john: tonight on “pbs news weekend,” a massive belt of seaweed in the atlantic ocean threatens the beaches of the united states, mexico, and caribbean. then, a new allegation that ronald reagan's 1980 campaign worked to sabotage president jimmy carter's election-year efforts to free the iran ian hostages. and a look inside the growing world of booktok, the online space where book lovers are sharing recommendations, and driving book sales. >> tiktok can really, really make an author. it can be a new author, it can get off as it's been around for a while, a book that's been around for a long time, a classic, a brand new novel, anything.

>> major funding for "pbs news weekend" has been provided by. >> for 25 years, consumer cellular's goal has been to provide wireless service that helps people communicate and connect. we offer aiety of no contract plans and our u.s.-based customer service team can help find one that fits you. to learn more, visit consumercellular.tv. >> and with the ongoing support of these individuals and institutions. and friends of the "newshour."

this program was made possible by the corporation for public broadcasting and by contributions to your pbs station from viewers like you. thank you. john: good evening. i'm john yang. russian president vladimir putin made an unannounced visit overnight to the ukrainian city of mariupol, once a symbol of defiance when ukrainian forces held out in a steel mill for nearly three months before russian forces seized the city last may. it's putin's first trip to russian-held ukrainian territory, and comes just days after the international criminal court charged him with war crimes and issued an arrest warrant. this week, putin is to meet with chinese president xi jinping in moscow. swiss investment bank ubs has agreed to take over its troubled rival, credit suisse, for more than $3 billion. the deal was engineered by swiss officials in an urgent effort to restore trust in the global banking system.

global markets tumbled last week on the news of vulnerabilities at credit suisse, following the earlier collapse of two u.s. banks. officials were eager to finalize the deal before asian markets begin a new trading week. later this week in the united states, the federal reserve is set to make its next move on u.s. interest rates. rescuers combed through rubble today, searching for survivors after a 6.8 magnitude earthquake shook the southern coastal regions of ecuador and peru on saturday, killing at least 15 people. the quake was felt as far as guayaquil, ecuador's second-largest city, which is home to more than three million people. former vice president mike pence came to donald trump's defense today, after the former president claimed he expects to be arrested tuesday on charges connected to hush money payments to several women who say they had affairs with him. speaking on abc's "this week," pence slammed the prosecutors, saying it's all about politics.

>> i'm taken aback at the idea of indicting a former president of the united states. it just tells you everything you need to know about the radical left in this country. it just feels like a politically charged prosecution here. john: if indicted, mr. trump would be the first former president e charged with a crime. still to come on “pbs news weekend,” a sloshing mass of seaweed making its way toward u.s. shores. and the boost authors and books are getting from the social media platform tiktok. >> this is "pbs news weekend," from weta studios in washington, home of the "pbs newshour," weeknights on pbs. john: almost from the moment iran freed the u.s. hostages in 1981, just minutes after president ronald reagan took the oath of office, there have been suspicions about a deal between the reagan campaign and iran.

the hostage crisis had consumed the last year of the carter presidency, contributing to a perception of weakness. now ben barnes, a prominent democratic politician at the time, tells the new york times he was a witness to republican efforts to prevent the hostages from being freed before election day. gary sick was the iran expert on president carter's national security council. he wrote a 1991 book making th case that there was a deal, sicn barnes said, what was your reaction? gary: my reaction was pretty straightforward. this was the first high-level official of any government that had specifically identified the fact that the reagan administration was trying to make contact with iran a tell them that they should keep the hostages until after the election of jimmy carter -- the

election which reagan was running against jimmy carter. we had pretty well figured that out. we had a bunch of evidence that that was the case. but this is the first, most credible of all of the sources that have talked about this story to this point. john: how does this fit in with the research that you did for your book, "october surprise"? gary: my book had dozens and dozens of sources, but a lot of them were people you would not trust. he would not want to go to a birthday party with these guys. arms dealers, people who were on the fringes of all the black operations going on around the world. so, their word, which was pretty much that the republicans wanted to keep the hostages in place until after the election, that v iew was held by a great many

people, and a lot of people in the middleast. of course i'm quite accustomed working in the middle east to the fact that there are conspiracy theories going on all the time. so i did not pay much attention to them in the beginning. but the evidence began to be overwhelming that something was going on here. but the problem was there was no smoking gun. john: there was a key moment in iran on the morning of election day in the united states. in 1989, jimmy carter spoke to jim lehrer about that. >> there was a flurry of activity in the iranian parliament, that they were going to vote on whether or not to release the hostages just before the votes were cast in this country. the parliament decided, under khomeini's pressure, that they would not release the hostages. and this devastating, negative news about hostages swept through the country on election day. i've always been convinced that this was a major factor. john: the hardline position by iranians on election day then january 15, five days before

