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Dating clams to study pollution history on St. Croix, US Virgin Islands

Underwater seagrass meadows are disappearing fast, Dr. Kelsey Feser investigates why with the support of the Paleontological Research Institution (PRI). 

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Dr. Kelsey Feser

The Paleontological Research Institution (PRI) in Ithaca, New York, USA is currently running a campaign to support its new dating laboratory.  Before you jump to conclusions, this is not a lab taking the likes of tinder to a new scientific level, it is a lab for gauging the ages of biominerals such as seashells and bones using a technique known as amino acid racemization (AAR) geochronology (for info on how this works see PRI’s project page).  The dating of biominerals and seashells has many applications in research. Fields such as paleontology, tectonics and marine conservation all benefit from accurate dating methods that can help scientists put their samples in temporal context and form a clearer understanding of what has been going on over a period of time.

We spoke with Dr. Kelsey Feser, a paleontologist from Cornell College in Iowa, USA, who is visiting PRI’s AAR lab to date seashells from St Croix, U.S. Virgin Islands. Dr. Feser collected the shells from sediment cores and is using them to investigate the history of seagrass meadows that are threatened by pollution.  During her visit to Ithaca, we took the opportunity to ask her a few questions about her research and why AAR dating is an important tool for her project…

How did you collect the seashell samples and what can they tell us about human impacts on the spectacular marine environments of St. Croix?

I collected the seashells by digging sediment cores while SCUBA diving in shallow seagrass meadows just off the coast.  The cores were 40cm deep, and contained all of the sand and seashells that have accumulated on the seafloor for hundreds, or even thousands of years.  By picking out the shells of thousands of clams and snails from several depths in the cores we were able to construct a record of how the abundances of these animals have changed over time. 

Dr. Feser coring a seagrass bed in St. Croix

Dr. Feser coring a seagrass bed in St. Croix

Clams and snails are very sensitive to environmental changes, particularly those imparted by human activity, so through this research we hope to determine whether the population changes we found were  caused by nearby sources of pollution.

The sorts of pollution sources that we think could be impacting marine clams and snails in St. Croix include runoff during heavy rains and contamination from a power plant and a large, unregulated dump.

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Human impacts on the coast of St. Croix are not hard to find—Dr. Feser photographed this decaying barge not far from the island’s main power plant.

Why is AAR dating important for your research on St. Croix? What do you hope to learn from the data you are collecting at PRI?

I’ve been working in St. Croix for six years, and the question that keeps popping up is “how old are these shells?”  And it’s not a trivial question.  I am interested in the effects of human impacts on populations of marine clams and snails through time, so it is incredibly important to know how recently these population changes took place.  If they happened 5,000 years ago, humans were likely not the cause!  By sampling in seagrass beds, where a thick root mat anchors the sand and prevents it from getting mixed up by waves, we are hoping to find that the deeper the shells are buried, the older they are. 

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The clam shells being dated are tiny—smaller than a fingernail!

This would help us better interpret the changes we see in clam and snail populations through our cores.  By collecting lots of shell ages throughout a given core, we can answer this question. 

Finally, we want to know how long-lived seagrass beds are through time; this is especially pressing given the alarming declines in seagrass meadows around the world. 

By combining our knowledge of change in seagrass-indicating mollusks, and the ages represented through the core, we can determine over what timescales seagrass beds have remained stable around St. Croix and hopefully improve our understanding of what the human impacts on these ecosystems have been over time. The results of this research could have important implications for the conservation of other types of marine life that rely on seagrass, such as sea turtles. 

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A sea turtle foraging in seagrass, a habitat which, sadly, is in decline worldwide

 AAR is the best option for me because I can date far more shells than I could using a more expensive technique like radiocarbon dating, and quantity is crucial for answering these questions

What have been the benefits of running your samples at PRI?

I was thrilled when I found out PRI was getting an AAR lab! By visiting the PRI lab, I have learned the AAR process first-hand and am processing my own samples. This has provided me with invaluable insight into the steps required to date a shell and has also brought down the cost of sample processing considerably. I also was able to bring along one of my undergraduate students, John Lewis, who is participating in a faculty-student summer research program with me. Neither of us could have gained this “insider’s insight” had we elected to mail our samples to a lab to have them run for us. Additionally, working with PRI researchers like Greg Dietl and Steve Durham has been valuable and hopefully will lead to new collaborations beyond my short stay here in Ithaca.

