Bioluminescence, Part 1

What’s all the fuss about bioluminescence? What IS bioluminescence? 

Sunset over White Gulch on Tomales Bay.
Photo by Casey Newman, 2011, All Rights Reserved. 

It’s the production of light by living organisms. It can be used to attract prey, to communicate, and to help an organism blend in with its surroundings. Bioluminescence is also responsible for the glow that can sometimes be seen on moonless nights in the waters of the ocean. In several places in the world, including our own Bay Area, conditions are perfect for an annual “bloom” of dinoflagellates, a type of single celled organisms that are bioluminescent.

Dinoflagellates are a type of unicellular planktonic organism (whew, what a mouthful). They drift with the currents of the ocean (planktonic), using two whip-like structures (flagella) to move their single-celled selves around a bit. They can photosynthesize, or get energy from sunlight, but some dinoflagellates also eat other, smaller organisms. Most of them have armored plates made of cellulose for a cell wall, which makes them tough for their size (and also beautiful under a microscope). Some dinoflagellate species cause red tides, and release toxins that are harmful to humans. Other species, like the species that is found in Tomales Bay certain times of year, are bioluminescent.

The species of dinoflagellates that bioluminesce operate on a circadian rhythm- they photosynthesize during the day and they only glow at night. Because they only glow when they are jostled, it is theorized that they glow as a defense mechanism. One of their main predators is a type of shrimp, and if they glow when they are about to be eaten, the light will hopefully attract a fish, which will hopefully eat the shrimp. The flash of light may also act as a distraction, blinding the predator to allow the dinoflagellate time to get away.

During certain times of the year, strong winds push the top layer of coastal water offshore, allowing cold, nutrient-rich water to flow up from the ocean floor. This is known as upwelling, and it is responsible for the surge in nutrients that feed an explosion in the population of single celled algae. One species of those algae are the dinoflagellates that produce the light we see on Tomales Bay. Their bioluminescence can occasionally be seen year round, but tends to be strongest in the summer and early fall. The amount of nutrients in the water affects when we can see the bioluminescence and how long it lasts.

The waters of Tomales Bay are a perfect location for viewing the bioluminescence. Tomales Bay has a narrow opening which limits the amount of water that is exchanged during the tides, concentrating the dinoflagelates in the bay. Beds of eelgrass, a plant with long blades, further trap and concentrate the dinoflagellates in the shallow parts of the bay. The northern end of the bay is relatively undeveloped, which keeps light pollution from washing out the flashes of green light when the organisms are moved. 

A paddle through the bioluminescent waters of Tomales Bay is an amazing experience. As we paddle through the water, our boats, paddles, and even hands can jostle the organisms and make them flash. The bioluminescence does not hurt the dinoflagellates, and they can continue to emit flashes of light for hours. On especially dark nights, fish can be seen setting off the bioluminescence as they swim through the waters underneath our boats. The peaceful waters of Tomales Bay provide a protected location filled with wonderful wildlife to paddle past, and the bioluminescence is truly breathtaking.

Sunset on Tomales Bay.
Photo by Casey Newman, 2011, All Rights Reserved. 

Want to know more about bioluminescence? Check out the Bioluminescence Web Page at http://www.lifesci.ucsb.edu/~biolum/, or tune in next week for more information about bioluminescent critters and about a specific type of bioluminescent fish that returns to Tomales Bay every summer.  

Drakes Estero Trail to Sunset Beach Hike

Details: about 9 miles round trip, approximately 4 hrs with photo stops and a lunch break. This trail is a hiking and biking trail. Note: As of 1/26/11 impassable on a bike after 2 miles, read on for details.

Getting out of the car at the Estero Trail parking lot, was enough movement to necessitate removing a layer. The sun was shining and the bright blue skies were filled with wispy and playful clouds stretching the horizon.

All rights reserved. Photo by Tressa Bronner 2011.

The first mile or so meanders through a thick pine stand. We welcomed the shady start to our hike as we were overdressed for this beautiful day. Amongst the trees we found several groupings of mushrooms poking out from beneath the duff. Once out of the pine stand, we reach the bridge across Home Bay. I have often stood on the bridge and watched countless leopard sharks swim beneath, in and out of the shallow feeding area past the bridge. But not today, the tide was out and only a small channel of water remained in the labyrinth that was the exposed mud of Home Bay. I stood and looked into the water reflecting the clouds and marveled, but not at sharks.

