer it on the show will save you a little surprise as a thank you catalog just ask. you'll find as i do w dot

com slash science or drop us a line at d w underscore site tech on facebook d w dot science. that's all for now next time we focus on food and ask could algae provide a sustainable alternative to meet 2 men to find out more see them. coming.

on the road with our superhero fly mission is clear kushti get anthony close early show explore in germany. they dive in and everything out and a lot going on in a. truly tried tested. trick. to w. . every journey begins with the 1st

step and every language the 1st word going to think of nikko he's in germany to search. why not born with him. to suffer it's simple are mine on your mobile and free. w z e learning course speak german made easy. where the real power resides. i come from there lots of people in fact more than a 1000000000 digits of was not just democracy that's one reason why i'm passionate about people and aspirations and they can sense. the television the book is fried chicken but after the for the fun in one i remember thinking at the time if the barley in bulk and what to get happened if people come together and unite for

a while. but i do the news i often confront difficult situations for conflicts between disaster i see despite my job to confront those details on policies and development to put the spotlight on issues that matter most. to security question marshall nice solution. or not has been achieved so much more needs to be john and i think people have to be at the heart of solutions my name is on the touchy and i work at g.w. .

this is a double news live from british. lol make us forcefully tolerant for a month prime minister parties johnson is suspending parliament after a king vote tonight but before they go lawmakers are likely to repeat their rejection of his call for a snap election also on the program she was a nazi even after the attempt to ban the n.p.t. he stayed loyal to the party which is close to hitler's nazi party outrages the neo nazis unanimously elected unopposed.