1. Heidi Jane de Guzman, Elizabeth Borda, Anja Schulze
Genotypic Diversity of Sabellid Worms from Carbon Dioxide Vents in the Mediterranean Sea
Heidi Jane de Guzman, Elizabeth Borda, Anja Schulze
Marine Biology Department, Texas A&M University, Galveston, Texas 77553
Introduction
Marine CO2 vents are very common in the Mediterranean, especially around Italy and Greece where they typically eject volcanic fluids containing up to 1-2% hydrogen sulphide (Dando et al., 1999). Natural CO2 venting sites have endemic fauna unique to them, and vent communities are generally distinct from the surrounding environment. Some marine CO2 vents are at ambient seawater temperature and lack toxic sulphur compounds. These may be used as natural experiments to provide better understanding of ocean acidification at the ecosystem level (Hall Spencer et al., 2008). Calosi et al. (2012) showed that polychaete species of both vulnerable and tolerant taxa collected in control areas (normal pH values) showed metabolic depression when exposed to elevated pCO2/low pH conditions at shallow-water CO2 vent system off Ischia (Naples, Italy). Meanwhile, specimens of tolerant species exposed to control condition did not show a reciprocal response to that shown by their conspecific from the control areas transferred into the acidified conditions. It remains to be examined whether tolerance to low CO2 conditions has a genetic basis or is the result of phenotypic plasticity.
Even though specimens of Amphiglena mediterranea are morphologically similar between vent and control sites, they may actually represent cryptic species. In recent years, molecular analyses have shown that many polychaete species that were previously considered geographically widespread actually represent complexes of cryptic species. A. mediterranea is one of the few species that thrives very well in naturally acidified water, and therefore a very good model species for local adaptations to climate change. In the Mediterranean Sea (Figure 1), A. mediterranea is reported as one of the most common polychaetes in waters associated with CO2 vents covered with photophilic algae (Sarda, 1990).
spineless.ucsd.edu
The tentacles area at the head end. Ventral view
showing the lateral ciliary
expansion (ci); continuous with the developing ciliation of the radiolar crown.
Ventral view of the anterior showing the prostomial
snout (st) between the incipient radioles (r3).
Objectives
Laboratory Operations
i) Sequence Generation:
Gene regions of the mitochodrial
genes for cytochrome oxidase subunit I
(COI) will be amplified by polymerase chain
reaction (PCR).
The following primers will be employed for
the amplications of the cytochrome oxidase I (COI)
gene: LCO1490 and HCO2198 .
Other primer combinations such as 16S
ribosomal RNA (rRNA) will be considered
aswell depending on the level of
variation contained in the
initial sequences.
To determine whether A. mediterranea populations from acidified vents are genetically distinct from those from non-acidified sites.
To determine the degree of gene flow among all sampling sites.
Hypothesis
Ho: There is no significant difference in the genotype diversity in A. mediterranea population from acidified and non-acidified locations.
Methods
(ii) Genetic Diversity
The average genetic distances within and among populations will be calculated in Mega 5 using the Maximum Composite Likelihood Model.
Population genetic analyses indices will be calculated with Arlequin v.3.5.
N1*
N2*
Future Study
N3 *
To study the relationship between genetic structure and geographic distribution of A. mediterranea and other sabellid species from Mediterranean Sea, Caribbean Sea, and Gulf of Mexico.
To study the phylogeny of the family Sabellidae which will involve detailed molecular and morphological studies.
S3 *
Figure 1. Distribution in the Mediterranean Sea
S2*
Literature Cited:
Dando, P.R., Stuben, D., Varnabas, S.P Hydrothermalism in the Mediterranean Sea. Prog. Oceanogr. 44,
Hall-Spencer, J.M., Rodolfo-Metalpa, R., Martin, S., Ransome, E., Fine, M., Turner, S.M., Rowley, S.J., Tedesco, D., Buia, M.C Volcanic carbon dioxide vents show ecosystem effects of ocean acidification. Nature, 454: 96–99.
Calosi, P., Rastrick, S., Lombardi, C., Hardege, J.D., Giangrande, A., Schulze A., Gambi, M Metabolic plasticity in polychaete species inhabiting a CO2 vent coastal system (Abstract). Third Symposium on the Ocean in a High-CO2 World.
Sarda, R Polychaete communities related to plant covering in the mediolittoral and infralittoral zones of the Balearic islands Western Mediterranean), Marine Ecology, Pubblicazionidella Stazione Zoologicadi Napoli, 12,
Field Operations
Specimens of A. mediterranea were collected
from different CO2 vent sites with different pH
concentrations. These locations were Castello S3 and Castello N3 (Figure 2). In addition to these sites, S. Anna, S. Caterina, and San Pietro promontory were chosen as a control site.
S1*
Figure 2. Location of sampling sites in Italy
Acknowledgement: The authors would like to thank Maria Christina-Gambi at the Stazione Zoologica “Anton Dohrn” di Napoli, Italy, for identifying and supplying all samples in this study. This project
is funded under NSF DEB (WormNet2) to Dr. Anja Schulze.