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This is the time of year when whales visit Monterey Bay and often come quite close to shore. Humpbacks, in particular, are commonly seen from beaches in the fall. Earlier in the summer they are out over the Monterey Canyon feeding on krill. In the late summer and early fall they switch to feeding on anchovies, which school in shallower water over the continental shelf. Last week they were putting on a show, to the delight of whale watchers who pay for whale watching trips out of Moss Landing and Santa Cruz.

Yesterday evening my husband and I borrowed a friend's little boat and went out looking for whales. A humpback had been seen from the beach around the cement ship at Seacliff State Beach, lunge-feeding and breaching. Even the Monterey Bay is a big body of water, and I'd rated our chance of finding a whale at about 50%. We did eventually find one swimming parallel to the shore. And I have pictures to prove it!

Humpback whale (Megaptera novaeangliae) near Aptos, CA
17 August 2017
© Allison J. Gong
Humpback whale (Megaptera novaeangliae) near Aptos, CA
17 August 2017
© Allison J. Gong

The Marine Mammal Protection Act of 1972 prohibits humans from approaching any marine mammals, so we kept our distance. The whale undoubtedly knew we were there and it did get a little closer than this, right around the time that we noticed a flock of ~25 pelicans fly overhead and start circling over an area a short distance away. It was starting to get dark and we had to turn around and head back, and on our way we ended up where the pelicans were hanging out.

As we approached we could see a bird flapping about on the surface of the water, but unable to get airborne. It didn't take long for us to see that it was somehow tied up with a dead common murre and a piece of kelp. We were able to pull the kelp toward the boat and grab the live bird. It appeared to be a juvenile gull.

Here's the dead murre:

Dead common murre (Uria aalge) tangled in fishing line
17 August 2017
© Alex Johnson

And here's the gull:

Injured juvenile gull tangled in fishing line
17 August 2017
© Alex Johnson

It had a hook in its right nostril and a hook in each foot. The hook in its beak was attached to line that went around its body, making the bird unable to raise its head. Fortunately Alex was able to cut the line while I held the bird. We didn't have the tools to try removing the hooks, so we decided to head back in. We wrapped the bird loosely in a towel to keep it from flailing around and held onto it for the long, wet ride back to the harbor.

When we back on land I called the Marine Mammal Center because: (a) I had the number programmed into my phone; and (b) I knew they'd have a live person to answer the phone, who would be able to tell me who to call about this bird. The person I talked to transferred me to Pacific Wildlife Care in Morro Bay. The recorded message told me to place the bird in a box or pet carrier on a towel and leave it in a warm, dark place until we could bring it in the morning. We weren't about to make a 2.5-hr drive to Morro Bay, but fortunately there is an organization right here in Santa Cruz that we've taken animals to before: Native Animal Rescue. We got home, dug out the kitty carrier, and tucked the bird in for the night. The only warm place we could think of that the cats couldn't get to was the pantry, so the bird spent the night there.

Injured gull
17 August 2017
© Allison J. Gong

I had a school meeting this morning, so Alex took the bird to Native Animal Rescue. The woman who met him said the bird was a juvenile western gull (Larus occidentalis)--another WEGU. She took the bird out, wrapped it in a towel, and calmed it by simulating a hood on its head.

17 August 2017
© Alex Johnson
17 August 2017
© Alex Johnson

Poor bird. Fortunately the hooks went through the webbing in the feet, so there wasn't any damage to bones or soft tissue.

Fishing hooks in the feet of a juvenile western gull (Larus occidentalis)
17 August 2017
© Alex Johnson

The woman pulled the hook out of the nostril pretty easily. To remove the hooks from the feet she had to first cut the barbs and then pull them back out. Alex said the whole thing took about 5 minutes. The bird seems otherwise uninjured. The folks at Native Animal Rescue will keep an eye on it for a few days and then release it back to the wild. I think I'll give them a call tomorrow and see if we can be there when the bird is released.

Update Sunday 20 August: We called Native Animal Rescue this morning and were told that the bird had been transferred to a wildlife care facility up in Fairfield. All of the seabirds that come into Native Animal Rescue get sent up there. So we won't get to see "our" gull be released back into the wild.

