Several people in the past few days have asked me why the ocean stinks. The answer is simple. The red tide that I documented a month ago is back, and worse than ever. The culprit is the same, but now it is present in even higher numbers. I can’t show you how it smells, but this is how it looks:
The brown discoloration is due to the high concentration of the dinoflagellate Akashiwo sanguinea. Since the marine lab brings water directly from right about where the waves are starting to crest, our water is also full of the cells. Water coming straight from the taps is tinged with brown, and filters clog like crazy. Animal care has been redefined as “flush, brush, and refill,” as in flush tables, brush or spray globs of brown slime off the animals, and refill the tanks. Only with the water coming in brown, the Akashiwo cells start settling out almost immediately.
This latest bloom of A. sanguinea coincides with the first storm of the rainy season, which could be either good or bad. The first rain causes a big influx of nutrients from land into the ocean–this is good for the blooming dinoflagellates because nutrients are fertilizers. But rain storms come from clouds, and the reduction of sunlight would be bad for photosynthetic critters such as Akashiwo. So what’s it going to be?
Akashiwo sanguinea isn’t a toxin-forming species. However, it does form surfactants when the water is agitated, and the surfactant can be irritating.
See all that foam? When a strong breeze picks up the foam you can smell it. Imagine the smell of rotting kelp, perhaps not quite that pungent, combined with a vague hint of sewer. That doesn’t look quite right but it’s the best I can do. Since I can’t share it with you here, you’ll have to go to the beach and smell it for yourself.
People who live in other parts of the world often say that California doesn’t have real seasons. I would argue that we do indeed have seasons, they’re just . . . subtle. Certainly here on the coast the Pacific Ocean moderates weather so that we don’t have to deal with temperature extremes. However, in the higher elevations the changes between seasons are more dramatic.
At this time of year the high Sierra becomes a destination for sightseers and photographers looking for fall colors. For a few weeks the aspen trees (Populus tremuloides) change from their green of summer into glorious golds, oranges, and reds. This year I have finally managed to get to the Lake Tahoe area in October. And, since I’m still in the market for a new camera, it was a great opportunity to test drive another candidate. This time it was the Canon EOS 80D, with an 18-200mm lens.
So, let’s see how it did with the brilliant scenery.
While we were up at Ebbetts Pass I took some video of the aspens, hoping to capture the rustling sound of the trembling leaves. A short way down the hill from this location there is a herd of cows, and their bells are also heard in this video. Confession time: I took this video with my phone.
Eh, okay, I guess. I took a lot of pictures with this camera, but relatively few of them really wowed me. It felt to me that the images straight out of this camera weren’t as sharp as those out of the Nikon D7200. And some of the exposures were off, too. Photography is a function of subject, equipment, and user, with the user being the biggest variable. For me, a decision between these two cameras was based on largely on which one I felt most comfortable with. And in terms of both figuring out how to do things with the equipment and getting good images out of the camera, the D7200 wins hands-down.
That said, the Canon 80D did a great job photographing a hawk I spotted in a snag.
After all was said and done, I didn’t feel that this was the camera for me. Even after working with it for a weekend it never became second nature to just pick up the camera and shoot. I found it much easier to figure out how to do stuff on the Nikon. That, combined with the fact that the images straight out of the Canon weren’t as good, sealed the deal. My grown-up camera will be a Nikon.
When the concept of conservation biology was first introduced in the 1970s, it applied to the species that were disappearing due to deforestation in the tropics. Biologists began to realize that species were going extinct as a direct result of human activity. As conservation science evolved over the decades it has become a multidisciplinary melding of population biology and ecology, economics, and sociology. Quite often the decisions about which species and/or habitats should be conserved are based on human exploitation of some resource. Conservation biology, like every other form of science, costs money, and often funding agencies have an implicit or explicit expectation of economic gain from conservation efforts.
There may also be direct conflicts between conservation activities within a habitat or ecosystem. Take, for example, the beaver and the kokanee salmon, two iconic animals of Taylor Creek. I was up at Lake Tahoe this past weekend, finally able to visit Taylor Creek during the spawning season for the salmon.
As I wrote about earlier, the kokanee is a land-locked sockeye salmon (Onchorhynchus nerka) that migrates from Lake Tahoe into Taylor Creek to spawn; it was introduced as a game fish to the Tahoe basin in the 1940s. It has since become a favorite denizen of Taylor Creek and has spawned a festival all of its own.
