Regional shifts in phytoplankton succession and primary productivity in the San Antonio Bay System (USA) in response to diminished freshwater inflows

2017 ◽  
Vol 68 (1) ◽  
pp. 131 ◽  
Author(s):  
Daniel L. Roelke ◽  
Hsiu-Ping Li ◽  
Carrie J. Miller-DeBoer ◽  
George M. Gable ◽  
Stephen E. Davis
Keyword(s):  
Primary Productivity ◽  
San Antonio ◽  
Sampling Period ◽  
Phosphorus Limitation ◽  
Trophic Levels ◽  
Human Consumption ◽  
Dry Period ◽  
Nitrogen And Phosphorus ◽  
Commercially Important ◽  
Freshwater Inflows

In many areas of the world, human consumption and climate change threaten freshwater inflows to coastal ecosystems. In the San Antonio Bay System, USA (SABS), freshwater inflows are projected to decrease in the coming decades. Our 30-month sampling period of SABS captured a prolonged period of higher inflows and a prolonged period of lower inflow. Our observations offer insights as to how this system might respond to lower freshwater inflows in the future. Of most importance in our observations was a regional shift that occurred in maximum primary productivity from the middle and lower SABS towards the upper SABS. In addition, a warm-month succession of phytoplankton taxa in the upper SABS that occurred during the wet period did not occur during the dry period. We also observed spatiotemporal shifts in apparent nitrogen- and phosphorus-limitation, with both appearing to influence phytoplankton biomass and primary productivity. Changes to SABS phytoplankton such as these might deleteriously affect organisms of higher trophic levels with life stages that are regionally confined by other factors, such as depth, macrophyte presence, and existence of hard-bottomed substrate, which in this bay system includes both commercially important and endangered species.

scholarly journals A direct test of nitrogen and phosphorus limitation to net primary productivity in a lowland tropical wet forest

Ecology ◽  
2013 ◽  
Vol 94 (7) ◽  
pp. 1540-1551 ◽  
Author(s):  
S. Alvarez-Clare ◽  
M. C. Mack ◽  
M. Brooks
Keyword(s):  
Primary Productivity ◽  
Net Primary Productivity ◽  
Phosphorus Limitation ◽  
Direct Test ◽  
Nitrogen And Phosphorus ◽  
Tropical Wet Forest

Phytoplankton co-limitation by nitrogen and phosphorus in a shallow reservoir: progressing from the phosphorus limitation paradigm

Hydrobiologia ◽  
2014 ◽  
Vol 744 (1) ◽  
pp. 255-269 ◽  
Author(s):  
Stefanie Müller ◽  
Simon M. Mitrovic
Keyword(s):  
Phosphorus Limitation ◽  
Nitrogen And Phosphorus ◽  
Shallow Reservoir

scholarly journals Nitrogen and phosphorus limitation in a coastal barrier salt marsh: the implications for vegetation succession

1999 ◽  
Vol 87 (2) ◽  
pp. 265-272 ◽  
Author(s):  
Harm. J. Van Wijnen ◽  
Jan. P. Bakker
Keyword(s):  
Salt Marsh ◽  
Phosphorus Limitation ◽  
Vegetation Succession ◽  
Nitrogen And Phosphorus ◽  
Coastal Barrier

Carbon, nitrogen and phosphorus storage in subtropical seagrass meadows: examples from Florida Bay and Shark Bay

2012 ◽  
Vol 63 (11) ◽  
pp. 967 ◽  
Author(s):  
James W. Fourqurean ◽  
Gary A. Kendrick ◽  
Laurel S. Collins ◽  
Randolph M. Chambers ◽  
Mathew A. Vanderklift
Keyword(s):  
Organic Carbon ◽  
Carbon Content ◽  
Primary Productivity ◽  
Florida Bay ◽  
Organic Carbon Content ◽  
Nitrogen And Phosphorus ◽  
Organic C ◽  
Shark Bay ◽  
Seagrass Meadows ◽  
C Storage

