How I do my science…

Hey guys!

It’s time for a new blog post today and I decided to do something a bit different on this one! I think that many non-scientists aren’t really familiar with the whole process of scientific research, how it all comes together and what it leads to. Since I’ve been doing research for quite a few years now, I thought I’d share what stages I go through in my studies to go from having a plankton sample in my hand, to having a publication in an international journal!

So in case you didn’t know I work on animals called arrow worms, which are found drifting in seas all over the world. I specifically work on the arrow worms that live in the Arctic. I’ve been working on these guys for a while now, but I’m into all kind of animals and I’d also love to be working on sharks, starfish or polar bears. It’s the interactions between the animals (e.g. predator-prey interactions) that I find the most interesting part. Also, despite what organism you’re working on, the kinds of analyses you do to answer biological questions can be very similar.

How do biologists shed light on the plankton?? Reproduced from: http://www.senckenberg.de/root/index.php?page_id=16989&PHPSESSID=bt63c90henjoljhfc610t837qr9km9nu
How do biologists shed light on the plankton?? Reproduced from: http://www.senckenberg.de/root/index.php?page_id=16989&PHPSESSID=bt63c90henjoljhfc610t837qr9km9nu

Any research project (on zooplankton) begins with catching the plankton! 🙂 We normally do that onboard a large ship, using nets that are specially made for catching these marine animals. The nets are pretty large but they have a small mesh size which keeps most of the plankton inside. When the nets are pulled back to the ship deck via a winch, we “fix” the plankton with a chemical preservative. Unfortunately this is gonna kill them, but the samples can then be used for many years to study and learn about the animals!

If you want to do the kind of research that I do (on the “seasonal ecology” of animals), it’s essential that you collect samples over a long time period, like every month for a whole year. It’s a hard task, but it allows you to investigate things like what depths the animals are found at in December and compare it with July. That’s really interesting because some plankton migrate kilometres up and down in the water during the course of one year, which is an incredible distance given their small size. They mainly do this for feeding reasons. Migration is kind of a hot topic in Arctic plankton research at the moment, like in regard to what cues these movements.

In the lab I pick out my arrow worms and separate them into species using a good microscope. That’s pretty easy in my case because there are only three species that live in the Arctic, and they look pretty different! I measure loads of different parameters, but one of the most important ones is the body length of each animal. That’s because body length can be used to separate the arrow worms into different size groups: groups that were probably born around the same time, will probably reproduce around the same time, and may have similar lifespans. I then make a graph from the body lengths in each month. You can see this kind of graph below, which shows data on one species (Parasagitta elegans) from Svalbard in October.

A 'histogram' of animal body lengths where different size groups are clearly seen.
A ‘histogram’ of arrow worm body lengths

You can clearly see from the graph that there were three size groups of arrow worms, based on their body lengths. There were relatively small ones (~7-15mm), middle sized ones (~19-28mm) and bigger ones (~30-43mm). The software I use highlights these groups (also known as size cohorts) using red and green lines. We know that the small ones were born quite recently: in the Arctic, it’s quite common that species are born in a relatively narrow time period when environmental conditions are just right for them! Next we want to work out which groups their parents are. To do this, I look at the gonads of the worms!! Arrow worms are very weird creatures because they are males and females at the same time, meaning that they can… fertilise themselves. They are able to reproduce when they well-developed ovaries AND testes. I’ve previously shown that Parasagitta elegans in Svalbard can reproduce when they reach around one-year old.

Then, using samples that were collected from different depths in the water column (like near the surface and also much deeper), I look at where both the young ones and their parents were found at different times of the year. This can reveal where reproduction takes place and to what extent the animals migrate.

And then we write all our exciting new findings up for publication in peer-reviewed journals! I have two publications already and I’d love a third one soon! Versions of your manuscript are read by other scientists that work in the same field or a closely related one. With their experience, they give you loads of useful comments and suggestions, which help you improve your paper. Even the best papers get checked and modified at least once, but when you re-submit, you will hopefully get accepted!

Front page of my first paper in Marine Ecology Progress Series
Front page of my first paper in Marine Ecology Progress Series!

And this is a brief summary of what I do!

If you have any questions, please send me an email at jordangrigor@gmail.com. I’m always happy to discuss more!

Cheers, Jordan 😉

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