Dive detectives

Lesson

Overview

In this virtual reality scavenger hunt, students search for tagged migratory animals: the giant manta ray, the green sea turtle, and the scalloped hammerhead. The students dive around Cocos Island, visiting open ocean, seamount, and island habitats. Along the way, they use their field guide to learn about what makes Cocos Island so special. After the VR experience, students use the evidence they collect in the experience to build their argument for why Cocos Island should be protected.

Background

Migration

Many marine species migrate, from the tiny zooplankton to the massive blue whale. Migration—the movement of species from one place to another—is an important adaptation to seasonal and geographic variation in food and other vital resources.

Migratory species may travel to find food, or to find more favorable living and breeding conditions. For example:

  • predators may time their migrations to match the seasonal reproduction patterns of their prey,
  • species may leave their usual hunting grounds to find mates, and
  • species may travel to spawning areas that provide safer habitats for vulnerable juveniles.

These migrations require a lot of energy, so migratory marine species tend to be larger, fast-moving, and capable of storing lots of energy to fuel their long journeys.

The Cocos Range

The habitats around Cocos Island provide a great case study to show how physical geography contributes to patterns of life in the ocean. Cocos Island is the peak of an underwater mountain chain, the Cocos Range, that includes the Las Gemelas seamount. Cocos Island is a volcanic island that is internationally recognized as a critical marine habitat for species such as the critically endangered scalloped hammerhead shark, and the vulnerable giant manta ray. The park is a protected area where fishing is forbidden. The Las Gemelas seamount has also become a protected area to provide greater protection to migratory species like the hammerhead shark, as well as various species of ray, tuna, and dolphin.

Biodiversity near underwater mountains

Biodiversity is very high near the Cocos Range compared to the open ocean for a variety of reasons:

  • Nutrient runoff — Water carries nutrients down from the tropical rainforest on Cocos Island into the ocean.
  • Structured habitat — The elevated seafloor of the underwater mountain range provides physical structures that create habitat, such as rocks where organisms like algae, sponges and corals can attach and grow.
  • Depth & light — The mountain range provides habitat closer to the surface of the water, where there’s lots of light that photosynthesizing organisms like algae need to thrive. These organisms form the base of the marine food chain.
  • Upwelling — Decaying organic materials tend to sink down throughout the water column. This means that the colder waters deep in the ocean become very rich with nutrients. The cold water gets pushed by currents up the slopes of the underwater mountain range, bringing nutrients up to the surface where organisms can use them.

Scientists use chlorophyll readings to monitor how much phytoplankton is present in a region. Like plants on land, phytoplankton use chlorophyll in photosynthesis. Phytoplankton grow best in nutrient-rich waters, giving the water a greenish appearance. Abundant phytoplankton attracts species higher up the food chain. The waters closest to Cocos Island tend to have the highest chlorophyll, followed by the seamounts.

Cleaning stations are a great illustration of species interdependence in aquatic environments that goes beyond food. Cleaning stations are often found on reefs or in rocky areas. Migratory species like sea turtles, manta rays, and sharks may stop by cleaning stations to have parasites removed from their bodies by small cleaner fish or cleaner shrimp. Both species benefit from this interaction.

Because it moves around, a migratory animal can play important roles in more than one marine ecosystem over its lifetime. For example, the scalloped hammerhead shark is a top predator in deeper waters, but it also frequents shallower reefs to visit the cleaning stations. The shark supplies the cleaner fish with food in exchange for health care, in a symbiotic relationship. The Dive detectives Field Guide provides background information about the species featured in the game, and their interrelationships.

Adaptation and conservation

Migratory species can adapt to changing environmental conditions, like changes in the feeding season, habitat loss, volcanic activity, pollution or the presence of invasive species (including humans). Currently, many believe that rising ocean temperatures are changing migration patterns in many species, as they seek waters that are more suitable for their feeding and breeding needs.

Migration can also make species vulnerable to anthropogenic threats such as overfishing or bycatch (accidental capture in fishing nets). Traveling species can be affected by changes in marine traffic and coastal development that is occurring over vast areas. This is a big challenge for conservation because migratory species often cross international boundaries. For example, satellite tracking data showed that a male Pacific green sea turtle named Argo travelled 1587 km (986 mi) in 55 days, swimming from Costa Rica, crossing through Colombian waters en route to turtle nesting areas in the Gulf of Panama.

Tagging and tracking technologies have become very important tools for conservationists. Each of the three MigraMar scientists featured in this experience have used tracking data to advocate for species conservation. The Dive detectives Field Guide includes a brief profile of each scientist and their work.


External resources


Learning outcomes

Students observe, collect and record data from three habitats: the open ocean, a seamount, and an island.

Students analyze observation data to describe relationships between marine species and their habitats.

Students synthesize scientific evidence into a persuasive presentation (e.g., an oral, written, graphic, or multimedia presentation) that communicates a position on an environmental conservation issue.

Competencies

Critical thinker, Collaborator, Communicator

Focus question

How can we protect critical habitat for migratory species?

Learning objectives

  • Make and record observations.
  • Describe observations using appropriate scientific vocabulary and concepts.
  • Synthesize information from multiple sources to describe interrelationships between species.
  • Organize and express ideas and information in a persuasive message.

Before you get started

Review the Dive detectives Web App Guide for how to use the app.

Review the Dive detectives Field Guide for descriptions of the habitats and species.

Steps

The Dive detectives Instructions prompt students to:

    1. Reflect on their diving experience.
    2. Analyze their observations of the open ocean, seamount, and island habitats.
    3. Interpret their observation data and construct an argument for conservation of Cocos Island.
    4. Communicate their argument(s) in a creative product.

Discussion points

    • Why do species migrate?
    • How does migration help species to survive?
    • Are humans also a migratory species?
    • How do human actions affect migratory species in both positive and negative ways?
    • How can we use technologies to help monitor and conserve migratory species?


Dive detectives - Web app guide

For more information on using the app, read the Dive detectives - Web app guide.