Celeste Sánchez-Noguera

Marine Biodiversity of Eastern Tropical Pacific Coral Reefs

The eastern tropical Pacific (ETP) is an isolated oceanic region exposed to extreme oceanographic conditions, including low salinity, low pH, high temperatures during El Nino, and low temperatures during La Nina and seasonal upwelling. The coral reefs in this region have a relatively limited suite of species compared to other coral reef areas of the world, but much like more diverse reefs the species present interact in complex ways. Here we synthezise the knowledge of taxonomic groups of reef organisms from prokaryotes to vertebrates, including algae, sponges, cnidarians, annelids and other worms, molluscs, crustaceans, echinoderms and fishes. We also present summaries on the biodiversity of associated functional groups and habitats, including (a) reef zooplankton and cryptic fauna, and (b) soft benthic environments, rhodolith beds and mesophotic environments. Several factors that structure the biodiversity of ETP coral reefs are explored, including biological, physical and chemical controls. ETP coral reefs are relatively simple systems that can be used as models for studying biodiversity and interactions among species. We conclude this review by highlighting pressing research needs, from very basic inventories to more sophisticated studies of cryptic assemblages, and to investigations on the impacts of natural and anthropogenic effects on ETP coral reef biodiversity.

Dynamics in benthic community composition and influencing factors in an upwelling-exposed coral reef on the Pacific coast of Costa Rica

Seasonal upwelling at the northern Pacific coast of Costa Rica offers the opportunity to investigate the effects of pronounced changes in key water parameters on fine-scale dynamics of local coral reef communities. This study monitored benthic community composition at Matapalo reef (10.539°N, 85.766°W) by weekly observations of permanent benthic quadrats from April 2013 to April 2014. Monitoring was accompanied by surveys of herbivore abundance and biomass and measurements of water temperature and inorganic nutrient concentrations. Findings revealed that the reef-building corals Pocillopora spp. exhibited an exceptional rapid increase from 22 to 51% relative benthic cover. By contrast, turf algae cover decreased from 63 to 24%, resulting in a corresponding increase in crustose coralline algae cover. The macroalga Caulerpa sertularioides covered up to 15% of the reef in April 2013, disappeared after synchronized gamete release in May, and subsequently exhibited slow regrowth. Parallel monitoring of influencing factors suggest that C. sertularioides cover was mainly regulated by their reproductive cycle, while that of turf algae was likely controlled by high abundances of herbivores. Upwelling events in February and March 2014 decreased mean daily seawater temperatures by up to 7 °C and increased nutrient concentrations up to 5- (phosphate) and 16-fold (nitrate) compared to mean values during the rest of the year. Changes in benthic community composition did not appear to correspond to the strong environmental changes, but rather shifted from turf algae to hard coral dominance over the entire year of observation. The exceptional high dynamic over the annual observation period encourages further research on the adaptation potential of coral reefs to environmental variability.

Effects of Seasonal Upwelling on Inorganic and Organic Matter Dynamics in the Water Column of Eastern Pacific Coral Reefs

The Gulf of Papagayo at the northern Pacific coast of Costa Rica experiences pronounced seasonal changes in water parameters caused by wind-driven coastal upwelling. While remote sensing and open water sampling already described the physical nature of this upwelling, the spatial and temporal effects on key parameters and processes in the water column have not been investigated yet, although being highly relevant for coral reef functioning. The present study investigated a range of water parameters on two coral reefs with different exposure to upwelling (Matapalo and Bajo Rojo) in a weekly to monthly resolution over one year (May 2013 to April 2014). Based on air temperature, wind speed and water temperature, three time clusters were defined: a) May to November 2013 without upwelling, b) December 2013 to April 2014 with moderate upwelling, punctuated by c) extreme upwelling events in February, March and April 2014. During upwelling peaks, water temperatures decreased by 7°C (Matapalo) and 9°C (Bajo Rojo) to minima of 20.1 and 15.3°C respectively, while phosphate, ammonia and nitrate concentrations increased 3 to 15-fold to maxima of 1.3 μmol PO4 3- L-1, 3.0 μmol NH4 + L-1 and 9.7 μmol NO3 - L-1. This increased availability of nutrients triggered several successive phytoplankton blooms as indicated by 3- (Matapalo) and 6-fold (Bajo Rojo) increases in chlorophyll a concentrations. Particulate organic carbon and nitrogen (POC and PON) increased by 40 and 70% respectively from February to April 2014. Dissolved organic carbon (DOC) increased by 70% in December and stayed elevated for at least 4 months, indicating high organic matter release by primary producers. Such strong cascading effects of upwelling on organic matter dynamics on coral reefs have not been reported previously, although likely impacting many reefs in comparable upwelling systems.

