Tuesday, March 26, 2013

A bit more on using oceanographic moorings as an educational tool

A light and temperature measuring HOBO attached to the top of a surface float destined for the waters off-shore of the Elwha River delta. Photo by Cordell Johnson, USGS Pacific Coastal and Marine Science Center Marine Facility

Oh how I do love HOBOs. If it isn't really clear yet, I am really a fan of these things. Cheap, robust and adaptable - perfect for the sort of low-budget science that I seem to end up involved in. A few months back I wrote a little story about a project that I had my Peninsula College Introduction to Oceanography class do, using HOBOs as the sensors on oceanographic moorings that we deployed in Port Angeles Harbor. While cheap, that project still had costs - primarily the few hundred dollars that we needed to buy the HOBOs themselves. Those costs were paid through a grant managed by the North Olympic Peninsula Skills Center and the Feiro Marine Life Center, as well as through a donation made directly by Onset, the company that makes HOBOs.

As a project wrap-up, Eliza Dawson (one of the students from my class) and I just published an article in Onset's newsletter on the project, with a focus on how to apply this sort of activity in a classroom setting.

Tuesday, March 19, 2013

KRABS: Kelp Rocks Along Beaches

A "kelp rock"

In 2009 I posted about observations of kelp-mediated clast transport (essentially non-buoyant kelps attaching to cobble in the shallow sub-tidal zone, and subsequently being transported apparently due to the increased drag of the kelp) in the Elwha coastal zone. These observations stayed with me as I wrapped up my dissertation and started with Washington Sea Grant. It didn't take long for an opportunity to arise to look further into how important this mechanism of sediment transport really is. With Dan Lieberman at the North Olympic Peninsula Skills Center I developed the KRABS (Kelp Rocks Along BeacheS) project, which was designed to fit in with existing projects that Dan's students' lead that look at marine debris and dead birds on local beaches. The essential idea behind the KRABS project is that students are quantifying the delivery of kelp-attached rocks to beaches on the Elwha delta and Dungeness Spit every month - at this point we have almost two years of data!

Karsten Turrey, a student at the Skills Center who has worked on the project, recently put together an essay titled, "Something Kelpish Going On"...

"Students on the Olympic Peninsula are conducting real-world research at the Elwha River to discover the marine environment, local beaches and themselves. In this blog post I will explain a little about what a kelp rock survey is, why kelp rock surveys are done, and where, when and how the surveys are done.

Some of the crew surveying the beach (from left, Hunter Baker, David Harwell, Karsten Turrey, Dan Lieberman and Conan McCarty).

Kelp is any large, brown, cold-water seaweed, it is not the small green seaweed. It grows in the cold water any where from 2 meters to over 30 meters along the Pacific Coast. A few of the species of kelp common in this area are Alaria marginata “Winged Kelp”, Cymathere triplicata, Nereocystis leutkeana “Bull Kelp” and Pterygophora. The part of the kelp that is attached to the rock is called the “holdfast.” Here is the history of kelp rock surveys on the Olympic Peninsula. The first person to want to do the surveys around here was Ian Miller, the University of Washington, Sea Grant Coastal Hazard Specialist. The first kelp rock survey and protocol on the Peninsula conducted by the North Olympic Natural Resources students was done on the 15th of March, 2011.

A kelp rock survey is where you have a team of people that comb the beach looking for rocks that have kelp attached to them. The group measures the size of the rock, gathers the GPS location, photographs the rock and kelp, determines what type of kelp it is and the condition the kelp is in (old, fresh). Kelp rock surveys are done to see how much of the sediment or rock which has washed up onto the shoreline are from the kelp and if this amount of sediment dragged up has an impact on the shoreline.

Surveys are done monthly on various beaches by Natural Resources students. The surveys are done along beaches. Here on the Olympic Peninsula, my Natural Resources class and I do them along the East Elwha Beach and the West Elwha Beach. Other students of Natural Resources Options Class do the same surveys along the Dungeness Spit in Sequim. There are 4 reaches at each of the Elwha Beaches. There is one reach at the Dungeness Spit. A reach is defined as a length of beach between any two points. For our surveys Ian Miller determined the reaches. We always start with reach 1, but if we finish reach 1, we roll a die and the number it lands on is the next reach we do, if it lands on 1,5 or 6 we roll again. It is important to have materials and procedures ready before starting the kelp rock survey, then we start walking the beach. When we find a kelp rock we put the ruler down to provide scale and take a picture of the rock. After the picture, we measure the rock size on the 3 axes, smallest, intermediate and largest, then we get the GPS location and then identify what type of kelp. We cut the kelp off of the rock so we do not recount it next time we survey.

During my class, October was the time of year we found the most kelp rocks. In one survey my class found over 90 kelp rocks in a small length of shore-line, around 100 yards. I think this is because the fall has stormy weather and rougher currents so it dragged more to shore, or maybe the life cycle of the kelp also has a role to play in it.

It is a very exciting project that I am glad I got to be a part of and I hope that future students can be a part of it as well. Here is a link to the site with all the kelp rock data thank you for reading my blog."

A big piece of kelp with small rocks on it

Friday, March 8, 2013

Tracking Change on the Elwha Shoreline (continued)

For the last seven days I've had the opportunity to participate in a variety of field campaigns focused on understanding shoreline change along the Elwha shoreline. We've just wrapped up a USGS-led survey that included everything from aerial imagery (from Andy Ritchie's PlaneCam), terrestrial LiDAR, topographic and bathymetric surveying (the photo above is of the USGS survey boat Snavely, with the new Elwha River mouth in the foreground), and grain size surveys. Almost simultaneously there was an effort by the WA DOE to map the bluffs of both the Elwha and Dungeness shorelines - a repeat survey to look at change since the initial survey in June of 2012.

The best part of the USGS survey work is that it will give us the first comprehensive look at the sub-tidal component of this winters' changes that have been so dramatic and obvious above water. I anticipate more on this to come in the weeks ahead as thousands of individual data points are processed and analyzed.

In the meantime,though, the BIG shoreline changes adjacent to the river mouth just keep getting bigger and better...but the interesting conclusion that I reached after three days of intensive work surveying grain size around the Elwha delta is that the influence of the pulse of sand that hit the shore in December really seems to be focused right around the river mouth - at least as far as its current influence on grain size on the intertidal foreshore. In this photo for example, taken from a point on the tip of the delta looking west, you can see how coarse the beach foreshore is even while, in the far field of the photo you can make out the now sandy river mouth (just beyond the last little person you can see in the photo).

One of the more interesting questions for me continues to be if and how the sediment delivered at the river mouth will nourish "downdrift" beaches - such that we will observe a reversal of chronic erosion and/or a reduction in the grain size on the beach foreshore. Some of the preliminary data from the bathymetric survey suggests that sediment is transporting to the east, but in the shallow water just off-shore. But as of yet, for most of the beach east of the river mouth, the name-of-the-game continues to be some degree of erosion and a beach composed, to an extent, of cobble. Near the river mouth, though, the changes are dramatic. For example, here is a shot taken on May 17, 2011 looking landward from a spot in the low intertidal zone taken on the beach just to the east of the river:

and here is a shot taken two days ago from the same vantage point:

Finally, one of the more dramatic consequences of the pulse of material that was delivered to the shoreline this winter was the formation and evolution of a large sandy bar attached to the west side of the river mouth. This time lapse video, shot from a point to the west of the river mouth (thank you Gene and Shannon Richardson), gives some sense of how that feature has evolved since December...

Note that it appears that you can get a slightly higher resolution version by viewing it directly at youtube.