The Baker Lab
Even in the most pristine coral reefs of the world, sites like this can be witnessed. The nearshore reefs of Chuuk exhibit classic signs of a phase shift from coral to algal dominance. Although common in Chuuk lagoon and the outer barrier islands, Acropora nearshore were diseased, or covered in macro algae. Photo credit: Ciemon Caballes
Gorgonian corals, like this common sea fan Gorgonia ventalina, accrete a proteinaceous skeleton. The protein is similar to our hair and fingernails and is very strong yet flexible. The fact that it is mostly protein means it's an abundant source of nitrogen for isotopic analysis. Moreover, the skeleton forms annual rings that can be micro-sampled for temporal reconstructions.
Even in the most pristine coral reefs of the world, sites like this can be witnessed. The nearshore reefs of Chuuk exhibit classic signs of a phase shift from coral to algal dominance. Although common in Chuuk lagoon and the outer barrier islands, Acropora nearshore were diseased, or covered in macro algae. Photo credit: Ciemon Caballes
Marine Pollution
The oceans are changing rapidly...
...and much of this change is due to accelerating coastal development for human use. Less than a century ago, the entire Caribbean Sea was a "larder" for Europe. Old growth forests were clear-cut to make room for farming crops like sugar cane, pineapple, and coconut. In Puerto Rico, over 99% of the island was deforested. By the mid-1900s agriculture became industrialized and production increased worldwide owing to the widespread use of synthetic fertilizers. Now, without any natural buffer zones afforded by mangrove forests and wetlands, the runoff from agriculture rapidly enters the sea.
However, agriculture is in decline. Puerto Rico now imports most of it's food and has become a global model for tropical reforestation. Tourism is the main driver of many Caribbean economies. As such, farm land is re-purposed for tourism. Mangrove forests are drained and poisoned, filled and built upon. Resorts, hotels, cruise ship ports, restaurants, shops, and entire residential communities to house the local workforce are spreading. Infrastructure, like wastewater treatment plants lags behind. As it was with agriculture, most of the wastewater ends up in the sea.
Relevant Works
1. M Moynihan*, DM Baker, AJ Mmochi (2012) Isotopic and microbial indicators of sewage pollution from Stone Town, Zanzibar. Marine Pollution Bulletin 64, 1348-1355.
2. DM Baker, K Kim, JP Andras, JP Sparks (2011) Light-mediated 15N fractionation in Caribbean gorgonian corals: implications for pollution monitoring. Coral Reefs 30, 709-717.
3. DM Baker, E Jordán-Dahlgren, MA Maldonado, CD Harvell (2010) Sea fan corals provide a stable isotope baseline for assessing sewage pollution in the Mexican Caribbean. Limnology & Oceanography 55(5) 2139-2149.
4. DM Baker, K Webster, K Kim (2010) Caribbean octocorals record changing carbon and nitrogen sources from 1862-2005. Global Change Biology, 16(10), 2701-2710.
5. DM Baker, SA MacAvoy, K Kim (2007) Relationship between water quality, δ15N, and aspergillosis of Caribbean sea fan corals. Marine Ecology Progress Series. 343, 123-130.