Since 2014, the Millennium Institute of Oceanography (IMO) has been working hard at leading, exploring, teaching and communicating the most recent discoveries made in the eastern South Pacific Ocean. This is why, during its more than three years of existence, it has successfully headed expeditions including Lowphox and MOPEX, and has also taken part in the CIMAR 21 and 22 expeditions.
It is important to note that IMO seeks to understand the ecological, physical and biogeochemical processes taking place in the eastern South Pacific, in addition to exploring the region’s deep sea and abyssal zones, so that its research areas are divided into microbial oceanography, zooplankton ecology, phytoplankton ecology, physical oceanography and biogeochemistry.
First expedition, Lowphox: ¿How are marine ecosystem structure and functioning affected by acidification and lack of oxygen? ¿How do organisms from the water column adapt to these drastic chemical changes? These are some of the questions that the Lowphox I expedition tried to answer on board the Cabo de Hornos research vessel. The study took place between November 20 and December 13, 2015.
The National Commission for Scientific and Technological Research (CONICYT) awarded IMO, along with the National Geology and Mining Service, the first period of use of the vessel Cabo de Hornos. During Lowphox I, research was carried out, focusing on evaluating food webs and the carbon cycle in low-oxygen and low-pH waters, which are characteristic of the oceanic region off the north coast of Chile. The expedition’s scientific leader was Dr. Osvaldo Ulloa, full professor in the Department of Oceanography at the University of Concepción and director of IMO. “We were finally able to start doing open-sea research with appropriate equipment and, most importantly, with a platform that allows us to undertake advanced oceanographic research. This is a tremendous responsibility and I trust that this will be the beginning of a new phase that will make Chile one of the world’s main actors in oceanographic research,” commented Dr. Ulloa.
Dr. Rubén Escribano, deputy director of IMO and also a member of the scientific group on board the cruise, highlighted the importance of this scientific expedition. “We managed to incorporate all the Institute’s working teams into a common project; for many of our younger people this was the first cruise of such importance, and, without a doubt, it was a great opportunity to learn with first-rate scientists and equipment.” Furthermore, Dr. Escribano emphasized that IMO has close relationships with highly prestigious scientists and international centers, and that it is expected that the results obtained from these studies will have a major impact across the world.
On this occasion, 25 scientists embarked on the expedition, forming a multidisciplinary team consisting of graduate students, postdocs, technicians and researchers from the University of Concepción, the Catholic University of Chile and the Center for Climate Research and Resiliency, in addition to foreign guests from Ohio State University and Woods Hole Oceanographic Institution, USA.
Oxygen minimum zones (OMZ) are broad subsurface zones in the ocean, the waters of which either have very low oxygen (O2) concentrations or even no concentration whatsoever, which is why anaerobic organisms predominate there. A characteristic of OMZs is that they lose molecular nitrogen (a nutrient vital for life in the ocean) by releasing it into the atmosphere. They also contain such high levels of dissolved carbon dioxide (CO2), that pH values in the seawater decrease and it becomes more acidic. These ocean zones reflect climate change, as they expand as a result of increases in ocean stratification caused by global warming. The results of the Lowphox I expedition will make it possible to begin to understand and to better predict the combined impact of acidification and oxygen loss in seawaters, the consequences of the on-going global change.
Sara Zamora worked on the Lowphox I expedition as an IMO postdoc. She appreciated the opportunity and said: “This is an interesting zone, because it is an oxygen minimum zone that has been studied very little. It has a lot of potential in terms of the study of zooplankton. Basically, we want to know if there is zooplankton that can survive in the oxygen minimum zone, and we need to understand that due to climate change these zones will spread and that there will be important changes in the food web. This is the importance of the zooplankton’s role in OMZs,” explained the scientist.
MOPEX: the challenge of advancing
With the purpose of getting to know the plankton communities existing in the ocean and deep environments and understanding how these communities can subsist on the primary production from surface ocean layers, IMO developed the so-called MOPEX expedition (Mesoscale Oceanic Plankton Expedition).
“It was an exploratory expedition. We were expecting to find some different life-forms and to determine the nature of their physicochemical environment. We were also expecting to find species that had not been reported in our zone. Thus, incrementing the inventory of the biodiversity in the eastern South Pacific would indeed be a major achievement,” claims Pamela Hidalgo, assistant researcher at IMO and research leader of the MOPEX cruise.
