Mark Vermeij

Genome size is a fundamental biological trait that is known to exhibit high diversity among eukaryotic species, but its intraspecific diversity has only scarcely been studied to date. In scleractinian corals, genome size data are only available for a few species. In this study, intra- and interspecific variations in genome size of the coral genus Agaricia collected from Curaçao were investigated. Morphology was congruent with genetic analyses of the nuclear markers internal transcribed spacer 2 (ITS2) and L-threonine 3-dehydrogenase (TDH) in delimiting three Agaricia species among our samples. A refined Feulgen Image Analysis Densitometry (FIAD) protocol yielded genome sizes that ranged from 0.359 pg to 0.593 pg within this genus (a 1.7-fold range). The highest intraspecific variation in genome size was recorded in the depth-generalist A. lamarcki (1.5-fold range), followed by the depth specialist A. humilis (1.4-fold range) and A. agaricites (1.3-fold range), the species with an intermediate depth distribution. The mean genome size of A. agaricites (0.495 pg) was significantly larger than that of A. lamarcki (0.448 pg) and A. humilis (0.434 pg). No correlation between average genome size and nucleotide polymorphism π was detected, but we found an almost linear correlation between intraspecific variance of genome size and π of ITS2 (Pearson’s r = 0.984, p = 0.113). Genome size and collection depths of both A. lamarcki (Pearson’s r = 0.328, p = 0.058) and A. agaricites (Pearson’s r = -0.270, p = 0.221) were also not significantly associated. To our knowledge, this study provides the first account of intraspecific variation in corals; the apparent correlation detected between the nucleotide polymorphism of a species and the variance of its genome size will have to be tested using a larger taxonomic spectrum of scleractinian corals as well as in other groups of animals.

Water quality is often cited as a key driver of coral reef health, yet this topic is rarely studied in the Dutch Caribbean. In coastal waters, the origin, abundance, and distribution of pollutants and other compounds can positively or negatively affect the survival of coral reef communities. These inputs are influenced by terrestrial processes (including groundwater effects, geological features, and coastal development) and water column processes (including hydrodynamics, boundary layer effects, and nutrient stoichiometry). The SEALINK Program will build an interdisciplinary research team to assess how land-derived and waterborne inputs (including sediments, nutrients, pollutants, organic carbon, and pathogens) affect the growth and survival of coral reefs in the Dutch Caribbean. We will integrate this information into a mathematical modeling and community co-design process to test how novel management approaches (on land and in the sea) can enhance the ecosystem services provided by coral reefs to local communities. The interdisciplinary project team includes geologists, geochemists, oceanographers, marine ecologists, microbiologists, environmental geographers, and social scientists. We will standardize methods from land to sea in order to fully track (for the first time) the pathways and fates of diverse inputs and stressors. Using this information, we will develop a suite of models to forecast future coral reefs under a variety of land-use and ocean management scenarios. These scenarios will be refined through stakeholder engagement and a community co-design process. We will also explicitly study the cultural and economic factors that promote the uptake and use of scientific information in policy and education. By integrating natural and social sciences across the land-sea continuum, the SEALINK Program will produce the first comprehensive understanding of land-sea interactions in Dutch Caribbean coastal zones, thus securing the local knowledge base needed to maintain functional coastal ecosystems, protect infrastructure, and support economies across the region.
 

This powerpoint walks through the recently published position paper entitled Nature based Solutions’: essential to safeguard the Dutch Caribbean against the consequences of climate change.

Background
There is almost no systematic information about the state of marine ecosystems in Aruba. A recent report commissioned by the United Nations Development Program (Pantin 2011) also noted an almost complete lack of information on Aruba’s ecological resources, carrying capacity, limits of acceptable change and the existing level of environmental stress. The Government of Aruba therefore aims to create an assessment program to monitor the status and changes in the reef communities along its coastline. CARMABI, a Curaçaoan foundation specializing in tropical marine research, was selected to conduct the baseline assessment in collaboration with the Scripps Institution of Oceanography (U.S.A.) and the Global Coral Reef Monitoring Network (U.S.A.).

Abstract

Human activities can degrade the quality of coral reefs, cause a decline in fish species richness and functional diversity and an erosion of the ecosystem services provided. Environmental DNA metabarcoding (eDNA) has been proposed as an alternative to Underwater Visual Census (UVC) to offer more rapid assessment of marine biodiversity to meet management demands for ecosystem health indices. Taxonomic information derived from sequenced eDNA can be combined with functional traits and phylogenetic positions to generate a variety of ecological indices describing ecosystem functioning. Here, we inventoried reef fish assemblages of two contrasted coastal areas of Cura¸cao, (i) in close proximity to the island’s capital city and (ii) in a more remote area under more limited anthropogenic pressure. We sampled eDNA by filtering large volumes of sea water (2 x 30L) along 2km boat transects, which we coupled with species ecological properties related to habitat use, trophic level and body size to investigate the difference in fish taxonomic composition, functional and phylogenetic indices recovered from eDNA metabarcoding between these two distinct coastal areas. Despite no marked difference in species richness, we found a higher phylogenetic diversity in proximity to the city, but a higher functional diversity on the more isolated reef. Composition differences between coastal areas were associated with different frequencies of reef fish families. Because of a partial reference database, eDNA only partly matched those detected with UVC, but eDNA surveys nevertheless provided rapid and robust species occupancy responses to contrasted environments. eDNA metabarcoding coupled with functional and phylogenetic diversity assessment can serve the management of coastal habitats under increasing threat from global changes.