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.

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 Biokinetic food chain modeling of waterborne selenium pulses into aquatic food chains: Implications for water quality criteria

2015 ◽  
Vol 12 (2) ◽  
pp. 230-246 ◽  
Author(s):  
David K DeForest ◽  
Suzanne Pargee ◽  
Carrie Claytor ◽  
Steven P Canton ◽  
Kevin V Brix
Keyword(s):  
Water Quality ◽  
Food Chain ◽  
Quality Criteria ◽  
Food Chains ◽  
Water Quality Criteria ◽  
Aquatic Food

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.

Trophic transfer and biomagnification of fullerenol nanoparticles in an aquatic food chain

2020 ◽  
Vol 7 (4) ◽  
pp. 1240-1251 ◽  
Author(s):  
Qiuyue Shi ◽  
Cheng Long Wang ◽  
Han Zhang ◽  
Chunying Chen ◽  
Xian Zhang ◽  
...  
Keyword(s):  
Food Chain ◽  
Trophic Transfer ◽  
Environmental Risks ◽  
Food Chains ◽  
Aquatic Food Chain ◽  
Aquatic Food

Understanding the trophic transfer and biomagnification potential of nanomaterials in aquatic food chains is crucial for assessing the environmental risks of such materials.

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.

Bioaccumulation and trophodynamics of the antidepressants sertraline and fluoxetine in laboratory-constructed, 3-level aquatic food chains

2016 ◽  
Vol 36 (4) ◽  
pp. 1029-1037 ◽  
Author(s):  
Marja L. Boström ◽  
Gustaf Ugge ◽  
Jan Åke Jönsson ◽  
Olof Berglund
Keyword(s):  
Food Chains ◽  
Aquatic Food

On the Origin of the Spices (and Other Foodstuffs)

2019 ◽  
Author(s):  
Alan Kelly
Keyword(s):  
Primary Production ◽  
Food Chain ◽  
Chemical Elements ◽  
Raw Materials ◽  
Biological Effects ◽  
Desirable Outcome ◽  
Starting Point ◽  
Calcium Magnesium ◽  
Good Starting Point

The beginning of the story of food is what is termed food production. This might sound logically like the process of making food, such as a chef or food company might, but this term is rather generally used in food science to refer to the so-called primary production of food, from growth of crops to harvesting of fish and minding and milking of cows. Primary production is, for example, what farmers do, producing the food that is brought to the farm-gate, from where the processors take over. So the food chain runs, according to your preference for a snappy soundbite, from grass to glass (for milk), farm to fork, slurry to curry, or (taking the food chain to its logical conclusion, and including the role of the human gut charmingly but appropriately in the chain) from farm to flush. But where do these raw materials that are yielded by primary production actually come from? It is often said that all things found on earth can be divided into categories of animal, vegetable, and mineral. To these could perhaps be added two more categories, microbial and synthetic (man-made). Within these five groups can essentially be placed everything we know as food, so using this classification to consider where our food comes from seems like a good starting point for this book. Perhaps the simplest group to start with is minerals, which might intuitively seem an unlikely source of foodstuffs (do we eat metal or rock?), until we consider where salt comes from and how much of it we add to our food (in other words, probably too much). Our bodies, however, absolutely need for us to consume certain metals and other chemical elements to survive, beyond the sodium and chloride we get from salt, and so many extracted minerals find their way from deposits in the earth into food products. This is particularly important where their biological effects are a desirable outcome (such as in carefully formulated nutritional products). In addition, products such as milk contain minerals like calcium, magnesium, zinc, and more, because the infant or calf needs them to thrive.

Sign in / Sign up

Export Citation Format

Share Document