Blog Written by Sofia Pareja
[Image Credit: Albert Calbet]
The vastness of the ocean has always captured the human imagination, conjuring images of gigantic whales, playful dolphins, and vibrant coral reefs. However, beneath the tranquil surface lies a hidden world of microscopic marine life that plays a pivotal and often underappreciated role in shaping the health and stability of marine ecosystems. In this blog, we embark on a journey of scientific discovery to shed light on the fascinating world of microorganisms in the ocean. We will delve into their diverse forms, ecological functions, and the indispensable roles they play in critical processes such as oxygen production and nutrient cycling, underscoring their significance as unsung heroes of the marine realm.
Microorganisms in the ocean, collectively known as plankton, encompass an astounding diversity of life forms. From tiny phytoplankton harnessing the power of sunlight to photosynthesize, to zooplankton gracefully drifting with ocean currents, these microscopic marvels form the foundation of marine food webs.
Phytoplankton, often referred to as the "lungs of the ocean," are primary producers that convert carbon dioxide and nutrients into organic matter through photosynthesis. As a result, they generate a substantial portion of Earth's oxygen supply, rivalling the output of terrestrial plants. While phytoplankton fuel the marine ecosystem with oxygen, zooplankton serve as vital links in nutrient cycling. These tiny organisms graze on phytoplankton and are subsequently consumed by larger marine animals, transferring essential nutrients up the food chain.
Beyond the visible world of plankton, marine microbes, including bacteria and archaea, orchestrate a complex dance in the carbon cycle. Through processes like carbon fixation and decomposition, these unsung heroes play a pivotal role in sequestering and recycling carbon in the ocean. Microscopic marine life is highly sensitive to environmental changes, making them valuable indicators of ecosystem health. In this section, we will explore how shifts in ocean temperature, pH, and nutrient availability can influence the distribution and function of planktonic communities. Understanding these responses will enable scientists to monitor and predict the effects of climate change on marine ecosystems.
By appreciating the crucial roles that microorganisms play in sustaining marine ecosystems, we can better understand the importance of preserving their habitats and addressing the threats posed by human activities. As we uncover the wonders of microscopic marine life, it becomes evident that these unsung heroes are the backbone of ocean health and vitality. From oxygen production to nutrient cycling and climate regulation, the influence of plankton and marine microbes reverberates throughout the globe. Acknowledging their significance and understanding their responses to environmental changes is paramount in safeguarding the delicate balance of marine ecosystems. By promoting awareness and conservation efforts, we can nurture these invisible marvels and ensure a thriving future for our ocean.
Consulted Bibliography:
Capone, Douglas G., et al. "A massive phytoplankton bloom induced by an ecosystem-scale iron fertilization experiment in the equatorial Pacific Ocean." Nature, vol. 383, no. 6600, 1996, pp. 495-501. DOI: 10.1038/383495a0
Ducklow, Hugh W., et al. "Seasonal dynamics of bacterioplankton communities in Chesapeake Bay as revealed by 16S rRNA gene sequencing." Applied and Environmental Microbiology, vol. 71, no. 6, 2005, pp. 3363-3373. DOI: 10.1128/AEM.71.6.3363-3373.2005
Dutkiewicz, S., et al. "Impact of oceanic circulation on biological carbon storage in the ocean and atmospheric pCO2." Global Biogeochemical Cycles, vol. 21, no. 2, 2007, GB2003. DOI: 10.1029/2006GB002857
Falkowski, Paul G., et al. "The global carbon cycle: A test of our knowledge of Earth as a system." Science, vol. 290, no. 5490, 2000, pp. 291-296. DOI: 10.1126/science.290.5490.291Hansen, J., et al. "Earth's energy imbalance and implications." Atmospheric Chemistry and Physics, vol. 11, no. 24, 2011, pp. 13421-13449. DOI: 10.5194/acp-11-13421-2011
Longhurst, Alan. "Seasonal cycles of pelagic production and consumption." Progress in Oceanography, vol. 1, no. 3, 1972, pp. 179-239. DOI: 10.1016/0079-6611(72)90002-4
Mitra, Aditee, et al. "Aerobic microbial respiration in oceanic oxygen minimum zones." PLoS ONE, vol. 8, no. 6, 2013, e58150. DOI: 10.1371/journal.pone.0058150
Siegel, David A., et al. "Global assessment of ocean carbon export by combining satellite observations and food‐web models." Global Biogeochemical Cycles, vol. 28, no. 3, 2014, pp. 181-196. DOI: 10.1002/2013GB004743
Steinacher, M., et al. "Projected 21st century decrease in marine productivity: a multi-model analysis." Biogeosciences, vol. 7, no. 3, 2010, pp. 979-1005. DOI: 10.5194/bg-7-979-2010
van Oppen, M. J., Palumbi, S. R., Sinclair-Taylor, T. H., & Willis, B. L. (2005). Partially isolated Pacific populations of the massive coral Favia pallida share haplotypes despite different Symbiodinium associations. Molecular Ecology, 14(10), 3187-3201.
Ward, Bess B., et al. "Respiration rates of marine bacteria and archaea as a function of depth in the water column." Marine Ecology Progress Series, vol. 441, 2011, pp. 1-15. DOI: 10.3354/meps09395