In biology, it is often the exceptions to the rules we teach that are the most interesting organisms. For example, every child knows that the sky is blue and the grass is green. With a few leading questions you can get a child to generalize that all plants are green. We all know this, right? Plants are green because they have chlorophyll, which allows them to perform the magic of photosynthesis. And yes, it really is magic. Harvesting the power of the sun to build complex molecules out of CO2 and H2O? Yeah, photoautotrophs are freakin' amazing.

But what about the plants that aren't green? How do they make a living?

I've already written about dodder, a parasitic plant that is commonly seen growing on pickleweed at Elkhorn Slough. A few weeks ago when I was at Lake Tahoe I encountered another plant that has a parasitic lifestyle: snow plant.

Snow plant (Sarcodes sanguinea) near Carson Pass in the Sierra Nevada
26 July 2017
© Alex Johnson

Snow plant (Sarcodes sanguinea) is a non-photosynthetic plant that has zero chlorophyll and thus zero green color, and is instead a rich blood-red color hinted at by its species epithet. It lives on the forest floor in close proximity to coniferous trees. The blood-red inflorescences shoot up from the ground, apparently out of nothing; the rest of the plant lives underground. If you break an angiosperm into its basic anatomical components you have: leaves, stems, roots, and flowers. Snow plant isn't photosynthetic, so it doesn't need or have leaves. And since stems are essentially support structures to hold leaves up to the light it doesn't have those, either. The roots and vegetative parts (rhizomes?) of snow plant are underground and for most of the year there's no indication that it's there at all, until it sends up an inflorescence in the late spring as the winter snow is melting.

Snow plant (Sarcodes sanguinea) near Carson Pass in the Sierra Nevada
26 July 2017
© Alex Johnson

Since snow plant isn't autotrophic and doesn't fix its own carbon, it has to obtain fixed carbon from elsewhere. Snow plant lives under conifers, but is not a parasite on the trees the way that dodder is a parasite on pickleweed. The relationship is much more complex and involves a third player. And all of the action happens underground.

Enter the third player, a mycorrhizal fungus. This fungus's mycelium spreads through the roots of the conifers with which it has a mutualistic relationship. The tree shares photosynthate (i.e., fixed carbon) to the fungus, which in turn provides minerals to and enhances water uptake for the tree. These mycorrhizal symbioses are very common in Nature, but most often go unnoticed because they occur in the soil.

Snow plant (Sarcodes sanguinea) near Carson Pass in the Sierra Nevada
26 July 2017
© Alex Johnson

Sarcodes sanguinea, the third partner in this unusual plant-plant-fungus ménage à trois, takes advantage of the intimacy between the conifer and the fungus. Instead of parasitizing the tree it targets the fungus, siphoning off part of the fungus's share of photosynthate. I suppose this makes snow plant an indirect parasite of the tree. The tree is doing all the work, as it is the only autotrophic member of the trio. It shares photosynthate with the fungus and gets something vital in return. Snow plant, on the other hand, doesn't contribute anything to either the fungus or the tree. Rather, it takes directly from the fungus and only secondarily from the tree.

It would be interesting to investigate the energetics of this three-way relationship. How do the fungus and tree react to parasitism by snow plant? On which of the mycorrhizal partners does snow plant have the strongest effect? The fungus, because its share of fixed carbon is being drained directly? Or the tree, which suffers because feeding the snow plant via the fungal intermediary means less photosynthate available to support its own metabolic activities? Does the tree have any way to stop the flow of fixed carbon to an area of the fungal mycelium that is being parasitized by the snow plant?

One last note. Many of the snow plants that we saw on the trail out of Carson Pass to Big Meadow had been surrounded by stones. We never saw any signs so aren't sure why, but I think hikers want to keep the snow plants from getting trampled. The species isn't endangered or threatened, although it is restricted to higher altitudes in California's mountain ranges.

Distribution of Sarcodes sanguinea in California

I think the stone rings were put there both to point out and protect the S. sanguinea inflorescences, although it would be hard to miss them. Nothing else is that bloody shade of red, and it really does stand out. Even small plants are very conspicuous.

Small snow plant (Sarcodes sanguinea)
26 July 2016
© Allison J. Gong

What a bizarre plant. It challenges our preconceived notions of what plants are all about. Ain't Nature grand, and weird?

