Chapter 1: Mid-October 1. Mid-October On the morning of October 27, 2016, our inflatable dinghy cut through frigid waters toward the northern shores of Livingston Island. It was the first land I''d seen since we passed the last southern islands of South America five days earlier. The Zodiac carried the Cape Shirreff crew--Matt, Sam, Whitney, Mike, and me--plus a Zodiac operator from the ship and a couple of people headed to the antarctic base Palmer Station, on Anvers Island, who came to help us unload. We were all swaddled tight in bright orange float coats. I sat on the side of the Zodiac gripping wet rope and watching the bright metal hull of the ship shrink as we rode the billowing dark swells toward the island''s coast. We''d just crossed the world''s stormiest stretch of ocean--the Drake Passage, the shortest crossing of the Southern Ocean from South America to the Antarctic Peninsula. At this latitude there are only a few scattered islands--no landmass significant enough to obstruct or slow down the antarctic circumpolar current, which whips around the globe unimpeded, speeding across the Southern Ocean with a ferocity unmatched anywhere else on earth.

On a broad orange ship, we''d climbed the rolling hills of ocean swells, pitching forward and back, forward and back. After five days of travel, we were finally on the Zodiac, pulling up onto a sheltered beach. The fog obscured everything except the rocky shore and our camp, which sat on a slight rise two hundred yards away. The huts looked like matchboxes scattered on a blanket of white, dropped from a giant''s pocket. I could barely discern the vague outlines of bigger hills. Cape Shirreff is one of two ice-free peninsulas on Livingston Island, 88 percent of which is covered by an ice cap. The island was just offset from the very northern tip of the Antarctic Peninsula, with nothing but open ocean between us and the southern edge of Chile, about five hundred and fifty miles away. King George Island, our more populated neighbor, was fifty miles east, the former home of the monitoring program and where many other bases still operated: South Korea, Chile, Russia, Argentina, Brazil, Poland, and Germany all have a presence there.

Livingston, in comparison, hosted the huts of our American camp on a northern peninsula, with two Chilean research huts nearby and small seasonal Spanish and Bulgarian bases on its southern coast. While the island was about forty miles long and fifteen miles wide, my world would exist solely on a tiny peninsula attached to the northern finger. I breathed in the biting air as I wrestled off my float jacket, relishing the stability of the ground beneath me. I still felt the world swaying: forward and back, forward and back. The air temperatures hovered around -1°C, and the beach was littered with huge chunks of ice. At the high-tide line, the shelf of snow that covered the island was almost as high as my head. The crew was composed of two seabird technicians and two seal technicians, one new and one returning on each team, plus one NOAA researcher from San Diego, where the Antarctic Marine Living Resources research program was headquartered, as our crew lead. When we accepted the job, we signed on for two seasons: one to learn and one to teach.

Matt, my fellow seabird technician, was returning for his second season, joined by Whitney, the lead seal tech. Sam and I were new, and Mike, the NOAA researcher, rounded out the crew. As Matt and Whitney well knew, our first task was to dig steps into the wall of snow that rose from the rocks. Sam and I followed their lead in all things. Shovels out, we carved. The world''s coldest and most remote continent sits like a blank white footer at the bottom of our maps, stretched to fit the flat cartography of a northern-centered worldview. But when mapped from a south pole perspective, Antarctica is close to round. East Antarctica--"East" in reference to Europe, of course--is the continent''s biggest component part, fanning out from the south pole like an ear.

East Antarctica holds the continent''s thickest ice shelves and vast, snowless dry plains, both largely lifeless save for microbes and the occasional Weddell seal that wanders too far inland. The Transantarctic Mountains mark the boundary between East and West Antarctica. West Antarctica faces the Pacific Ocean, with two massive waterborne ice shelves on either side. Sticking out like a curved thumb between the ice shelves is the Antarctic Peninsula, the only part of the continent that reaches north of the antarctic circle. Life on the continent thrives on the shore, where marine species use land to nap or breed, but there are no year-round terrestrial animals. The waters that fringe the continent teem with seals, whales, krill, fish, penguins, and strange and unique seafloor creatures, such as bright red sea urchins with vicious white spines and giant feathered sea stars. Most of antarctic biodiversity depends on the rich waters of the Southern Ocean. The 1959 Antarctic Treaty, however, only assured protection for the land itself.

