scholarly journals Oyster growth across a salinity gradient in a shallow, subtropical Gulf of Mexico estuary

2021 ◽  
Vol 2 ◽  
Author(s):  
Benoit Lebreton ◽  
Jennifer Beseres Pollack ◽  
Brittany Blomberg ◽  
Terence A. Palmer ◽  
Paul A. Montagna
Keyword(s):  
Soft Tissues ◽  
Salinity Gradient ◽  
Oyster Shell ◽  
Past Century ◽  
Oyster Reefs ◽  
Oyster Aquaculture ◽  
Subtropical Estuary ◽  
Oyster Farms ◽  
Freshwater Inflows ◽  
River Mouths

Abstract An increase in oyster aquaculture as a sustainable method of shellfish production is one response to overharvest and degradation of natural oyster reefs over the past century. Successful aquaculture production requires determining the environmental conditions optimal for oyster growth. In this study, the salinity, temperature, chlorophyll a concentration and the growth of Crassostrea virginica were monitored at four locations within the Mission-Aransas Estuary, Texas (USA), a shallow subtropical estuary influenced by relatively low freshwater inflow. Mean growth of the oyster shell (0.205 mm d–1 and 0.203 g d–1) and soft tissues (3.447 mg d–1) was highest when salinity was low (mean = 15.5) and chlorophyll a concentration was high (8.4 μg l–1). Oyster growth also varied temporally with periods of spawning. In low-inflow estuaries such as the Mission-Aransas Estuary, oyster farms should be sited close to river mouths so that oysters can benefit from freshwater inflows and lower salinities.

scholarly journals Shifts of Bacterioplankton Metabolic Profiles along the Salinity Gradient in a Subtropical Estuary

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Hidetoshi Urakawa ◽  
Jaffar Ali ◽  
Rheannon D. J. Ketover ◽  
Spencer D. Talmage ◽  
Juan C. Garcia ◽  
...  
Keyword(s):  
Salinity Gradient ◽  
Water Discharge ◽  
River Estuary ◽  
Metabolic Profiles ◽  
Wet Season ◽  
Biolog Ecoplates ◽  
Utilization Patterns ◽  
Subtropical Estuary ◽  
Discharge Patterns ◽  
Bacterioplankton Communities

Understanding the biodegradation potential of river bacterioplankton communities is crucial for watershed management. We investigated the shifts in bacterioplankton metabolic profiles along the salinity gradient of the Caloosahatchee River Estuary, Florida. The carbon source utilization patterns of river bacterioplankton communities were determined by using Biolog EcoPlates. The number of utilized substrates was generally high in the upstream freshwater dominated zone and low in the downstream zone, suggesting a shift in metabolic profiles among bacterioplankton assemblages along the estuarine gradient. The prokaryotic cell numbers also decreased along the estuarine salinity gradient. Seasonal and site-specific differences were found in the numbers of utilized substrates, which were similar in summer and fall (wet season) and winter and spring (dry season). Bacterioplankton assemblages in summer and fall showed more versatile substrate utilization patterns than those of winter and spring communities. Therefore, our data suggest that microbial metabolic patterns in the subtropical estuary are likely influenced by the water discharge patterns created by dry and wet seasons along the salinity gradient.

scholarly journals Occurrence of Microplastic Pollution at Oyster Reefs and Other Coastal Sites in the Mississippi Sound, USA: Impacts of Freshwater Inflows from Flooding

Toxics ◽  
2020 ◽  
Vol 8 (2) ◽  
pp. 35 ◽  
Author(s):  
Austin Scircle ◽  
James V. Cizdziel ◽  
Louis Tisinger ◽  
Tarun Anumol ◽  
Darren Robey
Keyword(s):  
Mississippi River ◽  
Natural Waters ◽  
Gulf Coast ◽  
Size Fraction ◽  
Nile Red ◽  
Dilution Effect ◽  
Relative Distribution ◽  
Oyster Reefs ◽  
Mississippi Sound ◽  
Freshwater Inflows