The kokanee, like other Pacific salmonids, requires cold, clear water to reproduce successfully. This brings it into direct conflict with Taylor Creek’s other iconic animal, the beaver (Castor canadensis). The beaver’s range historically extended into the Sierra Nevada; however, from the late 19th century into the first decades of the 20th century beavers were viewed as pests and systematically exterminated. As biologists began to understand how beavers affect overall riparian ecosystem health, state and federal agencies re-introduced beavers to the Tahoe basin in the 1930s and 1940s. Whether or not you consider beavers to be native to Taylor Creek, there is no disputing that they are there now.
Beavers, of course, are known for the logging and damming activities. They fell trees, strip off the branches, and use the logs to build dams across rivers. This forms a pond of still water above the dam, where the access to the beavers’ lodge is located. Beavers are herbivores, eating the bark and wood of trees in addition to some aquatic plants. They are nocturnal, but although we returned to Taylor Creek at dusk we did not see any. Evidence of their activities was all around. The phrase “busy as a beaver” is very apt; the dam in the photo above is about twice as tall as it was when I was here in August.
The conflict between the kokanee salmon and the beavers arises because these animals live in the same place but have different requirements for water flow. As I mentioned above, the salmon need cold, clear water. Their eggs will suffocate and die if water temperature is too high, because warm water holds less dissolved oxygen than cold water. Flowing water also helps guide the returning adults to their spawning grounds. Beavers, on the other hand, take active measures to stop or severely restrict flow in the creek. The pond that forms above a beaver dam is very calm and the bottom becomes silty or muddy, the exact opposite of what the salmon need.
Balancing the conservation needs of these popular animals has been a challenge at Taylor Creek. Do you promote the non-native salmon by destroying beaver dams? Or let the beavers do their thing, at the probable expense of the salmon? How much of the decision is due to the fact that beavers are probably native to the Tahoe basin, while the kokanee are undeniably not? And what do Tahoe’s human residents and visitors want more, salmon or beavers?
This year, the strategy has been to leave the dams, but install pipes running through them so that water continues to flow. However, you can see from the photo above that the dam is still holding back about half a vertical meter of water. Plus, as of now no salmon have made it up past the dam; rangers have been seining adult salmon from the creek below the dam and putting them into the stream profile chamber so visitors can see them. Perhaps the salmon are able to spawn in the creek below the dam.
The ecosystem of the Tahoe watershed has been severely affected by the introduction of non-native species. Lake trout, brook trout, rainbow trout, largemouth bass, bluegills, and even goldfish have been released (deliberately or inadvertently) into the lake, and have extirpated the Lahontan cutthroat trout (Oncorhynchus clarki henshawi), the only native salmonid in either Lake Tahoe or Fallen Leaf Lake. The kokanee salmon also falls into this category, and likely competes with the Lahontan cutthroats for food. Recent attempts to re-introduce the Lahontan cutthroat trout have had mixed success. Very interestingly, it appears that the Lahontan cutthroat can move back and forth across beaver dams while the kokanee cannot. Co-evolution, anyone? It seems clear to me that the Lahontan cutthroat trout, which after all shares a long ecological relationship with beavers, is the salmonid that is best adapted for the Taylor Creek ecosystem. As charismatic as the kokanee salmon is, from a biological perspective it really doesn’t belong in Taylor Creek. Perhaps one easy way to restore this ecosystem to a more natural state is to stop removing and damaging beaver dams, and let the kokanee go extinct.
Remember how I said that economics plays a part in conservation? There are several charter fishing companies at Lake Tahoe, all of which have an economic interest in the maintenance of several introduced species in the lake. So in addition to balancing the ecological needs of kokanee and beavers in Taylor Creek, conservation efforts must also address the economic needs of local businesses. These are challenges that we will continue to face all over the planet if we want to live more harmoniously with the natural world.
Autumn along the California coast can be spectacular. With the cessation of northerly winds and coastal upwelling, ocean and air temperatures rise. September and October typically offer the sunniest days of the year. Summer tourists who shiver in their jackets in July might be surprised to know that in September the natives run around in shorts and flip-flops. The ocean itself tends to be calmer now, and combined with the end of the seasonal phytoplankton bloom presents some of the best conditions for SCUBA diving.
Without the onshore air flow that results from coastal upwelling, it can get quite warm here; it’s not for nothing that the marine layer is called Nature’s air-conditioning. Yesterday and today the afternoon air temperatures have been over 95°F right next to the ocean. That’s too dang hot for my tastes. I miss the fog already. For those who dislike fog and complain about being cold all summer, though, these weeks of Indian summer must be heaven.
Unfortunately, the heat of Indian summer coincides with the driest part of California’s dry season. Without a blast of cool, damp fog every week or so the landscape desiccates and fire becomes a daily threat. This year the fire season has been intense, with the Soberanes fire near Big Sur (started by an illegal campfire on 22 July 2016) having become the costliest fire to fight in U.S. history as well as other large fires scattered throughout the state. Cal Fire anticipates full containment of this fire in the next several days.
