Detrital Subsidies in the Diet of Mytilus edulis; Macroalgal Detritus Likely Supplements Essential Fatty Acids

Detritus is a frequent, poorly defined, component of bivalve growth and carrying capacity models. The purpose of this study was to determine the proportional contributions of detrital material derived from primary producers (phytoplankton, macroalgae, Spartina alterniflora, and terrestrial leaf litter) to particulate organic matter (POM) and blue mussel’s (Mytilus edulis) diet within a temperate bay (Saco Bay, ME, United States). We assessed which detrital sources, if any, warranted incorporation into modeling efforts. Stable isotopes (δ13C and δ15N) and fatty acid biomarkers (FA) of mussels, size fractionated (<100 μm) POM, and primary producer endmembers (phytoplankton, Saccharina latissima, Ascophyllum nodosum, Chondrus crispus, Spartina alterniflora and leaf litter) collected between 2016 and 2017 were used to estimate endmember contributions to POM and mussel diets. Based on FAs dinoflagellates were the most abundant phytoplankton in Saco Bay, even during the fall diatom bloom. Diatoms within the bay were primarily centric, but pennate diatoms were at times present in the water column (e.g., in September). Following abundances of dinoflagellates, and centric and pennate diatoms, 22:6ω3 (DHA) was the most abundant essential FA (8.6 ± 0.1% total FAs), followed by 20:5ω3 (EPA: 7.0 ± 0.1%) and 20:4ω6 (ARA: 0.3 ± 0.1%). On average, phytoplankton derived organic matter contributed 22.1 ± 0.3% of the total POM in the bay. The concentration of non-fresh phytoplankton organic matter, or remaining organic matter (REMORG), was positively correlated with all endmember biomarkers. However, the proportion (%) of vascular plant, macroalgal, and detrital FAs was negatively correlated with the concentration of REMORG. This finding suggests in periods of low productivity, vascular plant and macroalgal detritus are proportionally more important contributors to POM. Mussels were broad spectrum omnivores, consuming phytoplankton, zooplankton, and detrital material. Detrital contributions to mussel diets were important (minimum of 16% of diet). Although small, macroalgae’s dietary contribution (8%) to M. edulis may be important. Macroalgal detritus contained essential FAs (20:5ω3 and 20:4ω6) that could supplement mussel diets, as M. edulis in Saco Bay were likely limited by 20:5ω3. Consideration of how macroalgal detritus affects the availability of essential FAs in POM may be useful to incorporate into aquaculture site selection.

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Significant but short time assimilation of organic matter from decomposed Exotic Spartina alterniflora leaf litter by mangrove polychaetes

Estuarine Coastal and Shelf Science ◽

10.1016/j.ecss.2021.107436 ◽

2021 ◽

pp. 107436

Author(s):

Hui Chen ◽

Jianxiang Feng ◽

Yihui Zhang ◽

Shudong Wei ◽

Zhongyi Chen ◽

...

Keyword(s):

Organic Matter ◽

Leaf Litter ◽

Spartina Alterniflora ◽

Short Time

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Macrophyte-derived detritus in shallow coastal waters contributes to suspended particulate organic matter and increases growth rates of Mytilus edulis

Marine Ecology Progress Series ◽

10.3354/meps13314 ◽

2020 ◽

Vol 644 ◽

pp. 91-103

Author(s):

D Bearham ◽

MA Vanderklift ◽

RA Downie ◽

DP Thomson ◽

LA Clementson

Keyword(s):