The treaty was signed by the twelve countries--Argentina, Australia, Belgium, Chile, France, Japan, New Zealand, Norway, South Africa, the Soviet Union, the United Kingdom, and the United States--that had been active in Antarctica during the international polar years between 1882-83 and 1932-33. The international polar years were organized to coordinate data collection on Antarctica and the upper atmosphere. In the years following the signing of the treaty, as mariners discovered the vast untapped "resource" of antarctic krill that bred and thrived in this remote marine environment, commercial interest in the Southern Ocean grew. Beginning in the 1970s, ships from the USSR began fishing for krill, soon joined by ships from Japan, South Korea, China, and Norway. Antarctic krill has the most biomass of any animal species on earth. If massed together, antarctic krill would weigh twice as much as the entire human population. Vast swarms spanning up to twelve miles--the largest animal aggregation in the world, another record--are scattered across the Southern Ocean in a patchy distribution that helps them avoid predators. Krill represent an abundance that challenges any reference we might have for the word, a staggering organic expanse coexisting in unified masses, suspended like a cloud of dust motes in cold and unforgiving waters.

Krill is the keystone species of the Southern Ocean''s food web, holding the whole ecosystem together. Seals, penguins, whales, and many fish all depend directly or indirectly on krill for their survival. As more countries began fishing for krill, the scientific committee that formed part of the Antarctic Treaty raised concerns that the krill fishery would impact the whole antarctic ecosystem. At the 1972 meeting of Antarctic Treaty Consultative Parties, representing the treaty''s signatories, a resolution was approved to invest in scientific study of the Southern Ocean and establish a system under which it could be protected. This led to years of working groups that developed a conservation system for "Antarctic marine living resources" as well as a huge research initiative to understand the basics of the Southern Ocean ecosystem. Emerging from these efforts, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR, pronounced kam-lar ) began operating in 1982. The twenty-five member countries of CCAMLR, including the United States, contribute to its budget, send representatives to meet yearly to make decisions, and participate in antarctic research. The Antarctic Treaty system is the overarching international governance structure for research and regulation on the continent, something like a continent-specific UN.

CCAMLR is a convention that forms part of the "treaty system" and is designed to address a specific antarctic issue--the conservation of marine life around Antarctica. CCAMLR takes an ecosystem approach to regulating the krill fishery, which involves establishing long-term ecosystem-monitoring programs throughout the continent, run by the parties that signed the convention. The United States contributes to ecosystem-monitoring research as a member of CCAMLR, and NOAA runs these research programs within the United States, as directed by a 1984 congressional mandate called the Antarctic Marine Living Resources Convention Act. The two goals of CCAMLR''s ecosystem-monitoring program are to detect and record changes in the marine ecosystem around Antarctica and to distinguish between changes due to the fishery and due to environmental variability. A blunt approach to regulating the fishery would entail studying the target species only: the population and growth rates of krill, and how much can be harvested without decimating numbers. But an ecosystem-monitoring approach sets fishing limits that also account for krill''s role in the Southern Ocean marine ecosystem and is designed to avoid significant impacts on other species due to the harvesting of krill. Fishing is not the only force acting upon the Antarctic food web. Climate change is poised to have a big impact on the ecosystem of the Southern Ocean, much of which depends on the yearly cycle of sea ice.

While the long-term monitoring program was initiated to measure the impact of the fishery, climate change has become a key focus of the research conducted at CCAMLR''s ecosystem-monitoring sites. With so many forces at play in these polar waters, how to distinguish between the effects of warming and the effects of commercial fishery? How does climate change imp.