Closer to my neck of the woods, Cal Fire has another tough battle on their hands. Yesterday afternoon at about 15:40 I noticed a big plume of smoke rising straight up from the Santa Cruz Mountains to the northeast.
Because there was almost no wind at ground level the smoke rose straight up quite a way before dispersing laterally. It looked like a mushroom cloud of death.
The Loma Fire, as it is now called, is burning in rural Santa Clara County along the Loma Prieta Ridge. Fortunately this are is not heavily populated. I kept an eye on the smoke yesterday and took a series of photos from roughly the same spot on my deck.
To escape the heat in the late afternoon and early evening yesterday we borrowed a friend’s boat and went for a short cruise at dinnertime. The smoke in the sky did make for a very nice sunset.
When we got home after dark last night we could see flames along the entire ridge. Wildfires always seem more menacing at night. When I got up this morning I could see that smoke from the fire had been blowing out over the ocean. This is fortunate for the people living in Santa Clara County.
As of 12:30 this afternoon, the latest update from Cal Fire reports that 1500 acres have burned and the fire is 5% contained. The weather is supposed to be cooler tomorrow, with a chance for some fog, which should help the firefighters. Indian summer may be lovely, but it comes with risks. Fire is scary stuff in the Golden State.
In addition to being the autumnal equinox, today also marks the four-month anniversary of the car accident that left me with bruises, some cracked/bruised ribs, and a concussion. All of the physical injuries have healed by now, except for some residual soreness when I push on the left side of my rib cage, but the concussion continues to be a pain in the head. While the overall trajectory is up, I still have bad days when I can’t do much of anything. I feel like I have an invisible disability because I don’t look sick or injured, but I’m definitely not functioning normally. For example, I can physically walk from the far end of any parking lot to the front door of a store, but having to negotiate walking through traffic and cars looking for parking might get me killed.
Headache: The headache has gotten much better in the past couple of weeks. I never was on anything but OTC pain meds and now I’m not taking anything on a daily basis. The headache has become more localized lately, and moves around. Usually when I’m aware of the headache it feels very concentrated through the top of my head. Sometimes it’s concentrated around my temples, and sometimes it feels like a really tight band around the crown of my head. The constant dull ache has ebbed, though, and that’s a good thing.
Now that I don’t always have the headache I’ve been paying closer attention to what triggers it. This helps me avoid situations that I know will be headache-producing. Unfortunately, not all of the triggers can be avoided, or at least avoided without major inconvenience. For example:
Noise. Background noise remains extremely problematic for me. Any restaurant with a “lively” atmosphere or acoustically reflective surfaces will be hell. A social gathering in which multiple conversations are going on at the same time makes my head hurt. I don’t think my brain is currently capable of distinguishing between background noise and sound that I’m supposed to pay attention to. It all gets overwhelming very quickly, and once my brain can’t manage my head hurts.
Light. Light itself is not a headache trigger, but rapid shifts between light and dark definitely are. Strobe lights would be awful, and riding in a car at night is bad, too. The lights of cars, traffic signal lights, and lighted buildings on the side of the road–my head can’t tolerate any of them. Even riding as a passenger with my eyes closed I can’t keep from seeing the flashes between light and dark from behind my eyelids. Wearing dark sunglasses at night helps a bit but doesn’t eliminate the problem. A similar thing happens in daylight when I’m riding in a car through alternating strips of sun and shade, as in a forest.
Mental activity. Having to concentrate for more than about 10 minutes at a time starts my head throbbing. This means not much work is getting done. No real science, either. I have started spending a couple of hours at the marine lab two or three days a week, just to get back into the swing of things. This week I’ve been cleaning things tanks, tables, and the little dishes I keep some of my animals in. In the process I’ve gotten nice and dirty, which makes me feel like I’ve accomplished something.
Cognitive deficits: In my nonconcussed state I have a pretty good sense of cardinal direction and elapsed time. These are still scrambled. From anywhere in the area I should be able to point to the ocean without thinking, but now I can’t. I can navigate to places I know well, but getting any place new to me is a crap shoot. The same thing has happened with my sense of time, although that does seem to be improving a bit. I still have to use timers and clocks more frequently than I used to.
I still feel extremely slow and stupid. In writing and in speaking I often can’t find the words that I know are there, and I can’t explain things very well. I’ve asked friends–people who are used to conversing with me–if I seem slow to them when we’re talking and they’ve all answered ‘no,’ so my own perception of how long it takes me to find words must be warped by my messed up sense of time. Or maybe they’re just being kind to me.
