Fernandina & Isabella Islands: The Newest Editions
Last night I decided to sleep on the sun deck to get some fresh air and be amongst the stars
without the presence of light pollution. The temperature drops significantly in the night and coupled with the strong headwinds
and ocean breeze it can make for a chilly experience. But it was not so bad bundled under a blanket, and it certainly paid off by
allowing me to experience one of the best sunrises I have ever seen.
I woke prior to the morning announcement to a sun just beginning its rise, clouds hinting at its arrival showcasing hues of soft
pinks and blues. To the port side of the boat loomed the northern most volcanic peak of Isabela Island, Volcán Wolf (Wolf
Volcano). In the foreground overshadowed by Wolf Volcano was the smaller Volcán Ecuador (Ecuador Volcano). Ecuador Volcano has
the typical conical shape with the rim of its crater half way up from where the peak used to be. Inside the crater a new cone was
rising up showing signs that it is still active and pressure is building under the Earth.
These volcanoes make up two of the six volcanoes on Isabela Island, all of them active, giving the island the shape of a sea
horse. To the starboard side of the boat another solitary volcano was rising on the horizon. Volcán la Cumbre (Summit Volcano) is
the youngest of the archipelago and forms what is known as Fernandina Island, our first stop of the day. Fernandina is dated to
about 500,000 to 750,000 years old and is located on the western edge of the island chain.
The seven volcanoes forming Isabela and Fernandina are the only active volcanoes in the archipelago. All the other islands in
the Galápagos were formed by volcanoes as well but none of the others are active today. The reason for this anomaly is explained
by tectonic theory, the theory of how the Earth's crust moves. The active volcanoes of Isabela and Fernandina sit on top of what
is called a hot spot. This is the area where the hot magmas below the Earth's surface push their way up and form the volcanic
cones.
The Nazca Plate where the islands are located is moving southeastward toward the South American plate where subduction takes
place. Subduction is the process where a heavier plate sinks underneath a lighter plate when they collide. The Nazca Plate is the
heavier plate and is sinking under the South American plate forming the Andes mountain range from the collision.
As the Nazca Plate moves south and eastward it is also moving downward pulling the oldest Galápagos volcanoes down. This theory
explains why the eastern islands of the Galápagos have lower altitudes than those of Isabela and Fernandina. And because these
other islands have moved eastward they are no longer over the hot spot and therefore are no longer active.
The Letty docked on the east side of Fernandina at Punta Espinosa (Spiny Point) and we boarded the pangas for a dry landing on
the island. Unlike Genovesa which was gray both on land and in the sky, Fernandina had a bright blue sky backdrop with even bluer
water surrounding the jet black lava outcroppings emanating from the main body of the island. These outcroppings are a result of
the volcanic activity when Fernandina erupted in 1978 spilling its lava beyond its former shores where bright green mangroves
continue to thrive. These
red mangroves (Rhizophora mangle)
are distinguished by their arrow-shaped leaves and their stilt-like roots rising from the water. The pangas took us up to an old concrete
dock that had once been directly accessible prior to the encroachment of lava in 1978 where we unloaded to start the day's hike.
On the island one had to be careful in getting around. The lava rocks were uneven with many pools of water in-between. It was
like hopping across the tops of rocks in a river but without the strong currents. The pools of water were the result of high tide
and along with the water came some marine wildlife. There were many small, shallow water fish swimming around and we spotted a red
octopus (Octopus oculifer)
likely looking to make a meal of the fish.
On the edge of the outcroppings I saw another juvenile heron standing in green moss near the shore scanning the water, but this one was a
great blue heron (Ardea herodias)
slightly different from the
night heron (Nyctanassa violacea)
we saw on Genovesa. Also dotting the lava rocks were the numerous
sally lightfoot crabs (Grapsus grapsus)
most of which were darker in color, a sign they were juveniles not yet matured to the brighter red adult form.
Making our way to the main body of the island we were met by a
Galápagos hawk (Buteo galapagoensis)
that flew in to investigate the human intruders. The hawk landed in a nearby tree and watched us as we continued our hike. The Galápagos hawk
is the only primary predator and the top of the food chain in the Galápagos Islands. These hawks were hunted to extinction on the inhabited
islands but one was spotted on Santa Cruz, so maybe they will make a comeback. Endemic to the Galápagos, this species of hawk has
one of the smallest populations and is the most inbred bird on the planet.
We were walking across the newest terrestrial surface in the Galápagos where one could clearly see the lava given that
vegetation had not begun to grow. Harry took the opportunity to explain to us that there were two types of lava found on the
islands. Here the lava is the same as you would see in the older Hawaiian Islands because they are formed in the same manner.
One type of lava is called 'pahoehoe' caused by the flow of hot lava that begins to cool and solidify on top leaving curvy and
ropy formations. The second type of lava is known as 'aa' lava that is spewed from the volcano and lands with jagged results.
