Corals are extremely sensitive to water that is too warm - even temperatures just 1°C above the highest average summertime temperature. If corals bathe in water above this critical threshold for just four weeks (or at higher temperatures for even shorter durations), the accumulated heat stress can induce coral bleaching, a condition where coral polyps expel their beneficial algae and starve. Bleached coral turns white and can die or remain weakened for years. Although coral can bleach for reasons other than warm water, in recent decades a worrisome pattern has emerged. Episodes of global coral bleaching are becoming more frequent. These widespread events are thought to be among the earliest distinct signs of climate change's effects on Earth's organism
According to NOAA scientists, 2010 tied with 2005 as the warmest year on record. Throughout the year, satellite monitoring from NOAA's Coral Reef Watch
program detected that sea-surface temperatures exceeded the bleaching threshold for several weeks in various regions of the world. Scientists and reef managers soon began to observe excessive bleaching in many areas in which it was predicted by satellite. The 2010 global bleaching event was the second ever recorded, with the first occurring during 1997-98.
The following datasets from the flat-screen visualization are included for spherical display. The movie contains:
A global image showing the location of reef-building corals (indicated in blue) between 35°N and 35°S latitudes. The location data are from the World Resource Institute's Reefs at Risk Revisited report
A 1 year (January to December 2010) time series of Degree Heating Weeks data from the NOAA Coral Reef Watch program. The dataset is based on sea-surface temperature measurements taken every three days from the AVHRR sensor on NOAA's polar-orbiting satellites. The Degree Heating Weeks dataset shows how much heat stress has accumulated in an area over the past 12 weeks. Scientists have calculated thresholds of accumulated heat stress that puts corals at risk for bleaching and death. These thresholds are represented by the indicated colors.
A single Degree Heating Weeks image that represents the accumulated heat stress for all of 2010.
A map indicating observations of bleached and dead coral in 2010. These observations were reported to ReefBase and the NOAA Coral Reef Watch program.
Coral Reefs in Hot Water was produced in collaboration with the NOAA National Environmental Satellite, Data, and Information Service (NESDIS), the NOAA Climate Program Office, and the Coral Reef Watch program at the NOAA National Environmental Satellite, Data, and Information Service. The flat-screen visualization and associated educator resources are available at http://sciencebulletins.amnh.org/?sid=b.v.coral_reefs.20110511
C2 Cause and Effect. Students classify relationships as causal or correlational, and recognize that correlation does not necessarily imply causation. They use cause and effect relationships to predict phenomena in natural or designed systems. They also understand that phenomena may have more than one cause, and some cause and effect relationships in systems can only be described using probability.
C3 Scale Proportion and Quantity. Students observe time, space, and energy phenomena at various scales using models to study systems that are too large or too small. They understand phenomena observed at one scale may not be observable at another scale, and the function of natural and designed systems may change with scale. They use proportional relationships (e.g., speed as the ratio of distance traveled to time taken) to gather information about the magnitude of properties and processes. They represent scientific relationships through the use of algebraic expressions and equations
C7 Stability and Change. Students explain stability and change in natural or designed systems by examining changes over time, and considering forces at different scales, including the atomic scale. Students learn changes in one part of a system might cause large changes in another part, systems in dynamic equilibrium are stable due to a balance of feedback mechanisms, and stability might be disturbed by either sudden events or gradual changes that accumulate over time
C1 Patterns. Students observe patterns in systems at different scales and cite patterns as empirical evidence for causality in supporting their explanations of phenomena. They recognize classifications or explanations used at one scale may not be useful or need revision using a different scale; thus requiring improved investigations and experiments. They use mathematical representations to identify certain patterns and analyze patterns of performance in order to re-engineer and improve a designed system.
C2 Cause and Effect. Students understand that empirical evidence is required to differentiate between cause and correlation and to make claims about specific causes and effects. They suggest cause and effect relationships to explain and predict behaviors in complex natural and designed systems. They also propose causal relationships by examining what is known about smaller scale mechanisms within the system. They recognize changes in systems may have various causes that may not have equal effects.
