scholarly journals Effect of a Once in 100-Year Flood on a Subtropical Coastal Phytoplankton Community

2021 ◽  
Vol 8 ◽  
Author(s):  
Lesley A. Clementson ◽  
Anthony J. Richardson ◽  
Wayne A. Rochester ◽  
Kadija Oubelkheir ◽  
Bingqing Liu ◽  
...  
Keyword(s):  
Phytoplankton Community ◽  
River Flow ◽  
Light Availability ◽  
Colored Dissolved Organic Matter ◽  
Phytoplankton Community Structure ◽  
Phytoplankton Species Composition ◽  
Cell Counts ◽  
Summer Flood ◽  
Coastal Phytoplankton ◽  
Reduced Light

Subtropical systems experience occasional severe floods, dramatically altering the phytoplankton community structure, in response to changes in salinity, nutrients, and light. This study examined the effects of a 1:100 year summer flood on the phytoplankton community in an Australian subtropical bay – Moreton Bay – over 48 weeks, from January to December 2011. Immediately after maximum flood levels were reached on the rivers flowing into the bay, the lowest salinity, and highest turbidity values, in more than a decade, were measured in the Bay and the areal extent of the flood-related parameters was also far greater than previous flood events. Changes in these parameters together with changes in Colored Dissolved Organic Matter (CDOM) and sediment concentrations significantly reduced the light availability within the water column. Despite the reduced light availability, the phytoplankton community responded rapidly (1–2 weeks) to the nutrients from flood inputs, as measured using pigment concentrations and cell counts and observed in ocean color satellite imagery. Initially, the phytoplankton community was totally dominated by micro-phytoplankton, particularly diatoms; however, in the subsequent weeks (up to 48-weeks post flood) the community changed to one of nano- and pico-plankton in all areas of the Bay not usually affected by river flow. This trend is consistent with many other studies that show the ability of micro-phytoplankton to respond rapidly to increased nutrient availability, stimulating their growth rates. The results of this study suggest that one-off extreme floods have immediate, but short-lived effects, on phytoplankton species composition and biomass as a result of the interacting and dynamic effects of changes in nutrient and light availability.

scholarly journals Phytoplankton community composition in the south-eastern Black Sea determined with pigments measured by HPLC-CHEMTAX analyses and microscopy cell counts

2014 ◽  
Vol 95 (1) ◽  
pp. 35-52 ◽  
Author(s):  
Ertugrul Agirbas ◽  
Ali Muzaffer Feyzioglu ◽  
Ulgen Kopuz ◽  
Carole A. Llewellyn
Keyword(s):  
Black Sea ◽  
High Performance ◽  
Phytoplankton Community ◽  
Phytoplankton Community Structure ◽  
The South ◽  
Coastal Station ◽  
Chl A ◽  
South Eastern ◽  
Cell Counts ◽  
Offshore Station

The phytoplankton community structure and abundance in the south-eastern Black Sea was measured from February to December 2009 using and comparing high performance liquid chromatography pigment and microscopy analyses. The phytoplankton community was characterized by diatoms, dinoflagellates and coccolithophores, as revealed by both techniques. Fucoxanthin, diadinoxanthin, peridinin and 19′-hexanoyloxyfucoxanthin were the main accessory pigments showing significant correlation with diatom-C r2 = 0.56–0.71, P < 0.05), diatom-C (r2 = 0.85–0.91, P < 0.001), dinoflagellate-C (r2 = 0.39–0.88, P < 0.05) and coccolithophore-C (r2 = 0.80–0.71, P < 0.05), respectively. Microscopy counts indicated a total of 89 species, 71% of which were dinoflagellates, 23% were diatoms and 6% other species (mainly coccolithophores). Pigment-CHEMTAX analysis also indicated the presence of pico- and nanoplankton. Phytoplankton carbon (phyto-C) concentrations were highest in the upper water column, whereas chlorophyll-a (Chl-a) showed a deep maximum. Average phyto-C was higher at the coastal station (291 ± 66 µg l−1) than at the offshore station (258 ± 35 µg l−1), not statistically different (P > 0.05). The coastal station also had higher Chl-a concentrations (0.52–3.83 µg l−1) compared to the offshore station (0.63–2.55 µg l−1), not significant (P > 0.05). Our results are consistent with other studies and indicate that the southern Black Sea is shifting towards mesotrophy with the increasing prevalence of dinoflagellates compared to diatoms.

Seasonal changes in phytoplankton community structure in a bioluminescent lagoon, St. Croix, US Virgin Islands

2018 ◽  
Vol 81 (2) ◽  
pp. 109-124 ◽  
Author(s):  
JL Pinckney ◽  
C Tomas ◽  
DI Greenfield ◽  
K Reale-Munroe ◽  
B Castillo ◽  
...  
Keyword(s):  
Community Structure ◽  
Seasonal Changes ◽  
Phytoplankton Community ◽  
Virgin Islands ◽  
Phytoplankton Community Structure ◽  
Us Virgin Islands

scholarly journals Response of ocean phytoplankton community structure to climate change over the 21st century: partitioning the effects of nutrients, temperature and light

2010 ◽  
Vol 7 (12) ◽  
pp. 3941-3959 ◽  
Author(s):  
I. Marinov ◽  
S. C. Doney ◽  
I. D. Lima
Keyword(s):  
Climate Change ◽  
Community Structure ◽  
Sea Ice ◽  
Phytoplankton Biomass ◽  
Phytoplankton Community ◽  
Vertical Mixing ◽  
Phytoplankton Community Structure ◽  
Marginal Sea ◽  
Small Phytoplankton ◽  
The Impact