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Dr. Feser and her undergraduate student, John Lewis, at work in the AAR lab last week

A big thanks to Kelsey for answering our questions. You can learn more about her research on St. Croix in the video below.

Please support our campaign to fund the AAR lab at PRI so that we can continue contributing to important projects by researchers like Dr. Feser!

You can also help us by spread the word about the project! Share on Facebook or tweet about it! 

 

Listen to the bees

There are twenty six different bumblebee species in the UK, and you can see perhaps ten of them in most suburban gardens if you have a few bee-friendly flowers and if you look hard enough. Honeybees are usually common enough too – these slim, brownish insects are of course the ones that give us honey, and that are kept in hives. But this is just the tip of the bee iceberg; there are also leafcutter bees, sweat bees, mason bees, mining bees, carpenter bees and many more, about 270 species in total in the UK!

Picture tweeted by @twaihaku for the #beeboxchallenge

Picture tweeted by @twaihaku for the #beeboxchallenge, click on image to find out more and to check out Prof Dave Goulson’s research proposal that is currently crowdfunding on Walacea and learn more about the photo competition.

Globally, there are an astonishing 20,000 known species of bee (and no doubt many more yet to be described by science). The large majority are solitary creatures in which a female makes her own small nest, rather than living in a colony with a queen and workers as do honeybees and bumblebee. Most people go their whole lives without ever even noticing these little creatures, yet they live all around us, they pollinate our garden flowers and vegetables, and they ensure that wildflowers set seed.

I’ve heard bees describes as tiny flying paint brushes; they are furry, and their fur helps them to collect pollen and hence spread it from flower to flower. When we humans resort to hand-pollinating a crop, for example if we want to ensure a specific cross takes place, we use a paint brush to mimic a bee. But the analogy with paint brushes can be viewed at another level, for without bees, our landscapes would have little colour. Back in the age of the dinosaurs there were no colourful flowers; plant relied on wind to carry their pollen, as grasses and pine trees do to this day, and hence they had no need of brightly coloured petals to attract pollinating insects such as bees. Eventually, plants evolved a much more efficient system to get their pollen moved from flower to flower; they co-opted bees and other pollinating insects, bribing them with sweet nectar, and vying with other plants to attract them via beautiful, scented flowers. The wonderful flowers that brighten our gardens, spring woodlands and hedgerows would not exist if it were not for bees and their kin.  

Worryingly, these vital creatures are in trouble. The modern world poses many threats to them: our countryside has far fewer flowers than it once did, with almost all of our hay meadows and downland having been ploughed up in the twentieth century. Herbicides enable farmers to grow weed-free crops, and where wild flowers do persist in the field margins and hedgerows they are often contaminated with insecticides. On top of that we have accidentally introduced new parasites and diseases from abroad that attack both honeybees and our wild, native bees. As a result, many of our bees are less common than they used to be, and some such as the short-haired bumblebee have gone extinct in Britain.

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This is an example of a short haired bumble bee, sadly now extinct in the UK.

Fortunately, we can all help to reverse these declines. Plant a few more bee-friendly flowers in your garden for a start; there are many to choose from. As a general rule, avoid annual bedding plants which tend to be the end result of years of intensive selection for huge blooms with extra petals, but which have often lost their nectar, pollen and scent, so that they are of no interest to bees. Instead, go for traditional cottage-garden favourites: lavender, thyme, aquilegia, alliums, marjoram, comfrey. Go for ‘single’ rather than ‘double’ varieties; for example single roses and dahlias are great for bees, while doubles are mostly hopeless. Try growing lovage and angelica, which are much loved by some of the smaller solitary bees. Squeeze in some native wildflowers – for example viper’s bugloss is a beautiful purple flower that sits well in a sunny herbaceous border and will attract a cloud of bees.

If you can, buy your plants from an organic nursery, grow them yourself from seed, or plant swap with a neighbour. Otherwise there is a serious risk that the plants you buy might have been soaked in pesticides and could do more harm than good, at least in the short term. Of course you should avoid using insecticides yourself; it is my view that there is absolutely no need for them in a garden setting, where you should have an abundance of natural enemies such as ladybirds and hoverflies ready to munch up pests as they appear. You might also try buying, or better still making, a ‘bee hotel’. These provide holes for solitary bees to nest in, and can be very successful; they are particularly popular with red mason bees, excellent pollinators of your apples and pears. Finally, consider taking part in a citizen science project to gather data on how our pollinators are faring over time.    

