Food Chain Structure in Ontario Lakes Determines PCB Levels in Lake Trout (Salvelinus namaycush) and Other Pelagic Fish

1990 ◽  
Vol 47 (10) ◽  
pp. 2030-2038 ◽  
Author(s):  
J. B. Rasmussen ◽  
D. J. Rowan ◽  
D. R. S. Lean ◽  
J. H. Carey
Keyword(s):  
Trophic Level ◽  
Lipid Content ◽  
Food Chain ◽  
Organic Contaminants ◽  
Lake Trout ◽  
Chain Structure ◽  
Food Chains ◽  
Species Introductions ◽  
Top Predators ◽  
Glacial Relict

The trophic structure of pelagic communities in lakes of glaciated regions is highly variable due to restricted dispersal of glacial relict taxa and recent species introductions. Much of the enormous between-lake variability in PCB levels in lake trout flesh (15–10 000 ng/g) from the St. Lawrence system results from differences in the length of pelagic food chains. Ontario Ministry of the Environment data (1978–81) on PCB concentrations in lake trout flesh indicate that PCB concentrations increased with the length of the food chain and tissue lipid content, and decreased with distance north of urban-industrial centres. Each trophic level contributed about a 3.5-fold biomagnification factor to the PCB concentrations in the trout, and the lipid content of the trout flesh increased by a factor of 1.5 for each additional trophic level. An empirical model capable of predicting PCB levels in pelagic salmonids and forage fish (smelt and coregonids) indicated that biomagnification of small atmospheric inputs of persistent lipophilic contaminants can explain the frequent occurrence of high levels of contaminants in some biota from remote areas, and that species introductions that lengthen food chains will lead to significant increases in levels of atmospherically dispersed persistent organic contaminants in top predators.

Pelagic Food Chain Structure in Ontario Lakes: A Determinant of Mercury Levels in Lake Trout (Salvelinus namaycush)

1994 ◽  
Vol 51 (2) ◽  
pp. 381-389 ◽  
Author(s):  
Gilbert Cabana ◽  
Alain Tremblay ◽  
Jacob Kalff ◽  
Joseph B. Rasmussen
Keyword(s):  
Food Chain ◽  
Lake Trout ◽  
Salvelinus Namaycush ◽  
Chain Structure ◽  
Food Chains ◽  
Micropterus Dolomieu ◽  
Species Introduction ◽  
Mysis Relicta ◽  
Recent Species ◽  
Glacial Relict

The trophic structure of pelagic communities in glaciated regions is highly variable due to restricted dispersal of glacial relict taxa and recent species introduction. Much of the between-lake variation in Hg in lake trout (Salvelinus namaycush) flesh from the St. Lawrence system (non-point-source contaminated lakes), which spans more than two orders of magnitude (0.03–3.96 μg/g), results from differences in the length of pelagic food chains. Hg levels from the longest food chains where pelagic forage fish and the crustacean Mysis relicta were present were about 3.6-fold higher than those from the shortest food chains where these last two trophic components were missing. A lack of correlation between Hg levels in small-mouth bass (Micropterus dolomieu), which do not exploit the pelagic food chain, and the length of the pelagic food chain confirmed that the positive relationship observed in lake trout could not be attributed to the confounding effect of some physicochemical factors covarying with our pelagic food chain classification. Our results confirmed that the food chain biomagnification model developed by Rasmussen et al. (1990. Can. J. Fish. Aquat. Sci. 47: 2030–2038) to predict PCB levels in lake trout can also be applied to Hg biomagnification.

Predation, Yield, and Ecological Efficiency in Aquatic Food Chains

1976 ◽  
Vol 33 (2) ◽  
pp. 313-316 ◽  
Author(s):  
L. M. Dickie
Keyword(s):  
Primary Production ◽  
Trophic Level ◽  
Food Chain ◽  
Food Chains ◽  
Ecological Efficiency ◽  
Aquatic Food ◽  
Predation Rates

Given constancy of biomasses and sizes of predators and prey, the basic ecological equations are used to show that relative predation rates must increase rapidly as trophic level in aquatic food-chains drops towards primary production. The implications of this conclusion for exploitation at different food-chain levels is discussed.