Organic Matter ◽

Mytilus Edulis ◽

Particulate Organic Matter ◽

Coastal Waters ◽

Gill Tissue ◽

Suspension Feeder ◽

Food Sources ◽

Suspension Feeders ◽

Blue Mussels ◽

Suspended Particulate

Benthic suspension feeders, such as bivalves, potentially have several different food sources, including plankton and resuspended detritus of benthic origin. We hypothesised that suspension feeders are likely to feed on detritus if it is present. This inference would be further strengthened if there was a correlation between δ13C of suspension feeder tissue and δ13C of particulate organic matter (POM). Since detritus is characterised by high particulate organic matter (POC):chl a ratios, we would also predict a positive correlation between POM δ13C and POC:chl a. We hypothesised that increasing depth and greater distance from shore would produce a greater nutritional reliance by experimentally transplanted blue mussels Mytilus edulis on plankton rather than macrophyte-derived detritus. After deployments of 3 mo duration in 2 different years at depths from 3 to 40 m, M. edulis sizes were positively correlated with POM concentrations. POC:chl a ratios and δ13C of POM and M. edulis gill tissue decreased with increasing depth (and greater distance from shore). δ13C of POM was correlated with δ13C of M. edulis. Our results suggest that detritus comprised a large proportion of POM at shallow depths (<15 m), that M. edulis ingested and assimilated carbon in proportion to its availability in POM, and that growth of M. edulis was higher where detritus was present and POM concentrations were higher.

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Elevated temperature and browning increase dietary methylmercury, but decrease essential fatty acids at the base of lake food webs

Scientific Reports ◽

10.1038/s41598-021-95742-9 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Pianpian Wu ◽

Martin J. Kainz ◽

Fernando Valdés ◽

Siwen Zheng ◽

Katharina Winter ◽

...

Keyword(s):

Climate Change ◽

Fatty Acids ◽

Organic Matter ◽

Food Webs ◽

Essential Fatty Acids ◽

Trophic Levels ◽

Climate Change Scenarios ◽

Essential Nutrients ◽

Aquatic Food Webs ◽

Aquatic Food

AbstractClimate change scenarios predict increases in temperature and organic matter supply from land to water, which affect trophic transfer of nutrients and contaminants in aquatic food webs. How essential nutrients, such as polyunsaturated fatty acids (PUFA), and potentially toxic contaminants, such as methylmercury (MeHg), at the base of aquatic food webs will be affected under climate change scenarios, remains unclear. The objective of this outdoor mesocosm study was to examine how increased water temperature and terrestrially-derived dissolved organic matter supply (tDOM; i.e., lake browning), and the interaction of both, will influence MeHg and PUFA in organisms at the base of food webs (i.e. seston; the most edible plankton size for zooplankton) in subalpine lake ecosystems. The interaction of higher temperature and tDOM increased the burden of MeHg in seston (< 40 μm) and larger sized plankton (microplankton; 40–200 μm), while the MeHg content per unit biomass remained stable. However, PUFA decreased in seston, but increased in microplankton, consisting mainly of filamentous algae, which are less readily bioavailable to zooplankton. We revealed elevated dietary exposure to MeHg, yet decreased supply of dietary PUFA to aquatic consumers with increasing temperature and tDOM supply. This experimental study provides evidence that the overall food quality at the base of aquatic food webs deteriorates during ongoing climate change scenarios by increasing the supply of toxic MeHg and lowering the dietary access to essential nutrients of consumers at higher trophic levels.

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Growth, mortality and production of organic matter by a rocky intertidal population of Mytilus edulis in the Quoddy Region of the Bay of Fundy

Marine Ecology Progress Series ◽

10.3354/meps039031 ◽

1987 ◽

Vol 39 ◽

pp. 31-36 ◽

Cited By ~ 21

Author(s):

JPA Gardner ◽

MLH Thomas

Keyword(s):

Organic Matter ◽

Mytilus Edulis ◽

Rocky Intertidal ◽

Bay Of Fundy ◽

Intertidal Population

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Reactivation of nutrient cycling in an urban tropical dry forest after abandonment of agricultural activities

REVISTA CHAPINGO SERIE CIENCIAS FORESTALES Y DEL AMBIENTE ◽

10.5154/r.rchscfa.2020.11.068 ◽

2021 ◽

Vol 27 (3) ◽

pp. 355-365

Author(s):

Juan D. León-Peláez ◽

◽

William Caicedo-Ruiz ◽

Jeiner Castellanos-Barliza ◽

◽

...