The MOPEX expedition took place between September 21 and September 30, 2016, during which period the Cabo de Hornos oceanographic vessel sailed in the area between Valparaíso and Caldera, specifically over the so-called Atacama Trench, about 100 km from the Chilean coast. On this occasion, scientists collected plankton samples that had never been collected before in Chile. In this respect, Rubén Escribano highlights the importance of this milestone. “For the first time in Chile it was possible to take measurements and to collect samples at depths surpassing 5,000 meters in an unexplored part of the Pacific Ocean, namely, the oceanic trench off the coast between Caldera and Valparaíso. At these depths, the environment is very stable and cold with very high pressures, but this environment still allows the existence of a great variety of organisms, including plankton, fish, mollusks and crustaceans.”
The region of the Pacific Ocean off Chile is acknowledged across the world for its important role in the regulation of the climate of the ocean and the planet. The results of the studies carried out during this expedition will have an international impact, since the measurements and observations carried out are unprecedented for the scientific community in general.
It is noteworthy that the nets used to collect samples of zooplanktonic organisms reached a depth of 3,000 meters, while the rosette, a piece of equipment used to take water samples for chemical analyses and to establish the existence or otherwise of microbial communities, reached a depth of 5,000 meters.
The current challenge is to analyze all the samples that were obtained through MOPEX, a process that could even take a year. “I believe that we have enough material to work for a year and the analysis could even provide material for a number of Master’s and PhD theses,” declared Pamela Hidalgo.
The working team was made up of 25 people under the guidance of IMO professors and researchers, both from the University of Concepción and the Pontifical Catholic University of Valparaíso, along with technicians and graduate students from these same universities.
CIMAR 21 and CIMAR 22
The purpose of the CIMAR 21 cruise was to conduct research into the oceanographic, physical, chemical and biological conditions in the eastern South Pacific between Caldera and Easter Island and also in the areas surrounding Easter Island and Salas y Gómez Islands.
In technical terms, CIMAR21 was a research cruise organized by the National Oceanographic Committee (CONA) using the Cabo de Hornos oceanographic vessel.
The main objective of IMO and of the research team that worked on this cruise was to understand the diversity, distribution, dynamics and biogeochemical function of the zooplanktonic communities present in the zone. In this regard, Daniel Toledo, marine biologist working at IMO, says: “My role on that cruise was to gather information on the zooplankton community through the use of plankton nets; on this occasion, we used multi-nets and Tucker trawls, reaching a maximum depth of 1,000 meters.” Some of the results are associated with zooplankton community composition, the composition of stable carbon and nitrogen isotopes, as well as with zooplankton size structures, which have never been reported in this zone.
The CIMAR 22 expedition took place in 2016 with a high level of IMO participation. This cruise established as its objective to carry out multidisciplinary oceanographic research in order to gain a better insight into the structure and functioning of the ecosystems existing off the central-northern coast of Chile, an area of the eastern South Pacific that has scarcely been studied.
Paula Ruz, who was then a PhD student and now holds a PhD in Oceanography, describes the expedition as follows: “The IMO team was in charge of collecting zooplankton present in an area ranging from the surface to depths close to 3,600 meters, with the aim of characterizing the zooplankton community associated with coastal environments, open sea, oceanic islands and seamounts related to the latter. This information was complemented by obtaining oceanographic variables (temperature, salinity, dissolved oxygen) and biogeochemical information (nutrients, gases, etc.).”
The study covered an area extending from the region near Caldera to the Desventuradas Islands, which is a transect parallel to the coast in the direction of the Juan Fernández Islands. It also covered a transect perpendicular to the coast in the direction of Valparaíso.
New challenges
The Millennium Institute of Oceanography continues to follow the path of the most amazing discoveries in oceanography. For this reason, its director, Dr. Osvaldo Ulloa, and its deputy director, Dr. Rubén Escribano, claimed in a recent activity organized by IMO students and postdocs that future expeditions will be even more ambitious.
In November 2017, a new oceanographic cruise will take place in the area over the Atacama Trench, the deepest point in Chilean waters, and it will seek to explore even greater depths than the previous expeditions.
