SEE-U 2000: Atlantic Forest - Module 1

## Module 1: Introduction to Global Biomes

### Course Introduction

Welcome to the Summer Ecosystem Experiences for Undergraduates course! We hope that your time with us will be enriching, stimulating, and tremendously enjoyable. The SEE-U course is divided into four major sections: Biomes, Biotic Processes, Abiotic Processes and Contemporary Issues. Within each section, topics are broken down into modules. There are 16 modules in the program involving 20 experiments and activities. Each module will take at least a day to cover. (Consult the syllabus for more information on how the curriculum is structured and the general curriculum overview page for a more in-depth description of the class, if you have not done so already.)

For each module you will be given a guide that includes general background information and specific instructions for the experiment or activity that you must complete. Often these will include questions that you should be thinking about as you conduct the activity.

The class is organized according to the ecological hierarchy. We will start at the highest level (biomes), then jump to the lowest level (individuals and natural selection), and work our way back up the hierarchy, through populations and communities, then through several abiotic factors that influence ecology. The class concludes with a brief discussion of how to apply the principles that are laid out earlier in the class to conservation biology, starting at more local features, and progressing up to those factors that affect the entire Earth.

We will cover three topics in this first introductory text: how the class is organized, what is a biome and what determines their distribution, and one important way that we now navigate around biomes. So without further ado, let’s study some ecology!

### Biomes

Generally speaking, what determines the distribution and location of biomes? Global patterns like latitude, altitude, wind and ocean currents, mountain systems, and distance from oceans, combine to determine the type and distribution of biomes. As these features increase, both average temperature and relative humidity tend to decrease. These global features, and their attendant temperatures and humidity, determine the type of biome that will be present.

These features also combine to create temporary changes in the functioning of biomes such as the El Niño/Southern Oscillation (ENSO) phenomenon. ENSO, which occurs in part by the temporary reversal of deep ocean currents in the Pacific Ocean and then ramifies around the planet from there, causes temporary global-level changes in the characteristic environmental conditions and biotic components of biomes around the Earth. These transitory changes also help us to better understand the forces that produce the more permanent distribution of biomes.

Thus, biomes are large-scale environments where similar climates support similar biotic communities. Ecologists recognize many different kinds of biomes. As we progress from the Poles to the Equator and from the center of a continent to the periphery, identifiable biomes include the Tundra, Taiga, Grasslands, Savannah / Sahel, Tropical Rainforest, and Marsh. Three biomes that will be included in the SEE-U program this year are all terrestrial, and include the Eastern Deciduous Forest, Southwestern US Desert Drylands, and Moist Tropical Atlantic Forest.

Although most field ecology research and education emphasizes terrestrial biomes—and our course is no exception—you should know that over 70% of the Earth is covered with ocean. Marine biomes are tremendously understudied, in part because there are fewer of them. Nonetheless, many of the most interesting ecological research questions are based there and humans will increasingly rely on them for sustenance. The features that structure marine ecosystems are mostly a consequence of the distance from shore. Progressing from the shore to deep water, the major marine biomes include the Intertidal, Coral Reefs, Continental Shelf, Abyssal, and Pelagic.

### GPS

We will be navigating around these biomes using, the Global Position System (GPS). GPS allows you to find your way around the world and to accurately relocate a site. The accuracy of these measurements can be as high as within centimeters, a previously unattainable level.

A two step process attains high accuracy GPS readings. First, the GPS receiver obtains geographic information in the field from a subset of the satellites that are constantly orbiting the planet. These readings are stored in the receiver. Then, software supplied by the GPS company (in our case, Trimble’s Pathfinder system) uses the information obtained from the satellites and integrates it to triangulate a more accurate location. This secondary data analysis, called differential post-processing, will allow us to attain 1-3 meter accuracy using the Trimble GeoExplorer 3 GPS units.

GPS will be used during this class to determine the precise latitude and longitude of all field sites so that when we enter the data into the central repository (eBiome), we can georeference all data points. As a consequence, current and future data can be queried and analyzed spatially. Spatial analysis and the benefits posed by it are subjects that we will discuss and explore in greater depth during Module Two.