Much of the seafood that humans consume comes from estuaries and coastal areas where microplastics (MPs) accumulate, due in part to continual input and degradation of plastic litter from rivers and runoff. As filter feeders, oysters (Crassostrea virginica) are especially vulnerable to MP pollution. In this study, we assessed MP pollution in water at oyster reefs along the Mississippi Gulf Coast when: (1) historic flooding of the Mississippi River caused the Bonnet Carré Spillway to remain open for a record period of time causing major freshwater intrusion to the area and deleterious impacts on the species and (2) the spillway was closed, and normal salinity conditions resumed. Microplastics (~25 µm–5 mm) were isolated using a single-pot method, preparing samples in the same vessel (Mason jars) used for their collection right up until the MPs were transferred onto filters for analyses. The MPs were quantified using Nile Red fluorescence detection and identified using laser direct infrared (LDIR) analysis. Concentrations ranged from ~12 to 381 particles/L and tended to decrease at sites impacted by major freshwater intrusion. With the spillway open, average MP concentrations were positively correlated with salinity (r = 0.87, p = 0.05) for sites with three or more samples examined. However, the dilution effect on MP abundances was temporary, and oyster yields suffered from the extended periods of lower salinity. There were no significant changes in the relative distribution of MPs during freshwater intrusions; most of the MPs (>50%) were in the lower size fraction (~25–90 µm) and consisted mostly of fragments (~84%), followed by fibers (~11%) and beads (~5%). The most prevalent plastic was polyester, followed by acrylates/polyurethanes, polyamide, polypropylene, polyethylene, and polyacetal. Overall, this work provides much-needed empirical data on the abundances, morphologies, and types of MPs that oysters are exposed to in the Mississippi Sound, although how much of these MPs are ingested and their impacts on the organisms deserves further scrutiny. This paper is believed to be the first major application of LDIR to the analysis of MPs in natural waters.

The communities and functional profiles of virioplankton along a salinity gradient in a subtropical estuary

2021 ◽  
Vol 759 ◽  
pp. 143499
Author(s):  
Chen Zhang ◽  
Xiao-Peng Du ◽  
Yan-Hua Zeng ◽  
Jian-Ming Zhu ◽  
Sheng-Jie Zhang ◽  
...  
Keyword(s):  
Salinity Gradient ◽  
Subtropical Estuary ◽  
Functional Profiles

scholarly journals Directly Measured Denitrification Reveals Oyster Aquaculture and Restored Oyster Reefs Remove Nitrogen at Comparable High Rates

2016 ◽  
Vol 3 ◽  
Author(s):  
Austin T. Humphries ◽  
Suzanne G. Ayvazian ◽  
Joanna C. Carey ◽  
Boze T. Hancock ◽  
Sinead Grabbert ◽  
...  
Keyword(s):  
Oyster Reefs ◽  
Oyster Aquaculture

scholarly journals Success of concrete and crab traps in facilitating Eastern oyster recruitment and reef development

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6488
Author(s):  
Emma E. Johnson ◽  
Miles D. Medina ◽  
Ada C. Bersoza Hernandez ◽  
Gregory A. Kusel ◽  
Audrey N. Batzer ◽  
...  
Keyword(s):  
Low Cost ◽  
Concrete Structures ◽  
Oyster Shell ◽  
Cost Effective ◽  
Eastern Oyster ◽  
Market Size ◽  
Oyster Reefs ◽  
Reef Development ◽  
Reef Restoration ◽  
Oyster Restoration

