Phytoplankton blooms see two-decade surge along world’s coastlines

Phytoplankton blooms see two-decade surge along world’s coastlines

Subject :Environment

Section: species in news

Context: Huge blooms of phytoplankton microscopic algae floating on the ocean’s surface have become larger and more frequent along the world’s coastlines, according to new research.

Phytoplankton:

• Phytoplankton are the autotrophic (self-feeding) components of the plankton community and a key part of ocean and freshwater ecosystems.
• Phytoplankton obtain their energy through photosynthesis, as do trees and other plants on land. This means phytoplankton must have light from the sun, so they live in the well-lit surface layers (euphotic zone) of oceans and lakes.
• In comparison with terrestrial plants, phytoplankton are distributed over a larger surface area, are exposed to less seasonal variation and have markedly faster turnover rates than trees.
• Phytoplankton form the base of marine and freshwater food webs and are key players in the global carbon cycle.
• They account for about half of global photosynthetic activity and at least half of the oxygen production, despite amounting to only about 1% of the global plant biomass.
• Phytoplankton are very diverse, varying from photosynthesizing bacteria to plant-like algae to armour-plated coccolithophores. Important groups of phytoplankton include the diatoms, cyanobacteria and dinoflagellates, although many other groups are represented.

Significance of Phytoplanktons:

• They contribute more than half of the oxygen in the environment.
• They reduce global warming by absorbing human-induced carbon dioxide.
• They also serve as the base of the ocean food chain.
• They are important bioindicators regulating life in oceans. Their abundance determines the overall health of the ocean ecosystem.
• The productive fisheries in the world’s ocean are driven by Phytoplankton blooms.

Causes of Phytoplankton Bloom:

• The primary cause of phytoplankton blooms is an increase in nutrient availability, particularly nitrogen and phosphorus.
• These nutrients can come from a variety of sources, including agricultural runoff, wastewater discharge, and atmospheric deposition. When there is an excess of nutrients in the water, phytoplankton can grow and reproduce rapidly, leading to a bloom.
• Other factors that can contribute to phytoplankton blooms include warm water temperatures, high light levels, and calm water conditions, which can allow the phytoplankton to remain near the surface and access the light they need for photosynthesis.

Impacts of Phytoplankton bloom:

• Phytoplankton blooms can have both positive and negative impacts on the environment.
• In some cases, they can support the growth of other organisms in the food chain and improve water quality by absorbing excess nutrients.
• However, in other cases, blooms can deplete oxygen levels in the water, leading to fish kills and other negative impacts on aquatic life.
• Some phytoplankton species can also produce toxins that can harm human health and the health of other animals that consume them.