Written by Rosanna Milligan

It’s the end of another successful cruise and we’ve collected thousands of animals and taken hundreds of physical and chemical measurements across the northern Gulf of Mexico. My job is now to take these data, integrate them with the data from our previous research cruises, and analyze them all to try to find patterns in them that will help us understand how the deep pelagic fish communities are structured.

Understanding how animals are distributed through different environments is one of the key questions in ecology, because the answers can tell us important information about which areas might be particularly valuable. This might be because they contain particularly high biodiversity and are important to conserve, or they might be areas that might contain particularly high abundances of animals that we might want to target for fisheries or drug development for example.

While it’s easy to imagine different terrestrial environments, like deserts, forests or mountain ranges, it’s much harder to imagine what the different environments that might exist in the open oceans are, because, frankly, one patch of seawater looks much the same as any other at first glance. But, when we start looking with scientific instruments like CTDs, or using satellite imagery, we can start to see how the oceans are structured by gradients and boundaries in the physical and chemical properties of the oceans like temperature, salinity or water currents. However, we still don’t really understand is how much this environmental variability influences the animals that live in the deep pelagic oceans. Do they care about different conditions or are they happy to live anywhere? Are they just pushed around randomly by water currents or do they actively swim against them to stay in the best locations?

CTD Instrument used to measure the physical properties of water and to collect water samples from different depths.

Our work with the DEEPEND project is starting to disentangle some of these ideas. For example, we’ve been working hard to figure out how to identify different water masses in the Gulf of Mexico in an ecologically-meaningful way, and separate out how and why different water types affect different deep-sea animals and their distribution patterns. We’re working with teams of geneticists, chemists and oceanographers too, to match up all the different research strands into a coherent story. All of this will be really important in understanding how resilient or vulnerable different organisms might be to human impacts in the Gulf of Mexico, in case something like the Deepwater Horizon disaster ever happens again.

So all the work we do at sea is really just scratching the surface of the work we do when we get back. We’ve got lots more work to do and many more questions to answer!

Another day at sea – one of our last for this cruise.

My name is Laura Timm and I am a PhD student at Florida International University. This is my fourth DEEPEND cruise and the data we collect from it will contribute to the last chapter of my dissertation.

I work on crustacean genetics. Specifically, I use the DNA of a few shrimp species to describe diversity and characterize how (or if) it is moving within the Gulf. These two things, diversity and gene flow, provide a lot of insight into the health and resilience of these target species. Most of my work with DEEPEND has focused on three shrimp: Acanthephyra purpurea is a bright red color and produces a bioluminescent spew to scare off predators.

Systellaspis debilis is also red (though younger ones can look orange), but with tiny light-producing organs called photophores polka-dotting its body.

Sergia robusta can be dark red or even purple and has photophores around its mouth and tail.

To me, all three are uniquely beautiful.

My research focuses on questions related to genetic diversity, which is a good metric for species health. Where is the most diversity found? Has this changed since 2011? How is diversity distributed? Is some genetic diversity unique to certain places? Answers to these questions provide unprecedented insight into how the Gulf copes with disturbances.

Now, a little perspective.

We trawl with a MOC10 net. It is very large. Every person on the ship could go stand in the frame of the net. However, when compared to the size of the ocean, it is tiny – it has been described as the equivalent of investigating terrestrial diversity using just a butterfly net. Yet, we still catch thousands of shrimp. Of these thousands of shrimp, a few hundred are targeted (A. purpurea, S. debilis, S. robusta). Of these hundreds, 96 are sequenced (this is due to the sequencing process; I can only sequence 96 at a time). The genomes of these species have not been sequenced, so I target a few thousand base pairs of DNA. A few thousand base pairs out of billions of base pairs. About 100 shrimp out of hundreds, hundreds out of thousands, thousands out of every shrimp in the Gulf. This tiny amount of data (which, in the history of science, is unprecedentedly large) can tell us so much about the animals living in the Gulf and how they came to be there and whether they are likely to survive whatever comes next.

For centuries, sailors and scientists have observed birds landing on ships. A ship out at sea is like a moving island in the ocean. Various birds may seek refuge on ships, especially when storms occur, or are attracted to the lights of the ship at night. It makes sense that many of these birds are sea birds, but a number of land birds may make migrations across ocean areas or get blown out to sea by storms along the coast. Given the several storms during our cruise, it is no surprise we have had a number of birds land on or fly close to our ship, while it was 100-150 miles off the coast of Louisiana, Mississippi, and Alabama. So, here is a short rundown of the birds we have seen recently…

Purple Gallinule – spent a couple days resting on one of the deck cranes until it took off.

Louisiana Waterthrush – this wood warbler took refuge in a corner of the deck for a while before flying away.

Northern Oriole – just showed up on the ship superstructure, rested for an hour, and took off.

Cattle Egrets – we have had several stay around the ship, with a flock of 14 circling the ship one morning.

Bobolink – a few individuals flew around the boat this morning and one perched on the anchor chains and other structures on the bow.

Barn Swallows – One morning just before another squall, there was a flock of approximately 100 circling the ship from 5-6 AM. A flock of about 8 flew by the ship yesterday after several days of clear weather. This morning 3 were perched on some fixtures.

We also had a very large flock of a small birds that might have been American Goldfinches, but it was too dark at 4-5 AM to see them clearly.

Coastal birds we have also seen far out at sea include…

Osprey – one landed on a container on the forward deck, sat for a few minutes, and then left when it was disturbed by a crew member.

Brown Pelicans – three juveniles paddled along with the ship and flew short stretches to catch up again.

Caspian Tern and Royal Terns – one Caspian and two Royals sought a perch on a part of the stern of the ship during a rain storm.

Laughing Gulls – 3 juveniles and 1 adult stayed around the boat for a day during and immediately after a storm.

Written by Tess Rivenbark

My name is Tess Rivenbark and I am representing the Optical Oceanography Lab at the University of South Florida College of Marine Science. Most of the scientists here focus on biology, but my job is to collect data that ties this biology to the physical processes happening in the ocean, looking at different types of particles in the water.