Looking Southwest into Home Bay from Bridge
All rights reserved. Photo By Tressa Bronner 2011

After the bridge, the trail proceeds uphill with views overlooking the estero. Bring your binoculars along as you are often within range to check out shorebirds and rafts of migrating water fowl. After about 3/4 of a mile, the trail got a bit tricky. Cows graze in the area and at some points it seems as if you are just following a cow trail, not an actual park trail. As we descended a shaded hill the wet mud had been trudged by cows and all that remained was a 4 inch wide bridge that was solid enough to support the weight of an adult. This bridge often shifted, as it was the residual non-path of the cows, so hopping back and forth between bridges was necessary to avoid the muddy hoof holes filled with puddles. This left us wondering how one would pass when the bridges were trampled. The trail continued in this way for quite some time: dry sections, muddy sections, followed by muddy almost impassable sections that left me wishing for rain boots but wondering about the bike tire tread tracks I saw, followed by dry sections. I enjoyed the challenge, but this trail is not suitable for all abilities nor bikes at this not-quite-dry time.

Lone Eucalyptus.
All rights reserved. Photo by Tressa Bronner 2011.

We decided on the trail out to Sunset Beach, the shorter of the two options, since we had a time restraint.  If you stay on the main path, you can continue on to Drakes Head and beyond.  The trail out to the beach has lovely views and a couple of fresh water ponds. We stopped at the bench for a picnic in the sunshine. There is also a trail that continues on, but since we weren't there for the sunset, we opted not to get out feet wet. Walking past the large sandbar we stopped to watch the harbor seals catching rays on their temporary beach. About thirty seals were gathered, stretched out, enjoying the balmy weather.

Turning around we received flyovers by two flocks of American White Pelicans that were roaming the estero. At one point they circled around us three times before finally coming in for a landing on a fresh water pond. What a treat to hear their wing flaps and watch their splash landing into the pond.

Estero Trail Overlook
All rights reserved. Photo by Tressa Bronner 2011.

All in all, a lovely day, gorgeous scenery, solitude, just a bit sloshy at points. This bike/hike will be much easier in summer and fall once dried out. I would say kayaking is the best way to explore the estero during these lovely winter days, as long as you check the tide first. Mud in your boots, while not fun, is much easier than a mud flat to cross in your kayak. Get out there soon! The estero closes annually to kayakers for harbor seal protection on March 1st until June 30th.

Glowing Green Halloween 2010

By Joyce Goldfield -Point Reyes Outdoors Customer

Halloween! What on earth does a 73 year old woman do on Halloween? I’m pretty game-I was going to drag out my old pumpkin costume and limp on down to the local happenings in Point Reyes. Just then the phone rang! Saved!



My friend Laurie, who owns Point Reyes Outdoors kayaking, hiking and biking company, spoke. Her question…

“Hey, we have an extra spot on our kayaking trip tonight. We’re going out on the bay to see the bioluminescence. Want to come?”

“Well, yeah!! I was just trying to get up the enthusiasm to don my pumpkin suit and go trick or treating!” My comment received her familiar laugh…

“Great. Meet me at the office at about 4pm and you can ride up with me. We plan to put in at Nick’s Cove in Marshall at 4:30pm. Wear a fleece and some warm socks. I’ve got everything else for you.”

So I did…and she did! She even brought me some extra socks! We rode up to Marshall, followed by her guide, who was driving the van, pulling a trailer of kayaks. The back of the van was stuffed full of gear.

We arrive at Nick’s Cove, just as the late afternoon serenity and softness was settling over the world. Somehow that time of day always inspires me to talk more softly and breathe more deeply.

Kayaks were unloaded and sat bobbing at the water’s edge, waiting. Customers arrived and Laurie greeted them warmly, quickly assessed our clothing and suggested we don one of her waterproof jackets with Velcro closures at the neck and cuffs. She also gave each of us a pair of warm kayaking gloves and waterproof pants. Over the top of all this was a kayaking spray skirt to keep us snug and dry as we paddled. All this was topped with a comfortable life vest. We looked at one another and giggled. I often spend time on the Bay so am accustomed to dressing in layers, but don’t own any of this waterproof gear – and definitely no spray skirt. I’m usually sopping wet halfway across the bay. Not tonight!!

Casey, the guide, gave each of us an individual brush up lesson on how to hold a paddle, advise on strokes, how to operate the rudder pedals (if you are seated in the stern of a two-person kayak) and some wise advice about giving plenty of room to the wildlife, not approaching close enough to flush them from their resting spots. And we were off!!

Tomales Bay Sunset
Photo by Alia Pasquale

Tomales Bay lay flat calm. I’ve lived here for 35 years and have spent many hours sailing and canoeing on this water. I’ve NEVER seen it like this…a shining sheet of glass! Just enough time had passed for the sunset to be at its most breathtaking. Not only was the sky all shades of pink/purple/orange/red, but this palette was reflected across the water, shore to shore. Floating on this amazingly brilliant canvas were all manner of sea bird: loons, cormorants, pelicans, gulls, ducks, herons. The guide knew facts and lore about all of them, which she happily shared. Remember how still and peaceful I told you it was? Now imagine the single call of a loon, floating across the still waters. Cormorants were making noise similar to an “oink”! Then as we approached Hog Island, in the middle of the bay, seals popped their heads up out of the water to view us as we passed. Many were pulled out on the sand spit of the island. Again, so still, we could hear them burp and scratch! Three very young, curious ones followed us. They kept bobbing their heads up to get a better look with their large dark eyes.

