Smurfing up the stats

Things have been ridiculously busy, and my final year of undergrad is flying by like its pants are on fire. I've been tied up with class, starting applications to graduate school and contacting potential advisors, and research. The field and lab part of my research is gone till January break, but there is always plenty of the other half: organising data and analysing data and writing, writing, writing.

Scuba Smurf is a little sad about being out of the water this long (as am I) but he is keeping me company as I try to run statistical routines that I am unfamiliar with, on software that I am fairly new to. And because I am working through it slowly and over long periods of time, I came up with another work song...


The Variances Song
(To the tune of 当我们都在一起 aka 'The More We Get Together')

What's wrong with my variances, my variances, my variances
What's wrong with my variances, they are unequal
Transformations are futile
Rank-sum tests lack power
And so to fix the variances
I tried GLMs*


* and by GLM, I mean a generalised linear model, not a general linear model

RI intertidalling

This weekend was the first weekend of the semester that I wasn't in Nahant, which was a bit of a relief. I really love being in Nahant and doing research there, but constantly traveling and doing homework on the train/in the lab is a little tiring. Nevertheless, I still got to go out into the field over part of the weekend to help set up an algal transplant experiment in Little Compton, RI.

Field site in Little Compton. I love how you can see the diversity of reds, greens and browns from a distance here.

Intertidal cormorants!

 Kylla's been setting up reciprocal transplants of Fucus vesiculosus (which Wikipedia says is the 'bladder wrack' - I don't know the common names for any algae!) from the low and high limits of its intertidal range, at sites spanning ~500 m of New England coastline to figure out if low and high zone Fucus show different survival rates and nutrient uptake, and if the patterns vary geographically. This weekend we set up the transplant for one 'south of the Cape' site in RI.

This means abducting the algae and re-attaching them either to the same tide height or the other end of their range over the course of 2 days' fieldwork. We have (bright! coloured!) cable ties around the algae to act as anchors into the z-spar on the rock. There are also temperature loggers deployed at the low and high tide height to monitor temperatures experienced by the transplanted Fucus.

 

Scuba Smurf helped out too. Here he is with the numbered setup and Fucus transplanted to the high zone!

Scuba Smurf with the little PVC hut that holds the temperature logger. 

Yay for interspecific variation!!

Old field romping

We're into the second week of Fall classes so things should be settling down somewhat. Yay for classes that have a field trip the second week. And yay for classes that make small sotongs and their marine friends do terrestrial fieldwork.

Yesterday we drove about 45 minutes from Providence and sampled old field communities in Glocester, RI for an experimental design class. I'm always slightly surprised by how big the quadrats for terrestrial work are...I'm not sure if this is a general pattern. We quantified white pine abundances at different distances from the forest edge, and milkweed abundances on 10 x 10 m grids.

Old field with goldenrod and milkweed, and the forest edge in the background.

Counting milkweed in a square metre quadrat on a 10 x 10 grid.

Also, everything was remarkably clean, i.e. there was nothing wet or slimy or particularly smelly. I guess everything is weather-dependent (we got a tiny bit of rain) but still, nothing comparable to algae-covered butt.

Scuba Smurf came along too. Somewhat out of his element, but he quickly made friends with the milkweed.

More fun with herbivory

School started on Wednesday, which means that I had to leave Nahant and go back to Providence and actually sit in classes. My classes this Fall are fairly interesting - Conservation Biology, Methods of Applied Math, an Introduction to GIS - plus I'm auditing an experimental design class. Still, interesting classes are less exciting than actual research, especially actual research that still needs to be done. I have a very nice 3-day class schedule (Tues-Thurs) so Friday found me right back at the Marine Science Center working, again.

This summer I ran a big herbivory experiment looking at Lacuna snail preferences among different species of subtidal algae. This weekend I'm trying to figure out if other herbivores like isopods may also be important in grazing the algae.

The baltic isopod, Idotea balthica. This is a fairly large individual; the ones we find in our algae are generally around 1 cm in length.

To do this we're running a much smaller-scale pilot experiment with just a couple of algal species and only 6 replicates each. The isopods go in little modified petri dishes with a similar structural theme to the containers I used for the Lacuna experiment - identical amounts of algae in both chambers of the dish, herbivores in one chamber.

One of my petri dishes. The right chamber has herbivores; you can just see an isopod at the top-right of the tag number 08. The left chamber is herbivore-free to account for loss/gain of mass that is not due to herbivory.

The overall setup. Petri dishes are zip-tied down to the aqua mesh to keep them submerged. You can see that they are arranged nonrandomly because my arms are short and I can't reach the area in the middle right of the water table. They are interspersed, though...

Scuba Smurf did a dive to check that everything was well attached and working.

Scuba Smurf approves of this experimental setup.

Introducing...Scuba Smurf!

Today I got a new dive buddy: Scuba Smurf.

Scuba Smurf was a gift from my five-year-old friend Caden. He is all decked out in his flashy dive gear, complete with octopus, power inflator and dive gauge/computer. Scuba Smurf is going to have great adventures, but first he needs a check-out dive in the lab touch tank...

Scuba Smurf meets our resident blue lobster (newly moulted!!)

You can follow the adventures of Scuba Smurf here, on his photo album.