Both types of lava get their name from the Hawaiian language, 'pahoehoe' meaning ropy and 'aa' meaning to hurt.
On Mosquera I had seen a single
marine iguana (Amblyrhynchus cristatus)
crossing the sandy island, but here basking on the black lava rocks were hundreds of black marine iguanas. There were so many iguanas they
were literally lying on top of one another absorbing the sunlight to warm their bodies. Their black color serves two purposes, one to absorb
heat because they are ectothermic and cannot make their own body heat, and two it provides camouflage while sunbathing.
The marine iguana is endemic to the Galápagos and is the only marine species of iguanas in the World. The islands have seven
subspecies of the marine iguana, all of which dive into the ocean and feed on
algae (Ulva).
Harry found a skull of an iguana and
was able to show us the fork-shaped teeth they use to scrape the algae from the submerged rocks. The waters surrounding the
Galápagos are very cold, so the iguana can only dive for a short time before resurfacing and basking in the sun to raise their body
temperatures.
As if the iguanas huddled together were not enough, there were several species of
lava lizards (Tropidurus)
leaping across the backs of the iguanas also absorbing heat to warm their bodies. There are seven endemic species of lava lizards in the
Galápagos that are all cousins to lava lizards found in South America. Some larger lava lizards were seen scurrying through the rocks most
likely in search of their favorite food, insects.
Just off the rocky shore a flock of
blue-footed boobies (Sula nebouxii)
were diving for their favorite food,
sardines (Sardinops sagax).
It is quite the spectacle to watch these blue-footed birds do their work. As a group there are always birds cycling
through their diving routine with some on the water, some at the top of their dive, some entering the water and some under the
water pursuing their food.
On the northern tip of the island we approached several nesting sites of the
flightless cormorant (Phalacrocorax harrisi).
The only flightless cormorant species in the world, these endangered birds are endemic to Fernandina and Isabela islands. In the 1983
El Niño more than 50% of the population of this species was wiped out, but they have recovered now having about 1500 breeding
pairs.
The Galápagos cormorant lost the use of its wings due to the lack of predators on the islands, they became unnecessary.
However, after a dive for food you can see them proudly holding up their wings to dry. These birds seldom venture further than a
kilometer from their nesting site and traverse the terrain awkwardly; however, in the water they are skilled swimmers.
Unfortunately, the battery in my camera chose this moment to run out of juice! I was able to get a few photos of these unique
birds; however, I missed the opportunity to photograph a male bringing his mate a 'sea wreath.' As part of the mating ritual the
male will dive into the ocean and gather seaweed that he will offer his female mate for nest building. On this day the female
refused the 'sea wreath' brought by her mate. Rejected, the male clumsily made his way back to the sea and returned with a much
larger 'sea wreath' and presented it to her. The second attempt paid off and the two love birds affectionately rubbed their heads
together, a sign the female was pleased with the gift.
As we were witnessing the romance between flightless cormorants Harry announced we needed to go back to the boat to keep our
schedule. Most everybody started making their way back to the pangas, everybody that is except for Dr. Church. She was enthralled
over the courtship and was busily taking photos of the cormorants not realizing the rest of us were heading toward the pangas. To
have a little fun Harry told us to board the panga and then we would paddle out as if we were leaving poor Dr. Church behind. When
she arrived at the loading area we were all laughing and telling her she was too late and would have to remain behind. Not fooled,
Dr. Church gave us a sarcastic smirk and we returned to pick her up and go back to the Letty for our afternoon snack.
Snorkeling off the Coast of Isabela
After everybody was on board and we were enjoying our snacks, the Letty lurched into motion
crossing the Canal Bolívar (Bolivar Strait) toward Isabela Island. It was a quick ride over to Caleta Tagus (Tagus Cove) where the
Letty's crew set anchor. The guides let us know we had a few minutes of rest time before we needed to gear up for another deep
water snorkel. This time I would be mentally prepared to take on snorkeling even though it would take place in water that reaches
depths of 500 m (1,640 ft)!
During my down time I ventured up to the sun deck to take in the view. We had anchored in a small inlet just south of Caleta
Tagus surrounded by mountainous terrain appearing desolate and devoid of life. On the lower peaks the ground provided a dull red
backdrop for gray ghostly looking trees. The trees were dormant during the time of our visit having dropped their leaves for the
dry season.
These trees are called
palo santo (Bursera graveolens),
a tree that has white bark with leaves only during the rainy season.
The red background behind the trees is caused by the oxidation of iron, more commonly known as rust, found in the basaltic lava
rocks. This color change is drastic from the deep black lava on Fernandina that I could still see from my current vantage point.