The neurologist has told me that I shouldn’t try to learn anything new while my brain recovers. To pass the time I’ve been knitting and listening to audiobooks. It would be nice to say that I’ve been doing housework while I can’t do much else, but that would be a lie.
I’ve come to appreciate exactly how much concentration it takes to drive, and exactly how little attention most drivers pay to what’s going on around them. There’s a lot to keep track of–the general flow of traffic, pedestrians, cyclists, and distracted drivers in other cars. It drives me crazy to see drivers fiddling with radios or phones, or simply not paying attention. Any time a car makes an unexpected movement my heart jumps. I don’t trust anybody on the road these days. The guy who hit us wasn’t driving distracted, so far as we know, but now I know how little time it takes to get into a really bad accident even when you’re not doing anything wrong. I no longer listen to anything while I’m driving, and I’m not driving any distance at all these days.
Executive function: Making decisions is incredibly difficult and painful. I can answer ‘yes or no’ questions better now than I could a month ago, which is a welcome improvement. I deal with the complexities of a dinner menu by ordering the first thing that catches my eye. If I put much more effort than that into the decision my head starts hurting. I’ve been telling people not to give me options other than ‘yes’ and ‘no,’ and it actually does help me cope.
In a similar fashion, prioritizing and multi-tasking are also difficult. I can just about manage a short string of consecutive activities if I tackle them one at a time. I’ve also gotten worse at knowing how long a given task will take, even if I’ve done it many times before. That’s probably the wonked-out sense of time at work.
Psychological effects: These have improved, except for the stress of driving or even riding as a passenger in a car. I have minor panic attacks when something unexpected happens. It’s much easier for me, psychologically and mentally, to ride with my eyes closed. I think this is a minor case of PTSD. For the most part I don’t feel depressed but sometimes I think I’m not making much progress and that’s a bummer. Patience is not one of my virtues, but I am trying to be patient with myself. On the days that I feel good I can get things accomplished, which makes it easy to overtax my brain and bring on the headache. I’m having to learn how to pace myself and not do too much at once. My brain seems to allow one excursion a day, and I’m honoring that restriction as much as I can.
So, I’m getting better but slowly. I still have a long way to go.
This past weekend I was trying to manage some concussion headache issues and stayed away from the marine lab for four days. Usually that’s not a big deal. Since I’ve been absent so much of the summer due to the head injury, the lab assistants whose job it is to make sure that everybody has air and water and food have been told to check my stuff and change water daily. They’ve been keeping things alive when my headache wouldn’t tolerate my being at the lab, and I’ve gone in when I could (usually on weekends) to take care of the big chores. And so far, under normal conditions at the lab, this has worked.
But every so often conditions stray from the norm, and we are in one of those situations now. It isn’t uncommon at this time of year for us to experience an algal bloom in Monterey Bay. This isn’t the sort of spring phytoplankton bloom we get in the upwelling season, but a massive population explosion of a single species, usually a dinoflagellate. This kind of algal bloom is referred to as a “red tide,” even though the organism that causes it isn’t so much red as golden.
I went to San Francisco yesterday afternoon, and the water was brownish like this all the way up the coast. The bloom wasn’t evenly distributed; there were large patches of brown water interspersed with areas of clear blue water. At Scott Creek and Waddell Creek the breaking waves were distinctly tea-colored, which did not keep the kite surfers out of the water.
It might be easier to see the discoloration when the water is moving:
The seawater intake for the entire marine lab is straight off the point here in the surf zone, so this mucky water is the exact same stuff that’s trickling through our labs. When I returned to the lab on Monday after a 4-day absence the first thing I noticed when I opened the door was the smell, which I recognized immediately because we get red tides like this every year or so. It’s not really a horrible smell, like the smell of dead sea things, but it gets classified in my mind as ‘bad’ because of what it connotes. And it can get really bad, if the gunk accumulates and begins to rot.
When the cell concentration is this high, filter apparatuses get clogged up fast. This applies to both mechanical and biological filters. Unlike, say, small sediment particles that get suspended in water but act more or less independently of each other, the cells of these blooming dinoflagellates are sticky. They glom together in stringy mucilaginous masses, and tend to settle out in little eddies and areas with less water movement. When this muck settles on animals’ bodies, it can clog up gills or other respiratory surfaces, making gas exchange difficult or impossible. So while the red tide persists we siphon out tanks and flush tables at least once daily.
I guess when you see the color of these masses of cells, it makes sense to call this phenomenon a red tide. Under the microscope, however, the cells are golden. Based on the guilty party of the last big red tide event we had and some sampling data from Santa Cruz and Monterey dated 7 September, I’m pretty sure the cells are Akashiwo sanguinea. The cells are fairly large by dinoflagellate standards, ~100 µm long, and have the usual pair of flagella (1 wrapped around the middle and the other trailing free) that propel the cells through the water.
