Marine biologist Adrian Munguia Vega is looking for species never seen before. – People believe that, okay, we are just traversing an empty ocean, that there is not much going on because we cannot see it. But there is a lot going on, you know.
The Gulf of California is 1126 kilometers long and between 50 and 240 kilometers wide, separating the Baja California Peninsula from the rest of Mexico. The gulf is part of the Pacific Ocean, but it is so vast that many consider it its own body of water, the Sea of Cortés.
It’s not the size that fascinates marine biologist Adrian Munguia Vega - it’s the depth, more than 3000 meters at its deepest point.
Genetic technology
Vega is a researcher affiliated with the University of Arizona in Tucson in the USA, and also the founder and director of a private genomics lab based in La Paz in Mexico. The laboratory he leads is developing new techniques to measure biodiversity with genomic tools in the ocean.
Vega is collecting the tiny particles that all animals and plants leave behind where they live, particles that contain DNA - genetic material.
– The ocean is a soup of DNA. You know, every animal, plant, anything that lives in the ocean releases its DNA the same way that when we go into a pool - you know strains of your hair fall out, and cells from your skin will peel off. It is the same with fish, and all the invertebrates - they release DNA to their environment. And over the last ten years the DNA sequencing technologies have advanced very far, and now we have the ability to sequence millions of sequences simultaneously, Vega explains.
To sequence DNA means identifying the order of the four building blocks that all DNA consists of, shortened A, T, C and G. The sequence is unique to each species. Once you know it, you can determine which animal or plant the particle comes from.
The method is called eDNA, short for environmental DNA, and Statsraad Lehmkuhl has the equipment scientists need both to collect water samples and to filter them so the particles can be analyzed.
One of the most diverse regions
The Gulf of California sits where the Pacific and the North American tectonic plates meet. Twelve to fifteen million years ago, the Pacific plate tore away the piece of the North American plate that is now the California Peninsula, and the gulf opened up in the rift that formed.
This is one of the most diverse regions in the world, home to more than 5,000 species of small invertebrates. Parts of the Gulf of California are listed as a UNESCO World Heritage Site. But only a small share of all species is known, far fewer than scientists once believed.
A bias in their knowledge
It used to be common knowledge that most species live near the ocean surface, and that their numbers decline the deeper you go. Now the marine biologists understand that this was due to a bias in their knowledge.
– As we are starting to get more samples from the deep ocean, we are realizing that that's not the case. Some of the water samples from the deep have the same number of species, and sometimes even more species, than at the surface. And we are realizing that samples from the deep ocean are very diverse. At the same time the species that we see at the surface, where we can dive, where we can observe them, are very different from what we see in the deep ocean. So, you know, it's changing our view, the deep is not a very lonely, empty space. It is a place that has a rich biodiversity, we just didn't have the tools before to observe it, and we just assumed that there was not much going on there, Vega says.
Never observed before
Vega compares the DNA sequences in his samples with sequences registered in genetic databases. One is maintained by the US, one in Europe, and another in Japan. All three are updated daily and contain DNA sequences for all known species.
Often, there is no match, meaning the species that shed a particle in the deep has never been observed before.
– When we sample the deep ocean many of the sequences, maybe half, don't have a match, which means that nobody has seen anything like it. And that just tells you that we haven't spent much time exploring the deep ocean, and there are not a lot of people doing DNA sequences to try to understand what lives there, Vega says.
– It is first when we understand what is living there, we can try to understand, okay, are these species maybe for human consumption? Are they a source of protein that we can exploit or not? Are there any endangered species here that we need to protect, and what ecosystem services are these species doing, and why are they important for us?
A unique opportunity
For Vega and his colleagues, joining Statsraad Lehmkuhl sailing along the California Peninsula and into the Gulf of California is a unique opportunity.
– There is not a lot of information from the deep ocean in general in the world, and very little especially in Mexico. So we hope to maybe describe for the first time which animals and plants that live in this place. The research tools that the ship has, give us access to parts of the ocean that are very difficult to reach unless you have a large vessel with a lot of cable and tools that you can deploy to take water samples from the deep ocean, he says.
Vega uses “the rosette,” one of the scientific instruments on board Statsraad Lehmkuhl, to collect water samples. He also deploys a camera to film what exists down in the depths.
– Every time we drop a camera, we see something. Sometimes we are able to reach the bottom, and every time it's just like a space exploration. You don't have any idea where you're gonna land, he says.
– Sometimes you land in very cool places that you never dreamt of, and you are maybe the first one seeing it. We have found rocky surfaces full of sponges, really big sponges, like a sponge garden, beautiful. People believe that, okay, we are just traversing an empty ocean and there might be just sand down there. That there is not much going on because we cannot see it - but there is a lot going on, you know. So for me, my real goal is to make people understand by showing it.
It’s easy to see that what drives Vega is not only scientific curiosity, but also a deep and personal desire to explore.
– Well, you know for me, exploring the ocean depths is really exciting because it's so close to home. But you are at the surface all the time, it is unreachable, you know. So for me, it's just the concept of being there but not being able to see - and then suddenly having these new technologies that allows you to understand and see what's going on. I think that's really amazing.