Seagrass meadows in Florida Bay and Shark Bay contain substantial stores of both organic carbon and nutrients. Soils from both systems are predominantly calcium carbonate, with an average of 82.1% CaCO3 in Florida Bay compared with 71.3% in Shark Bay. Soils from Shark Bay had, on average, 21% higher organic carbon content and 35% higher phosphorus content than Florida Bay. Further, soils from Shark Bay had lower mean dry bulk density (0.78 ± 0.01 g mL–1) than those from Florida Bay (0.84 ± 0.02 mg mL–1). The most hypersaline regions of both bays had higher organic carbon content in surficial soils. Profiles of organic carbon and phosphorus from Florida Bay indicate that this system has experienced an increase in P delivery and primary productivity over the last century; in contrast, decreasing organic carbon and phosphorus with depth in the soil profiles in Shark Bay point to a decrease in phosphorus delivery and primary productivity over the last 1000 y. The total ecosystem stocks of stored organic C in Florida Bay averages 163.5 MgCorg ha–1, lower than the average of 243.0 MgCorg ha–1 for Shark Bay; but these values place Shark and Florida Bays among the global hotspots for organic C storage in coastal ecosystems.

scholarly journals Active reconfiguration of cytoplasmic lipid droplets governs migration of nutrient-limited phytoplankton

2021 ◽  
Author(s):  
Anupam Sengupta ◽  
Jayabrata Dhar ◽  
Francesco Danza ◽  
Arkajyoti Ghoshal ◽  
Sarah Elisabeth Mueller ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Red Tide ◽  
Mechanical Energy ◽  
Optimal Growth ◽  
Active Role ◽  
Phosphorus Limitation ◽  
Vertical Movement ◽  
Nitrogen And Phosphorus ◽  
And Migration ◽  
Motile Species

As open oceans continue to warm, modified currents and enhanced stratification exacerbate nitrogen and phosphorus limitation, constraining primary production. The ability to migrate vertically bestows motile phytoplankton a crucial – albeit energetically expensive – advantage toward vertically redistributing for optimal growth, uptake and resource storage in nutrient-limited water columns. However, this traditional view discounts the possibility that phytoplankton migration may be actively selected by the storage dynamics when nutrients turn limiting. Here we report that storage and migration in phytoplankton are coupled traits, whereby motile species harness energy storing lipid droplets (LDs) to biomechanically regulate migration in nutrient limited settings. LDs grow and translocate directionally within the cytoplasm to accumulate below the cell nucleus, tuning the speed, trajectory and stability of swimming cells. Nutrient reincorporation reverses the LD translocation, restoring the homeostatic migratory traits measured in population-scale millifluidic experiments. Combining intracellular LD tracking and quantitative morphological analysis of red-tide forming alga, Heterosigma akashiwo , along with a model of cell mechanics, we discover that the size and spatial localization of growing LDs govern the ballisticity and orientational stability of migration. The strain-specific shifts in migration which we identify here are amenable to a selective emergence of mixotrophy in nutrient-limited phytoplankton. We rationalize these distinct behavioral acclimatization in an ecological context, relying on concomitant tracking of the photophysiology and reactive oxygen species (ROS) levels, and propose a dissipative mechanical energy budget for motile phytoplankton for alleviating nutrient limitation. The emergent resource acquisition strategies, enabled by distinct strain-specific migratory acclimatizing mechanisms, highlight the active role of the reconfigurable cytoplasmic LDs in vertical movement. By uncovering a mechanistic coupling between dynamics of intracellular changes to physiologically governed migration strategies, this work offers a tractable framework to delineate diverse strategies which phytoplankton may harness to maximize fitness and resource pool in nutrient-limited open oceans of the future.

scholarly journals Screening of Ciguatoxins in the Philippines by Animal Assay: Symptoms, Levels, and Distribution in Fish Tissue