Background Abundance of the commercially and ecologically important Eastern oyster, Crassostrea virginica, has declined across the US Eastern and Gulf coasts in recent decades, spurring substantial efforts to restore oyster reefs. These efforts are widely constrained by the availability, cost, and suitability of substrates to support oyster settlement and reef establishment. In particular, oyster shell is often the preferred substrate but is relatively scarce and increasingly expensive. Thus, there is a need for alternative oyster restoration materials that are cost-effective, abundant, and durable. Methods We tested the viability of two low-cost substrates—concrete and recycled blue crab (Callinectes sapidus) traps—in facilitating oyster recovery in a replicated 22-month field experiment at historically productive but now degraded intertidal oyster grounds on northwestern Florida’s Nature Coast. Throughout the trial, we monitored areal oyster cover on each substrate; at the end of the trial, we measured the densities of oysters by size class (spat, juvenile, and market-size) and the biomass and volume of each reef. Results Oysters colonized the concrete structures more quickly than the crab traps, as evidenced by significantly higher oyster cover during the first year of the experiment. By the end of the experiment, the concrete structures hosted higher densities of spat and juveniles, while the density of market-size oysters was relatively low and similar between treatments. The open structure of the crab traps led to the development of larger-volume reefs, while oyster biomass per unit area was similar between treatments. In addition, substrates positioned at lower elevations (relative to mean sea level) supported higher oyster abundance, size, and biomass than those less frequently inundated at higher elevations. Discussion Together, these findings indicate that both concrete and crab traps are viable substrates for oyster reef restoration, especially when placed at lower intertidal elevations conducive to oyster settlement and reef development.

scholarly journals Oyster condition index in Crassostrea rhizophorae (Guilding, 1828) from a heavy-metal polluted coastal lagoon

2005 ◽  
Vol 65 (2) ◽  
pp. 345-351 ◽  
Author(s):  
M. F. Rebelo ◽  
M. C. R. Amaral ◽  
W. C. Pfeiffer
Keyword(s):  
Heavy Metal ◽  
Organic Matter ◽  
Soft Tissues ◽  
Oyster Shell ◽  
Condition Index ◽  
Oyster Tissue ◽  
Rapid Reduction ◽  
Cd Contamination ◽  
Metal Body ◽  
A New Technique

The condition index (CI) of oysters represents an ecophysiological approach to estimate meat quality and yield in cultured bivalve mollusks. In the present study, the CI of oysters from a heavy-metal polluted bay was analyzed with respect to Zn and Cd contamination in soft tissues, spawning, and polychaete infestation. The CI was calculated through a new technique based on molds made to measure the volume of oyster-shell internal cavities. The higher CI values (over 9 in the dry season) were probably related availability of suspended particles rich in organic matter in the bay, while the rapid reduction in the CI from one season to the next at some stations suggests the effect of spawning. Polychaete infestation was considered low (18.7%) and produced no clear CI effects. The Cd in the oyster tissue collected during the rainy season was weak, although still significantly correlated with the CI (r = -0.36; p < 0.05). All other comparisons of CI and metal concentrations demonstrated a non-significant correlation. The CI variations observed on the temporal and spatial scale were likely to have been caused by availability of organic matter and spawning, rather than spionid infestation or metal body burdens.

Foraminiferal record of ecological impact of deforestation and oyster farms, Mahurangi Harbour, New Zealand

2007 ◽  
Vol 58 (5) ◽  
pp. 475 ◽  
Author(s):  
Hugh R. Grenfell ◽  
Bruce W. Hayward ◽  
Mark Horrocks
Keyword(s):  
New Zealand ◽  
Sediment Cores ◽  
Ecological Impact ◽  
Rapid Change ◽  
Oyster Shell ◽  
Ecological Changes ◽  
Lower Oxygen ◽  
Oyster Farms ◽  
Foraminiferal Record ◽  
On Farm