The groove around the middle of the cell is called the cingulum; one of the cell’s flagella sits in this groove like a belt going around your waist. The other indentation that runs from the cingulum to the posterior end is the sulcus, and houses the other flagellum that trails free like a very skinny tail. The beating of this pair of flagella causes the cell to swim in a spiral fashion:
People always want to know if a red tide is toxic, and if they need to stay out of the water. Akashiwo sanguinea, as far as anybody knows, does not produce toxins like some other dinoflagellates do. However, it does secrete surfactants that produce foam in agitated water, and a report from 2007 correlates a mass stranding of seabirds in Monterey Bay with a large bloom of A. sanguinea. The authors hypothesize that the foam from the surfactants of A. sanguinea coated the feathers of seabirds and hindered their ability to thermoregulate.
This afternoon I am heading out to the intertidal. One of the things I’ll be looking for is signs of the bloom. I do want to take some pictures in the tidepools, so I hope the discoloration isn’t too bad. Fingers crossed!
Seeing as today is the third anniversary of the first blog post I wrote about sea star wasting syndrome (SSWS), I thought it would be appropriate to take inventory of my remaining stars and see how they’re doing. Right now I have custody of ~10 bat stars (Patiria miniata), 7 ochre stars (Pisaster ochraceus–collected last year for the juvenile survival experiment I did with Scott), and 1 Mediaster aequalis. For whatever reason the M. aequalis hasn’t been affected by SSWS so I’m going to disregard it for now. Of the 10 or so bat stars, four live in one of my seawater tables, roaming free-range in quite a large volume of water. The other half-dozen or so live in a tank in a different building. The Pisasters live in 1s and 2s in tanks distributed in two rooms in the same lab.
After the initial horror and shock of the spectacular onset of SSWS, in which we watched stars rip themselves into pieces right before our eyes, what we’ve seen has followed the standard epidemiology pattern. Any time a novel pathogen enters a population, the individuals that have no immunity or resistance are the first to die. The disease spreads rapidly through the population, wiping out all of these weaker individuals. However, not everyone dies. Even during the Black Death of the 14th century, the very fact that 1/3-1/2 of the human population died of bubonic plague means that 1/2-2/3 survived. Those survivors presumably had some degree of resistance to the disease.
At the same time three years ago that all of my forcipulate stars died, divers were noticing similar phenomena happening subtidally. It didn’t take long for us to realize that Something Big was going on, which was eventually dubbed SSWS. Fast-forward three years and now I’m seeing healthy, hand-sized P. ochraceus in the intertidal again. These individuals are certainly survivors from the SSWS outbreak; they were likely small juveniles during the plague, and were able to come out of hiding and expand into open niches after so many of the adults died. Whether or not natural populations will recover completely remains to be seen, but as of right now things look promising.
About a year ago, having gone two years without showing any signs of being sick, one of my bat stars developed lesions on its aboral surface. It’s the red star in the middle of that blog post. This star is one of the four that live in my shallow table. It has now been sick for a year. See how it has changed since then:
The lesions have all gotten worse–the largest is about 2 cm long now–and the body margin has some ripples that it didn’t have before, but the star is still alive. For a while it wasn’t eating, as far as I could tell, but two days ago I watched it eat a piece of fish. Perhaps the return of cooler water is helping this animal survive.
One of its tablemates, however, hasn’t been so lucky. I first noticed apparent SSWS damage in a second star several months ago. Today was the first chance I had to look closely at it.
The most noticeable injury to this star is that big interradial divot. It looks like someone took a bite out of the body at that spot. The margins of the wound are white and fluffy, similar in appearance to the lesions caused by SSWS.
For years now this star has had an abnormal spot on its aboral surface. I’ve been calling it a bubble, for lack of a better word. The bubble may be an over-inflated papulla (skin gill) and it didn’t seem to be causing any problems for the star. I’d touch it and it would deflate, then re-inflate almost immediately. When I touched it today, it shrank back a little but didn’t really deflate.
If you look really closely at the above photo, you can make out clusters of small, clear, clublike projections. These are papullae, extensions of the internal body lining that project through the skeletal ossicles to the outside and act as gas exchange surfaces. The bubble is many times larger than the normal papullae. Because it has been there for so long, years before the divot in the interradial margin, I don’t think the bubble is due to SSWS. I don’t even know if it’s a wound, or merely an overinflated papulla. The largest star in this table has also had a bubble for many years, but no lesions or wounds indicating SSWS or other disease.
