Direct Observations

An increase in carbon dioxide (CO2) in the atmosphere leads to a variety of changes that are collectively known as climate change. Among the changes that will occur, is that the sea will become warmer and the acidity (pH) of the sea decreases.

Natural fluctuations are high in marine ecosystems, but with climate change, permanent changes can be expected.

On the sea floor there are diverse communities of invertebrates, which can be defined by the animal species in each community and the relative number of individuals. These communities of invertebrates are constantly changing, number of species are decreasing or increasing.

In this webpage, the communities are described graphically, by showing which species are present at any given time and the relative number of individuals within a species.

Data used in the project are from Berufjordur in east-Iceland. Sampling was done at three sampling locations where no anthropogenic impact was deduced, a) before fish farming starts in that area, b) at 200 meters or more from a fish farming area that has been rested for several months, and c) at 1000 meters from the next fish farming area.

Most of the coastal areas are under some influence of human activities, but it is assumed that the influence is small in the areas that were selected for this website and similar from year to year. Here you can see snapshots of the communities from different years, so you can see how the communities change from year to year. Furthermore, the average number of individuals of each species at any given time is shown (y-axes on the graph), and thus you can see how the number of individuals of the respective species (Latin names on x-axis) changes from year to year.

By looking at benthic communities from year to year and the number of individuals of each species, you can see if changes seem random or if there is a trend, e.g. are the numbers increasing or decreasing? Changes can occur in certain aspects of communities such as species composition or the number or relative number of individuals of individual species.

If there are permanent changes in the benthic communities, so that e.g. certain species disappear, or that other species appear, they are probably due to changes in environmental factors in the sea that can possibly be attributed to climate change, e.g. higher temperature and lower acidity in the sea (lower pH).

It should be noted, however, that the data shown on the site do not say whether changes in the species composition and number of benthic animals are attributable to climate change.