The distinct roles of two intertidal foraminiferal species in phytodetrital carbon and nitrogen fluxes – results from laboratory feeding experiments
<p>Benthic foraminifera play a major role as primary consumers and detrivores redistributing organic carbon and nitrogen in intertidal environments. Here we compared the differences of phytodetrital carbon and nitrogen intake and turnover of two dominant intertidal foraminifera, <i>Am...
| Main Authors: | , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2018-10-01
|
| Series: | Biogeosciences |
| Online Access: | https://www.biogeosciences.net/15/6185/2018/bg-15-6185-2018.pdf |
| Summary: | <p>Benthic foraminifera play a major role as primary consumers and detrivores
redistributing organic carbon and nitrogen in intertidal environments. Here
we compared the differences of phytodetrital carbon and nitrogen intake and
turnover of two dominant intertidal foraminifera, <i>Ammonia tepida</i> and
<i>Haynesina germanica</i>. Their lifestyles in relation to feeding
behavior (feeding preferences, intake and turnover of phytodetrital carbon
and nitrogen) and temperature adaptations were compared to obtain a closer
definition of their specific roles in intertidal organic matter processing.
For this comparison, we carried out a series of short-term laboratory
incubations with stable-isotope-labeled (<sup>13</sup>C and <sup>15</sup>N) detritus as
the food source. We compared the response of the two species to diatom detritus
at three different temperatures (15, 20,
25 °C). <i>Ammonia tepida</i> showed a very high,
temperature-influenced intake and turnover rates with more excessive carbon
turnover, compared to nitrogen. The fairly low metabolic nitrogen turnover in
<i>H. germanica</i> was not affected by temperature and was higher than the
carbon turnover. This might be related with the chloroplast husbandry in
<i>H. germanica</i> and its lower demands for food-derived nitrogen
sources. <i>Ammonia tepida</i> prefers a soft chlorophyte food source over
diatom detritus, which is harder to break down. In conclusion,
<i>A. tepida</i> shows a generalist behavior that links with high fluxes
of organic matter (OM). Due to its high rates of OM processing and
abundances, we conclude that <i>A. tepida</i> is an important key player in
intertidal carbon and nitrogen turnover, specifically in the short-term
processing of OM and the mediation of dissolved nutrients to associated
microbes and primary producers. In contrast, <i>H. germanica</i> is a
highly specialized species with low rates of carbon and nitrogen budgeting.</p> |
|---|---|
| ISSN: | 1726-4170 1726-4189 |