Bees have been around for 120 million years or so, far, far longer than we humans have. They have been quietly pollinating our crops since we first started growing them, in the Middle East about ten thousand years ago. Now, after all this time, they are in trouble, and it is entirely down to us. We owe these little creatures. Together, if we all do our bit, we can ensure a future for all of our bees and other pollinators, and ensure that our grandchildren grow up in a world where the buzzing of bees is still a familiar, reassuring sound of summer.

If you would like to learn more about wild bees and other pollinators, read the bestselling books “A Sting in the Tale” or “A Buzz in the Meadow” by Dave Goulson which you can recieve signed copies of through supporting Dave Goulson research on Walacea. Prof Goulson plans to investigate whether neonics or other pesticides dangerous to bees are present in plants sold in garden centres, potentially labelled as bee friendly.

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Picture tweeted by @canonuser101 as part of #beeboxchallenge, click on image to learn more about the competition and check out Prof Goulson’s crowdfunding page.

 

Alzheimer’s Reversed In Mice: What Does This Mean For Us?

Alzheimers

Image credit: *Ann Gordon/Flickr CC BY-SA 2.0

An increasing burden on public health across the globe, Alzheimer’s is an intensely studied disease and promising research often hits the headlines. Just the other day, for instance, a study published in the prestigious journal PNAS kicked up a storm in the media because of the potential implications of the results: that Alzheimer’s could be reversed. 

One of Walacea’s successful crowdfunding campaigns is an Alzheimer’s project, and interestingly there are some links between this research and the recently published study. We therefore decided to catch up with the scientist behind the former, postdoctoral researcher Dr Eloise Mikkonen, to chat about both pieces of research and what we could learn from them, and whether the hype is justified. 

But first things first, what did the new study find? Researchers from Hong Kong and Glasgow universities managed to reverse the memory problems of mice with Alzheimer’s-like disease, in addition to reducing the build-up of toxic clumps of protein, called beta-amyloid plaques, which are characteristic of the condition. 

They achieved this by giving them injections of a molecule called IL-33, a signalling protein produced naturally by the body which plays various important roles in mediating immune system responses. The rationale for testing this out as a potential treatment stems from the fact that the brains of people with Alzheimer’s commonly show lower than normal levels of IL-33, and several different mutations in the gene that makes IL-33 have been linked with Alzheimer’s.  

The team thinks that the injections changed the activity of a type of immune cell called microglia, which are the brain and spinal cord’s primary defence system, boosting their ability to gobble up beta-amyloid and putting them in anti-inflammation mode. That’s an important find, as work by Mikkonen and others has found that inflammation plays a role in the progression of Alzheimer’s, something that she intends to scrutinize further in her crowdfunded research. 

But as is often the case with science, things aren’t quite as black and white as they may first seem. As Mikkonen explains: “Genetic investigations of Alzheimer’s disease have revealed that inflammation plays a role, but it isn’t clear as to how. It could be that some inflammatory factors decrease and others increase, and there needs to be a certain pattern which leads to Alzheimer’s disease. 

“It should be noted that some inflammatory factors are beneficial in certain diseases, whilst being detrimental in others… all in the same body at the same time!”

Mikkonen also points out that mice don’t naturally produce the proteins which result in the characteristic brain lesions seen in Alzheimer’s, so the animals have to be mutated for this kind of study. We should therefore be cautious about jumping to conclusions in humans, a message that the researchers have actually been quite clear about. That said, animals models are incredibly useful tools in medical research, so we shouldn’t dismiss this as irrelevant. 

Another important issue Mikkonen raises is that removing the beta-amyloid plaques could actually release toxic molecules into the brain, and therapies that have attempted to do this before have failed. In addition, her work has shown that these plaques are surprisingly common in non-demented individuals. 

“Does this mean that if they lived long enough, they would eventually develop Alzheimer’s?” Mikkonen ponders. “Or do they have some additional protective factor that we don’t know about that differs from those that succumb to the disease?”

These are questions that she seeks to address in her research, which will involve analysing one of the biggest brain samples in the world, totalling more than 1,300 people. Fewer than 30 of these individuals had memory problems or early stages of dementia, so Mikkonen will look for the presence or absence of brain lesions linked with Alzheimer’s and attempt to identify certain genetic factors or lifestyle choices which could influence the risk of developing them. 

So far, the campaign has exceeded its fundraising goal by more than £1,000. As a result, she has introduced stretch goals which, if met, will allow further rounds of data analysis to look for potential links between disease progression and various factors, like exercise and blood type. Each set of analysis costs £1,000, so do something amazing and dig deep for this brilliant cause! 

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