Coming around the island, in the middle of the bay, we saw a strange sight. A great Blue Heron was standing ON the water, not wading near shore, but in the middle of the bay. We gave him a wide berth, but perplexed as we tried to figure out his illusion. Floating near us there was a small cluster of bull kelp, a species seldom seen in the bay, but often found in large piles on ocean beaches. These stragglers could have floated in from the ocean, over the sandbar at the mouth, and into the bay. Seems the Heron was standing on a slightly submerged knot of kelp.

The light was slowly fading as we approached White Gulch, on the opposite shore. We cruised in and out of all the nooks, crannies, and caves along the bluff. They pointed out all manner of sea life: Sea anemones gently swaying their fronds to capture food, gorgeous, graceful brown jellyfish pulsing their way along in calm waters, bright star fish and one ethereal white moon jelly. The guide explained that river otters often hang out by the small caves near the bluff.

We paddled toward a small white beach and we pulled ashore. Laurie and the guide pulled out a table and a delightful repast of grapes, chocolate cherry cookies, almond pastries, a three-fruit buckle, and best of all, mugs of steaming hot chocolate.

The night sky was upon us and millions of stars were blooming in the black velvet. Because the water was so calm, every star was reflected therein. Our entire world – sky and water – was a tapestry of golden lights. Behind us, one single elk stood on the hill, silhouetted against the waning light. A huge lone, silent owl flew over us, so low you could feel the rush of the wind from his wings. Having just recently lost my beloved, I smiled, assuming it was his spirit, wishing us well.

Returning to the kayaks, the instant my paddle touched the water, I gasped. I was paddling in molten mercury! In quick silver! I thrust my hand into the water: gloves, jacket and all, wet, just to stir the water with my hand. Everyone was doing the same. We had been conversing in whispers. Not anymore. Everyone was uttering “oohs” and “ahhs” of delight! Then, it got better! EVERYTHING beneath the water was etched in silver and neon green! We could see the sea lettuce and kelp sway beneath. Big, little, wee tiny fish, swimming this way and that…shooting past us, beneath us, in front of us…leading us on their path of silver and brilliant green. Behind us, our wakes were a trail of silver. I scooped up a paddle full of glowing sea lettuce and dropped it back into the water, in a shower of sliver – and laughed aloud.

There was no reason to hurry. We were allowed to wander about (everyone had a red glow stick attached to their kayak for safety). We separated, came together, separated, awestruck!! Where to look? The star strewn black velvet sky? The silver and neon streaked bay, glittering with reflected golden stars? Somehow, it all blended together, it was difficult to see where the horizon line actually was. We were drifting and rotating in a gigantic illuminated bubble. Nobody wanted the evening to end.

As we slowly made our way across Tomales Bay, past the sleep murmurs of the critters on the darkened Hog Island, to the landing at Nick’s Cove…thoroughly relaxed, enchanted, soul satisfied, spirit uplifted, and completely mesmerized by the peace and beauty of it all.

I think I can safely say, that none of us will ever forget this evening as long as we live. None of us will be swept up in life to the extent that this evening doesn’t still dance behind our eyes…in our souls.

Leopard Sharks in Tomales Bay and Drakes Estero

Leopard Shark. Photo by Kambiz Kamrani. 2005

The easily identified Leopard Shark is often encountered in our waters near Point Reyes, often when paddling near them in our kayaks on tomales Bay and Drakes Estero. But it is in the turbid estuarine environment where this attractive little hunter really shines. Paddling around in June and July we often see the water roiling about with tails and fins as these beautiful fish find mates and give birth.

Leopard Sharks do not rule these murky waters uncontested. They share estuaries with, among other, Shovelnose Guitarfish, Bat Rays, and the Brown Smoothhound Shark. The Leopard Shark and Brown Smoothhound are closely related and would be expected to be competing for the same resources. A study looking at the feeding habits of the Leopard Shark and the Brown Smoothhound in San Francisco Bay found that both species feed predominantly on shrimps, crabs, and fishes, but that Brown Smoothhounds hunt predominantly in rocky intertidal areas while the Leopard Shark tends to feed more in muddy areas of estuarine waters.

Leopard Shark at Point Dume. Photo by Heal the Bay. 2008

Leopard Sharks have a richly varied diet and employ several predatory tricks to secure their meals. Some Leopard Sharks feed heavily on Fat Inn-Keeper Worms, which are forcefully sucked from their U-shaped burrows. Others mutilate burrowing clams by nipping off their fleshy siphons (breathing tubes which stick out of the mud), completely ignoring the rest of the critter. When feeding on circling, densely packed schools of anchovies, Leopard Sharks have been reported to circle in the opposite direction with their jaws open, snatching up the small fish that crash right into their mouths. Their adaptable feeding behavior and appetite for several different species, undoubtedly contribute to their success.

