Responses of benthic foraminifera to changes of temperature and salinity

Benthic foraminifera are widely used as paleoenvironmental proxies because of their high sensitivity to environmental changes and excellent preservation potential in sediment. Affected by global changes, environmental factors such as seawater temperature and salinity are changing, which will affect the distribution and species composition of benthic foraminifera. A recent study revealed how the benthic foraminiferal community respond to the change of temperature and salinity.

Micrographs of benthic foraminifera from culture experiment
[Credit: : © Science China Press]

This study is published in the journal Science China Earth Sciences with title 'Responses of benthic foraminifera to changes of temperature and salinity: Results from a laboratory culture experiment'. Prof. Yanli LEI from Institute of Oceanology Chinese Academy of Sciences is corresponding authors of this article. Through laboratory culture experiment, the researchers only changed the temperature and salinity, while controlling other environmental parameters consistent. They conducted a two-factor crossed experiment in which foraminiferal communities were cultured at different temperatures (6, 12, and 18°C) and salinities (15, 20, 25, and 30 psu) for 10 weeks. The research revealed the different response of benthic foraminifera communities to the change of temperature and salinity.

Scientist knows little about the response of benthic foraminifera to environmental factors. Environmental factors are not independent, and the responses of foraminifera usually reflect the combined effects of the measured environmental factors and other unknown biotic and abiotic factors in the field. Therefore, it is difficult to discern cause-effect relationships between environmental factors and changes in benthic foraminiferal community in field studies, especially with interactive effects.

To solve this problem, laboratory-controlled culture methods were used in this study. The researchers cultured the entire foraminiferal communities with the natural sediments from the intertidal area of Qingdao Bay for 10 weeks. They analyzed and compared the foraminiferal community under different conditions of temperature and salinity. The study showed that temperature affected foraminiferal community more significantly than salinity. In addition, with increasing temperature, the species composition shifted from hyaline taxon to porcellaneous taxon.

This study indicates that the benthic foraminiferal community is very sensitive to the change of environmental factors (e.g., temperature and salinity) and it can be used to indicate the changes in the marine ecosystem. At the same time, this finding has important scientific significance and reference value for reconstructing the paleoenvironment by using benthic foraminiferal community composition.

Source: Science China Press [January 11, 2019]