Ocean winter warming and the relationship between predator and prey



by   |  VIEW 260

Ocean winter warming and the relationship between predator and prey

The thermoregulatory action of the sea is a process that takes place in the areas near the coast. Due to its enormous mass of water, and therefore its very high thermal capacity, the sea changes its temperature much slower than the land.

This mechanism generates a difference in temperature between the sea and the earth which causes an exchange of heat between them, so that in summer the sea (colder than earth) spontaneously absorbs heat from the nearby land and in winter releases it gradually.

The consequence of this phenomenon is that the environments surrounding the sea, and in general the large bodies of water, have a milder climate with less annual temperature range: less sultry in summer and slightly warmer in winter.

An example of this phenomenon is well represented by the Mediterranean Sea. This sea, being closed (that is, it communicates with the oceans through shallow and shallow openings), is therefore composed of warm waters. By slowly releasing the heat absorbed by solar heating, they soften the climate of the regions bordering them, which is so very pleasant: in summer the air is dry and warm, but breezy; in winter it is cold but never freezing.

The temperature range will therefore be not very high, thanks to the sea that attenuates the sudden changes in temperature. But what is the relationship between Ocean winter warming predators and prey? The study: Ocean winter warming induced starvation of predator and prey, published on the Proceedings.

Biological sciences, said: "Ocean warming impacts the fitness of marine ectothermic species, leading to poleward range shifts, re-shuffling of communities, and changes in ecosystem services. While the detrimental effects of summer heat waves have been widely studied, little is known about the impacts of winter warming on marine species in temperate regions.

Many species benefit from low winter temperature-induced reductions in metabolism, as these permit conservation of energy reserves that are needed to support reproduction in spring. Here, we used a unique outdoor mesocosm system to expose a coastal predator-prey system, the sea star Asterias and the blue mussel Mytilus, to different winter warming scenarios under near-natural conditions.

We found that the body condition of mussels decreased in a linear fashion with increasing temperature. Sea star growth also decreased with increasing temperature, which was a function of unaltered predation rates and decreased mussel body condition.

Asterias relative digestive gland mass strongly declined over the studied temperature interval (ca twofold). This could have severe implications for reproductive capacity in the following spring, as digestive glands provide reserve compounds to maturing gonads.

Thus, both predator and prey suffered from a mismatch of energy acquisition versus consumption in warmer winter scenarios, with pronounced consequences for food web energy transfer in future oceans."