Sentences with phrase «of food webs»

Given the lack of detailed proxy records to trace simultaneously biochemical baselines and length of food webs, assessing the extent to which biogeochemical cycling and community structure in pelagic ecosystems have changed over the past century is difficult, as is attributing change to natural cycles versus anthropogenic disturbances.

For example, the resulting changes in ocean salinity and pH can inhibit calcification in shell - bearing organisms that are either habitat - forming (e.g., coral reefs, oyster reefs) or the foundation of food webs (e.g., plankton)(The Copenhagen Diagnosis 2009).

Now, I open my eyes upon hearing of the marvelous complexity of food webs that make our ecosystems possible.

Scientists, using such information, can then speculate on the consequences of an ocean without leatherbacks, but we recognize that the inherent complexity of food webs prevents our speculations from becoming what we would like to call predictions.

Five vignettes, illustrated in realistic and detailed paintings, give eloquent descriptions of food webs at various times of day.

However, for students to understand, and communicate, some of the important ecological, conservationist arguments, they benefit from a conceptual understanding of food webs, ecological interactions, and natural selection.

Duration: Approximately 45 mins The Activities Sheet provides a range of activities for students to enhance their knowledge of food webs by putting it into practice.

They are also important as not only can they cause terrible diseases but they can be critical elements of food webs and contribute to biodiversity.

Exactly how sea - ice decline might affect species interactions in this and other types of food webs on land in the Arctic is a question that deserves greater attention,» Post said.

«For each time slice, we used a «real» pre-extinction ecosystem full of the species we know existed to help create several alternate models of food webs for the same place and time.

Such changes in populations of certain animal groups can upset the balance of food webs.

The selective extinction of large - bodied animals could have serious consequences for the health of marine ecosystems, the scientists say, because they tend to be at the tops of food webs and their movements through the water column and the seafloor help cycle nutrients through the oceans.

But, by modeling a variety of food webs using established ecological principles, the researchers were able to find such species and they hope that the algorithms that they created might eventually be able to identify target species in the real world.

Thomas cited wildlife studies in Minnesota and Europe showing that animals at the top of food webs had lower concentrations than animals at the bottom.

Among the team's findings: following an experimental flood, sites near the dam had the most dramatic changes in the structure and function of their food webs.

At these locations, the flood didn't cause major changes in the structure of food webs or the productivity of species.»

Repeated pulses of volcanism at the end of the Permian may have led to several periods of irradiation that sterilized the forests, causing a catastrophic breakdown of food webs, the researchers say — an indirect but effective way to kill.

The particular aspects of food webs to be assessed through this work will likely comprise aspects of the following:

For their study, Weiss and her team also documented the impacts of higher CO2 levels on freshwater crustaceans at the bottom of the food web — specifically, two species of Daphnia, also known as water fleas.

This nearly vodka - clear water is not the sign of a healthy lake; it's the sign of one in which the bottom of the food web is collapsing.

Under some conditions, the plankton - feasting mussels can now «filter» all of Lake Michigan in less than two weeks, sucking up the life that is the base of the food web and making its waters some of the clearest freshwater in the world.

The researchers removed one species of wasp and found that it led to secondary extinctions of other, indirectly linked, species at the same level of the food web.

The researchers warn that removing marine animals at the top of the food web could significantly disrupt the ocean's overall ecology for potentially millions of years, which is why effective management strategies will be critical.

Even the species identification methods are deficient, regardless of the fact that gelatinous zooplankton can be abundant in the ecosystem and have a major effect on both the upper and lower levels of the food web,» says Majaneva.

Sargassum, carrying the weight of the food web, floats in the Gulf of Mexico.

Clearly, what is happening at the base of the food web reverberates up to the top of the food web.»

He says using fatty acids to track energy flow through so many parts of the food web is an intriguing approach.

«Our understanding of what's likely to happen has been hampered by an over-reliance on simplified laboratory systems centred on single levels of the food web.

And invertebrates that were once an important part of the food web, such as mayflies and net - spinning caddisflies, are conspicuously absent.»

And at high global latitudes, cold lakes normally covered by ice in the winter are seeing less ice year after year — a change that could affect all parts of the food web, from algae to freshwater seals.

«Oceans in the future may provide less fish and shellfish for us to eat, and larger animals that are at the top of the food web, in particular, will suffer.

Nutrients help sustain phytoplankton and zooplankton, the tiny aquatic plants and animals at the base of the food web that support other aquatic life, including prey fishes.

The various compounds containing nitrogen (such as nitrate, nitrite or ammonia) are essential nutrients for ocean life, particularly for phytoplankton that serve as the foundation of the food web.

«And as a species on top of the food web, understanding their status and contribution to the ecosystem is important for understanding the status of the ecosystem as a whole.»

«And we are part of this food web.»

This shift in the balance of the food web isn't healthy or sustainable, the researchers argue.

«Since the microbial community is a critical part of a food web, global warming will have direct impacts on organisms feeding on plankton... What exactly and how large this impact will be will require more data to understand.»

Atlantic menhaden (Brevoortia tyrannus) are small fish in the herring family, which filter - feed on phytoplankton and live at the base of the food web.

The fungicides were found below levels that would kill creatures at the bottom of the food web, such as zooplankton and amphipods, the authors said.

It's the first indisputable evidence that species at the bottom of the food web are mistaking plastic for food, which raises troubling questions about species that rely on these invertebrates for food, such as B.C. salmon.

Tiny ants may seem like an odd food source for black bears, but the protein - packed bugs are a major part of some bears» diets and a crucial part of the food web that not only affects other bugs, but plants too.

The researchers looked at the nitrogen stable isotope composition of different members of the food web at suburban ponds.

And that means there's finally a perk to being the foundation of the food web.

At the base of that food web are phytoplankton, single - celled organisms that survive by turning sunlight into food sources such as sugars and carbohydrates.

Around the same time, Shahid Naeem, director of Columbia University's Earth Institute Center for Environmental Sustainability in New York City, was also looking beyond species numbers to study ecosystem function, zeroing in on the diversity of species at different levels of the food web.

First - of - its - kind analysis of hundreds of food web models shows that the decrease has mostly taken place since the 1970s

Invasive Asian carp consume plankton from the base of the food web and reproduce prolifically which could pose substantial environmental risks and economic impacts to the Great Lakes if they become established.

Now, in the first study of its kind, researchers have pinpointed early warning signs for the disruption of a food web in a lake.

Marine scientists are raising the alarm about a proposal to drop tonnes of iron into the Pacific Ocean to stimulate the growth of phytoplankton, the base of the food web.

Current research includes studies of the food web structure and biogeochemistry of Arctic streams and rivers, nitrogen cycling in headwater streams and estuaries, and the impacts of climate change on the freshwater cycle of the Arctic.