Lecture 13: Anthropogenic Climate Change

What are the seasonal cycles of light in the North Atlantic?

Light is dark in winter and fall, lighter in summer and spring.

How do nutrient levels vary seasonally in the North Atlantic?

Nutrient levels are high in winter and fall, but lower in spring and summer due to warmer waters and increased stratification.

What happens to chlorophyll levels in the North Atlantic during different seasons?

Chlorophyll is low in winter and fall due to less light and photosynthesis, and high in summer and spring, but declines in summer due to nutrient depletion.

What are the main impacts of El Nino on ocean conditions?

El Nino produces warmer waters in the eastern Pacific, weakens trade winds, causes more rainfall in the east, droughts in the west, leading to decreased fish productivity.

What are the main impacts of La Nina on ocean conditions?

La Nina produces colder waters, strengthens trade winds, results in less rain in the eastern Pacific and more in the west, increasing ocean productivity.

How does anthropogenic climate change affect ocean stratification?

Increasing warming and salinity changes lead to increased stratification, reducing nutrient delivery and ventilation in the ocean's surface.

What is one consequence of oceans becoming warmer due to climate change?

Warmer oceans can cause abnormal algal blooms that may be poisonous to aquatic life.

What effect does increased global warming have on sea levels?

Warming water expands, leading to sea level rise, though not necessarily adding more water as ice melts.

How might climate change impact food supply?

Warmer temperatures necessitate crop adaptations to ensure food availability.

What changes to human health can result from climate change?

Heat waves caused by climate change have contributed to thousands of deaths.

How could marine organisms respond to climate change?

Organisms may move, change behavior, acclimate physiologically, evolve, or experience changes in fitness and abundance.

What is the expected change in primary productivity in high latitude regions due to climate change?

In high latitude regions, net primary productivity is projected to increase as plankton move to the surface to access light.

What happens to biomass of diatoms due to climate change?

Diatom biomass decreases due to nutrient limitations caused by increased stratification.

What does export production refer to?

Export production is the flux of particles out of the euphotic zone, where light penetrates.

How does increasing CO2 levels affect phytoplankton?

Increased CO2 can hinder growth of some phytoplankton, while benefiting others.

What is a potential impact of climate change on the timing of phytoplankton blooms?

Phytoplankton blooms may occur earlier than expected and may shift out of their normal range.