California Academy of Sciences
The California Academy of Sciences in San Francisco is a scientific and educational institution dedicated to exploring, sustaining, and explaining life on Earth. it is among the largest museums of natural history in the world, housing over 26 million specimens.
It includes aquariums, rainforest enclosures, a living green roof, 40,000 live animals, and more.
The room we are in houses hundreds of skulls allowing you to gaze 3.3 million years into the past. From the enormous bull elephant to a tiny elephant shrew, skulls tell a story about life, death, and evolution of vertebrates.
Sea Lion Skulls
400 California sea lion skulls are on the 90-foot-wide wall. The skulls allow scientists to study the health of California’s sea lion population and the impacts of pollution, disease, and other threats. Can you spot different-looking skulls?
There are also wolf, walrus, warthog, and others hidden among the wall. Scientists have come to understand a great deal about the evolution of skulls by studying the fossil record. They know that prior to about 500 million years ago, no creature possessed a skull.
Over time, skulls changed from a primitive collection of bony plates to the highly reinforced, structural marvels most vertebrates carry around today.
Colossoma Macropomum (Tambaqui) Skull
Though this fish is similar in shape and size to a piranha, its teeth tell a different story. It fasts for months, then comes inland with floodwaters, swimming up under trees to eat fallen fruit.
Deforestation in Brazil
Over the past 50 years, about half of the world’s original forest cover has been lost, mainly because of unsystematic use of its resources.
Paraíba do Sul river in Campo dos Goytacazes by Gledson Agra de Carvalho (CC BY-NC 4.0)Museu do Amanhã
Deforestation is the destruction of forests to convert the land for other uses, such as fuel, making the land available for housing and urbanization, or harvesting timber to create commercial items such as paper.
The Juma Reserve
We are in the Juma Sustainable Development Reserve in Brazil, in the southern region of the State of Amazonas. The Brazilian Amazon is under great pressure of deforestation. It is estimated that 17% of the original forest cover has already been lost.
Agriculture and cattle production expansion makes the large expanses of sparsely populated forests of the Amazon even more vulnerable to deforestation.
We are at the Rio Mariepaua Amazonian river. The Juma reserve is located in one of the two most important interfluvial regions in Amazonas, between the Madeira and Purus Rivers.
The area is drained by a complex system of rivers and streams, including both banks of the lower region of the Aripuanã River, the main tributary of the Madeira River.
Loss of Arctic sea
The Arctic and surrounding regions are going through rapid changes due to climate change. The area covered by sea ice has decreased considerably during the last fifty years. Shiny ice and snow reflect a high proportion of the sun's energy into space.
As the Arctic loses snow and ice, lost sea ice exposes dark, open waters that instead of reflecting, absorbs most of the sun’s energy, making water temperatures ever warmer. This is called the albedo effect.
The loss of Arctic sea also increases air temperatures in the region, further delaying the formation of ice in the fall. Canada’s northern communities have also been experiencing the effects of global warming and loss of summer ice.
You are now looking at the town of Churchill, Manitoba, in Canada. This area is famous for polar bears that move toward the shore from inland in the autumn.
Polar bears most preferred habitat is on top of the ice that covers the arctic seas much of the year. They depend on ice for all parts of their life, and are threatened by a warming climate. With less ice, there are more polar bears on land.
Churchill attracts polar bears because it sits on the coastline of Hudson Bay, and polar bears follow the coast in search of ice floes. Longer ice-free periods hinder the ability of polar bears to reproduce and nurture their young.
Polar bears need the ice to hunt for ringed seals, their primary food source, in order to build up and store weight for the rest of the year.
The Sinking City of Venice
Venice is the capital of northern Italy’s Veneto region. Founded in the 5th century, Venice is built on a marshy lagoon and spreads across 100 small islands on the Adriatic Sea.
Venice: The Dogana and San Giorgio Maggiore (1834) by Joseph Mallord William TurnerNational Gallery of Art, Washington DC
The city was a major maritime power during the Middle Ages and Renaissance, and is known for it’s art and architecture.
Floods known as acque alte (“high waters”) are common in Venice, and strike when spring tides coincide with storm surges in the Adriatic Sea.
However, the frequency and severity of high tides have increased dramatically over the past hundred years. A combination of sea-level rise and geological land subsidence has lowered the lagoon floor, and caused the shoreline to retreat around the lagoon circumference.
