Comments for i'm a chordata! urochordata!

Comment on Living a Dream: Back to SML by Hilary

Hilary — Tue, 21 May 2013 00:34:28 +0000

Oh man, I would have loved to do that sort of thing as an undergrad! Looks awesome.

Comment on Favorite Wave Sensor? by Jared Figurski

Jared Figurski — Mon, 06 May 2013 17:58:40 +0000

Pressure gauges have been used and can be made fairly cheaply if you are technically inclined. I believe the Denny Lab has done this. Using something that responds to drag forces may give you a more direct measure of the forces experienced by organisms in that area, so pressure gauges may not be as effective in shoaling areas of complex bathymetry. You are right though, URSKIs require a bit of maintenance in environments with a lot of drift algae. The accelerometers are memory limited, which is silly in this day and age. With more memory, they could be run a LOT longer. Shorter deployments during swell events could allow you to characterize your study area, even if you are unable to sample throughout the your study. The value of this approach, of course, depend on your question. Good luck and please let us all know how you proceed.

Comment on Favorite Wave Sensor? by jebyrnes

jebyrnes — Mon, 06 May 2013 17:27:05 +0000

Indeed, I’m thinking of building a few and trying them out. My problem is that I’d like to get some long-term data on wave heights or energy. The URSKI looks awesome, but would have to be checked regularly for fouling. Have you run into any longer-term solutions? I’ve been wondering if it would even be possible to somehow use a digital pressure gauge for this – or are they not sensitive enough?

Comment on Favorite Wave Sensor? by Jared Figurski

Jared Figurski — Mon, 06 May 2013 17:14:11 +0000

I was just forwarded this blog posting. I am happy to answer questions about using URSKI wave gauges. I originally came up with idea after talking Dr. Lohse at UCSC. He had the original idea of using accelerometers to measure wave energy in the intertidal. I don’t know if he has had success with that, but I am sure it is possible. I imagine applying an accelerometer to something like a Denny ball (a Mark Denny invention) could work. One student, Kroeker, in the Michelli lab used used the traditional URSKI in a shallow environment in Italy. I don’t know if she ever worked up those data though. As long as they don’t go dry or get too tangled by seaweed, they can be modified for shallow environments. The key is that they can at the very least provide a more quantitative relative measurement of wave exposure across your study area. They were not tested in shoaling environments, but in theory they are effective in environments with current as long as you use the standard deviation approach outlined in the paper.

Comment on Favorite Wave Sensor? by jebyrnes

jebyrnes — Wed, 24 Apr 2013 18:57:29 +0000

Yeah, I’m looking nearshore. CDIP does a great job for coastal California, but I haven’t yet found its equal for here. I’ll check in on the OpenROV community, though. That might be fantastic!

Comment on Favorite Wave Sensor? by Kim Martini

Kim Martini — Wed, 24 Apr 2013 18:07:59 +0000

I don’t have any experience with coastal wave sensors, so I can’t help you there. But if you need significant wave heights, you should check out this ocean forecast model for the Gulf of Maine:
http://neracoos.org/datatools/forecast/wave
It seems to be based on NOAA’s wavewatch model, of which a regional Northwest Atlantic Grid can be found here:
http://polar.ncep.noaa.gov/waves/viewer.shtml?-multi_1-NW_atlantic-
and also a smaller more local wave model by researchers at Texas A&M
http://www.tamug.edu/mase/Wave_file/GulfofMaine.htm
Also check out buoy data from the National Buoy Data Center http://www.ndbc.noaa.gov/ and more locally, the Gulf of Maine Ocean Observing system http://www.ndbc.noaa.gov/

But it sounds these sensors are going to be deployed very close to shore, so these open water wave forecasts may not capture all the variability in your study area as the waves are likely modified while shoaling. But they might be good enough…

You might want to check out the OpenROV community to see what they have come up with in terms of cheap pressure sensors. I am not exactly sure what the accuracy of the pressure resolution you need to resolve waves, but what they have come up with might be good enough. Allie Barner (who commented above) might be the person to ask…

Comment on Favorite Wave Sensor? by jebyrnes

jebyrnes — Wed, 24 Apr 2013 16:00:06 +0000

Yup – I think that’s what is used in the Figurski et al. technique discussed above. It seems like a great approach, and actually measures what I’m more interested in – how much disturbance is being felt, rather than just wave height. We all know these things can attenuate with depth, and given that I’m not dealing with canopy forming species here, that technique might be far more relevant.

Comment on Favorite Wave Sensor? by Drjaylow

Drjaylow — Wed, 24 Apr 2013 15:55:03 +0000

Not sure how relevant they are but have you seen the hobo accelerometers? I think they’re mostly useful for seeing how many G’s you experience on roller coasters. And I don’t even want to consider how you would use those measurements to back-calculate wave height. Might be useful measure of sheer stress for attached macroalgae?

Comment on Favorite Wave Sensor? by jebyrnes

jebyrnes — Wed, 24 Apr 2013 15:37:53 +0000

Oh – Figurski et al 2011, you say? Link! This is interesting. Definitely email me the appendix – I’d love to see it. I can see how this would be difficult in the intertidal, though. Subtidally, aside from fouling, it might even be easier. Good luck with getting them out, and I’d love to hear how it works out!

Comment on Favorite Wave Sensor? by Allie Barner

Allie Barner — Wed, 24 Apr 2013 15:05:55 +0000

Hi Jarrett! I’m excited to talk to someone about this – it’s been my pet project for the past 2 years of my dissertation. Though not directly related to my research and definitely not my area of expertise, I’ve been looking for a way to measure intertidal wave height at different scales (among sites and within sites on the Oregon coast). Like I mentioned on twitter, I have used the RBR Virtuoso with great success. But it was lent to me by a collaborator, and is far outside my budget as a graduate student, as are the Onset pressure gauges. So I’ve settled on using the Onset Pendant Gs, for cost effectiveness. And they have been used subtidally before – there’s a methods paper on it by Jared Figurski (Figurski et al. 2011, Limnol. Oceanogr.: Methods). A lot of the details are in the appendix which is not available online, but I have that file from the author if you are interested in it.
I’m not sure if this is relevant to your work (is it benthic?) but I’ve been struggling to deploy these in the intertidal because they need to be fixed to the substrate inside a wire cage to protect from dislodging. Last summer I built stainless steel mesh cages and suspended the pendants with bungee cord within the cage. I piloted them at a wave protected and wave exposed site and the data look good – you can definitely see a difference between sites! This summer I’ve changed the design to use stainless extension springs and streamlined the design to make it more replicable. I’ll be putting them out tomorrow on the low tide. The final struggle will be understanding the physics and pulling out useful metrics from the data, but I’ll put that off until after the field season…
I hope this was helpful and not too long – I’d love to talk more about it if you are interested.