Ep 5. Seasonal Seas

In the fifth episode of Blue Planet - Seas of Life Season 1, viewers are taken on a journey through the seasonal seas. The ocean is constantly changing and nowhere is this more evident than in areas where the sea experiences major shifts in climate throughout the year. This episode explores how ocean life adapts to the changing seasons and the challenges that each new season presents.

The episode begins by showcasing the vibrant coral reefs of the Palau Islands. The pristine waters surrounding these islands are home to a diverse range of sea creatures, from tiny colorful fish to giant manta rays. The reef ecosystem is a delicate balance, and the timing of the seasons plays a crucial role in the success of its inhabitants. Viewers are taken on a time-lapse journey, showing the drastic transformations that occur underwater as the seasons change. The coral polyps spawn in sync with the full moon, releasing millions of eggs and sperm into the water column, leading to an explosion of new life.

As the seasons change, the water temperature and nutrient levels shift, creating a domino effect throughout the food chain. The currents bring in a new wave of nutrients, attracting schools of small fish, which in turn attract predators. The Palau Islands are also home to one of the world's greatest migrations, as millions of golden jellyfish descend from the surface waters to deeper waters, following the movements of the sun. This unique phenomenon is a testament to the adaptability of ocean life and its ability to navigate around the changing seasons.

Viewers are then transported to the Arctic and the challenges of surviving in one of the harshest environments on the planet. The Arctic Ocean is covered by a thick layer of ice for much of the year, but during the brief summer months, the sea ice begins to melt, triggering a series of changes in the underwater ecosystem. The meltwater brings in new nutrients and fresh water, which changes the salinity levels and temperature of the water. This sudden shift creates ideal conditions for phytoplankton to flourish, as they are able to take advantage of the extra light and nutrients. Phytoplankton serves as the base of the Arctic food chain, supporting a range of sea creatures, including some of the world's largest mammals like bowhead whales, narwhals, and beluga whales.

The episode also explores the effect seasonal changes have on small creatures, like copepods and krill. These tiny creatures are the backbone of the marine food web, and their survival is crucial to the survival of many species. During the winter months, sea ice covers much of the Antarctic Ocean, making it hard for these creatures to survive. The warmer summer months bring in an abundance of food, and krill populations surge. However, with increased food comes increased competition, and the struggle for survival is constant.

The final section of the episode takes viewers to the temperate seas around Japan, where the largest migration on the planet takes place. Each year, millions of tiny sardines travel from the southern coast of Japan to the northern coast in a great feeding frenzy, attracting predators like dolphins, sharks, and birds. The sardines are part of a complex ecosystem that involves not just predators, but also bait fish and plankton, making the annual migration an event that impacts the entire food chain.

Overall, Seasonal Seas takes viewers on a fascinating and eye-opening journey through some of the world's most unique and remarkable ocean environments. The episode highlights the crucial role of the changing seasons in shaping ocean life, showcasing the adaptability and resilience of sea creatures in the face of constant environmental change. The stunning footage and engaging narration make this episode of Blue Planet - Seas of Life a must-watch for anyone interested in the world's oceans and the creatures that call them home.