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Sea ice interposes a solid interface between two fluid phases, the biologically productive sea water and air. It modifies environmental conditions in the sea below and also provides a platform on which air-breathing birds and mammals can live, breed, and base foraging forays into the water. It also forms a temporary habitat in which a diverse biology is able to thrive. This chapter discusses the physical characteristics of sea ice, the biology of sea ice, the ice edge or marginal ice zone, polynyas, and the wider significance of sea ice biology.

This chapter explores linkages and feedbacks between global environmental change and globalization. It first shows how interactions between the two processes may enhance global connectivities and contribute to accelerating rates of global change. It then presents a case study of feedback double exposure in the arctic region. The Arctic is changing rapidly as the result of both climate change and the expansion of international shipping. Direct linkages between the processes emerge because climate change-related reductions in sea ice open new shipping routes and provide greater access to the oil and gas resources of the region. Feedbacks may occur as consumption of the region's oil and gas leads to further increases in greenhouse emissions and further arctic melting. The case shows how efforts to exploit the benefits of climate change and globalization without considering the feedbacks may lead to an acceleration of both processes, with significant implications for sustainability.

Sea ice covers a significant area of the polar regions, particularly in winter. This chapter discusses the formation and nature of different types of sea ice. The biological makeup of sea ice communities, which includes a significant metazoan component, is complex. Sea ice photosynthetic communities are often dominated by highly abundant diatoms. Sea ice communities face the challenge of continuous freezing temperatures and considerable variations in salinity, as well as low levels of photosynthetically active radiation. Despite the challenging environment, biological activity in the sea ice can be high and this is illustrated by an exploration of photosynthesis and bacterial production rates. Bacteria and phototrophs are in turn exploited by a range of protozoan and metazoan grazers within the sea ice community. Viruses appear to be important in sea ice, as they are in glacial environments (cryoconite holes), and may play an important role in carbon cycling. By comparison, lake ice is poorly researched, but functional largely cyanobacterial communities have been described in the perennial ice covers of lakes in the McMurdo Dry Valleys of Antarctica. Annual ice covers on alpine lakes support microbial communities that include rotifers. The limited information on photosynthetic rates and rates of bacterial production in lake ice are outlined.

This chapter surveys the many forms in which ice occur in nature. Lake and river ice have characteristic polycrystalline structures and these are different from sea ice. In the atmosphere water vapour crystallizes to form snowflakes and leads to rain, hail and thunderstorm electricity. Snow falling on the ground has specific properties and over many years it becomes consolidated into ice. Such ice flows under gravity eventually melting into rivers or the oceans. Cores drilled from ice sheets in Antarctica or Greenland contain information about past climatic conditions, and their study depends heavily on the electrical properties of ice. In cold regions ground becomes frozen to form permafrost. In the Solar System many of the moons of the outer planets are formed from ice, which may exist as some of the high-pressure phases in the interior. The surface features of Europa are particularly intriguing. Finally comets are largely composed of ice.

This introductory chapter summarizes the most prominent abiotic components of recent climate change to establish the environmental context from which the discussion in the rest of the book proceeds. From an ecological perspective, climate change is most meaningfully considered as the suite of abiotic changes occurring across Earth coincident with the onset of the Industrial Revolution and progressing over the past 150 years. These abiotic changes include rising temperatures, temperature variability, changes in precipitation and snow cover, and diminishing sea and land ice. All these changes can be linked to ecological dynamics, though it is probably fair to state that most research to date on the ecological consequences of climate change has focused on temperature changes.

This chapter discusses the physical and chemical nature of ice and snow environments, and their biology. The communities of ice and snow environments are dominated by microorganisms, including species of heterotrophic and photosynthetic bacteria, heterotrophic and photosynthetic protozoans, and algae. Metazoans are few, and include rotifers and tardigrades. The exception is sea ice, which supports a more complex metazoan community. Viruses that mostly infect bacteria (bacteriophage) are important in icy habitats, where they appear to play an important role in the recycling of carbon and other nutrients. The glacial history of the Earth is outlined and an introduction to chemistry, physics, and the biological functioning of sea ice, lake ice, supraglacial aquatic environments, subglacial environments, and snow is provided to provide a framework for understanding subsequent detailed chapters.

This chapter discusses the critical role glaciers play in reflecting solar heat back into space and how the melting of glaciers reveals darker land and water surfaces that leads to surface heat absorption and global warming. The chapter gets into the dynamics of albedo and surface heat, explaining the causes of color change on glaciers, such as soot and volcanic ash deposits. It reviews the significant albedo contributions of glacier and sea-ice covered surfaces of the Arctic, Greenland, and Antarctica and discusses the urban heat island effect in cities as an analogy to glacier surface warming due to darkening. The chapter also examines geological history and anthropogenic causes of glacier surface albedo changes, such as the industrial revolution.

Ringed seals and fur seals inhabit the Bering Sea portion of the North Pacific Coast. This chapter provides evidence that Neoglacial sea ice expansion pushed Bering Sea populations of pack ice-breeding ringed and bearded seals south as far as the eastern Aleutians and kept them there until early summer, making these Arctic-adapted species easily accessible to ancient Aleut hunters. Extensive pack ice development would also have made the Pribilof Islands unsuitable as early summer pupping grounds for fur seals, forcing them to establish rookeries away from ice-covered waters and icy winds. These conclusions are based on a comprehensive analysis of skeletal remains recovered from an archaeological site off the Unalaska Island in the eastern Aleutians that was occupied at the height of the Neoglacial period, ca. 3500 to 2500 BP. Pack ice extent in the southern Bering Sea changed markedly during the Neoglacial, which sheds significant new light on the origins of Thule culture and on important aspects of ringed seal and fur seal life history.

