Pacific Salmon Move Nutrients From Sea to Forests

Biological Strategy

C.K. Unsworth

Cycle Nutrients

In ecosystems, there is no such thing as waste. Instead, one organism’s waste can be considered as another organism’s resource, and the cycling of nutrients may be the most important form of recycling in living systems. But sometimes those nutrients are transformed by one organism into a form that isn’t readily used by other organisms. For example, lignin is a complex organic molecule found in the cell walls of plants. In a forest, it’s one of the hardest molecules to break down in woody vegetation. Therefore, ecosystems include organisms that are particularly well-adapted to break down different types of nutrients. In the case of lignin, some fungi and bacteria release lignin-modifying enzymes that can break down the lignin to form carbohydrates and other life-supporting chemicals.

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Fish

Class Agnatha (“without jaws”), Class Chondrichthyes (“cartilage fish”), Superclass Osteichthyes (“bone fish”): Sharks, eels, snapper, hagfish

The fish are a diverse group, comprising multiple classes within Phylum Animalia. The most well-known classes are Chondrichthyes, which has sharks and rays, and superclass Osteichthyes, which has all bony fish like cod and tuna. Unlike other vertebrates, fish only live in water. They use special adaptations like fins, gills, and swim bladders to survive. Most are ectothermic, meaning their body temperature depends on the water temperature around them. Over half of all vertebrates are fish. They’re found from the bottom of the sea to high mountain lakes.

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Pacific salmon are keystone species that connect aquatic and terrestrial ecosystems, highlighting the need for ecosystem-based management to sustain biodiversity and ecological balance.

Introduction

Pacific salmon (Oncorhynchus species) are vital keystone species whose life cycles connect aquatic and terrestrial ecosystems, supporting biodiversity and ecological balance. These fish migrate between freshwater streams and the ocean, transferring nutrients and energy that sustain a wide range of organisms. Their presence is essential for maintaining the health and productivity of both aquatic and terrestrial environments.

The Strategy

Pacific salmon link ecosystems through their anadromous life cycle. Born in freshwater, young salmon migrate to the ocean, where they accumulate nutrients. When they return to freshwater to spawn, their bodies release marine-derived nutrients into streams and surrounding landscapes. These nutrients boost the productivity of algae, aquatic invertebrates, and fish, while also enriching terrestrial vegetation and feeding animals like bears, eagles, and wolves.

Salmon also shape habitats through their spawning activities, which aerate streambeds and improve oxygen flow, benefiting eggs and other aquatic life. Their nutrient contributions have been shown to enhance the growth of riparian vegetation, which stabilizes streambanks and provides shade for aquatic ecosystems. The interconnected role of salmon in these processes ensures the resilience and balance of ecosystems.

However, human activities like habitat destruction, overfishing, and climate change have significantly reduced salmon populations, disrupting these vital ecological functions. Protecting salmon populations is critical to sustaining the ecosystems they support.

The Potential

The intricate relationship between salmon and their environments highlights the need for ecosystem-based management. Restoring riparian zones, removing barriers like dams, and adopting sustainable fishing practices can protect the ecological benefits salmon provide. Salmon-inspired nutrient cycling could inform sustainable farming or water management. Their role as ecosystem connectors reminds us of the importance of maintaining biodiversity to ensure resilience and balance in natural systems.

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Last Updated January 14, 2025

References

Journal article

Relationships between Pacific salmon and aquatic and terrestrial ecosystems: implications for ecosystem-based management

Ecology | April 8, 2020 | Jessica C. Walsh, Jane E. Pendray, Sean C. Godwin, Kyle A. Artelle, Holly K. Kindsvater, Rachel D. Field, Jennifer N. Harding, Noel R. Swain, John D. Reynolds

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Reference

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