Flat foram

Windy ride
By  Nicole Webster

I had a thin section made of one of my shells, and it came back with a serendipitous hitchhiker. A foraminiferan, you know, those single celled protists that make a gorgeous test (shell) usually out of calcium carbonate? Well it was at just the right place to be beautifully sectioned itself. The section is 30um thick of a 5cm shell, and the foram itself is only 0.5mm wide.

Foram thin section in plane polarized light. Credit N. Webster

Foram thin section in plane polarized light.  The darker spots inside the test are probably dried up tissue, and the little balls underneath the test are probably the glue used to attach the foram to the shell. Credit N. Webster

Foram thin section in cross polarized light. Credit N. Webster

Foram thin section in cross polarized light. Credit N. Webster

Thin sections are typically used in geology to identify different crystals, and thus the rocks that they are made up of. I recommend a quick Google image search, some are really quite pretty. Here I was using it to see how many layers and in what orientation the crystals are layed down in my snails.
A chunk of rock (or shell) is ground down as smoothly as possible to 30um (0.03mm) so that it is transparent. Once under the microscope, a polarizing filter is used to see crystal features better. A cross polarizing filter is used to see interference colours, allowing greater characterization of the mineral. That is why the second image looks a little like something from the 60s. Although the CaCO3 is relatively clear, the glass of the slide refracts the light quite a bit, making a psychodelic pick rainbow. This is a very simplistic view of thin sectioning, please correct me if I’ve misunderstood something.

PS I learned a new word making this post. Arenaceous. It means sandy, or likes sand (for plants), and specifies a geologic grain size ranging from 2 to 0.625mm. In this context it means those foraminifera that don’t grow their own shell, but rather glue bits (read:sediments particles) together to make a shell.

References
1. Rock-Forming Minerals in Thin Section. Steve Dutch, Natural and Applied Sciences, University of Wisconsin. https://www.uwgb.edu/dutchs/Petrology/thinsect.htm
2. Corliss, B. H. 1985. Microhabitats of benthic foraminifera within deep-sea sediments. Nature 314:435-438.

Jack O’ Lanterns Made with R

Figure 1.

Figure 1. Jack O’ Lanterns carved with the statistics application R, by students in the Bamfield Marine Sciences Centre Fall Program.

Maybe you already know that the computer programming language R can be used for statistics, and data visualization. You can also use it to draw pictures. The easiest way to do this is by using the ‘locator’ and ‘polygon’ functions. You can make your own Jack O’ Lantern with R using the script provided in the previous post “Pumpkin Carving with R”.

And now for something completely different

By Nicole Webster

Perhaps we are a little focused on invertebrates here, or perhaps this gorgeous weather has gone to my head, but I have a ‘treat’ for you for an Image Fest Friday.

Fish bones dried on the docks. Not that interesting. Can anyone ID the parts?

Fish bones dried on the docks. Not that interesting. Can anyone ID the parts?

Yeah, sorry, its poop. but whose?

Yeah, sorry, its poop. but whose?

That is clearly no bird poop. From the diameter I was thinking cat-sized.

That is clearly no bird poop. From the diameter I was thinking cat-sized.

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It was all over the docks, to the dismay of Janice who washed it all off. She also solved my mini mystery. Its river otter poop! It is regularly appearing on the docks, and I saw a couple playing there earlier in the year, so there may be some living nearby.

Some Intertidal non-crustacean arthropods

By Nicole Webster

The intertidal is a transitional zone, from the water to the air, but also from salt to fresh water. A lot has been said about the ecological consequences of this transition, perhaps idealized by salmon’s migration and how they transfer nutrients from the marine to terrestrial/freshwater ecosystems (Cross-boundary subsidy). I’m not going to say anything in depth about this, and if you are interested, I recommend speaking to Caroline Fox (uvic website), who is in and out of Bamfield semi-regularly and is completing her PhD on this topic.

This post is nothing so ecological or philosophical. This summer I came across a couple arthropods (non-crustacean) that are not commonly mentioned and wanted to expand your view of the intertidal.

This is Diaulota densissma (I believe).

BEETLE-006

This is a rove beetle (Diaulota densissma) in a petri dish, with possibly a larva. They are not easy to photograph. I could have sedated one for better ID and imaging, but didn’t. Credit: N Webster

I encountered these beetles on the barnacle rocks that I heave to the lab to feed my greedy snails. Quite a few of them I found regularly swimming desperately on the water in my seatable and crawling around on the dry rocks. At first I thought they were unfortunates brought in from a true terrestrial habitat, but there were too many, and too consistent. It was suggested to me to check out Kozloff’s Seashore life of the Northern Pacific coast. It is not a field guide, nor is it like his Key to Marine Invertebrates. It is really a nice introductory book about the seashore, looking from high to low intertidal, from sandy to rocky shores, and describing the types of organisms found there.

BEETLE-005

This is the beetle on a barnacle rock. Credit: N Webster

Indeed my rove beetle is in the book. It is a small intertidal predator that eats mainly amphipods and other tasty arthropods at low tide. According to Ahn (1996) these beetles live even in the low intertidal, and can spend most of their day submerged. They don’t have gills, they just find an air pocket (barnacle test, under a rock) and wait. Watching them swim, they obviously have a highly hydrophobic coating, probably with lots of hairs to trap air bubbles.

 

This is Neomolgus littoralis. It is an intertidal mite, known as the red velvet mite.

Red velvet mite on some Ulva, in the high intertidal on Edward King. They are ~3mm in length. Credit: N Webster

Red velvet mite on some Ulva, in the high intertidal on Edward King. They are ~3mm in length. Credit: N Webster

These mites are found in the high intertidal and eat kelp flies (another intertidal insect). They are very easy to spot, as they are shockingly red.

 

References

  • Kozloff, E.N. 1993. Seashore life of the Pacific Northwest: an illustrated guide to northern California, Oregon, Washington, and British Columbia. 370 p.
  • Kozloff, E.N. 1974. Keys to the marine invertebrates of Puget Sound, the San Juan Archipelago, and adjacent regions. Seattle, Washington, University of Washington Press, 226 p.
  • Kee-Jeong Ahn. 1996. A Review of Diaulota Casey (Coleoptera: Staphylinidae: Aleocharinae), with Description of a New Species and Known Larvae.The Coleopterists Bulletin Vol. 50:3, pp. 270-290

 

“Why Bamfield, British Columbia is unique, awesome and you should go there” part III

Bridgette just posted the last of her 3 part series on Why Bamfield, British Columbia is unique, awesome and you should go there. Part 3: Learning.

Do go check it out. I praised her and her blog last week, which you can check out here.

Bracket (shelf) fungus. Why? Because. Credit: N Webster

Bracket (shelf) fungus. Why? Because. Credit: N Webster

 

“Why Bamfield, BC is unique awesome and you should go there” – Bridgette Clarkson

A friend of mine has a wonderful blog. It is insightful, delightful and full of photos. Bridgette just completed a stint working as a public educator for BMSC, and described herself as a biologist and science education consultant.


Crashing Bull kelp (c) Bridgette Clarkson

In honour of World Oceans day (yesterday), she posted the 2nd part of her 3 part series about her time in Bamfield this year.

I strongly encourage you to check them out, if only for the breathtaking imagery.

Do check out some of her other posts like how to check marine forecasts, or her flickr stream.