Equilibrium Model of Fate of Microcontaminants in Diverse Aquatic Food Chains

1981 ◽  
Vol 38 (3) ◽  
pp. 280-296 ◽  
Author(s):  
Robert V. Thomann
Keyword(s):  
Food Chain ◽  
Chain Transfer ◽  
Body Burden ◽  
The Body ◽  
Food Chains ◽  
Chain Model ◽  
Bioaccumulation Factors ◽  
Top Predators ◽  
Food Chain Model ◽  
Food Chain Transfer

Bioconcentration and bioaccumulation factors of PCB, 239Pu, and 137Cs are compiled from the literature as a function of organism size. The distribution of field-observed bioaccumulation factors varies markedly between each substance but similarly to order of magnitude within each substance across diverse food chains. It can be inferred from the literature that PCB levels in top predators are due primarily to food chain transfer. A steady state compartment food chain model is derived for estimation of the relative effect of uptake directly from water versus food chain transfer. The model food chain transfer number f, given by αC/K + G for α = chemical absorption efficiency, C = specific consumption, K = excretion rate, and G = net organism growth rate indicates the degree of food chain accumulation. For f > 1, food chain transfer is significant; for f < 1, uptake from water is more significant. Application of the model suggests that (a) PCB body burden in top predators is due almost entirely to consumption of contaminated prey, (b) for 239Pu all of the body burden is due to uptake from the water only, and (c) observed 137Cs concentration factors are due principally to food chain transfer with a high dependence on the salinity-dependent phytoplankton adsorption.Key words: food chain model, bioconcentration, bioaccumulation, PCB, 239Pu, 137Cs, water uptake, food chain transfer

scholarly journals Higher reproductive performance of a piscivorous avian predator feeding on lower trophic-level diets on ponds with shorter food chains

2021 ◽  
Author(s):  
Janusz Kloskowski ◽  
Andrzej Trembaczowski ◽  
Maciej Filipiuk
Keyword(s):  
Habitat Quality ◽  
Trophic Level ◽  
Food Chain ◽  
Trophic Position ◽  
Nitrogen Isotope ◽  
Predatory Fish ◽  
Food Chains ◽  
Small Fish ◽  
Food Chain Length ◽  
Aquatic Food

AbstractVariation in food-chain length may influence a predator’s trophic position. In aquatic food webs, the energy value of prey typically increases with its trophic rank; hence a higher trophic-level diet is often assumed to indicate better habitat quality. We related the body and health condition of pre-fledged Red-necked Grebes Podiceps grisegena to their dietary trophic level (estimated using stable nitrogen isotope signals of feathers) in two managed pond habitats with contrasting prey availability due to different fish population structures. Ponds stocked with young, small common carp Cyprinus carpio provided abundant fish and non-fish (insects and amphibians) resources for chicks. In ponds stocked with large carp, which also supported populations of small predatory fish, the breeding success of grebes was comparatively poor, because carp exceeded the size suitable for chicks and adversely affected non-fish prey. Pre-fledged grebes were in better condition (greater body mass, lower heterophil/lymphocyte ratio) in the food-rich small-fish ponds than in the food-poor ponds dominated by large fish. Values for δ15N suggested shorter food chains and a lower trophic-level diet for grebes in the food-rich ponds. Bayesian carbon and nitrogen isotope mixing models demonstrated the dietary prominence of small fish, both carp and predatory species. Between-habitat differences in food-chain length and grebe trophic position resulted from the higher trophic rank of small predatory fish in the food-poor ponds compared to the omnivorous carp in the food-rich ponds. Our results suggest that in aquatic food webs, feeding at higher trophic levels by strongly size-limited generalist avian predators can be associated with overall food scarcity due to the impact of fish, and thus trophic status cannot be used uncritically as a proxy for aquatic habitat quality.

scholarly journals THE EFFECT OF SELENIUM ON MERCURY TRANSPORT ALONG THE FOOD CHAIN

AGROFOR ◽  
2016 ◽  
Vol 1 (3) ◽  
Author(s):  
Primož ZIDAR ◽  
Špela KRŽIŠNIK ◽  
Marta DEBELJAK ◽  
Suzana ŽIŽEK ◽  
Katarina VOGEL MIKUŠ
Keyword(s):  
Food Chain ◽  
Contaminated Soil ◽  
Local Population ◽  
Trophic Levels ◽  
Food Chains ◽  
Chemical Transformations ◽  
Soil Concentration ◽  
Preliminary Results ◽  
Mercury Transport ◽  
Hg Accumulation