C3 Scale Proportion and Quantity. Students understand the significance of a phenomenon is dependent on the scale, proportion, and quantity at which it occurs. They recognize patterns observable at one scale may not be observable or exist at other scales, and some systems can only be studied indirectly as they are too small, too large, too fast, or too slow to observe directly. Students use orders of magnitude to understand how a model at one scale relates to a model at another scale. They use algebraic thinking to examine scientific data and predict the effect of a change in one variable on another (e.g., linear growth vs. exponential growth).
C7 Stability and Change. Students understand much of science deals with constructing explanations of how things change and how they remain stable. They quantify and model changes in systems over very short or very long periods of time. They see some changes are irreversible, and negative feedback can stabilize a system, while positive feedback can destabilize it. They recognize systems can be designed for greater or lesser stability
ESS2.D Weather & Climate. Complex interactions determine local weather patterns and influence climate, including the role of the ocean.
ESS3.C Human Impact on Earth systems. Human activities have altered the biosphere, sometimes damaging it, although changes to environments can have different impacts for different living things. Activities and technologies can be engineered to reduce people’s impacts on Earth.
ESS3.D Global Climate Change. Human activities affect global warming. Decisions to reduce the impact of global warming depend on understanding climate science, engineering capabilities, and social dynamics.
LS1.C Organization for Energy Flow and Matter in Organisms. Plants use the energy from light to make sugars through photosynthesis. Within individual organisms, food is broken down through a series of chemical reactions that rearrange molecules and release energy.
LS2.A Interdependent Relationships in Ecosystems. Organisms and populations are dependent on their environmental interactions both with other living things and with nonliving factors, any of which can limit their growth. Competitive, predatory, and mutually beneficial interactions vary across ecosystems but the patterns are shared.
LS4.D Biodiversity & Humans. Changes in biodiversity can influence humans’ resources and ecosystem services they rely on.
ESS2.A Earth Materials and Systems. Feedback effects exist within and among Earth’s systems.The geological record shows that changes to global and regional climate can be caused by interactions among changes in the sun’s energy output or Earth’s orbit, tectonic events, ocean circulation, volcanic activity, glaciers, vegetation, and human activities.
ESS2.D Weather & Climate. The role of radiation from the sun and its interactions with the atmosphere, ocean, and land are the foundation for the global climate system. Global climate models are used to predict future changes, including changes influenced by human behavior and natural factors
ESS3.C Human Impact on Earth systems. Sustainability of human societies and the biodiversity that supports them requires responsible management of natural resources, including the development of technologies that produce less pollution and waste and that preclude ecosystem degradation.
ESS3.D Global Climate Change. Global climate models used to predict changes continue to be improved, although discoveries about the global climate system are ongoing and continually needed.
LS1.C Organization for Energy Flow and Matter in Organisms. The hydrocarbon backbones of sugars produced through photosynthesis are used to make amino acids and other molecules that can be assembled into proteins or DNA. Through cellular respiration, matter and energy flow through different organizational levels of an organism as elements are recombined to form different products and transfer energy.
LS2.A Interdependent Relationships in Ecosystems. Ecosystems have carrying capacities resulting from biotic and abiotic factors. The fundamental tension between resource availability and organism populations affects the abundance of species in any given ecosystem.
LS2.C Ecosystem Dynamics, Functioning and Resilience. If a biological or physical disturbance to an ecosystem occurs, including one induced by human activity, the ecosystem may return to its more or less original state or become a very different ecosystem, depending on the complex set of interactions within the ecosystem
LS4.B Natural Selection. Natural selection occurs only if there is variation in the genes and traits between organisms in a population. Traits that positively affect survival can become more common in a population.
LS4.D Biodiversity & Humans. Biodiversity is increased by formation of new species and reduced by extinction. Humans depend on biodiversity but also have adverse impacts on it. Sustaining biodiversity is essential to supporting life on Earth