Polar Crustacea show high taxonomic and functional diversity and hold crucial roles within regional food webs. Despite the differences in the evolutionary history of the two Polar regions, present data suggest rather similar species richness, with over 2,250 taxa recorded in the Antarctic and over 1,930 noted in the Arctic. A longer duration of isolated evolution resulted in a high percentage of endemic species in the Antarctic, while the relatively young Arctic ecosystem, subjected to advection from adjacent seas, shows a very low level of endemism. Low temperatures and seasonal changes of food availability have a strong impact on polar crustacean life histories, resulting in their slow growth and development, extended life cycles, and reproduction well synchronized with annual peaks of primary production. Many species, Antarctic amphipods in particular, exhibit a clear tendency to attain large size. In both regions, abundant populations of pelagic grazers play a pivotal role in the transport of energy and nutrients to higher trophic levels. The sea-ice habitat unique to polar seas supports a wide range of species, with euphausiids and amphipods being the most important in terms of biomass in the Antarctic and Arctic, respectively. Deep sea fauna remains poorly studied, with new species being collected on a regular basis. Ongoing processes, namely a decline of sea-ice cover, increasing levels of ultraviolet radiation, and invasions of sub-polar species, are likely to reshape crustacean communities in both Polar regions.

Beaches and associated dunes are constituted of unconsolidated materials, such as sand, and thus are low-strength land forms less robust than rocky cliffs (van der Meulen et al. 1991). It is estimated that 70% of sand-based coastlines in the world are presently subject to erosion (Bird 1985; Wind and Peerbolte 1993). However, natural dune systems are inclined to adjust after stress without permanent damage (Brown and McLachlin 2002), and when stabilized by plant cover they offer a first line of coastal defence against assault from wave action (Wind and Peerbolte 1993; Broadus 1993; De Ronde 1993). Natural self-sustaining dune systems interact with the sea and closely reflect changes in sea levels. At any given time no single sea level characterizes all oceans, that is, the resting position of the ocean surface, or geoid, is not uniformly elevated over the earth. Eustatic sea levels, free of influence from tides, waves and storms, thus vary from place to place as well as over time. Satellite altimetry, which permits more accurate as well as more numerous observations than older tide-gage methods of measuring sea levels, shows that the ocean is actually a spheroid modified by depressions and elevations. For example, in parts of the Indian Ocean sea levels are as much as 70 m lower than the global mean and in the North Atlantic 80 m higher (Carter 1988). Climate is governed by long-term periodic variations in the earth’s orbit that effect changes in solar radiation and, consequently, also in sea levels (Bartlein and Prentice 1989; Woodroffe 2002). As a result, ice ages repeatedly alternate with periods of interglacial warming in which ice masses contract and sea levels increase. Most of the time that has passed since the Cambrian period—approximately 500 million years—sea levels, although fluctuating on several timescales, have been higher than they are today. Because of the difficulties in documenting conditions so far in the distant past estimates of these sea levels vary considerably, but those shown in Fig. 13.1, based on different kinds of evidence, are representative of attempts at reconstruction (personal communication RA Rohde 2008).

This chapter examines the effect of climate change on Arctic ecosystems using social-ecological systems (SES) analysis. It also considers the effect of global climate change on the social dynamics of people living in the Arctic and how it might continue to do so. The chapter examines the effects of rapid climate change on Arctic SESs by focusing on two examples of ecological processes: wildfire disturbance and sea-ice coverage.

This chapter illustrates the various effects of shifting location and thickness of sea ice in Alaska. It discusses how these changes affect the Inupiat's means of living, polar bears, whales, and bowheads among others. The second part of the chapter explores the distinctive features of the movement of animals as climate changed during the Pleistocene era. It not only discusses animal mobility, but also the changes in the geography of the land that it provokes and the extinction of larger animals that then results.

This chapter details the increase in fossil fuel production and consumption that led to climate change. In 2005, the U.S. Energy Policy Act exempted shale gas drilling from regulatory oversight under the Safe Drinking Water Act, leading to massive increases in shale gas production. Also, the melting of the Arctic sea ice opened seaways that permitted further exploitation of oil and gas reserves in the North Polar Region. As gas became cheap, its usage increased in transportation and home heating, and it became an additional energy source, satisfying expanding demand without replacing other forms of fossil fuel energy production. As new gas-generating power plants were built, infrastructures based on fossil fuels were set, and total global emissions continued to rise. By 2012, more than 365 billion tons of carbon had been released into the atmosphere from fossil fuel combustion and cement production. An additional 180 billion tons came from deforestation and other land use changes.

Over the North Atlantic the eddy-driven jet stream finally separates from the subtropical jet, forming a split jet structure. Free from the steady influence of the Hadley cell, the northern jet is highly variable and its shifts and meanders affect weather and climate patterns around much of the hemisphere. This chapter introduces the North Atlantic Oscillation, the dominant pattern of jet variability, giving an overview of its history and impacts.