Viewing Phytoplankton From Space

Viewing Phytoplankton From Space

What a difference a month makes! I've downloaded some wonderful MODIS satellite imagery (brought to you by NASA) that measures the amount of chlorophyll in the water. Chlorophyll is a green pigment that powers photosynthesis inside plants and algae. Remember that photosynthesis is the process where the sun powers the conversion of carbon dioxide and water into sugars and oxygen. The hotter colors here in the April 17 image (bottom right) show that there is more phytoplankton in the water right now compared to the March 16 image (top left). You may be wondering how the camera is able to pick out the chlorophyll in all that blue water? The satellite is picking up on the red-light wavelengths emitted by the chlorophyll pigment at 680 and 720 nm.

Getting the satellite overhead on a cloudless day is a bit tricky, so if you notice a grey/black area, those are clouds. The people who do this remote sensing work have come up with very careful calibration methods for their image processing algorithms. Each region has undergone extensive testing to normalize for unique water quality properties like particulates in the water, depth, dissolved organic matter, and common algal pigments. As great as these satellite images are, there are limitations in how close a pixel can come to land. Dirt really interferes with a signal, particularly in Puget Sound which is why there is no color south of Tacoma. The more fine-scale the resolution of the camera on the satellite, the more useful future models will be to us.

These images came from the NANOOS website. Those folks at UW-APL (and a whole host of other partners) have been doing an amazing job creating this web tool to visualize the research on the Salish Sea. I visited it tonight because I wanted to download data from a PRISM research cruise I was on in the fall of 2009. I couldn't believe how much they had enhanced the site in the past few years. This image is of the chlorophyll at varying depths along the transect of Puget Sound main basin (red line) from North to South. The far left point is out beyond Dungeness Spit. It shows that there was a subsurface algae patch next to Port Townsend, and a denser algae patch down by Vashon Island.

Who is in the water?

There is a lot of phytoplankton in the water today. It is primarily composed of dinoflagellates. The dinoflagellates are little swimming beasts that can not only photosynthesize like grass, but also love to eat their competitors. Imagine a venus fly trap that runs around catching flys. Mostly, the species swimming round right now are 'gymnodiniod' in shape. (we used to classify all these into the Gymnodinium genus, but with DNA and scanning electron microscopy, it became clear that using only shape grouped many organisms together that were unrelated.)

Our water sample (a glass of water) also had three great big pink pigmented Calanus copepods swimming in it; see its facebook page! These large copepods are zooplankton that eat dinoflagellates. These copepods are beautiful animals, and my son enjoyed seeing the huge singular eyespot on the top of its head.

The fine green fuzz on the rocks has moved up a few feet in the last two weeks. It sure is slippery. When walking down to the boat ramp at low tide, we noticed a lot of small green Ulva, then some tufts of Ectocarpus (dark purple). As you continue towards the water some tiny Fucus starts appear mixed in with the fuzzy red Polysiphonia. Right where the tide is at its lowest point, the iridescent Mazaella shines up at you, mixed with some larger Fucus plants, several larger spiral roped Neorhodomella with many epiphytes. As we waded into the water we noticed a nice thick crop of young Alaria with its prominent single mid-rib.

Most notable of all was that the cobble rocks to our right and left were bare of all macroalgae save the green Ulva slime. The boatramp is several feet higher than the surrounding rocks, so it is exposed to air much longer than the neighboring cobble rocks are. This is the difference having a fixed surface makes. If those cobbles were magically cemented in place so the winter storms couldn't tumble them, they would look much more like the boat ramp. Seaweeds would be able to hang on through the winter, and get an early start on spring growth. The main disturbance on the boat ramp is the annual dose from the pressure washer! And it is a good thing that pressure washer works - or we'd never be able to walk on the slippery ramp.

Butter Clams Finally OK!

Good news - the butter clams at Diamond Point are finally safe to eat! The problem has been that the butter clam (Saxidomas) hangs on to the toxins from the algae, Alexandrium for over a year. Those tricky butter clams actually do this for a reason; by holding onto the toxin, they discourage predators from eating them. Their cousins, the Native Littlenecks, and Manillas (Steamer clams) clear out the toxins much sooner - about three months - depending on the toxin dosage they received from the algae.

The problem at Diamond Point has been that just about the time the butter clams were about to become safe, another algae bloom came along and re-dosed the clams. Alexandrium may bloom from June through September. You won't see these toxic 'red-tide' events by just looking at the water color. Toxicity is dependent upon the strain of the species of algae, and the conditions that strain is growing under. These confounding details have been frustrating to sort out by all of us in the Harmful Algal Bloom scientific community.

Many of you who live on the Discovery Bay side of the point should be thinking, "But I saw a Red Tide last summer!" Yes, you did. That red tide is tomato soup colored and is one of my favorite annual bloom events. It is caused by this HUGE dinoflagellate cell called Noctiluca. It is not toxic, and it is a major predator of just about all plankton. Noctiluca grows up at the end of an algal bloom (usually August) and eats up anything it can get to. Noctiluca blooms have been here a long time; Captain Vancouver noted a Noctiluca red tide event when he was anchored in Discovery Bay.

What is certain is that the toxin levels measured by the State Marine Biotoxin Lab are very reliable, and they do a great job testing the seafood for safety. If it says don't eat it - there is no reason to flirt with this toxin that will paralyze you and stop your breathing. If you do notice symptoms (tingling, numbness, and burning of the lips, ataxia, giddiness, drowsiness, fever, rash, and staggering) get to the hospital so they can give you respiratory support and you should recover.

If you look closely at the north shore line, you will notice it is orange, not green. In this case it means that the state lab did not do a test for bacterial contamination like they did in the other regions.

I recommend you look carefully at the state website before digging to look for updates. For instance, Sequim Bay's butter clams are still not safe to eat. The link is at right.

Happy Clam Digging! Oh, one more thing, the areas with no line are private tidelands and the state does not test. You may not dig on those beaches without the owner's permission. As the caretaker for the Thompson Spit land, please do not dig there. There are barely any clams to be had, and it is awful digging anyways. I am hoping that if we all don't harvest there, the population levels will increase to the decent levels I remember as a little girl.

Seaweed is a-coming!

The rocks at low tide are just beginning to show their green color. The seaweeds are just now starting their annual push for the sunshine. This winter had many strong wave action storms hit at low tide so there are not very many cobble rocks with last year's perennials attached. If you go down to the waters edge at low tide, be sure to keep your balance because these new algal starts are very slippery.

Last week I saw two adult bald eagles mating while on the north shore pilings. It was a precarious event - the male fluttered onto the female's back while she was eating a fish they had been flirting over. He kept his perch there for about ten seconds as he did his business, flapping all the while. The female looked like she was enjoying the fish more than the loving. Ah well, girlfriend. At least she had a good view.

This is the season for it. The Bald Eagles are gathering from all over the region to await the seagull hatch on Protection Island. Has anyone counted how many eagles there are in the area now? We are certainly getting an increased number of visits to the North Pilings.