More than 500 years of mercury (Hg) production in Idrija (Slovenia) resulted in aconsiderable pollution of Idrija region with Hg. Although the mine is closed formore than 20 years, the total soil concentration of Hg may still reach up to severalhundred mgkg-1dry weightin local gardens and more that thousand inother urbanregions. Hg in soil undergoesdifferent chemical transformations and in someformsit may enterplants and higher trophic levelsin food chains, also withbiomagnification pattern.The local population is, besides air and dust, thus exposedto mercury also via consumption of locally produced food.Several studies showedthat the increased level of selenium in soil may reduce the uptake of mercury inplants but very few include other trophic levels in a food chain as well.In our pilotstudy we followed an impact of Seon Hg transport from soil to plants(Lactucasativa) and further to soil dwelling animals (Porcellioscaber). Lettuce wasplanted in a contaminated soil from Idrija and in soil with added HgCl2. The leavesof half of the plants weresprayed with Sesolution (5μg L-1)threeand five weeksafter planting.After six weeks plants were analyzed for Hg and Se and offered asfood to terrestrial isopods for two weeks. Our preliminary results revealed thatfoliar treatment of plants with Se may affect Hg accumulation in plants andtherefore further transport of Hg across the food chain.

The transfer of65Zn and 59Fe along a Fucus serratus (L.)→ Littorina obtusata (L.) food chain

1975 ◽  
Vol 55 (3) ◽  
pp. 583-610 ◽  
Author(s):  
M. L. Young
Keyword(s):  
Trace Metals ◽  
Radiation Exposure ◽  
Marine Environment ◽  
Food Chain ◽  
Sea Water ◽  
Food Chains ◽  
Fresh Weight ◽  
Littorina Obtusata ◽  
Fucus Serratus ◽  
Marine Food

In marine organisms the fresh-weight concentrations of the trace metals zinc and iron are 102–105 times the concentrations in sea water. Study of the transfer of these metals along marine food chains is of interest because of the possibility of their being pollutants of the marine environment. Also65Zn and 65Fe are released to the marine environment and have been found, in many instances, to be the predominant radionuclides in food chains leading to man (Lowman, Palumbo & South, 1957; Lowman, 1960; Osterberg, Pearcy & Curl, 1964; Preston, 1967). The transfer of these metals along marine food chains is thus of interest also in the context of human radiation exposure.

scholarly journals Polychlorinated Alkanes in Fish from Norwegian Freshwater

2002 ◽  
Vol 2 ◽  
pp. 136-140 ◽  
Author(s):  
Anders R. Borgen ◽  
Martin Schlabach ◽  
Roland Kallenborn ◽  
Eirik Fjeld
Keyword(s):  
High Resolution ◽  
Lipid Content ◽  
Lake Trout ◽  
Industrial Area ◽  
Arctic Char ◽  
Negative Ion ◽  
High Lipid ◽  
Fish Samples ◽  
Polychlorinated Alkanes ◽  
Negative Ion Mode

Short-chain polychlorinated alkanes (sPCAs) have been measured in freshwater fish samples from different lakes all over Norway and from the Norwegian Arctic. The analyses were performed with high-resolution GC coupled to high-resolution MS in electron capture negative ion mode. The species investigated were trout, Arctic char, and burbot (Lota lota). Muscle tissue in the lake trout and Arctic char, and liver in burbot, were selected for analyses because of their high lipid content. ∑sPCA concentration ranged from 108 to 3700 ng/g fat. The highest value was found in the south of Norway near an industrial area.

scholarly journals Trophic cascades alter eco-evolutionary dynamics and body size evolution

2020 ◽  
Vol 287 (1938) ◽  
pp. 20200526
Author(s):  
Thomas M. Luhring ◽  
John P. DeLong
Keyword(s):  
Body Mass ◽  
Trophic Level ◽  
Evolutionary Dynamics ◽  
Trophic Cascades ◽  
Trophic Levels ◽  
Chain Model ◽  
Top Predator ◽  
Predator Prey ◽  
Top Predators ◽  
Time Changes

Trait evolution in predator–prey systems can feed back to the dynamics of interacting species as well as cascade to impact the dynamics of indirectly linked species (eco-evolutionary trophic cascades; EETCs). A key mediator of trophic cascades is body mass, as it both strongly influences and evolves in response to predator–prey interactions. Here, we use Gillespie eco-evolutionary models to explore EETCs resulting from top predator loss and mediated by body mass evolution. Our four-trophic-level food chain model uses allometric scaling to link body mass to different functions (ecological pleiotropy) and is realistically parameterized from the FORAGE database to mimic the parameter space of a typical freshwater system. To track real-time changes in selective pressures, we also calculated fitness gradients for each trophic level. As predicted, top predator loss generated alternating shifts in abundance across trophic levels, and, depending on the nature and strength in changes to fitness gradients, also altered trajectories of body mass evolution. Although more distantly linked, changes in the abundance of top predators still affected the eco-evolutionary dynamics of the basal producers, in part because of their relatively short generation times. Overall, our results suggest that impacts on top predators can set off transient EETCs with the potential for widespread indirect impacts on food webs.

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