president reagan was inaugurated, you have written that the iranian position changed dramatically. was that suspicious to you? gary: at the time, as i say, we were really tied up. it was a hectic time, everything was happening at once. but i later talked with the secretary of the treasury in iran in doing research for my book. and he said he had actually been one of the people in iran who wanted to see the hostages released. he thought it was a mistake to hold the hostages. but he said when he found out what kind of terms they were offering in this last second deal to get the hostages out of there, he changed his mind because he said iran should not have had to pay a price that high. they were actually paying off loans that cost them an enormous amount of money. basically they lost in the order of $8 billion in that trade.

and at the very last second they changed their terms totally, and basically were willing to make sensations we would have never even asked for. john: william casey was the campaign chairman in 1980 in the reagan administration, and he was the director of the cia. based on what you know about it, is it conceible that he could have been behind all of this? gary: we know for a fact that he actually made a trip to madrid, where we believe he met with iranian officials. but again, wean't tie that down beyond the dates and the times. we know that he sent his emissaries out talking to the palestinians, asking them to again touch with the iranians and deliver this message that they did not want the hostages released and that they would pay a price for it. a lot of things hpened around the casey during that period of time. john: as we know, president carter is in hospice care.

ben barnes said one reason he wanted to speak up is because the president is near the end of his life. how do you think the president is going to respond to this? gary: i have talked to president carter a number of times about this, but very generally. basically, as far as i know, he believes that this did, in fact, happen, and has become as much of a believer as i am. i think he was also skeptical at the beginning, but i think he has come to believe that this really did happen. and people are -- the amazing thing is that mr. barnes waited for 43 years to tell his story. and it's really too bad, because i thin the american people would really have deserved to know if something like this happens, if an election is being fixed, we ought to know about it.

and i am sorry that this story did not come out much, much sooner. john: fascinating bit of history. gary sick, thank you very much. gary: pleasure to be with you. ♪ john: sounds like science fiction -- a 5000-mile-long belt of seaweed weighing more than 11 million tons is crossing the atlantic ocean. and when some of it reaches florida, it threatens to wreak havoc in the coastal waters and on the beaches. but it is very real. it's called the great atlantic sargassum belt, so big that it can be seen from space, spanning the tropical atlantic from west africa to the caribbean. earlier i talked with ajit subramaniam, an oceanographer at columbia university's lamont-doherty earth observatory.

ajit: sargassum is a seaweed that grows entirely on the surface of the ocean. it is never attached to land. and the sargasso sea is called the sargasso sea because of the prevalence of sargassum in the northern part. the great sargassum belt is a new population of sargassum that seems to have developed since about 2011. we didn't see it then in satellite imagery before that. and then we saw this explosion of a new population about then. that seems to basically slosh back and forth between the coast of west africa and the yucatan mexican coast on the other side of the caribbean on an annual basis. john: is this one bed of seaweed? is it multiple plants? ajit: actually, it is made up of individual strands. so when you're out on a ship, we often sea band of sargassum that may be a couple of meters wide, let's say 10 feet wide, and that stretches sort of disconnected into the horizon. so you have these streaks that are continuous only to about 200 meters, 0 meters, each one. but then they line up one behind

the other because of the wind. john: and you say that this was first seen in imagery in 2011, and it's grown a lot since then. why did it suddenly appear and why is it growing so fast? ajit: there are a couple of theories on that that have been published. one has to do with the change circulation and the deep mixg which brought nutrients to the surface in 2010 that seems to -- that could have initiated this new population. the other theory is that it is changes in agricultural land use patterns in the amazon basin that has increased the flow of nutrients coming out of the river. i personally think the both may be partially right, but i do not know that either one explains it completely. so for me, it is still a little bit of a mystery as tohat caused the new population, but it is obvious it is there and it has been growing since. john: and i also understand that in the open sea there can be benefits from this is that right? ajit: that's right. so in the sargasso sea, for example, where this population has existed since before the

