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By Michael Harris 11/07 I wouldn't think seawater the color of coffee would be a signature of a healthy ecosystem in the mostly pristine Monterey Bay. But that's what is happening this week, even two. The water for miles around the Wharf is experiencing a "red tide," or "plankton bloom," which is to say, a monstrous population growth of one or a few phytoplankton species too small for us to see, most days. "Plankton" is Greek for "wandering," and comprises a big club of diatoms, dinoflagellates, silicoflagellates , coccolithophorids, bacteria, and viruses. They are tossed by the tides and currents. These members form the first windings of the marine food web, primary producers that eat sunlight (photosynthesis) and use that energy to fix carbon dioxide into organic compounds that the rest of life in the seven seas feed on. The dinoflagellates, with their pigmented bodies, are the main players in the "red tide," and have been thriving in the sea surface like this for some 600 million years. Such plankton blooms come and go all the time in the ocean. One can paddle or boat through lucent blue-green water and abruptly zoom into an acre of rust, as if something has leaked out. But it's not a spill, just another mix and tumble of biological play in the Bay. The sea acts at times like a poker hand turning a kaleidoscope; ever a new shuffle and puzzle. This shuffle occurs when some phytoplankton strike it rich in nutrients or easy conditions and suddenly out-populate all their neighbors in a blink. A milliliter full of a resulting plankton bloom can host a few hundred to a few thousand of these dinoflagellates, where the week before they were just faces in the crowd. Blooms can be triggered by area runoff after a rain followed by sunny days at sea. Just as likely, though, are events sprung from the sea, ushered by a current, an upwelling, a mix and jumble of sea and sun. This bloom is proving to be the strongest in record and memory, partly because no one has kept records longer than living memory about plankton blooms. No one cared until recently. It's an old story, possibly, since microscopic plankton species have been sea-bound since life evolved in the brine, or a brand new one because they are all mutating in a fast shuffle. A few reports have come up with a few culprits. The names in the couple reports this week are members like Akashiw, and cochlodinium. Tomorrow another bucket might show something else. After a few days of it I thought the area just needed a good swell to switch things around and bring in new water. But a swell did come in and only brought more red tide. It only seems to get thicker, not thinner, and has remained so for two weeks now.
The first thought in anybody's head is, "if it's that ugly it must be harmful." And the truth turns out to be, it can, but not necessarily, and not now. The fact that a plankton bloom, or red tide, is a just a natural event is not reassuring-so is the plague natural. And all ocean newshounds know by now that plankton can generate "natural" toxins and pass them on to whatever eats them, to magnify, or "bioaccumulate.". The good news is this bloom is not a hand dealing toxins, such as demoic acid attacking nerves nor paralytic shellfish poisoning attacking muscles and nerves. Nobody has dropped, or even gone hospitalic. And mussels and anchovies don't truly bioaccumulate these toxins, they purge when the bloom wanes. Still, the fact that no sea lions have stranded on the beach does not mean the event is benign. For several days I noticed sea birds sitting on Main and Cowell's beach that don't normally, like surf scoters and grebes--the first scoops up clams and sand crabs, and the second chases fish such as anchovies. Are they a little ill with the nasty tide? Hard to say. A.J. working at Cowells Surf Shop reports getting some kind of sinus bug after surfing the day before. Whatever harmless dinoflagellates are shimmering here to give the water its nice coffee color may be jostling with other unsavory faces in the crowd enjoying the same conditions. How's the fishing in a red tide? It doesn't seem to matter. In my experience, fish will bite anyway-things might be harder to see, but fish don't operate only by sight the way we do. Yet if they eat demoic acid-tainted anchovies or sardines that have been feasting on the phytoplankton, that seems like it could be a problem. There must have been some aching bellies or worse among the natives over the centuries at the Costanoan shell middens (read dump) at Ano Nuevo, Scott and Laguna Creeks. These sites and others host cumulative mussel, clam, and abalone shell feasts from 5,600 years ago. Did the Indians learn the hard way, or did they have clues how to tell when mussels were poisoned with toxins? History