Keyword(s):

Organic Matter ◽

Leaf Litter ◽

Residence Time ◽

Mean Residence Time ◽

Dry Forest ◽

Agricultural Activities ◽

Forest Fragment ◽

Leaf Litterfall ◽

Passive Restoration ◽

Standing Litter

Introduction: Standing leaf litter represent an essential source of organic matter and nutrients to dynamize biogeochemical processes at the ecosystem level. Objectives: To characterize the accumulation and decomposition of organic materials and flow of nutrients from standing litter in an urban dry tropical forest in a successional stage, after 10 years of abandonment of agricultural activities, and to determine the potential use of three species in future active restoration activities. Materials and methods: Standing litter samples were collected from a forest fragment in Santa Marta, Colombia, separating leaves, reproductive material, woody material and other residues. Additionally, leaves of three species of interest for ecological restoration (Albizia niopoides Spruce ex Benth., Cordia alba [Jacq.] Roem. & Schult. and Machaerium milleflorum Dugand G. A.) were separated and Ca, Mg, K, N and P concentrations were determined. Results and discussion: Total standing litter was 8.3 Mg∙ha-1 with a mean residence time of two years. The leaves represented 20% of the standing litter, with a mean residence time of 1.4 years. Based on the decomposition constant (kj = 0.73) and the rate of leaf litterfall, organic matter returns accounted for 3.4 Mg∙ha-1∙year-1. Leaf decomposition rate decreased in the following order C. alba > M. milleflorum > A. niopoides. P represented the greatest limitation with low release rates (0.1 to 1.2 kg∙ha-1∙year-1). Conclusions: The passive restoration strategy allowed reactivation of biogeochemical cycle via fine leaf litter. Cordia alba showed potential for inclusion in restoration activities, with lower values for leaf N/P ratio, and higher rates for leaf litterfall, litter decomposition and nutrient release.

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Contributions of organic matter and nutrients via leaf litter in an urban tropical dry forest fragment

Revista de Biología Tropical ◽

10.15517/rbt.v66i2.33381 ◽

2018 ◽

Vol 66 (2) ◽

pp. 571 ◽

Cited By ~ 1

Author(s):

Jeiner Castellanos-Barliza ◽

Juan Diego León-Peláez ◽

Rosalba Armenta-Martínez ◽

Willinton Barranco-Pérez ◽

William Caicedo-Ruíz

Keyword(s):

Organic Matter ◽

Leaf Litter ◽

Tropical Dry Forest ◽

Soil Surface ◽

Dry Forest ◽

Litter Production ◽

Forest Fragment ◽

Litter Bags ◽

One Year ◽

Degraded Ecosystems

The litterfall and decomposition represent the main transfer of organic matter and nutrients from the vegetation to the soil surface and determine positive trajectories in the process of rehabilitating and restoring degraded ecosystems. The aim of this study was to evaluate the contributions of organic materials and nutrients through the characterization of fine litter in an urban dry forest fragment. Litter production was monitored for one year by collecting 29 traps (0.5 m2). To evaluate leaf nutrient resorption, green leaves were collected from 5-10 individuals that represented the dominant tree species. Litter-bags (20 x 20 cm, 2 mm pore) were used for six months to evaluate the decomposition of leaf litter. Annual fine litter production was found to be 8 574 kg ha-1, with the Cordia alba species contributing the most leaf litter (1 134 kg ha-1) and nutrients (N: 6.16; P: 0.21; Ca: 4.72; Mg: 0.47; K: 1.27 kg ha-1). Decomposition rates (k constant) followed the decreasing order: C. alba (k: 4.6) > Machaerium milleflorum (k: 3.5). M. milleflorum and Albizia niopoides presented a pattern of rapid N and P release in the first 30 days, with more than 80 % and 60 % released from M. milleflorum and C. alba, respectively, by the end of the experiment. The litterfall monitoring carried out in this urban dry forest fragment revealed some important aspects of the functioning of an ecosystem as seriously threatened as the tropical dry forest. Rev. Biol. Trop. 66(2): 571-585. Epub 2018 June 01.

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Drag on Nets Fouled With Blue Mussel (Mytilus Edulis) and Sugar Kelp (Saccharina Latissima) and Parameterization of Fouling

Volume 6: Ocean Space Utilization ◽

10.1115/omae2017-62030 ◽

2017 ◽

Author(s):

Lars C. Gansel ◽

Per Christian Endresen ◽

Kristine Braaten Steinhovden ◽

Stine Wiborg Dahle ◽

Eirik Svendsen ◽

...

