Influence of environmental factors on burrow irrigation and oxygen consumption in the mudflat invertebrate Urechis caupo
Julian, D.; Chang, M.L.; Judd, J.R.; Arp, A.J. (2001). Influence of environmental factors on burrow irrigation and oxygen consumption in the mudflat invertebrate Urechis caupo. Mar. Biol. (Berl.) 139(1): 163-173. http://dx.doi.org/10.1007/s002270100570
In: Marine Biology: International Journal on Life in Oceans and Coastal Waters. Springer: Heidelberg; Berlin. ISSN 0025-3162; e-ISSN 1432-1793, more
|  |
| Authors | | Top |
- Julian, D.
- Chang, M.L.
- Judd, J.R.
- Arp, A.J.
|
|
|
| Abstract |
We examined burrow irrigation activity by the mudflat worm Urechis caupo in response to suspended food, ambient hypoxia (down to 3.3 kPa PO2), hydrogen sulfide exposure (up to 100 µmol l–1), and short-term temperature change (range 10–22°C). In normoxic, nutrient-free water at 14°C, O2 consumption (M?O2) was 45 nmol min–1 g–1, water flow rate (V?W) was 27 ml min–1 (0.66 ml min–1 g–1), frequency of peristaltic waves (F P) was 2.6 contractions min–1, stroke volume (SV) was 11 ml, and O2 extraction coefficient (EO2) was 0.27. Adding suspended food to the burrow water occasionally elicited stereotypical feeding behavior but had no effect on any measured variables during nonfeeding periods. Hypoxia greatly decreased M?O2 (75% reduction at 3.3 kPa PO2) but did not affect V?W , F P, SV, or EO2. Sulfide at 50 µmol l–1 or less had no effect on burrow irrigation activity, whereas 100 µmol l–1 sulfide decreased V?W by 58% and F P by 50% but had no effect on SV. Temperature strongly affected V?W (Q 10 of 1.9 from 10°C to 22°C). We propose that U. caupo's ability to live in the hypoxic, sulfidic mud of productive mudflat environments, combined with its very efficient mucous net, allows it to process much less water for feeding than other suspension-feeding invertebrates. This, in turn, necessitates an efficient O2 extraction mechanism, which is provided by the water lung activity of U. caupo's unique hindgut. |
|
