Far beneath the surface of the ocean, as sunlight fades to darkness, exists an almost hidden
world home to an incredible diversity of life.
Despite the vastness of the ocean and the abundance of marine life that thrives there,
this environment is still virtually unknown.
With still so much to explore, discover, and learn about the depths of our ocean planet,
deepwater ecosystems provide an amazing platform for scientific research.
So understanding the deep ocean is of fundamental importance to understanding the planet as
a whole.
So you think about the size of the ocean, and especially the deep ocean, makes up more
than 90% of the volume, or the space we can inhabit, or that any living organism can inhabit.
A team of dedicated scientists and engineers from Lehigh University and Woods Hole Oceanographic
Institution are developing revolutionary new ways to study deepwater ecosystems.
The cutting edge methodologies have the power to enhance the scope and efficiency of ocean
exploration, as well as provide a more complete picture of marine biodiversity, which can
inform the management and conservation of deepwater resources around the globe.
In the Gulf of Mexico, approximately 100 nautical miles off the coast of Texas, is Flower Garden
Banks National Marine Sanctuary.
Marked by spectacular shallow-water coral reefs home to a bustling community of marine
species, from intricate vertebrates to dazzling megafauna.
Farther down, as darkness begins to take over, flourishing marine communities in form of
deepwater coral ecosystem continue to persist.
Aboard NOAA Research Vessel, the R/V Manta, these researchers are on a mission to use
innovative methodologies to explore the biodiversity of deepwater ecosystems near Flower Garden
Banks National Marine Sanctuary as well as the deeper continental slope.
Better understanding these less explored and less understood deepwater ecosystems is crucial
as they, like their shallow water relatives, play a vital role in an overall healthy ocean
system.
So how are these scientists exploring the biodiversity of deepwater ecosystems?
With eDNA. eDNA or environmental DNA is composed of small traces of genetic material that organisms
leave behind in the water column.
From jellyfish to corals to fish and even whales, marine animals are constantly leaving
invisible signs of their presence in the environment.
eDNAis short for environmental DNA and the idea behind it is somewhat similar to forensic
science.
It's this idea that all Eukaryote organisms, including people, shed their DNA into the
environment.
One of the great advantages of using environmental DNA is that we can capture in true seawater
the diversity of organisms that live in an area.
We have estimates from different studies that tell us that maybe more than 90% of the biodiversity
that exists in the ocean remains to be discovered.
So eDNA could act as a tool to give us hints of what that missing biodiversity we haven't
discovered is.
To collect eDNA, water samples from various depths in the ocean must first be obtained.
Enter Mesobot.
This state-of-the art autonomous deepwater robot from Woods Hole Oceanographic Institution
is designed to study deepwater organisms without disturbing their environment and behavior.
While Mesobot's primary focus is to track elusive twilight zone organisms using cameras
and dimmable lights in a non-invasive way, in this research collaboration, as part of
the Ocean Twilight Zone Project, Dr. Annette Govindajaran is using pumped, filter seawater
samplers on Mesobot in order to filter eDNA from the water while at depth in the Gulf
of Mexico.
The Mesobot is a new kind of robot that's designed to actually emulate a skilled scientific
diver with, of course, a whole of additions.
Okay, so it can hover, it can see the ocean without disturbing it, it can see the animals
without disturbing them, and it can actually follow animals using stereo cameras, but it
has a lot of other functions too.
On this particular expedition, we are using it to sample environmental DNA.
We're not sampling animals, we're not sampling pieces of animals, we're sampling traces of
the DNA that the animals leave in the water.
Water samples were also collected at depth using a CTD rosette.
A staple in the world of oceanography, this instrument array houses sensors to measure
salinity, temperature, and depth, as well as a series of bottles that can be individually
triggered to close and collect seawater at specific depths.
While at sea, filtered eDNA was preserved by freezing.
Back in the lab, the groups of Dr. Santiago Herrera, Dr. Jill McDermott, and Dr. Annette
Govindajaran are working to purify the eDNA and use modern gene sequencing technologies
to identify coral, fish, and invertebrate species that call this region of the deep
Gulf of Mexico home.
So in order to get the DNA out of the eDNA samples, what we do is we collect fresh seawater
using either the Mesobot or with the CTD rosette.
That water gets pumped through sterilized tubing into a sterile, very fine mesh filter
that traps cells and extracellular DNA within the mesh of those fibers.
That material gets frozen on dry ice here on board, gets shipped cold back to our university
where it's then extracted, undergoes a polymerization reaction, and then we can then bar-code those
samples in order to match them up with coral or fish organisms.
Herrera and McDermott are also pursuing new lines of research in exploring how varying
ocean conditions like temperature, chemistry, and pH, along with the speed and direction
of localized currents, affects the stability and persistence of eDNA in the deep ocean.
Another important thing that we're trying to do with the samples we collect this expedition
is to understand how the DNA preserves in seawater.
How long can we detect the DNA after it has been shed from an animal in the seawater?
Generating a model to estimate for how far and for how long eDNA remains in the water
column will provide an important framework for marine scientists around the world to
use eDNA as an accurate means for studying biodiversity of deepwater ecosystems.
Overall, eDNA allows for a more cost-effective and less intrusive way to study the deep ocean.
By simply collecting samples of seawater, scientists are able to gather important genetic
information about the species that call the depths of our planet home.
eDNA research can be carried out for a fraction of the price compared to more traditional
methods and rather than having to continue to collect physical tissue samples or whole
specimens to obtain genetic information, these deepwater ecosystems can now be learned about
without disturbance.
eDNA also allows for a more broad analysis of deepwater ecosystems since identification
of a wide variety of species can be detected from a single water sample.
Taking an eDNA sample really only requires water and sterilized equipment.
And so it has a real value of not harming an organism, not requiring a physical collection
of a specimen, and so in that sense it's completely non-invasive and it doesn't impact the environment
that we're interested in.
With eDNA we can just pump water and establish baselines for wider coverage in biodiversity
throughout the world's oceans.
The results from this eDNA research will be directly applicable to the management and
conservation of areas currently being considered for protection as part of the proposed expansion
of Flower Garden Banks National Marine Sanctuary, which has the potential to encompass a much
larger and deeper area of the Gulf of Mexico.
So there's been a lot of interest in potentially the national marine sanctuary here in the
Gulf of Mexico.
We believe that this eDNA research can be important groundwork for underpinning that
expansion and identifying which of the banks contain hotbeds of biodiversity.
With that knowledge in hand, we can then make informed decisions about which of these banks
is most important to protect as we expand the sanctuary.
The deep ocean is an integral part of our planet, the planet that sustains us all.
This vast, relatively unexplored environment plays a key role in regulating ocean chemistry
and biology, which in turn strongly affects global climate.
With threats from over-fishing, climate change, and oil spills looming, better understanding
the deep ocean is ideal for everyone on Earth.
With the use of eDNA as a more effective and less disruptive methodology, science is unlocking
the secrets of the deep ocean and the incredible variety of animals that live there one drop
of seawater at a time.