So. Three years after the outbreak of SSWS I still have stars that are sick. They’ve been sick for a long time and aren’t getting worse very quickly, from which I conclude they may eventually recover. At the very least they must have some resistance to the SSWS pathogen because they’ve managed to survive so far. One more thing. Way back in 2013 when all of the forcipulates were tearing themselves into pieces and melting into piles of goo, these bat stars were among them, scavenging on the dead and decaying tissue. For a while I feared that eating contaminated tissue might cause the disease, but that doesn’t seem to be the case, as these two didn’t get sick until two years after the initial exposure.
I hope these two stars make it. Cooler water temperatures should help. When they’re really sick they stop eating (they haven’t eaten much in the past year) but if they’re going to eat now I’ll keep feeding them. Fingers crossed!
For the past several years now I’ve been using various iterations of an Olympus point-and-shoot camera, mostly for field and lab work. My current version, which I’ve had for over a year now, is the TG-4, in which the ‘T’ stands for Tough. This camera really stands up to its name. I routinely clamber over slippery rocks in the intertidal with the camera dangling from my wrist, and it is pretty banged up already. Not a problem! It is also completely waterproof so in addition to knowing that it will take fantastic photos underwater, I don’t have to dry my hands before using it! Plus, it fits easily into a side pocket of my daypack for hiking, although I usually just leave it looped around my wrist. This little camera also has a microscope setting that takes great macro shots, which I love. The one thing it doesn’t do very well is line up with either of my real microscopes, but I have a gadget that aligns the camera on my phone with the microscope objective lenses so even that contingency is covered.
Lately I’ve been thinking that it’s time to graduate up to a real grown-up camera, one that has interchangeable lenses for more versatility. I particularly want a camera that will take photos of the birds and other wildlife that my TG-4 doesn’t allow me to get close enough for, as well as one for general use, travel, etc. I asked my Facebook friends for DSLR recommendations and the consensus is that Canon and Nikon have the best selection for photo quality, build quality, and lens options. I started digging through online reviews and quickly became overwhelmed with technical specs and jargon. Given that image quality is comparable for cameras in the same price range I decided that the most useful bits of information are (1) whether or not I can figure out how to make the dang thing do what I want it to do; and (2) will I want to carry it around so I can use it.
In early August I was up at Lake Tahoe for an extended weekend with family. A friend had suggested renting a camera at lensrentals.com, which was a great idea. I rented a Nikon D7200, the new addition to their advanced hobbyist line, and an 18-140mm lens for the weekend. I took a lot of pictures, trying the camera in different outdoor lighting conditions. I gotta say, the images coming out of this camera are really nice. I didn’t alter anything about them, except to decrease the overall file size so the photos load more quickly.
First test: Photos of outdoor scenery. The atmosphere was hazy due to smoke from various wildfires in the greater area, so I had to go up to Carson Pass to get some blue sky.
Second test:Macro. I borrowed a macro lens from a friend who owns the Nikon D7100, just to fool around and see what happens. I took some macro shots of tree bark. Of course, any time you shoot macro you lose depth of field, which can look sort of cool in itself.
Test 3: Wildlife photography. I learned that for wildlife photography, the quality of the camera and lens has a HUGE effect on how the pictures look. I found that this Nikon was pretty responsive, which is important when the subject of the photo is active.
I have no idea if these rodents are squirrels or chipmunks.
But the best wildlife photo was taken at nightfall. We had gone out to Taylor Creek one evening to look for birds. It was almost full dark and we were about to leave when we saw a large grayish blob in a tree. Looking through binoculars we could see that it was clearly a creature of some kind, but we couldn’t tell what. A large owl, getting ready to go out hunting? A roosting raptor?
Surprise! It was a mother porcupine nursing a baby.
This photo was the most impressive shot I got from this camera. Its performance in low light conditions was phenomenal. It was almost completely dark when I took this shot, but the exposure looks like it was taken during the day. Color me very impressed!
Spending the summer trying to heal a concussion brain injury means that not much science has been happening in my life lately. Now three months post-accident, I’m finally able to do a little bit of thinking and am not quite as exhausted as I was, although extended periods of concentration are still taxing and usually result in what I’ve come to call the concussion headache. I’m very disappointed to have been on the DL (disabled list) for most of the summer intertidal season, and hope that when the afternoon minus tides return this fall I’ll be able to take advantage of them. Fortunately my condition has progressed to the point that I can drive myself out to the wharf to collect a plankton sample and spend a couple of hours looking through microscopes at what I’ve caught. That’s about the limit of what I can do these days; it’s not much, but at least it’s something.
As we approach the autumn equinox I would expect to see signs that the summer growing season is winding down. Days are noticeably shorter than they were a month ago, and the major upwelling season has passed. In terms of plankton, this should mean a reduction in phytoplankton abundance and diversity, with an overall shift in population makeup away from the strictly photosynthetic diatoms and favoring dinoflagellates, many of which are at least sometimes heterotrophic.
