JC010: Mud volcanoes and submarine canyons


Cruise diary

Day 19: Wednesday 20 June 2007...last day!!
Position: 39º 30’ 052 N, 09º 55’ 881 W , Nazare Canyon
Weather: Sunny

Virginia writes:

"The ROV Isis was recovered from the sea at about 7am when I was waking up. Observing the nice photos of deep-see organisms (macrofauna) taken by the ROV over the last few days, and taking a look at some photos of microorganisms, I began to think about the importance of the studies on biodiversity.


Some dep sea organisms (macrofauna) found in the Canyons


What is biodiversity? Biodiversity is the variability of all living organisms - including animal and plant species - of the genes of all these organisms, and of the terrestrial, aquatic and marine ecosystems of which they are part.

Why is biodiversity important? Biodiversity makes up the structure of the ecosystems and habitats (the place where the orgamisns live) that support essential living resources, including wildlife, fisheries and forests.

Ecosystems are dynamic interactions between plants, animals, and microorganisms and their environment working together as a functional unit. Ecosystems vary in size. They can be as small as a puddle or as large as the Earth itself. Any group of living and nonliving things interacting with each other can be considered as an ecosystem.

The habitat must supply the needs of organisms, such as food, water, temperature, oxygen, and minerals. If the population's needs are not met, it will move to a better habitat or can disappear.

Biodiversity in a ecosystem helps it to stay resilient.

Biodiversity also helps provide for basic human needs such as food, shelter, and medicine. In addition, ecosystems can maintain oxygen in the air, enrich the soil, purify water, protect against flood and storm damage and regulate climate. Biodiversity also has recreational, cultural, spiritual and aesthetic values.

But human activity has affected a large proportion of the Earth. Because of their widespread effect, the human economy interests and biodiversity can be in conflict. We are eliminating species very rapidly.

But what is the evolutionary context? Has this happened before? The fossil record shows a number of gains and losses of biodiversity with changes in species associations. There have been at least five mass extinction events. In the most recent, about 65 million years ago, marine reptiles and terrestrial dinosaurs were eliminated, but that opened niches for the diversification of mammals, including, eventually, Homo sapiens.

Despite the mass extinction events of the past, the overall trend has been towards greater diversity; losses have been exceeded by the evolution of new species. The rate of extinction that has been occurring in recent centuries, mostly as a result of human activity, equals or exceeds the rate of extinction during the last mass extinction event.

So to protect biodiversity we need to know the ecosystems´ composition and functioning.

Biodiversity is closely linked to Biogeography which is the geographic distribution of species and taxa (groups of species included in taxonomic groups, genera, families, orders, classes, kingdoms) in our biosphere.

Even though roughly three quarters of the earths surface is covered by ocean with more than 90 % being deep sea (continental slopes to hadal depths), with an average depth of 3729 m, the abyss (3000-6000 m) covers about 50 % of the deep sea. However information on biodiversity is still very much concentrated on terrestrial ecosystems most prominently on tropical rain forests. In contrast the faunas living in the largest ecosystem on earth, the deep sea floor are very poorly known.

So the studies of Paul Tyler and the other biologists on board on the diversity, distribution and abundance of macrofauna in the Portuguese canyons are very important.

I think that could be very interesting to know if the species that dominate in some sites are also dominating at the same depths in other areas of the open slope of the Iberian Margin or if the assemblages found in the canyons are special and if they develop due to specific environmental conditions only generated inside them. Andy, for instance, would like to compare benthic foraminifera (microfaunal) assemblages found in Nazare Canyon and other ones existent in the open slope near this canyon at similar depths."

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The cruise contrinues on 22 June with the third and final part of the expedition. Teachers Tina and Richard join the team on board the James Cook to explore the mysteries of the Whittard Canyon on the Irish margin...check back after 22 June for the latest!!

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