Abstract. The response of ocean phytoplankton community structure to climate change depends, among other factors, upon species competition for nutrients and light, as well as the increase in surface ocean temperature. We propose an analytical framework linking changes in nutrients, temperature and light with changes in phytoplankton growth rates, and we assess our theoretical considerations against model projections (1980–2100) from a global Earth System model. Our proposed "critical nutrient hypothesis" stipulates the existence of a critical nutrient threshold below (above) which a nutrient change will affect small phytoplankton biomass more (less) than diatom biomass, i.e. the phytoplankton with lower half-saturation coefficient K are influenced more strongly in low nutrient environments. This nutrient threshold broadly corresponds to 45° S and 45° N, poleward of which high vertical mixing and inefficient biology maintain higher surface nutrient concentrations and equatorward of which reduced vertical mixing and more efficient biology maintain lower surface nutrients. In the 45° S–45° N low nutrient region, decreases in limiting nutrients – associated with increased stratification under climate change – are predicted analytically to decrease more strongly the specific growth of small phytoplankton than the growth of diatoms. In high latitudes, the impact of nutrient decrease on phytoplankton biomass is more significant for diatoms than small phytoplankton, and contributes to diatom declines in the northern marginal sea ice and subpolar biomes. In the context of our model, climate driven increases in surface temperature and changes in light are predicted to have a stronger impact on small phytoplankton than on diatom biomass in all ocean domains. Our analytical predictions explain reasonably well the shifts in community structure under a modeled climate-warming scenario. Climate driven changes in nutrients, temperature and light have regionally varying and sometimes counterbalancing impacts on phytoplankton biomass and structure, with nutrients and temperature dominant in the 45° S–45° N band and light-temperature effects dominant in the marginal sea-ice and subpolar regions. As predicted, decreases in nutrients inside the 45° S–45° N "critical nutrient" band result in diatom biomass decreasing more than small phytoplankton biomass. Further stratification from global warming could result in geographical shifts in the "critical nutrient" threshold and additional changes in ecology.

scholarly journals Physiological and ecological consequences of the water optical properties degradation on reef corals

Coral Reefs ◽  
2021 ◽  
Author(s):  
Tomás López-Londoño ◽  
Claudia T. Galindo-Martínez ◽  
Kelly Gómez-Campo ◽  
Luis A. González-Guerrero ◽  
Sofia Roitman ◽  
...  
Keyword(s):  
Optical Properties ◽  
Population Decline ◽  
Light Availability ◽  
Potential Effect ◽  
Optical Quality ◽  
Light Penetration ◽  
Reef Corals ◽  
Orbicella Faveolata ◽  
Light Quantity ◽  
Reduced Light

AbstractDegradation of water optical properties due to anthropogenic disturbances is a common phenomenon in coastal waters globally. Although this condition is associated with multiple drivers that affect corals health in multiple ways, its effect on light availability and photosynthetic energy acquisition has been largely neglected. Here, we describe how declining the water optical quality in a coastal reef exposed to a turbid plume of water originating from a man-made channel compromises the functionality of the keystone coral species Orbicella faveolata. We found highly variable water optical conditions with significant effects on the light quantity and quality available for corals. Low-light phenotypes close to theoretical limits of photoacclimation were found at shallow depths as a result of reduced light penetration. The estimated photosynthetically fixed energy depletion with increasing depth was associated with patterns of colony mortality and vertical habitat compression. A numerical model illustrates the potential effect of the progressive water quality degradation on coral mortality and population decline along the depth gradient. Collectively, our findings suggest that preserving the water properties seeking to maximize light penetration through the water column is essential for maintaining the coral reef structure and associated ecosystem services.

scholarly journals Mesophotic.org: a repository for scientific information on mesophotic ecosystems

Database ◽  
2019 ◽  
Vol 2019 ◽  
Author(s):  
Pim Bongaerts ◽  
Gonzalo Perez-Rosales ◽  
Veronica Z Radice ◽  
Gal Eyal ◽  
Andrea Gori ◽  
...  
Keyword(s):  
Large Scale ◽  
Scientific Information ◽  
Temporal Trends ◽  
Light Availability ◽  
Research Community ◽  
Future Research ◽  
Photosynthetic Organisms ◽  
Future Research Directions ◽  
Available Information ◽  
Reduced Light

Abstract Mesophotic coral ecosystems (MCEs) and temperate mesophotic ecosystems (TMEs) occur at depths of roughly 30–150 m depth and are characterized by the presence of photosynthetic organisms despite reduced light availability. Exploration of these ecosystems dates back several decades, but our knowledge remained extremely limited until about a decade ago, when a renewed interest resulted in the establishment of a rapidly growing research community. Here, we present the ‘mesophotic.org’ database, a comprehensive and curated repository of scientific literature on mesophotic ecosystems. Through both manually curated and automatically extracted metadata, the repository facilitates rapid retrieval of available information about particular topics (e.g. taxa or geographic regions), exploration of spatial/temporal trends in research and identification of knowledge gaps. The repository can be queried to comprehensively obtain available data to address large-scale questions and guide future research directions. Overall, the ‘mesophotic.org’ repository provides an independent and open-source platform for the ever-growing research community working on MCEs and TMEs to collate and expedite our understanding of the occurrence, composition and functioning of these ecosystems. Database URL: http://mesophotic.org/

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