The water at the wharf is remarkably clear right now. Visibility would be fantastic for anyone who wanted to dive under the wharf. September and October tend to be the best months for SCUBA diving in Monterey Bay because the natural cessation of coastal upwelling results in clearer and warmer surface water. I didn’t have a Secchi disk or any other way to measure turbidity, but judging by how far below the surface I could see the plankton net as it sank I’d guesstimate that visibility was about 7.5 meters. For people used to diving in the oligotrophic waters of the tropics this level of visibility is downright awful, but for those who dive in productive areas this is not bad.
As expected, when I pulled up the net there wasn’t much phytoplankton in the net, and none of the diatom smell I get in spring plankton tows. The net came up pretty clear and rinsed easily into my jar. There was, however, a lot of zooplankton. When I got back to the lab I started looking through small aliquots to see what was there.
The usual suspects were quite plentiful. These included:
copepods, in both larval and adult stages
polychaete worms
veliger larvae, of both gastropod and bivalve types
medusae from the hydroid Obelia sp.
tintinnids, a type of protozoan that lives in a goblet-shaped glass shell
echinopluteus larvae, probably of the sand dollar Dendraster excentricus
Especially beautiful in today’s sample were the acantharians:
Acantharians are large single-celled protozoans; I’ve seen some that are 3 mm in diameter. They build spines of strontium sulfate, which are arranged in precise geometric formations. The protoplasm of the cell extends partway along the spines, which are thought both to deter predation and provide buoyancy. Acantharians are predatory, feeding on smaller unicellular organisms, but also form symbiotic relationships with unicellular algae. The algae are given safe harbor within the cell of the acantharian, and in return provide fixed carbon to the protozoan. Although the players are different, this is pretty much the exact same symbiosis as occurs between reef-building corals and zooxanthellae in the tropics (and also between some of our temperate sea anemones and zooxanthellae).
Here’s a puzzle for you. Take a look at this pair of animals:
Both consist of a roundish body and a tail. The one on the left is much larger, about 5 mm long, and more opaque. The one on the right is about 2 mm long and is very transparent.
Question: Do you think these animals are the same thing?
Answer: It can often be a mistake to assume any close evolutionary relationship between animals that appear to share a morphological similarity, but in this case shape does result from genetic relatedness. Both of these animals are chordates, my (and your!) closest invertebrate relatives. Yes, we share a closer kinship to these critters than we do to any other invertebrates. We also share with them the following morphological characteristics: pharyngeal gill slits, a dorsal hollow nerve cord, a notochord, and a post-anal tail. Of course, for us the gill slits, notochord, and tail are gone long before we are born, but if you look at pictures of human embryos you can see them. Once we are born the only chordate characteristic remaining to us is the dorsal hollow nerve cord, which runs up through our vertebral column.
The animal on the left is called a tadpole larva, probably of one of the benthic solitary or colonial tunicates. Tadpole larvae are short-lived and lecithotrophic (i.e., non-feeding); the opacity of the body is an indicator of energy reserves stored in body tissues. Tadpole larvae have a short larval life. They typically don’t disperse far from the parent, and within a few hours metamorphose into new tunicates.
The animal on the right is a larvacean. It bears a superficial resemblance to the tadpole larva, but is an adult. Larvaceans are entirely planktonic and have one of the most interesting lifestyles imaginable. They live in a house of snot. The house is secreted from an area on the back of the animal, and is inflated as the animal pumps its tail up and down in a rhythmic sinusoidal fashion. The mucus house actually consists of two distinct meshes: the outer mesh is coarse and serves to keep large particles from clogging up the finer feeding mesh. The feeding mesh collects very small particles, which are transported in a mucus thread to the animal’s mouth.
Larvacean in its mucus house.
Larvaceans are prodigious mucus makers. As any filter does, the house eventually clogs up. Instead of trying to backflush and clean out its house, the larvacean wiggles out of it and secretes a new one. They can build up to three houses a day when the water is full of plankton! The discarded houses of countless larvaceans slowly sink from the surface and are a major source of food to animals in the deep sea.
Larvaceans caught in a plankton net are almost always dislodged from their houses. In a dish or a drop of water on a microscope slide, they thrash about in a characteristic larvacean sort of way. Only once have I caught a larvacean and then been able to watch it build a new house in my dish of water. What I saw today is much more typical.
This poor animal was trapped under a cover slip so it can’t move freely, but the tail still thrashes about. You can also see its little heart beating like mad.