times of christopher columbus, it is seen as a habitat for fish. when we are out in the ocean, we often see fish like mahi-mahi that are hanging out under these big rafts of sargassum. so it's a very active ecosystem. i've sometimes compared it to an upside-down coral reef ithat it's a hotspot of biological activity. john: what are the threats if it gets -- when it gets closer to land? ajit: there are just multiple threats. one is that when it washes up on beaches -- and in barbados, i've seen piles of sargassum five feet high, which and you do not want to go to the beach when it is covered with sargassum, both because it really smells very badly when it rots. but then people have now done studies to show that pregnant women are affected by the hydrogen sulfide that is produced due to the rotting of sargassum. methane is produced when it rots. and that is a very potent greenhouse gas. you also have environmental damage, because while in the process of cleaning up sargassum, you have heavy trucks going on the beach and damaging

the rather delicate environment, the beaches. there is increasing erosion when sargassum is washing up on the beaches and gets washed away. it's been suggested that hatching turtles have a difficult time finding wirrgasao th beach, and therefore it might be affecting turtle populations. john: is there anything that can be done about this? ajit: the ideal way to deal with this is to try and prevent it from beaching. the question is, where do you put it? you know, because you don't have enough land area to then go dump it someplace. i have been working with colleagues. we have been working on this idea that if we can collect the sargassum when it is still in deep water offshore and sink it, then we are actually coming up with a nature-based solution for basically mitigating against climate change, because when these sargassum grow, they do photosynthesis, which basically means they take up carbon dioxide from the atmosphere and convert it into omass. and if you sink that biomass to depths greater than maybe 2000 meters, you're taking the carbon

dioxide out of circulation for about 100 years from the atmosphere. john: we've seen a lot of discussion about seaweed, replacing plastics, and they're starting to farm it in the oceans. are there any ecological concerns about farming in the ocean? ajit: if you are doing this in a seaweed, you just want to makee sure that you're doing some sort of lifecycle analysis where you're not spending more carbon in harvesting less amount of carbon. i always say you can't spend 100 kilos of carbon to then get rid of 10. and so that licycle analysis is something that needs to be done and pple are doing research on that. but do not know that that's a settled fact that you can actually do this in a carbon efficient way if your objective is to mitigate against climate change. john: ajit subramanian of columbia university's lamont-doher earth observatory, thank you very much. ajit: thank you. pleasure. ♪

john: the publishing world has a new infusion of enthusiasm and energy, all because of an online community of book lovers gathering on tiktok. known as "booktok," it's not just a place for book recommendations and reviews, it's also helpi to drive book sales. geoff bennett takes a look at this growing phenomenon. lee: i remember going to a barnes & noble and i saw a booktok table and i kind of went over there and looked at some of the books that were on that. i remember seeing those books and being like, oh, i'm interested in this. like, what is this? geoff: lee lynch isn't alone. step inside a okstore in the last year, colorful tables like this one are now a common part of the book buying experience. by day, lynch works as a therapist. in her spare time, she creates videos on the social media platform tiktok. focused entirely on books. lee: you are new here. my name is lee and i'm reading a

book from every independent country in africa in 2022. because i had a ton of time. kindf. geoff: lynch says shused that time to immerse herself in booktok, a space for anyone who loves books. >> a little life, the magnum opus of sadness. fun fact, the cover is actually just a picture of me when i finished reading it. >> and it has a black queer main character, black witches, paranormal, ghosts, a little bit of romance but mostly thriller and horror. >> january, february, march. geoff: booktok is having a major impact on the book industry. in 2021, adult fiction, driven by booktok, grew by 25% over the previous year. last year it grew another 8%. adrian: i think a lot of people hopped on tiktok, especially during the pandemic, because we were isolated. geoff: adrian cepeda, who owns a bookstore, has himself jumped into the world of booktok.

adrian: this was a way for me to reach people again through books and recommendations and really try and talk to them again about what they wanted to see and what they wanted to read. geoff: cepeda says his own booktok videos, and others, ar driving sales at his store. adrian: the minute a booktok video goes viral, the sales in my store gup for that book. geoff: booktok has become the go-to platform for readers looking to find recommendations for books in all kinds of genres, not always in the mainstream. chioma: it's like a mini universe of books that is encompassed in a social media platform. geoff: chioma nwuzi, who goes by "chibereading" on tiktok, has 17,000 followers. chioma: you're going to get your nonfiction, your true crime, your fantasy, your romance, all of it. click on one of those videos like, "i like fantasy, lord of the rings is cool," and now all of a sudden you find this book about like in 2500 humans have become robots and they now live on jupiter, and you were just loing for a book. geoff: the diversity of books featured on booktok is also expanding the type of books that are selling, says kristen mclean, the executive director

