Prelims: Current events of national and international importance
Why in News?
Global review identifies 57 new living species of tiny marine Foraminifera, including three from New Zealand waters.
Classification & Nature - Foraminifera are single-celled protists (eukaryotes) belonging to the supergroup Rhizaria.
They have granuloreticulose pseudopodia, thread-like extensions used for feeding, movement, and building their shells.
Shell (“Test”) -Many foraminifera build a shell, called a test, which can have one or multiple chambers.
The composition of the test varies, common materials include calcium carbonate (calcite or aragonite), agglutinated sediment particles, chitin, or sometimes silica.
These tests often have openings (pores) that connect different chambers (“foramen” means “hole-bearer”).
Ecology / Habitat - Marine - The majority of foraminifera are marine.
Benthic vs. Planktonic -Benthic forams live on or in seafloor sediments (macro-, meio-, micro-benthos).
Planktonic forams float in the water column; many belong to the suborder Globigerinina.
Other environments-Some foraminifera are found in brackish or freshwater, and a few even in terrestrial/soil environments.
Reproduction & Life Cycle - Forams generally have an alternation of generations- sexual (haploid) and asexual (diploid) phases.
Importance in Science
Fossil record - Foraminifera have an extensive fossil record, it makes them very useful in biostratigraphy (dating rock layers) and paleoclimatology (reconstructing past climates).
Environmental indicators - Because different foram species prefer different environmental conditions (e.g., temperature, salinity, depth), they are used as indicators of past and present marine conditions.
Carbonate production - Their calcium carbonate shells contribute significantly to marine sediments.
Size & Diversity - There are thousands of species estimates suggest 6,700–10,000 living species and many more fossil species.
Size-wise, many are small (less than 1 mm), but some species’ tests can grow much larger (up to ~20 cm for rare species).
Significance
Climate Research - Because forams record chemical signatures in their shells (e.g., isotope ratios), scientists use them to infer past ocean temperatures, ice volume, and even CO₂ levels.
Oil Exploration - Foraminifera fossils help geologists date and correlate sedimentary rock layers, which is crucial in hydrocarbon exploration.
Marine Ecology - They’re part of marine food webs and carbon cycling.