Earlier this week I accidentally came upon a baby bird. I was on my way out to the cliff at the marine lab to dispose of a corpse (a fish that died of natural causes) when I noticed a western gull perched on the fence railing and allowing me to get unusually close. It was wary, though, and very alert. When I stopped to listen and watch for a while I heard a high-pitched "cheep-cheep-cheep" coming from beyond the shrubs on the other side of the fence. To get to the point where I could throw the dead fish off the cliff I had to pass closer than I wanted to the chick, which I could then see standing among the ground cover.

Western gull (Larus occidentalis) adult and chick at Terrace Point
2 August 2017
© Allison J. Gong

The western gull (Larus occidentalis), or WEGU in birders' parlance, is a California Current endemic species. It is a bird of the Pacific coast of North America, and is rarely found more than a few miles inland. So if you don't live right on the coast and have problems with gulls in landfills or parks, you cannot pin the blame on a WEGU. Western gulls are present year-round, feeding on whatever they can get. Like many gulls they are quite efficient scavengers and have a varied diet that often includes human refuse. They have become quite adapted to human presence, and have taken advantage of the fact that we tend to leave our garbage all over the place.

Western gull (Larus occidentalis) adult and chick at Terrace Point
5 August 2017
© Allison J. Gong

Yesterday the chick was in the same area, only a little more visible from directly above. I'd seen as many as five adults hanging around the chick, with no idea who the actual parents are. The chick is big and feathered enough to thermoregulate on its own but is still entirely dependent on its parents (and other cooperative adults) for food.

Being a gull, it is very vocal. It doesn't sound like a gull, though. The calls sound like they're coming from a much smaller bird. It cheeped continuously during the 20 minutes or so I was watching it, even with its parents standing right next to it. When this chick fledges, the only direction it can go is out over the water. Unless it can steer its flight well enough to land on one of the intertidal benches to the left of its present location, it'll end up in the water. I imagine it will be able to swim just fine, but the next thing it will have to learn is how to get up in the air from the water.

Western gulls do not migrate and, garbage notwithstanding, depend on the California Current for most of their food. And while it may seem that there are gulls all over the place with plenty to burn, the WEGU's restricted range makes this species vulnerable to perturbations in the ecology of the coastal ocean. Not only might their food supply be interrupted as prey species' distributions change, but their nesting sites on cliffs may be inundated as sea level rises due to climate change.

Western gull (L. occidentalis) in adult breeding plumage
5 August 2017
© Allison J. Gong

Gulls have a reputation as trash birds, but the adult WEGU really is beautiful. Their large-ish body size, pure white head and front, and pink legs/feet are pretty distinctive. WEGUs are the only gulls that I feel at all comfortable IDing in the field, and that's only when the birds are in adult plumage. This species, and many other gull species, takes four years to attain the adult coloration. The juveniles of many species all look very similar, which makes field identification a hazardous exercise. To make things even more complicated, western gulls are known to hybridize with the glaucous-winged gull (Larus glaucescens); fortunately for California birders, the hybridization zone is further north in Washington State.

Seabirds of all types depend on their feathers for insulation. Small-bodied endotherms like birds have an unfavorable surface area:volume ratio and would be unable to maintain their body temperature in cold water if they didn't have insulation. One of the adaptations that enables a life in cold water is a preen gland near the base of the tail. This gland secretes an oily substance that the bird spreads over its feathers as a waterproof coating, very effectively shielding the body from the cold water. Feathers themselves have water-shedding properties of their own, but augmenting this feature with oil is sheer genius. You've heard the phrase "like water off a duck's back"? We can say that because ducks and other water fowl have preen glands.

Feathers must be clean and lie properly for a bird to fly and thermoregulate, and birds at rest spend a lot of time grooming. All birds preen, but for aquatic birds this activity is especially crucial. Watching a bird preen is like watching a cat take a bath: the sequence of actions appears to be haphazard, but eventually the whole body gets attention.