of npd books & entertainment, a company that tracks book sales. kristen: the largest categories that have grown are also the largest categories on booktok. so things like romance, contemporary women's fiction, thrillers and mysteries, fantasy. all of those have very strong followings on tiktok, and we've seen the authors that are embraced by tiktok being the leading authors driving the growth in these categories this year. elizabeth: it completely took people by surprise. geoff: new york times journalist elizabeth harris has been reporting on the meteoric rise of booktok. elizabeth: tiktok can really, really make an author. it can be a new author, it can get off as it's been around for a while, a book that's been around for a long time, a classic, a brand new novel, anything. there's kind of no limit to how much -- how many people can kind of take off on tiktok. geoff: samantha shannon is one of those authors. her 2019 book "the priory of the orange tree" is filled with dragons and queer characters. shannon recalls a conversation

with her grandmother, wondering if the book would succeed. samantha: i remember telling her what it was about and she said, samantha, arwe absolutely certain that anyone's going to want to read a book about dragons and lesbians? i know that "game of thrones" is successful, so people definitely want the dragon part. i'm hoping that they will also want the rest of it. >> i want to be so immersed that i'm thinkingbout the book even when i'm not reading it. and i was thinking about "the priory of the orange tree" all the time. >> i feel so quenched by this book. quenched. samantha: with tiktok, i've discovered there's actually a huge community of readers that really want to read those kinds of books. i often have readers asking me, you know, like, is it sapphic? is it about women loving women? that's something that they're actively looking for and asking for. geoff: adrian says booktok is a place to find connections that are relevant to his identity. adrian: i didn't see myself in stories until i was in clege and then i had to work backwards. right? and i thought it was a very singular experience for myself.

but when i got into booktok, it showed me that, oh, we all went through the same thing. we're all just trying to help people diversify their shelves so their kids don't feel like we did. geoff: and lee says the connections are even broader. they're global. lee: being able to join this community and find other people who not only look like me, but also share this interest, was such a big moment for me. it made me just feel a part of a community, of a greater community than what i grew up in. ♪ john: for women's history month, we're spotlighting another figure whose contributions have often been overlooked. tonight, a 20th century physicist who made indelible changes to her field. over the course of her trailblazing career, chien-shiung wu was known by a number of monikers. "the first lady of physics," "the queen of nuclear research," "the chinese marie curie."

she was one of the most influential physicists of the 20th century. her work helped hasten the end the second world war and changed our understanding of subatic particles. at a time when it was rare to educate girls in china, she studied physics at national central university in what is now nanjing, graduating at the top of her class. with the financial support of an uncle, wu came to the united states and in 1940 earned her phd at the university of california, berkeley. she could't find a research position at a university, so became a teacher. she was the first woman in princeton university's physics department. in 1944, she was asked to join the faculty of columbia university to become a senior scientist on the top-secret manhattan project, the government's world war ii effort to develop an atomic weapon. hework primarily involved uranium enrichment and radiation detection.

columbia, where she worked until retiring in 1980, was the site of her most significant work. in 1956, theoretical physicists tsung-dao lee and chen ning yang asked her to come up with a way to test their theory on the behavior of subatomic particles. the results of her ingenious method, known as the "wu experiment," shattered a fundamental concept of nuclear physics that had been universally accepted for 30 years. lee and yang were awarded the 1957 nobel prize in physics. but wu, like many women scientists of her day, was left out. in a speech at mit in 1964, she asked whether the tiny atoms and nuclei, or the mathematical symbols, or the dna molecules have any preference for either masculine or feminine treatment. her 1965 book "beta decay" is still considered standard reading for nuclear physicists.

while her work wasn't recognized for the nobel prize, she earned many other honors, including the national medal of science in 1975 and the first wolf prize in physics in 1978. and in 2021, 24 years after her death in 1997, wu was honored with a u.s. postage stamp. and that is "pbs news weekend" for this sunday. on monday, we look back at the start of the iraq war 20 years ago, with an update on one marine unit that hoped lead the invasion. i'm john yang. for all of my colleagues, thanks for joining us. have a good week. >> major funding for "pbs news weekend" has been provided by. >> for 25 years, consumer cellular has been offering no-contract wireless plans designed to help people do more of what they like. our u.s.-based customer service team can help find a plan that fits you. to learn more, visit consumercellular.tv.

>> and with the ongoing support of these individuals and institutions. this proam was made possible by the corporation for public broadcasting and by contributions to your pbs station from viewers like you. thank you. [captioning performed by the national captioning institute, which is responsible for its caption content and accuracy.] >> you're watching pbs. by pure encapsulations,

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