Archive by Author | tombellkelp

Kelp Forest on Artificial Reef

If you have been classifying images in California over the past few months, you may have come across an array of square kelp forests and wondered, “How did those get there?!” The story behind this amazing man-made kelp forest involves a nuclear power plant, a state agency, and some remarkable researchers.

Artificial reef modules in the lower right corner!

In the early 1970’s the San Onofre Nuclear Generating Station (SONGS) proposed adding two additional reactor units to increase its power generation capacity. The California Coastal Commission (CCC) granted the permit in 1974, but as a condition of the expansion a Marine Review Committee was established to direct impact assessment studies on nearby coastal ecosystems that could be negatively affected by the additional reactor units. As a result of these studies, the CCC added new conditions for the mitigation of identified impacts, one of the conditions was the construction of an artificial reef to replace kelp bed resources lost as a result of SONGS’ cooling water discharge.



The additional reactors are cooled by a single pass seawater system. As the warm water is discharged back to the environment it is cooled with additional seawater using diffusers. This process draws in ambient seawater at rate about 10x the discharge flow and is swept up along with sediments, which are transported offshore. This warm, sediment-laden plume led to substantial reductions in the abundance and density of kelp plants within the San Onofre kelp bed, as well as reductions in many kelp bed fish and invertebrate species.

Locations of artificial reef modules, SONGS, and San Onofre kelp forest including sediment plume.

The mandated artificial reef had to be large enough to sustain 150 acres of kelp forest as compensation for the loss of 179 acres within the San Onofre kelp bed. This process began with a 5-year experimental phase that entailed building a smaller 22.4 acre reef to determine the substrate types and configurations that would support a giant kelp forest and associated biota during the later mitigation phase. The plan involved testing eight different reef designs that varied in substrate composition, substrate coverage, and the presence of transplanted kelp. Reef designs were implemented as 56 (40 m x 40 m) modules (7 replicates of the 8 designs), with construction completed in 1999. These are the squares seen on your images! Results obtained from monitoring the 5-year experiment showed a near-equally high tendency of all reef designs to meet the performance standards established for the mitigation phase, and the final recommendation was to build out the reef using low relief quarry rock or concrete rubble that covered between 42-86% of the bottom.


Dr. Wheeler North

Construction of the full artificial reef was completed in 2008 with the use of approximately 126,000 tons of boulder-sized quarry rocks, deposited into 18 polygons. When combined with the experimental reef, these areas provide 174.4 acres of hard substrate for the growth of giant kelp and associated species. The reef was named after the late Dr. Wheeler North, a pioneer in the understanding of kelp forest ecology. The coastal development permit to operate SONGS requires ongoing monitoring of the artificial reef, which is led by UCSB researchers Dan Reed, Steve Schroeter, and Mark Page. These efforts evaluate whether the reef is meeting performance standards, and if necessary, determining why standards are not being met and recommending remedial measures.


Artificial reef (mitigation reef + experimental modules) covered with giant kelp!!!

Another amazing story behind the green blobs on your computer screen!

For more information about the Wheeler North Reef click here!


Floating Forests at Western Society of Naturalists 2014!

octopus_shirt_back_small.241163727_stdHi All,

Kyle, Alison, and I are just back from the annual meeting of the Western Society of Naturalists where we presented our progress with Floating Forests. The meeting took place in downtown Tacoma, Washington with over 500 marine ecologists, naturalists, and students in attendance.


We had some exciting discussions about the project at the poster session and the prospects of global coverage of kelp forest canopy dynamics has the potential to aid in the research of many scientists. Please click on the link below to download a high resolution copy of the poster.

Click Here for a Hi-Res Floating Forests Poster!

Great job everyone!

Open Ocean Kelp Forest?

Talk about serendipitous discoveries! Superuser artman40 recently posted an image on the discussion boards with a question, is this kelp out in the middle of the ocean?


The answer is YES! There is a kelp forest located about 100 miles off the coast of San Diego, CA, on a seamount known as the Cortez Banks. Many of you may have already heard about this place as it is one of the premier sites for big wave surfing in the world, with waves over 80 ft high! Check out this video:

While this was a surprise for us, spear fishers and sea lions have known about this spot for years! Check out this video where you can clearly see giant kelp:

With this new information we can begin to look more closely at this very unique kelp forest and ask interesting questions like: How often is this forest present? How does kelp get there? How are ocean circulation patterns affecting kelp’s presence and growth?

And we couldn’t have done it without YOU, our awesome citizen scientists! Great job FloatingForests team!

Tips and Tricks for Error-free Classification!

Hi! My name is Tom Bell and I am a scientist with Floating Forests. For the past 3 years, I have been working with Landsat images to estimate giant kelp biomass along the California and Baja California coasts. I have also had the opportunity to advise over 20 undergraduate analysts at the University of California, Santa Barbara to help process these images.

face_pic_sq One of the great things about Floating Forests is that image processing has been simplified so that users need very little training before they are off and running. However, this does not mean that every image will present a straightforward classification. Today, I want to take you through some common kelp classification errors and give you some tips on how to determine if that the questionable blob is kelp.

First lets start with the natural history of giant kelp and the general characteristics of the environment where it exists. Giant kelp is a coastal marine alga that forms dense stands in the Eastern Pacific, as well as off the coasts of South Africa, Australia, and New Zealand. Giant kelp anchors itself to the sea floor using a holdfast that tightly grips onto hard bottom, like a rocky reef. Kelp fronds can grow up to 45 meters long, but the maximum depth for an individual is about 30 meters, this is due to the limited sunlight where the newly settled microscopic kelp begin to grow. Waves are a major destructive force to kelp forests and can set its nearshore limit along rocky coastlines.

So now that we know the environment where kelp exists, we can use this information to better inform our kelp classification decisions. Let’s go through a few examples!



See these white (sometime blue) blobs along the coast? These are breaking waves. We know that breaking waves can be a major destructive force on a kelp forest, so you usually don’t see kelp where you see breaking waves. Remember, kelp forests will show up as green blobs. You can clearly see this large kelp forest growing just outside of the breaking waves.



This sure does look like a dense kelp forest, bright green blobs right off the coast, but in fact these are tidal mudflats. This can be one of the most difficult issues you may face. Algae or seagrass growing on these mudflats is going to show a similar green color as kelp, but we know that giant kelp only grows on hard seafloor, like rocks and boulders.

Screen Shot 2014-08-20 at 4.45.44 PM

One way to make sure this is the right type of habitat for giant kelp is to use Google Maps or Google Earth. You can click on the coordinates above each image to automatically take you to a new page showing the approximate area of that image. Then, I like to copy just the coordinate numbers and paste them into the Google Maps search bar like, ‘38.557, -123.300’, this will place a pin on that exact location and show you a satellite image of the area with better spatial resolution.



Small islands off the coast can sometimes appear to be dense kelp forests. Again, if you are unsure, I recommend using the Google Maps trick I explained above. You should then be able to confirm whether or not the green blob is kelp or a small rock/island.



Giant kelp will never be growing in inland lakes or water bodies. This is a coastal marine species. If you see a green blob in a lake or some kind of inland river/delta/estuary/bay, it is probably something cool, but it is definitely not giant kelp. Again, if you are unsure, use the Google Maps link to see if the body of water you are looking at is coastal ocean or a lake/river/canal.

That is all for today! I am having a great time interacting with everyone on Zooniverse Talk, please keep the questions coming!