The Sierra snowpack is California's largest single reservoir of fresh water, accounting for 1/3 of the state's water supply1. A state with a mediterranean climate, such as California, receives precipitation only during the short rain/snow season. During years of drought, when the average Californian frets about how little rain is falling, state water managers are keeping a worried eye on the amount of snow falling in the Sierra. Snow surveyors use remote sensing and field measurements to estimate the water content of the snowpack. The snow water equivalent on 1 April is used to compare snowpack water content across years.

The 2016-2017 snow year was a productive one, dumping near-record amounts of 'Sierra cement' on the mountains. (Skiers accustomed to the powder snows of Utah and Colorado often disparage the heavy snow in the Sierra, but Sierra cement carries a lot more water than powder so is much more beneficial to the state's water supply). Most of that snow eventually melts, births streams and rivers, and flows from the mountains to lower elevations. After a good snow year, though, snow fields remain at high altitudes even during high summer. That definitely is the case around Lake Tahoe.

A few days ago my husband and I hiked from Carson Pass to Big Meadow, a through hike about 8 miles long. The hike goes through some gorgeous alpine meadow, with an absolutely stunning display of wildflowers. Even in late July we had to cross several streams and saw lots of snow.

Round Top Mountain, viewed from meadow above Carson Pass
25 July 2017
© Allison J. Gong
Snow field in the high Sierra
25 July 2017
© Allison J. Gong

If you look closely at the bottom photo, you may notice some faint pink streaks on the face of the snow field. This pink snow is called 'watermelon snow' because of the color. It is a phenomenon that occurs only at high altitudes or polar regions in the summer. Here's a closer look, taken with a 70-200 mm lens that I rented for the week.

Watermelon snow
25 July 2017
© Allison J. Gong

Given the color of those streaks, you'd think the organism producing it would be a red alga of some sort, wouldn't you? I did, too, until I did some research and learned that it is a green alga! Chlamydomonas is a genus of unicellular green algae, most of which are indeed green in color because the only photosynthetic pigments they contain are chlorophylls. However, Chlamydomonas nivalis also contains reddish carotenoid pigments that serve to shield the cell's photosynthetic pigments from excess radiation, which is intense at the high altitudes where the algae live. The pigments absorb heat, which increases the melting of snow in the immediate vicinity and provides liquid water that the algae require. Watermelon snow is found in alpine regions across the globe, although it isn't known whether or not the same species of alga is responsible in all cases.

Cross-country skiers and snowshoers pass through these areas in the winter, and never report seeing watermelon snow. What happens to the cells in the winter? Do they die?

It turns out that the alga persists year-round, although in different life history stages. Given the inhospitality of their habitat, most of the life cycle involves waiting in a dormant stage, with a short burst of activity in the spring. The red form that we see in the summer is a dormant resting stage, having lost the pair of flagella possessed by swimming unicellular green algae. These spores, former zygotes resulting from fertilization, are non-motile and cannot escape to deeper snow to avoid UV radiation, so they use carotenoids to serve as sunscreens. They are not dead, though, and continue to photosynthesize all summer. They rest through the winter and germinate in the spring, stimulated into activity by increased light and nutrients, and flowing water. Germination involves the release of biflagellated cells that swim to the surface of the snow, where at least some of them function as gametes. Fertilization occurs, with the resulting zygotes soon after forming the resting spores that result in watermelon snow.

It may seem strange that this organism spends most of its time in a dormant stage, but this is not at all uncommon for things that live in hostile habitats. When conditions for life are difficult, the best strategy can be to hang out and wait until things get better. Chlamydomonas nivalis does this on a yearly basis, as do many of the marine unicellular algae. And some animals, namely tardigrades, can dry out and live for decades or perhaps even centuries in a state of suspended animation, returning to life when returned to water. As with many natural phenomena, this kind of lifestyle seems bizarre to us because it is so unlike how we do things. But if C. nivalis could observe and think about how we live, it would no doubt consider us inconceivably wasteful, expending enormous amounts of energy to remain active at times when, clearly, it would much more sensible (from C. nivalis's point of view) to sleep until better conditions return.

 


1 California Department of Water Resources

The marine macroalgae are, as a group, the most conspicuous organisms in the intertidal. Yet, most tidepool explorers dismiss them as "seaweeds" and move on to the next thing, which they hope is somehow more interesting. This is akin to visiting the jungles of Brazil and not paying attention to the lush foliage that defines that particular biome. I will admit that, as a zoologist whose primary interest is the marine invertebrates, I have been guilty of this offense. I've also felt guilty about the oversight and thought to myself, "I really should know the algae better." I have no formal training in phycology beyond auditing marine botany labs after I finished graduate school, but I've got the basics down and really have no excuse for the continuation of this gap in my knowledge.