The tadpole larva, on the other hand, is a much more sedentary creature. It doesn’t disperse far so its tail remains still, and its heart rate is much slower than that of its pelagic cousin:
To shift to a completely different taxon there were, as usual, many crustaceans. In addition to the larval and adult copepods, today I saw several examples of Podon, a type of crustacean called a cladoceran. The most familiar cladocerans are the freshwater Daphnia species, but in Monterey Bay we see Podon on a fairly regular basis. Cladocerans reproduce via parthenogenesis, in which unfertilized eggs develop into daughters, and in the springtime most of the Podon I catch are gravid. At this time of year, however, they are not reproducing, at least not parthenogenetically.
The most striking feature of Podon is its large compound eye, which causes problems. For many creatures living up in the water column, the only way to hide is to be transparent. This invisibility would be interrupted by any pigment in or on the body. Unfortunately for Podon and other animals that try to hide in plain view, eyes are, at bare minimum, a collection of pigmented cells that detect light. For them, eyes are both a useful sensory structure and a big “Here I am!” signal for predators.
The best thing I saw in today’s sample, aside from the acantharians, was a small ciliated blob with little ciliated flaps. This cute little creature is the Müller’s larva of a polyclad flatworm. It’s hard to appreciate the cuteness of Müller’s larva in a 2-dimensional still shot, so here’s a video:
Okay, so maybe it’s not the cutest larva in the plankton. It was swimming really fast and I had to squash it a bit under a cover slip to slow it down enough that I could keep up with it. But I don’t come across them very often, so it’s always a pleasure when they show up. You’ll have to take my word that they’re cute.
Oh, and by the way, I kept the tadpole larva and a couple of other shmoo-like larvae in a dish of seawater to see what they will turn into. Tomorrow I may have new things to look at. I dumped the rest of the plankton into a tank of filter-feeders, where they will resume their place in the food chain.
At the marine lab we have many seawater tanks and tables in various shapes sizes. For my purposes the most useful are the tables. The tables are shallow, about 20 cm deep, but what’s nice about them is that water depth can be managed by varying the height of the stand pipe in the drain. I have some critters wandering free within tables and others confined to tanks, colanders, or small screened containers. One of my tables contains the paddle apparatus that stirs jars of babies when I’m raising larvae.
All of these tables are gravity fed from a supply of semi-filtered seawater supply in the ceiling of the building. The seawater flows through some sand filters before being pumped to the top of the building, but is by no means entirely clean. We get all kinds of things recruiting to the surfaces of tables, jars, or anything that sits in a seawater table for more than a few days. Some of the stuff that recruits is a nuisance, such as the spirorbid worms that build tiny calcareous spiral tubes on just about anything and scrape up the knuckles something awful. Other stuff is benign, and more or less ignored until it gets in someone’s way. Or until I decide to take a close look at it.
Last year I finally decided to look at some of the red filamentous stuff growing on the bottom and sides of one of the tables. To the naked eye it doesn’t look like much, which is why I love having access to a good compound scope. Here’s my notebook page from that day:
I am always gratified when I look back at drawings I made in the past, and find that they still hold true and can be corroborated by photographs. The filamentous reds are so pretty! This is not the best time of year to find sexy algae, and I saw no reproductive structures on any of the filaments I examined. Maybe next spring.
In a different table (the table where the paddle apparatus is, actually) there is some brownish fluffy stuff growing on the bottom surface. I took a look at some of it and noticed right away that the threads didn’t have their own inherent structure the way the Antithamnion defectum does. These threads seemed to be sticky, and when I picked up a little piece of the fluff it collapsed into a blob. I had to tease apart the threads in a drop of seawater to make sense of what was going on.
These diatoms are really cool! I have no idea which species they are, though. We do have local diatom genera (Thalasionema and Thalassiothrix) in which adjacent cells stick together at their ends to form this kind of wonky chain, but the cells themselves look different. So for now these are unidentified diatoms.
There’s no doubt that they are diatoms, though. They have the typical diatom color, a golden-brown that I would name Diatom if I got to name colors, and I could see through the microscope that the cells are enclosed in a silica structure called a frustule.
At higher magnification the sculpting on the frustule surfaces becomes visible. Unfortunately, at higher magnification you necessarily have less depth of field, so it’s more difficult to take photos that show this kind of detail.
Some of these cells appear to be doubled. I think one of two things is going here: either the cells simply remain attached to each other by a thin layer of mucilage, or a cell has recently divided and the two cells that are stuck together are the resulting daughter cells. Throughout the growing season diatoms reproduce clonally (each cell divides to produce two genetically identical daughter cells), and their populations can expand very rapidly in response to either natural or artificial nutrient inputs. Because the cells are enclosed by a rigid frustule, however, this clonal replication cannot continue indefinitely. Perhaps diatom reproduction is fodder for another blog post, if people are interested.
