Diving Deeper…

What is Noctiluca scintillans?

This Noctiluca scintillans mixotroph specie of algae can get its energy in two ways: through photosynthesis (using sunlight) and by eating other organisms. this dual ability helps Noctiluca survive and thrive in different conditions.

Over the past decade, the northern Arabian Sea has seen a major change in its winter phytoplankton blooms. Once dominated by diatoms, these blooms are now mostly made up of Noctiluca scintillans, a large green dinoflagellate.

Environmental Context

• Monsoons:

  • Summer: The summer monsoon brings very strong winds that travel northeast from the open ocean into the Northern Arabian Sea. Choppy and slightly turbid waters are its results, boosting phytoplankton growth.

  • Winter: Winter monsoons reverse the summer's winds. Weak winds travel out from the continent south into the Arabian Sea. With little power, they create minimal disturbance of the waters, turning them glassy, boosting phytoplankton growth.

• Himalayan Snow Cover:

  • Decreased snow cover leads to greater temperature and pressure differences, influencing monsoon winds to mix ocean waters. This mixing enhances phytoplankton growth.

• Impact of Climate Change:

  • Reduced snow cover and stronger winds due to climate change have intensified phytoplankton blooms.

  • These large blooms can consume oxygen and produce nitrous oxide, a potent greenhouse gas, further exacerbating climate change.

Research Focus @ Lamont Doherty Earth Observatory

• Experiments: Testing Noctiluca's response to different CO2 and O2 levels, and comparing growth in fed vs. unfed cultures.

• Goals: Understanding the symbiotic relationship between Noctiluca and Pedinomonas noctilucae, and how blooms affect marine ecosystems.

  Publications:

  
  Gomes, H.do R., Goes, J.I., Matondkar, S.G.P., Buskey, E.J., Basu, S., Parab, S., Thoppil, P., 2014. Massive outbreaks of Noctiluca scintillans blooms in the Arabian Sea due to spread of hypoxia. Nature Communications, 5, 10.1038/ncomms5862.

  Werdell, P.J., Roesler, C.S., Goes, J.I., 2014. Discrimination of phytoplankton functional groups using an ocean reflectance inversion model. Applied Optics 53 (22), 4833-4849.

  Gomes, H.do R., Goes, J.I., Matondkar, S.G.P., Parab, S.G., Al-Azri, A., Thoppil, P.G., 2009. Unusual Blooms of the Green Noctiluca Miliaris (Dinophyceae) in the Arabian Sea during the Winter Monsoon. In: J.D.Wiggert, Hood, R.R., Naqvi, S.W.A., Smith, S.L., Brink, K.H. (Eds.), Indian Ocean: Biogeochemical Processes and Ecological Variability. American Geophysical Union, Washington, DC; USA, pp. 347-363.

  Gomes, H.do R., Goes, J.I., Matondkar, S.G.P., Parab, S.G., Al-Azri, A.R.N., Thoppil, P.G., 2008. Blooms of Noctiluca miliaris in the Arabian Sea – An in situ and satellite study. Deep Sea Research Part I 55 (6), 751-765.

Significance

• Ecological Impact: Essential for predicting marine ecosystem changes, and dying populations. In ecosystems, energy typically flows from producers (like phytoplankton) to consumers (like fish), gradually decreasing in quantity as it moves up the food chain. This flow of energy sustains the entire ecosystem, with each organism relying on the energy provided by those below it in the food chain. When there are significant alterations in the abundance or composition of phytoplankton populations (which are primary producers), it can lead to a cascade effect throughout the entire ecosystem. For example, if there is a sudden increase in phytoplankton blooms, it could lead to an overabundance of energy at the lower trophic levels of the food chain. This excess energy might not be efficiently utilized by higher trophic levels, leading to imbalances and potentially causing disruptions or even declines in populations of organisms at various trophic levels.

• Climate Implications: Provides insights into how climate change affects marine life and greenhouse gas production. This is because Noctiluca's symbiotic relationship with its endosymbiont, Pedinomonas noctilucae, might indirectly contribute to CO2 production under certain conditions. When Noctiluca blooms and then dies off, the decomposition process of its organic matter could potentially release CO2 into the water. Additionally, the overall ecosystem changes caused by Noctiluca blooms, such as altering the food web and nutrient cycling, could indirectly influence CO2 levels in the environment.

• Social Implications: N. scintillans blooms could disrupt the traditional diatom-sustained food chain to the detriment of regional fisheries and long-term health of an ecosystem supporting a coastal population of nearly 120 million people