So a couple of years ago I decided to start filling in that gap. I dragged out my marine botany notebook and have slowly been adding to it, building up my herbarium collection at the same time.

The red algae (Rhodophyta) are the arguably the most beautiful of the seaweeds, and inarguably are the most diverse on our coast. Some of them are easy to identify because nothing else looks like them, but many share enough morphological similarity that field IDs can be tricky if not downright impossible. For example, to ID a specimen and distinguish it from a close relative you may need to examine the number, size, and arrangement of cells in a cross-section of a blade. Some species are impossible to identify beyond genus (or even family, in some cases) unless you can look at their reproductive structures, which they might not have at the time they're collected.

One of the most ubiquitous red seaweeds, and one that is easily identified to genus, is Mazzaella. The genus name for this group of species used to be Iridea, which gives a hint as to the appearance of the thalli--many of them are iridescent, especially when wet. The species that I see most often are M. flaccida in the mid intertidal and M. splendens lower down. These species are usually not difficult to tell apart once you get used to looking at them and their respective habitats.

Mazzaella splendens at Whaler's Cove at Pigeon Point
28 June 2017
© Allison J. Gong
Mazzaella flaccida at Natural Bridges
9 July 2017
© Allison J. Gong

Mazzaella splendens is generally a solid brown with sometimes a green or purple cast. It is soft and floppy, and the blades are long (up to 50 cm) and taper to a point. The Marine Algae of California, which we call the MAC, uses the term "lanceolate" to describe this shape. Mazzaella flaccida is green or greenish-purple, sometimes more brownish along the edges; its blades are flexible but a teensy bit crisper than those of M. splendens, and its blades are described as cordate (heart-shaped) or broadly lanceolate.

Got it. That's not too bad, right?

But then you see something like this, and a whole other set of questions comes to mind.

Thalli of Mazzaella flaccida at Natural Bridges
9 July 2017
© Allison J. Gong

Based on habitat alone these are both M. flaccida. The greenish thallus on top looks like textbook M. flaccida, but the lower thallus looks more ambiguous. It has the right size and shape but is the wrong color, and what's up with all those bumps? I brought these thalli back to the lab to examine them more closely. Here are the entries from my lab notebook:

 

 

 

 

 

 

 

Now is the time to bring up the subject of life cycles in red algae. Algae such as Mazzaella alternate through three generations: male and female gametophytes, both of which are haploid; a diploid sporophyte; and a diploid carposporophyte. Here's a diagram that shows how this alternation of three generations works:

Life cycle of some red algae, showing alternation of three generations
© McGraw-Hill

It was easy to see that the bumpy thallus I collected was sexy, while the smooth green thallus was probably not reproductive. Having both thalli in hand, along with the MAC and phycology texts in the lab, I was able to determine that the bumpy brown thallus is actually two generations in one body. So cool! But how does this work? The bumps on the thallus are called cystocarps. In Mazzaella a cystocarp contains the diploid tissue of the carposporophyte surrounded by the haploid tissue of the female gametophyte. Et voilà! Two generations in a single thallus.

Now, what's inside the cystocarp? What does the carposporophyte tissue actually look like? To find out I had to do some microsurgery, first to remove a carpospore (1-1.5 mm in diameter) from the female gametophyte and then to cut it open to see what's inside. What's inside were microscopic diploid carpospores, which grow into the macroscopic sporophyte generation. Forcibly dissected out as they were, they don't look like much, just tiny round cells about 2 µm in diameter.

Carpospores of Mazzaella flaccida
12 July 2017
© Allison J. Gong

The next logical step would be to isolate some of the carpospores and try to grow them up. I wasn't thinking about that at the time and pressed both thalli. However, I do have another female gametophyte with cystocarps that I can investigate further tomorrow. It's probably a fool's errand, as I am not going to bother with sterile media and whatnot. Oh well. Nothing ventured, nothing gained, right?