Keyword(s):

Mytilus Edulis ◽

Structural Integrity ◽

Blue Mussel ◽

Numerical Models ◽

Flow Speed ◽

Saccharina Latissima ◽

Detailed Knowledge ◽

Fish Welfare ◽

Fish Cages ◽

The Relationship

Biofouling is a serious problem in marine finfish aquaculture with a number of negative impacts. Marine growth obstructs net openings, thereby reducing water exchange through the net and affecting fish welfare and health, as well as the spreading of dissolved nutrients, particles and pathogens. Furthermore, additional water blockage leads to increased hydrodynamic forces on fish cages, which potentially threaten the structural integrity of the fish farm. However, detailed knowledge about the effects of biofouling on the flow past, and the resulting forces on fish cages, is limited and systematic investigations of the effects of different types of fouling have been called for. This study investigates the effects of different amounts and sizes of two important fouling organisms in Norwegian aquaculture, blue mussel (Mytilus edulis) and kelp (Saccharina latissima) on the drag on net panels. Drag forces on a number of clean and fouled nets were measured in a flume tank at a flow speed of 0.1 m/s. Net solidity was calculated from images acquired of all nets in the current. The relationship between net solidity and drag was then found for clean nets and for each type of fouling, and biofouling was parameterized by comparing clean and fouled net results: for a given fouled net, a clean net can be found that experiences the same drag. The latter can then be used in numerical models to estimate the effect of fouling on net drag. That means existing models can be used to model the drag effect of fouling. This study found a solidity increase due to mussel and kelp fouling to affect drag roughly at the same rate as an increase in clean net solidity at a flow speed of 0.1 ms−1 and within the tested fouling size range for two net types. Therefore, existing models, describing the relationship between net solidity and drag, can be used directly or with minor alterations (especially at high solidities) to estimate effects of additional mussel and kelp fouling on drag. In contrast, wet weight seems to be unsuitable as a measure to estimate drag on nets fouled with seaweed or mussels. It should be noted that these findings are only valid under similar conditions, and that other fouling types and sizes, as well as test parameters and tank size can affect the relationship between solidity and drag.

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Organic Matter Cycling

Biogeochemistry of Estuaries ◽

10.1093/oso/9780195160826.003.0017 ◽

2006 ◽

Author(s):

Thomas S. Bianchi

Keyword(s):

Organic Matter ◽

Salt Marshes ◽

Vascular Plant ◽

World Ocean ◽

Analytical Techniques ◽

Marine Biota ◽

Natural Ecosystems ◽

Redfield Ratio ◽

Structural Support ◽

Transformation Of Organic Matter

In this chapter the general processes involved in controlling production and transformation of organic matter will be discussed as well as some of the associated stoichiometric changes of a few key biological elements (e.g., C, N, P, S). Stoichiometry is defined as the mass balance of chemical reactions as they relate to the law of definite proportions and conservation of mass (Sterner and Elser, 2002). For example, if we examine the average atomic ratios of C, N, and P in phytoplankton we see a relatively consistent ratio of 106:16:1 in most marine species. This is perhaps the best example of applied stoichiometric principles in natural ecosystems and is derived from the classic work of Alfred C. Redfield (1890–1983) (Redfield, 1958; Redfield et al., 1963). More specifically, Redfield compared the ratios of C, N, and P of dissolved nutrients in marine waters to that of suspended marine particulate matter (seston) (essentially phytoplankton) and found straight lines with equal slopes (figure 8.1; Redfield et al., 1963). This relationship suggested that marine biota were critical in determining the chemistry of the world ocean, clearly one of the most important historical findings linking chemical and biological oceanography (Falkowski, 2000). Moreover, the Redfield ratio has been further validated with recent data using improved analytical techniques (Karl et al., 1993; Hoppema and Goeyens, 1999). Other work has shown that there are predictable deviations from the Redfield ratio across a freshwater to open ocean marine gradient (figure 8.2; Downing, 1997). For example, N-to-P ratios in estuaries have commonly been shown to be lower and/or higher than the predicted Redfield ratio because of denitrification and anthropogenic nutrient enrichment processes, respectively. Inputs of vascular plant organic matter (e.g., mangroves, salt marshes, seagrasses) to estuarine systems presents another problem in causing deviations of C:N:P from the Redfield ratio. Vascular plants have been shown to deviate from this ratio in part because of relatively high amounts of C and N compared to algae due to a higher abundance of structural support molecules (e.g., cellulose, lignin) and defense antiherbivory (secondary) compounds (e.g., tannins), respectively (Vitousek et al., 1988).

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