An Impact to U.S. Naval Operations: Predicting Jellyfish Blooms in the Arabian Sea
Abstract
Operations of two U.S. Navy aircraft carriers in the Arabian Sea were inhibited by the Crambionellaorsini (c. orsini) jellyfish bloom in 2020, causing degradation to their propulsion systems. C. orsini bloom also occurred in 2002, but did not impact naval operations. We compared the two bloom years by calculating Ekman transport to characterize upwelling, using Empirical Orthogonal Function analysis to detect oceanic variability patterns, and analyzing temperature, chlorophyll-a, and mixed layer depth as potential bloompredictors. This research found no single cause but a combination of environmental conditions, which include upwelling-favorable monsoonal winds and moderate sea surface temperature (SST). Upwelled nutrient-rich waters cause increased primary productivity of mixed diatoms eaten by dinoflagellates, a food source for C.orsini. The jellyfish and their food source are advected to moderate temperature regions by the monsoonal circulation. It was shown that when SST is below 25 degrees C or above 30 degrees C, c. orsini cease blooming as their foodsource diminishes. To forecast a bloom, c. orsini must be present in coastal waters with an overabundance of nutrients during either monsoon season. The main environmental driver of a c. orsini bloom is the monsoon season, and the limiting factor is the SST. The blooms, although rare, can jeopardize our effectiveness to prevail in day-to-day competition; understanding these blooms allows warfighters to maintain the Navys advantage at sea.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2023
- Accession Number
- AD1213276
Entities
People
- Stephanie A Geant
Organizations
- Naval Postgraduate School