Exploring Aquatic Food Webs and Marine Ecosystem Processes BY ANUSCHKA FAUCCI, JOANNA PHILIPPOFF, AND CRISTINA VERESAN CONTENT AREA Life sciences, engineering GRADE LEVEL 6–8 BIG IDEA/UNIT Plankton are the basis of the aquatic food web and reflect the physical and chemical components of the surrounding ecosystem. ESSENTIAL PRE-EXISTING KNOWLEDGE Food webs are composed of producers, consumers, and decomposers. Most producers convert water and carbon dioxide into food and oxygen using light energy from the Sun through the process of photosynthesis. Many organisms in the food web have unique and diverse life cycles. TIME REQUIRED Approximately 4–8 50-minute classes (not including optional field trip to collect plankton) COST Approximately $25/ class (not including transportation for optional field trip to collect plankton) SAFETY See the Safety Note on p. 57 P lankton are some of the most diverse and numerous organisms on Earth. They reside in all bodies of water, including the ocean, lakes, ponds, and estuaries. The term plankton comes from the Greek word planktos , meaning wanderer or drifter. Hence, plankton cannot swim against major currents. They are also tiny—over one million plant-like phytoplank- ton can ft in a teaspoon (5 mL) of water. Viewing marine plankton under a microscope reveals spikes, coiled shells, jointed appendages, and delicately woven chains. Focusing on plankton is an excellent way to introduce students to aquat- ic food webs and marine ecosystem processes, which are often neglected, even though understanding these processes is essential to understanding the more than 70% of our Earth that is covered in water. In this series of lessons, students create a plankton net to collect live specimens for obser- vation with a microscope. Then, students construct a food web model to better understand how populations of plankton (despite their small size) affect aquatic ecosystems around the world. The lessons align with the Next Generation Science Standards (see NGSS box, p. 61). January 2019 51