Geologically speaking, this difference gives us another way to compare the ages of the two islands. The black lava on
Fernandina has not been around long enough to achieve the red coloring from the oxidation that will eventually occur with its iron
content; hence Isabela is the older of the two islands.
The higher peaks ultimately disappeared into a ceiling of gray clouds, but higher up existed bright green vegetation resembling
a plush carpet. The contrast of the differing environments was surreal making one wonder how such a desertscape could co-exist
immediately adjacent to such lush green mountainsides.
The answer involves the layer of clouds usually found resting on the peaks of the Galápagos. In what is known as the Scalesia
Zone, 200 - 400m (656 - 1,312 ft.) in altitude, there is constant precipitation originating from 'garua' or fine rain from the
loitering clouds during the dry season. From this persistent moisture the grasses, mosses and ferns abundant in this area are able
to thrive and create two very distinct microclimates in a relatively small space.
The other observation of note was the graffiti on the north facing rocky slopes of the inlet. I had noticed graffiti on the
Cliff in Genovesa the day before and had thought it took away from the natural beauty of the island. I was having the same
thoughts as I scanned the graffiti in front of me until I noticed the dates - some of the graffiti had been around since at least
1832! That is three years before Darwin arrived on San Cristobal during the Voyage of the Beagle.
It suddenly occurred to me that the graffiti is part of the storied history of this remote island chain. People had been
visiting this area for at least 200 hundred years and leaving their marks on the Galápagos. I asked Harry about the graffiti and
he told me that in the 1980s they outlawed the practice, now it serves as a reminder of the days before the islands were granted
government protection and what man will do without restraints.
The pre-departure message warned we had only fifteen minutes to be ready to board the pangas en route to our snorkeling
expedition. Initially we went to the southern edge of the cove where the steep slopes continue their trajectory under sea level
creating very deep marine environments. Resting on the water's surface looking through my mask it was impossible to see into the
depths due to the murkiness, but Harry had told us it was greater than 500 meters (1,640 ft).
With my camera attached to my wrist I began snapping shots of the few species I could see. It was not what I had expected to
see thinking that it would be more lush and colorful than what I had witnessed in the Caribbean on my snorkeling adventure in
Jamaica. In fact, the sea creatures were few and far between and the coral was not nearly as complex and diverse as what I had
seen in Jamaica, mostly just patches of bright
orange cup coral (Tubastrea coccinea).
I did get a shot of a
Mexican anemone (Bunodactis mexicana)
with an orange center and gray/brown tentacles, a
green sea urchin (Lytechinus semituberculatus)
with bright green spikes, a bright red
panamic cushion sea star (Pentaceraster cummingi),
a
chocolate chip star (Nidorellia armata)
and some small colorful fish leisurely swimming by. Unfortunately, due to the murkiness of the water, all of the photos I took were grainy.
Because the visibility was less than desirable we made our way to the northern side of the cove just off Punta Tagus (Tagus
Point) where the sloping land mass was gentler giving us a shallower backdrop in which to view the life under the sea. Over on the
northern side of the inlet the water was much clearer so I could start taking some underwater photos. But, as luck would have it,
my underwater case had developed condensation on the inside obscuring the lenses view - another snorkel without any photos.
Letting my camera hang from my wrist I decided to enjoy the experience and watch the animals do their thing in this environment.
The first major encounter with the locals involved curious
sea lions (Zalophus californianus)
that apparently wanted to play with us. The sea lions, probably juveniles, would start swimming right toward me building up great speed so that
it seemed they would collide with my mask. This was an event that definitely got my heart rate up making me want to dodge the bullet. But inches
before they approached they would quickly dive down under my body, circle and do it again. I am not so sure I really liked the
game of chicken at first, but once I realized they would not hit me I relaxed and the sea lions lost interest or maybe went to play
with the other snorkelers.
Having survived the sea lion threat I glanced deeper into the water where I saw a
green sea turtle (Chelonia mydas agassizii)
gliding across the rocky bottom in search of algae. It was beautiful to observe the turtle use its large fins to effortlessly move
through the water as if it were floating through air.
While watching the sea turtle do its thing I saw fast movement out of the corner of my eye. Luckily I turned to see it before
it was gone. The fast moving objects were three
Galápagos penguins (Spheniscus mendiculus)
literally flying through the water. The three birds were in a familiar formation with a lead bird in the center and another bird on either
flank creating a V-formation.
I am not sure about the aerodynamics of water, but I would assume, similar to air, the drag and thrust properties are such that
the two birds in back benefited from the V-formation by needing less energy to propel themselves by using the turbulence from the
lead bird. Back in Colorado one often sees flocks of
Canadian geese (Branta canadensis)
flying in the V-formation and researchers have shown it benefits the geese in back by enabling them to catch the turbulence from the lead bird.
