Here is a real scientific article co-authored by Professor Bob Carter of James Cook University:
http://adsabs.harvard.edu/abs/2004AGUFMPP23B1426N
Basically, what it says is that they took several coral cores, compared their O18 isotope content (which can be used to deduce ocean temperature change), and found that the data obtained this way was no different than data obtained with a single coral core. Thus confirming that the published data based on single coral core are correct.
(Guess what the published data say about the temperature? You guessed it!)
This is a perfect example when it comes to scientific publications there is no real difference between scientists. What they say in public, however, is a totally different matter.
The abstract of Bob Carter's article:
"Climate variability in the western equatorial Indian Ocean reflects the combined influence of seasonally changing sea surface temperature (SST), ocean currents, and monsoon circulation, as well as inter-annual to -decadal variability associated with ENSO in the Pacific. However, the Indian Ocean also exhibits variability that appears unrelated to ENSO in the Pacific. The nature of interactions between air-sea variability in the Indian and Pacific oceans is not yet fully resolved, in part because of the lack of long-term, high-resolution SST records from key localities in the Indian Ocean. Such records are now being obtained using oxygen isotope profiles measured on corals from East Africa, Indonesia, Australia, and Indian Oceania (Maldives, Seychelles), with the longest coral-based time series from Malindi, Kenya, covering the last 300 years at near-monthly resolution. The value of these developing coral records depends on the fidelity with which they record regional climate variability. In order to assess the fidelity of oxygen isotope ratios (\delta18O) in Indian Ocean corals as a proxy for sea surface temperature, we have generated stable isotopic time series from multiple Porites lutea coral heads collected along the coast of Kenya. Coral-based isotopic paleoclimatology is labor and time-intensive so detailed analyses using multiple coral heads from different sites within a region are extremely rare. Most published records are produced from a single coral head, yet questions have been raised about the accuracy of such records. To address such concerns, near-monthly resolution isotopic profiles, spanning 10 to 50 years prior to 1997, were measured on a total of 8 cores from five sites along a north-south transect between 2° and 4° S (Kiwayu: 2° 2'S, 41° 2'E, Malindi: 3° 14'S, 40° 8'E, Watamu: 3° 23'S, 39° 52'E, Mombasa: 3° 59'S, 39° 5'E, and Kisite: 4° 43'S, 39° 23'E. Correlations among individual \delta18O time series (r values range from 0.65 to 0.80) reveal that sample- and site-specific effects do not sufficiently bias \delta18O such that regional climate signals cannot be discerned from any of the 5 sites. Furthermore, correlation of all individual oxygen isotope time series with instrumental monthly SST yields r values between -0.70 and -0.75, demonstrating that fluctuations in \delta18O primarily reflect variations in SST. Although correlation coefficients between \delta18O and instrumental monthly SST are higher using either single-site composite \delta18O time series, such as for Malindi (r = -0.76), or a multisite, multi-core composite (r = -0.81), these correlation coefficients are only slightly higher than those for individual coral \delta18O time series. We conclude that in this case, the cost of developing replicate coral delta18O time series from individual sites may not be warranted in terms of a marginal gain in signal-to-noise ratio. Our work suggests that a 300 year long, near-monthly \delta18O record from a single coral head from Malindi, can be used with confidence for environmental reconstructions in the western equatorial Indian Ocean."
