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.
And here's my favorite shot of the weekend, also taken near Hope Valley. The aspens in this location were at their peak colors. So gorgeous!
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.