The Galápagos penguin is endemic and the only penguin found on the equator. Primarily located on Fernandina and Isabela
islands, there are small populations on some of the others. One of the smallest penguin species it is thought they arrived in the
Galápagos via the Humboldt Current, the current of cold water moving north alongside the South American coast towards the
equator.
It is known that this same current is the source of not only the penguin's food supply, but all life in the Galápagos. The cold
waters of the Humboldt are what carry the nutrient rich waters to the islands and is the base of the food chain. Moreover, because
penguins require cold waters the Humboldt provides the perfect habitat to sustain the penguin at this equatorial location.
It turned out to be a very good snorkel having witnessed some of nature's amazing inhabitants, although I was unable to get the
good underwater pictures I was after. Other students on the snorkel did, however, manage to snap some photos. Chris McGee was the
luckiest guy with a camera this day as he shot great photos of the sea turtles, a colorful sea cucumber and even landed a picture
of a flying penguin!
A Panga Ride Along the Coast of Isabela
When we finished the snorkel we loaded into the pangas and went back to the Letty to rest
and have lunch. But the day was not over. After lunch we were going to go for a panga ride to look for wildlife on the shores of
Isabela. Because of the limitations of our trip, namely time, we were not able to actually step foot onto Isabela. The area where
we were required special permits for people to enter the island. Isabela does have areas in which tourism is allowed, but they
were on the opposite side of the island and we did not have time in our itinerary to visit.
To make the most of the situation and still get a glimpse of the wildlife that lives on Isabela, we set out on the pangas
following the shoreline out of the inlet traveling to the north. As we began the ride we saw many penguins returning from their
day of foraging and entering shallow caves and crevices in the rocks where they would nest for the night. At the water's edge
there were bright orange sponges clinging to the rocks as well as a large grouping of barnacles.
When stationary you do not see the depths, twists and turns of the geology, but by slowly roaming along the shore watching the
landscape unfold one realizes the complexities of the geological history of the island. In and around Caleta Tagus on Isabela
Island all of the slopes were going up at roughly a 45 degree angle. Most of the rock was oxidized basaltic lava as evidenced from
its red color. However, some of the rock was light gray and others were more brownish in color.
The browner rock wall was large rising less than 45 degrees, but still having a relatively steep slope. The biggest difference
was the erosion when comparing it to the other rocky walls in the vicinity. It appeared that this particular section of rock had
been eroded by water due to its more rounded features. It is likely that it was pushed up and out of the sea by what is known as
island uplift, seismic activity that pushes the earth up. A quick look in our Galápagos text confirmed the likely origin of this
rock wall. In 1954 there was island uplift in Bahía Urvina (Urvina Bay), just south of Caleta Tagus, that pushed the Earth up by
five meters (17 ft) after which was followed by an eruption in Volcán Alcedo (Alcedo Volcano) a few months later.
As we made our way out of the bay into open water a
brown pelican (Pelecanus occidentalis urinator)
landed near the pangas. The navigator killed the engine and allowed us to photograph the bird. Brown pelicans can be found from
California and the Caribbean to the Galápagos, but the one here is considered a subspecies P.o. urinator.
While we were watching the pelican I noticed a group of penguins swimming around on the surface of the water. On closer
inspection I saw a school of sardines literally jumping out of the water trying to escape the entrapment by the penguins. The
penguins had corralled the sardines and were circling them coming closer with each revolution. It was a nifty strategy the
penguins had devised, using cooperation to catch their meal.
Continuing north along the coast there was a group of blue-footed boobies nesting on red rocky ledges covered in white guano.
This species typically makes a circular nest of its own guano, but this area was covered with large quantities so that any
particular nest was indistinguishable.
I saw a few Nazca boobies and
brown noddy terns (Anous stolidus)
on the rocky walls as well. The brown noddy subspecies is endemic to the Galápagos Islands and gets its name from nodding its head during
courtship displays. These sea birds build their nests on the cliffs using twigs. When feeding, they usually skim the water and grab small
fish with their long beaks, sometimes landing on the heads of larger birds such as the brown pelican to wait for their prey.
As we were about to turn around and go back to the Letty we spotted a large cave and asked if we could go inside. The guides
decided to humor us and had the navigators take us in. The cave was large and likely the remnant of a lava tube that had once been
an avenue for lava flowing into the sea. The cave only went back about 10 m (33 ft) before it narrowed too much for the panga to
pass. Inside there were purple and orange moss looking beings spread over the rocks underneath the water. They were quite
beautiful and seemed to provide camouflage cover for some sally lightfoot crabs.
We exited the cave and went back to the Letty to relax and have dinner. After dinner I went up to the sun deck to gaze at the
stars. Tonight we would travel north back around the top of Isabela on our way to Bartolomé Island where the activities for the
following day would take place. Bartolomé is the site of Pinnacle Rock, one of the most well-known landmarks in the Galápagos.
|