as anecdote In the summer of 1991, I had just moved over to Santa Cruz and was living on a boat moored between the Wharf and the Boardwalk. I was working at Gamil's restaurant at the time (now Octopus's Garden) and would commute by a skiff and a paddle. It was total fun. That summer the whole area was full of anchovies, diving pelicans, and jackmackerel. Cowell's cove bubbled with jackmackerel stitching the surface. These fish are a different species from Pacific mackerel, and I have not seen jackmackerel as numerous since. Anglers were pulling up them up along the Wharf for two months straight. The anchovy schools were so dense they exuded a fish-oily sheen on the surface. Pelicans were dive bombing the area all day and night. I noticed a few of them seemed to have a problem; they would take off from the surface into the air, flap a few times, then go into a seizure and cartwheel out of the sky back into the water. As I was commuting from the Wharf to the boat one day, I noticed a woman on Wharf Landing 1 attempting to toss a throw net into the water. I started chatting with her as I untied my commute vehicle and she told me she was trying to capture some plankton. I said I go out fishing almost every morning since I live here and I would give it a try for her. Somehow or another she gave me her tow net or another net and I said I'd give it a try. Her name was Mary Silver. So I went out fishing the next morning or two and dragged the net behind my boat, called her a day later or so and said I have some plankton for you. She invited me to her lab to take a look with the electron microscope in the Marine Sciences lab at UCSC. I don't recall if it was the samples I dragged or somebody else dragged, but the culprit she was looking for was there. A colleague in Florida emailed back and confirmed, yes, this is Alexandrium, and report it to the authorities. She explained that this culprit bioacumulates in shellfish like mussels and plankton- scooping fishes like anchovies and was deadly. I said, no, that can't be right, because I had been catching anchovies for weeks and frying them. They are delicious! She looked at me with a strange light in her eyes and asked if I had felt any tingling in my face lately. Actually, now that she mentioned it, I had: like soda spritzels in my cheeks and jaw. I didn't think much of it. Later I learned that Alexadrium and friends are responsible for Paralytic Shellfish Poisoning (PSP), and symptoms can be tingling, and then much worse. But that can't be right, I'm still here, I think That same summer I struck up a conversation on the same Wharf Landing 1 with a guy that collected clams from the area for lab tests in other places. He and an associate went scuba diving off Wharf Landing 1 and raked up clams to put in a box for shipping to wherever. He related a couple things. First, was that the sandy bottom around the Wharf was a supremely healthy environment for clams and such. The other was his team actually needed beat-up wetsuits since they were on their knees on the bottom most of the time. He noticed the Elvis-flared the ski pants I used for a wetsuit at the time that I snagged from Bargain Barn, I think, for pennies. He mentioned that oysters and clams were probably the healthiest thing anybody could eat raw. The subject of natural toxins came up and he mentioned that Japanese males, when he was studying in Japan, would eat demoic or PSP (I forget which) tainted sushi on a dare for the buzz, like hot peppers, flirting with death. Autumn of the Red Tide But it's changing as we read. I went out for my lazy-man's-mile-swim on my surfboard with fins today, out to the kelp beds and back. There is a water quality test called a secchi dish where one drops a white plate into the water and measures how long one can see it with depth. I have been testing this red tide every day with the tip of my surfboard, or secchi board. I can report that for the last week or two, I could barely see it a couple feet below when I sat on it. I saw the color of the coffee I had that morning staring me back in the sea that afternoon. But today, I saw the tip of the surfboard, like Groundhog Day. Pennsylvania has nothing on Santa Cruz. By my reckoning, the red tide is diminishing; the phytoplankton has spent its bankroll, and the swell is coming in. We'll be talking about it for years. "Remember that red tide, dude? It was so thick I cut you off at the Lane because the plankton got in the way, I couldn't see you, that's why, dude, c'mon forget about it, it's over…!" Footnotes;
for a look up close, here are some plankton links: http://www.waterencyclopedia.com/Oc-Po/Plankton.html http://www.botany.hawaii.edu/BOT201/Algae/Phytoplankton%20lecture%20notes.htm To: wharf@ci.santa-cruz.ca.us |
