Global Warming Impacts Micro-Phytoplankton at a Long-Term Pacific Ocean Coastal Station

Abstract

Understanding impacts of global warming on phytoplankton-the foundation of marine ecosystems-is critical to predicting changes in future biodiversity, ocean productivity, and ultimately fisheries production. Using phytoplankton community abundance and environmental data that span ∼90 years (1931-2019) from a long-term Pacific Ocean coastal station off Sydney, Australia, we examined the response of the phytoplankton community to long-term ocean warming using the Community Temperature Index (CTI), an index of the preferred temperature of a community. With warming of ∼1.8 • C at the site since 1931, we found a significant increase in the CTI from 1931-1932 to 2009-2019, suggesting that the relative proportion of warm-water to cold-water species has increased. The CTI also showed a clear seasonal cycle, with highest values at the end of austral summer (February/March) and lowest at the end of winter (August/September), a pattern well supported by other studies at this location. The shift in CTI was a consequence of the decline in the relative abundance of the cool-affinity (optimal temperature = 18.7 • C), chain-forming diatom Asterionellopsis glacialis (40% in 1931-1932 to 13% in 2009 onward), and a substantial increase in the warm-affinity (21.5 • C), also chain-forming diatom Leptocylindrus danicus (20% in 1931-1932 to 57% in 2009 onward). L. danicus reproduces rapidly, forms resting spores under nutrient depletion, and displays a wide thermal range. Species such as L. danicus may provide a glimpse of the functional traits necessary to be a "winner" under climate change.

Seasonal bacterial niche structures and chemolithoautotrophic ecotypes in a North Atlantic fjord

“…Measuring temporal change in these ecosystems is an issue of ongoing concern, given the valuable ecological, cultural and economic services they provide 1,5 . Monitoring programs that generate multi-disciplinary time-series datasets have been instrumental in detecting temporal patterns of change and seasonal shifts/cycles, alongside variability in environmental parameters and biological communities 6,7 . Furthermore, high-frequency sampling has allowed quantification of the impacts of short-and long-term stressors on coastal ecosystems specifically 8-10 and marine ecosystems in general 11,12 .At the base of the marine food web, pro-and eukaryotic microorganisms sustain, inject and control the fluxes of energy and nutrients, and provide the organic matter for all higher trophic levels 13 .…”

Vertically Resolved Pelagic Particle Biomass and Size Structure Across a Continental Shelf Under the Influence of a Western Boundary Current

“…At long-term observing stations in the southeast Australian region, warming waters have resulted in a reduction in the spring phytoplankton bloom and >60% decline phytoplankton growth during spring (Thompson et al, 2009). These changes may have significant bottom-up effects on the overall distribution of particulate biomass, size structure and community composition on continental shelves as zooplankton impacted the globe in similar ways (Richardson, With the impacts of warming oceans already being observed at coastal observing stations and phytoplankton communities increasingly dominated by warm-water tolerant chain forming diatoms (Ajani et al, 2020), impacts from projected reductions in both phytoplankton and zooplankton biomass are likely to be amplified up the food web with potentially large impacts on fisheries. If we hypothesize based upon the results of the current study and the EAC warming and penetrating further south as already being observed (Li et al, 2022;Malan et al, 2021;Wu et al, 2012), it is likely that particulate communities may show reduced biomass, and larger mean sizes with more efficient trophic transfer of energy as the warm EAC water displaces the cooler more productive Tasman Sea waters.…”

Keterkaitan Parameter Oseanografi dengan Fitoplankton di Perairan Pesisir Maros Sulawesi Selatan

“…Menurut Ajani et al, (2020), parameter oseanografi seperti suhu memberikan pengaruh yang sangat signifikan terhadap perkembangan fitoplankton. Pencermatan terhadap fenomena perkembangan fitoplankton berdasarkan pengukuran suhu yang disukainya (Community Temperature Index: Indeks Suhu Komunitas) dimulainya sejak tahun 1931 sampai 2019.…”