Venice is surrounded by canals. The Grand Canal is the main waterway in the city. There are no cars allowed in Venice, and public transport is provided by water taxis, water busses (vaporetti), or gondolas, like the one we are looking at.
The canals rise every year, and a higher than average tide is enough to flood entire areas of the city.
Great Barrier Reefs, Australia
One of the seven wonders of the world, the Great Barrier Reef is home to 3,000 reef systems and contains over 1,500 species of fish, over 400 species of coral, over 130 species of sharks and rays, 6 out of the 7 marine turtle species and 30 species of marine mammals.
This ecosystem is renowned for its ecological importance and the beauty of its seascapes and landscapes. However, changes in environmental variables due to climate change are severely impacting many reefs, species, and their habitats.
Climate change affects the Great Barrier Reef in numerous ways, including rising sea temperatures, ocean acidification, rising sea levels, and increased frequency of extreme weather events.
Temperature-sensitivities of other species, such as microbes, plankton, fishes, marine turtles and seabirds are also impacted in the trophic system.
These are structures built mainly from calcium carbonate (limestone) laid down by hard corals. These corals are highly vulnerable to higher-than-normal sea temperatures and acidification of the ocean.
When corals are stressed by environmental changes such as light, temperature, or nutrients, they turn white. This is called coral bleaching. Ocean acidification, the decrease in pH of Earth’s oceans due to uptake of carbon dioxide (CO2) from the atmosphere, causes mass coral bleaching events, and the calcification rate of corals is reduced.
Bleaching have already caused serious damage to over 16% of the world’s coral reefs. Climate change is also leading to an increase in extreme events such as severe storms. Reef recovery from such severe storms is slow because fewer corals survive to recolonise affected areas.
There are 7 species of sea turtles, all that are considered endangered. The diet of many sea turtles consists of algae and jellyfish. Floating plastic debris looks much like their diet, their dead carcasses are often found filled with plastic debris. This and human poaching of sea turtles are the top reasons why they are all considered endangered.
Turtles are huge migratory animals. They can span oceans within their lifetime. What is fascinating about them is that they will return to the same beach where they were born to mate. This is called homing behavior.
They use a chemical trail and a magnetic sensory to navigate them back to the very same beach. Females will only exit the ocean (different than a marine tortoise) to lay her eggs.
Sea turtle hatchlings (2010) by TAMAR Image BankOriginal Source: http://www.tamar.org.br
At night, she will dig a nest deep enough to fill with her eggs, then she will cover them and head back into the ocean. The hatchlings will emerge and making the riskiest trip of all, from the nest back into the ocean.
Sea turtle hatchlings. Baby sea turtles moving towards the ocean, after hatching in the late afternoon. (2007) by Banco de Imagens Projeto TAMARTAMAR
Many beaches that are known breeding grounds to turtles will either be shut down or regulated during the mating season. Something as simple as having a flashlight on the beach can alter the trip of the hatchlings back into the sea.
Retreating Glaciers and the Matterhorn Mountain
Due to the warming planet, mountains around the world are seeing accelerated changes of glacial melt, erosion, and mudslides. A glacier is dense ice made up of fallen snow that over many years, compressed into large ice masses.
Global warming has led to rapid glacier retreat and even the disappearance of glaciers in some locations, making them key indicators of climate change.
Glacier retreat affects the availability of freshwater, animals, and plants that depend on glacier-melt, and create either flood or water shortage in ecosystems. Numerous mountains around the world are affected by this rapid change in composition.
We are at the trail toward the Matterhorn mountain, which rises above surrounding glaciers. The Matterhorn is a mountain in the Alps, on the border of Switzerland and Italy. It is 4,478 metres (14,692 ft) high, making it one of the tallest mountains in the Alps and Europe.
Due to rising temperatures glaciers on the peak are retreating, and scientists now claim that rising temperatures are also prompting the disintegration of the mountain itself.
Cracks and crevices
The Matterhorn is mainly composed of a type of rock called gneisses, which was originally fragments of the African Tectonic Plate. The current shape of the mountain is the result from erosion due to multiple glaciers diverging from the peak, forming a pyramidal peak.
Melting water mostly from retracting glaciers permeate exposed cracks and crevices on the mountain. Then, cycles of freezing and thawing in these gaps create small movements under the rock surface and cause fissures that lead to rocks falling off the mountain.