Whether your family is doing is doing in-person classes, online learning, homeschooling, or has given up altogether, you should check out Outschool.com. The site has over 100,000 classes to choose from, for students 3-18 years old (though quite a few look interesting for adults, as well). The coolest part is that there are SO many classes on marine biology, including subjects like:

Ocean Ecosystems in Minecraft & the Real World

Are all ocean habitats the same? What is a coral reef? What do sea turtles and dolphins eat? This “Marine Biology – Ocean Ecosystems in Minecraft and the Real World” course will teach students about deep-sea biology, food chains, coastal ecology, aquatic adaptations and more!
On average, students will complete about 2-3 hours of work per week in the online classroom plus another 1-2 hours of building time in Minecraft. Students can spend more time on their Minecraft construction projects they create during the course if they wish. Optional labs and activities based on the science concepts of the week are also provided.
The weekly tasks include reading articles, taking quizzes, watching video lessons, participating in online classroom discussions, creating your Minecraft builds, and posting screenshots/pictures of your Minecraft builds so your classmates and teacher can see them.

Advanced Coral Reef Ecology

The topic of Coral Reef Ecology will be taught at an advanced level and require some basic biology experience and understanding of natural cycles. The pace of the class is as follows:
Video 1: What is a Coral Reef, How are they formed, Where are they found, What types of Coral Reefs are there?
Project 1: Students will complete an activity for submission, feedback and review regarding the life cycle and reproduction of coral polyps.
Video 2: Coral Zones, Symbiosis and Food Webs; Relationships between the various biota in the reef.
Project 2: Students will complete an activity to demonstrate understanding of the impact of damage to a single piece of a food web through creative writing, videography, or storytelling. Projects will be shared with classmates via outschool.
Video 3: Environmental Impact on Today’s Reefs; students will learn about various ecological threats and coral diseases that can affect their health and what larger global impact that can have.
Project 3: Final Project will be summative in nature and provide students a way to demonstrate their understanding of class content.

All the classes look great, and you can read reviews from parents and students on the website. Happy learning!