2021 ◽  
pp. 87-95
Author(s):  
Bryan Tanyag ◽  
Karl Bryan Perelonia ◽  
Flordeliza Cambia ◽  
Ulysses Montojo
Keyword(s):  
Coral Reef ◽  
Fish Tissue ◽  
Reef Fishes ◽  
The Philippines ◽  
Coral Reef Fishes ◽  
Human Consumption ◽  
Mouse Bioassay ◽  
Major Protein ◽  
Commercially Important ◽  
Fish Viscera

The Philippines is an archipelagic country that belongs to the biologically diverse Pacific Coral Triangle, rich in marine resources, including corals, reef fishes, and algae. This explains the continuous sustenance of the Filipinos on fish as a major protein source. Despite their contribution to human consumption, some commercially important coral reef fishes are a threat to food safety, compromising public health. Currently, ciguatera fish poisoning (CFP) has been focused on by scientists since it is the most frequently reported seafood-toxin illness in the world acquired from contaminated coral reef fishes. The present study investigates the contamination of reef fishes in the West Philippine and Sulu Seas using animal assay. Ciguatoxins (CTX) are present in commercially important reef fishes such as barracuda (Sphyraena barracuda), parrotfish (Scarus quoyi), rabbitfish (Siganus guttatus), grouper (Plectropomus leopardus), moray eel (Gymnothorax melanospilos), and snapper (Lutjanus campechanus). Scarus quoyi had the highest toxicity of 0.65 ± 0.55 ppb and 0.48 ± 0.36 ppb found in flesh and viscera, respectively. Although higher toxicities were observed from fish viscera, toxicities between fish parts did not vary greatly (p > 0.05). Positive samples exceeded the 0.01 ppb guideline established by the US Food and Drug Administration and the Philippines’ regulatory limit set by the Bureau of Fisheries and Aquatic Resources. Symptoms of mice showing the presence of Pacific CTX-1 were noted. Since mouse bioassay was used in screening reef fishes that pose non-specificity and insensitivity problems, the researchers suggest that analytical methods must be used in characterizing and quantifying these types of toxins. Establishing the methodologies in detecting CTX would greatly help monitor and manage CFP in commercially identified reef fishes in the country.

scholarly journals Denitrifying bacteria in the limnetic zone of Lake Tota, Colombia

2021 ◽  
Vol 26 (1) ◽  
pp. 1-16
Author(s):  
Julian Esteban Másmela-Mendoza ◽  
Luz Marina Lizarazo Forero
Keyword(s):  
Rainbow Trout ◽  
Fish Farming ◽  
Sampling Period ◽  
Denitrifying Bacteria ◽  
Most Probable Number ◽  
Nitrogen And Phosphorus ◽  
Probable Number ◽  
Physicochemical Factors ◽  
Reducing Bacteria ◽  
Nitrate Reducing Bacteria

The objective of study was to isolate and determine the identity of denitrifying bacteria from limnetic areas of Lake Tota (Colombian Andes) with and without rainbow trout production activities. We examined the relationships between the lake’s physicochemical factors (oxygen, nitrogen, and phosphorus content) and two bacterial communities (denitrifying bacteria and coliforms). Water samples were taken 20m below the surface from July to September at five limnetic zones; two of which were close to rainbow trout farming areas. In each zone, the concentrations of oxygen, nitrogen, and phosphorus were measured. To identify and quantify the abundance of bacteria, the most probable number (MPN) technique was used, employing minimal medium for denitrifying bacteria and medium for nitrate reducing bacteria (NRB). A greater number of denitrifying bacteria were found in the fish farming zones, identifying bacteria of the genera Bacillus, Pseudomonas, Nocardia, and Streptomyces. The number of nitrate-reducing bacteria revealed statistically significant differences throughout the sampling period, increasing from July to September and was related to a decrease in precipitation. The density of NRB and total phosphorus were directly correlated. High bacterial densities of denitrifyingbacteria and coliforms are indicative of changes from oligotrophic to eutrophic states in the studied limnetic areas.

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