Context:
A study finds that excess iron stimulates phytoplankton blooms, increasing the rate of nutrient consumption and leading to a faster transition to nutrient poor conditions in the oceans
Phytoplankton:
- Microscopic, autotrophic organisms found in aquatic ecosystems.
- Primary producers, forming the base of the marine food chain.
- Responsible for nearly 50% of global oxygen production via photosynthesis.
- Supports marine life, including zooplankton, fish, and whales.
- Types –
- Major groups include diatoms, dinoflagellates, cyanobacteria.
- Diatoms have silica-based cell walls; cyanobacteria can fix atmospheric nitrogen.
- Environmental Indicators –
- Sensitive to temperature, salinity, and nutrient levels.
- Changes in their population signal ecosystem shifts or pollution levels.
- Role in Carbon Cycle –
- Carbon Sequestration: Absorbs CO₂, helping mitigate climate change.
- Forms part of the biological pump, transferring carbon to deep oceans.
- Threats –
- Ocean acidification, pollution, eutrophication, and climate change.
- Harmful algal blooms (HABs) caused by excessive nutrient inflow, leading to fish mortality and ecosystem disruption.
- Applications –
- Used in biofuel production, pharmaceuticals, and as nutritional supplements.
- Research ongoing to harness phytoplankton for carbon capture strategies.
Source: PNAS
Previous Year Question
Consider the following kinds of organisms:
1.Copepods
2. Cyanobacteria
3. Diatoms
4.Foraminifera
[UPSC Civil Services Exam – 2018 Prelims]
Which of the above are primary producers in the food chains of oceans?
(a) 1 and 2
(b) 2 and 3
(c) 3 and 4
(d) 1 and 4
Answer: (b)