Algae fits into both the NGSS MS-LS1 (From Molecules to Organisms:  Structures and Processes) and MS-LS2 (Ecosystems: Interactions, Energy, and Dynamics) 

MS-LS2: Ecosystems: Interactions, Energy, and Dynamics

We think the entire MS LS2 can be taught HANDS-ON with algae and zooplankton for only a few dollars per student.  

MS-LS2.A  

LS2.A: Interdependent Relationships in Ecosystems

• Organisms, and populations of organisms, are dependent on their environmental interactions both with other living things and with nonliving factors. (MS-LS2-1)

We focused on the "environmental interactions" in this section.

• NON-LIVING Experiments and Demonstrations
• Temperature as a function of algae and zooplankton growth
• Salinity as a function of algae and zooplankton growth
• LIght as a function of algae and zooplankton growth
• Nutrient availability as a function of algae and zooplankton growth
• Turbulence /  Mixing as a function of algae and zooplankton growth
• Availability of oxygen as a function of algae and zooplankton growth
• LIVING Experiments and Demonstrations
• Zooplankton growth with and without algae
• Mate availability in zooplankton
• Over population of grazing zooplankton

• In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. (MS-LS2-1)
• In any ecosystem, organisms and populations with similar requirements for food, water, oxygen, or other resources may compete with each other for limited resources, access to which consequently constrains their growth and reproduction. (MS-LS2-1)
• Growth of organisms and population increases are limited by access to resources. (MS-LS2-1)
• Similarly, predatory interactions may reduce the number of organisms or eliminate whole populations of organisms. Mutually beneficial interactions, in contrast, may become so interdependent that each organism requires the other for survival. Although the species involved in these competitive, predatory, and mutually beneficial interactions vary across ecosystems, the patterns of interactions of organisms with their environments, both living and nonliving, are shared. (MS-LS2-2)