"Jaws" Leopard Shark. Photo by Kambiz Kamrani. 2005

The Facts:

Size: At birth, Leopard Sharks are 7-8 inches. At maturity males are 28-47 inches, females are larger, 43-51 inches. The maximum recorded length is 71 inches.

Reproduction: Males mature at 7years, females at 10 years. They are ovoviviparous, meaning that they give birth to live young that have hatched from eggs within the body. The gestation period is around 12 months, at which point they give birth to 4-30 pups alternate years.

Diet: Juveniles mainly eat shore crabs. While adults have learned a scattered diet of small fish, rock crab, worms, clam siphons, and fish eggs.

Habitat: Leopard sharks are found in and around estuaries, sand bars, rocky reefs, kelp forests and especially like pliable muddy bottoms where food can be found and pried out easily.

Depth: Intertidal, literally inches deep, to about 300 feet.

April Showers, Flowers, and Sunshine

Springtime in Point Reyes is keeping the hills green. Beautiful weather followed by showers have kept the grounds lush and provided swells of wildflowers.  The peninsula is covered with colors as new flowers pop up daily. Checkerbloom, lupine, iris, poppies, blue eyed grass, and pussy ears color the green hillsides.

             

Walk out to Kehoe beach in a sea of mustard's brilliant yellow, or walk out to Chimney rock to a kaleidoscope rainbow of color dotting the path.  Gray whales are still being seen on their northward migration. A few lingering elephant seals are starting their molt.  Kayaking on Tomales Bay has been phenomenal, as the bay is teaming with wildlife. Harbor seals and their pups can be seen on Hog Island and swimming in the bay. Rafts of migratory waterfowl are foraging and resting, some here just for a break before continuing on, others stopping for the summer.

Plenty to see and do, the question right now is rain or shine? Bring your rain coat and your sunscreen and have a great time.Call us today to plan your next great adventure. Point Reyes Outdoors 415.663.8192

Picnics, Valentines and Nature News

Click here for our full calendar..

Point Reyes Nature News
A full moon on the 28th means the lowest tides of the month (the 26th at 3:45pm) will be the preceding two days. Head out for tide pooling in the afternoon and see what's uncovered.

On the Trail: February starts the mating, breeding, and birthing season. While hiking, look out for foxes, coyotes, and bobcats as they seek mates. Newts and salamanders are heading toward the water for breeding also. Look for the amphibians crossing the trail when hiking in shady, damp areas, especially near puddles, pools, and streams. While in those damp areas, don't forget to look for mushrooms popping out from underneath the duff.

By the Shore: Sea otters and Harbor seals begin having pups. Look for them at Drakes Estero. The Northern Elephant seals are still here with continued birthing and mating. The females leave just four weeks after birthing in search of food, leaving their pup to fend for themselves. See them at Chimney Rock or Ano Nuevo.

Elephant seals spend 80 percent of their lives in deep water. They can hold their breath for over 120 minutes and dive to depths well over 2000ft. Their huge blood volume provides large stores of oxygen for diving. Extraordinary in the water they are equally surprising on land where they can move faster than the average human over sand dunes.

Their average life expectancy is about 20 to 23 years and they reach maturity between 3 to 5 years. Males weight up to 6000lbs and females weight in at around 2000lbs. Pups are born in January after an 11 month gestation.Pups are born shiny black and weight about 75lbs, gaining at a rate of 10lbs per day while nursing.

On the Water: The Pacific Herring spawn continues in Tomales Bay. Look for fish-eating critters getting their fill, including the Great Blue Heron who is on the prowl for a mate, as well as lunch.

White's Gulch 2/4/09

Well, 'round the Hog we went. It was a short morning adventure, as we had to be back before lunch, and a gorgeous day on Tomales Bay greeted us. Today the group was high school students from SF, a teacher, and myself, the guide. The fog lifted leaving blue skies with white clouds streaking over the bay. Out on the bay there were rafts of buffleheads, a few red breasted mergansers, a pair of loons, and some brown pelicans with their mating colors. The moon jellies were everywhere in the water beneath us, their translucent purple seen below the surface. We stopped on the western side of Hog Island to stretch our legs and have a snack. The tide was low enough to see aggregate anemones, sea urchins, limpets, chitons, and both bat stars and ochre stars. As we started back towards our launch site we were followed by a harbor seal who kept popping up on either side of our group. All in all a good wildlife day paddling on the bay.

For more info: http://www.pointreyesoutdoors.com/WhitesGulch.htm