The microfossils in eight short sediment cores in Mahurangi Harbour, northern New Zealand, record major ecological changes since colonisation by Europeans. During the period of catchment deforestation (1850s–1900) these changes include increased sedimentation rates, decline of soft-shore molluscs, increased diatoms and seaward migration of brackish, agglutinate-dominated, foraminiferal associations, inferred to be due to increased freshwater runoff and decreased pH. The interval of most rapid change (1950s–1980s) occurred before and during the establishment of oyster farms, which therefore are not implicated. Comparison of the microfossil content of surface sediment samples taken inside and outside of four oyster farms indicates variable effects dependent on farm location. In less saline sites, the presence of oyster-shell debris in sediment beneath oyster farms appears to have buffered the foraminiferal faunas from some of the impacts of lowered salinity and pH. At more tidally flushed, saline sites, the oyster farms influence a wider surrounding area that has lower relative abundance of three species of Elphidium and other calcareous Foraminifera, attributed to slightly muddier sediment, higher nutrients and consequently lower oxygen. A newly arrived exotic foraminifer, Elphidium vellai, appears to be an indicator species for the enhanced nutrient, carbonate-rich conditions beneath oyster farms.

Isotopic Composition Reveals the Impact of Oyster Aquaculture on Pelagic Nitrogen Cycling in a Subtropical Estuary

2020 ◽  
Vol 187 ◽  
pp. 116431 ◽  
Author(s):  
Hao Jiang ◽  
Wenlu Lan ◽  
Tianshen Li ◽  
Zhifang Xu ◽  
Wenjing Liu ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Nitrogen Cycling ◽  
Oyster Aquaculture ◽  
Subtropical Estuary ◽  
The Impact

scholarly journals Relative genomic impacts of translocation history, hatchery practices, and farm selection in Pacific oyster Crassostrea gigas throughout the Northern Hemisphere

2019 ◽  
Author(s):  
Ben J. G. Sutherland ◽  
Claire Rycroft ◽  
Anne-Laure Ferchaud ◽  
Rob Saunders ◽  
Li Li ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Crassostrea Gigas ◽  
Pacific Oyster ◽  
Past Century ◽  
Chinese Populations ◽  
Introduced Populations ◽  
Oyster Aquaculture ◽  
Outlier Loci ◽  
Polymorphism Rate ◽  
Non Local

ABSTRACTPacific oyster Crassostrea gigas, endemic to coastal Asia, has been translocated globally throughout the past century, resulting in self-sustaining introduced populations (naturalized). Oyster aquaculture industries in many parts of the world depend on commercially available seed (hatchery-farmed) or naturalized/wild oysters to move onto a farm (naturalized-farmed). It is therefore important to understand genetic variation among populations and farm types. Here we genotype naturalized/wild populations from France, Japan, China, and most extensively in coastal British Columbia, Canada. We also genotype cultured populations from throughout the Northern Hemisphere to compare with naturalized populations. In total, 16,942 markers were identified using double-digest RAD-sequencing in 182 naturalized, 112 hatchery-farmed, and 72 naturalized-farmed oysters (n = 366). Consistent with previous studies, very low genetic differentiation was observed around Vancouver Island (mean FST = 0.0019), and low differentiation between countries in the Japan-Canada-France historical translocation lineage (France-Canada FST = 0.0024; Japan-Canada FST = 0.0060). Chinese populations were more differentiated (China-Japan FST = 0.0241). Hatchery-propagated populations had higher inter-individual relatedness suggesting family structure. Within-population inbreeding was not detected on farms, but nucleotide diversity and polymorphism rate was lower in one farm population. Moving oysters from nature onto farms did not result in strong within-generation selection. Private alleles at substantial frequency were identified in several hatchery populations grown in BC, suggesting non-local origins. Tests of selection identified outlier loci consistent with selective differences associated with domestication, in some cases consistently identified in multiple farms. Top outlier candidates were nearby genes involved in calcium signaling and calmodulin activity. Implications of potential introgression from hatchery-farmed oysters depends on whether naturalized populations are valued as a locally-adapted resource or as an introduced, invasive species. Given the value of the industry in BC and the challenges the industry faces (e.g., climate change, crop losses, biotic stressors), this remains an important question.

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