Upwelling Increases Net Primary Production of Corals and Reef-Wide Gross Primary Production Along the Pacific Coast of Costa Rica

Photosynthetic production is a key ecosystem service provided by tropical coral reefs, but knowledge about the contribution of corals and other reef-associated organisms and the controlling environmental factors is scarce. Locations with occurrence of upwelling events can serve as in-situ laboratories to investigate the impact of environmental variability on production rates of reef-associated organisms. This study investigated individual and reef-wide net (Pn) and gross primary production (Pg) for the dominant autotrophic benthic organisms (hard corals Pocillopora spp., crustose coralline algae (CCA), turf algae, and the macroalga Caulerpa sertularioides) associated with a coral reef along the Pacific coast of Costa Rica. Oxygen fluxes by these organisms were measured at a weekly to monthly resolution over one year (May 2013 - April 2014) via in-situ chamber incubations. The influence of simultaneously measured environmental parameters (temperature, light, inorganic nutrient concentrations, dissolved and particulate organic matter concentrations) on Pn of the different taxa were tested via linear model fitting. Turf algae showed highest individual Pn and Pg rates per organism surface area (35 and 49 mmol O2 m-² h-1), followed by Pocillopora spp. (16 and 25 mmol O2 m-² h-1), CCA (9 and 15 mmol O2 m-² h-1) and C. sertularioides (8 and 11 mmol O2 m-² h-1). Under upwelling conditions (February – April 2014), Pn rates of all algal taxa remained relatively uniform despite high nutrient availability, Pn of corals increased by 70 %. On an ecosystem level, corals on average contributed 60 % of total Pn and Pg per reef area (73 and 98 mmol O2 m-² h-1, respectively) due to high benthic coverage, followed by turf algae (25 %). Under upwelling conditions, reef-wide Pg increased by >40 %, indicating acclimatization of local reef communities to upwelling conditions.

Community Perception and processes of Integrated Coastal Zone Management in the North Pacific of Costa Rica.

Las tendencias en la percepcion sobre el uso y manejo de los recursos marino-costeros en el Pacifico Norte de Costa Rica se investigaron a traves de talleres de consulta en las comunidades de Cuajiniquil, Villarreal, Montezuma y zonas aledanas. En total 112 personas provenientes de ocho comunidades asistieron a la convocatoria. En general se registro una mayor participacion de hombres que de mujeres. Los principales recursos marinos identificados fueron los pesqueros y el de playa/olas; las actividades destacadas, la pesca y el turismo. Se asigno a Incopesca una deficiente participacion en la administracion de los recursos y se otorgo una baja participacion a los sectores de pesca artesanal y turismo. Fue destacada la participacion de lideresas en Montezuma, lo que planteo la necesidad de fomentar la autonomia de la mujer costena para que mas ciudadanas esten en condiciones de contribuir en la toma de decisiones como un actor legitimo. Los principales retos detectados fueron la pesca ilegal en las Areas Marinas Protegidas y la sobreexplotacion pesquera. Como soluciones, las comunidades propusieron elementos de pesca sostenible, ademas de la eliminacion de la pesca de arrastre y de buceo con compresor. El proceso de consulta revela la necesidad de proponer alternativas economicas a la pesca, educar a las comunidades, enfocar la atencion en categorias de manejo que no prohiban la pesca artesanal y promover la participacion de la sociedad civil en la toma de decisiones. Se recomienda aprovechar los mecanismos ya existentes para la inclusion de la sociedad civil y de implementarse procesos participativos, que estos velen por el interes publico del pais aunque el proyecto sea de caracter local. Se evidencia que la gobernanza marina del Pacifico Norte del pais enfrenta retos, entre ellos la falta de una gestion participativa de los recursos marino-costeros, pero a su vez cuenta con propuestas ciudadanas concretas que podrian contribuir con una toma de decisiones mas representativa de los distintos intereses de la region.

Rapid bioerosion in a tropical upwelling coral reef

Coral reefs persist in an accretion-erosion balance, which is critical for understanding the natural variability of sediment production, reef accretion, and their effects on the carbonate budget. Bioerosion (i.e. biodegradation of substrate) and encrustation (i.e. calcified overgrowth on substrate) influence the carbonate budget and the ecological functions of coral reefs, by substrate formation/consolidation/erosion, food availability and nutrient cycling. This study investigates settlement succession and carbonate budget change by bioeroding and encrusting calcifying organisms on experimentally deployed coral substrates (skeletal fragments of Stylophora pistillata branches). The substrates were deployed in a marginal coral reef located in the Gulf of Papagayo (Costa Rica, Eastern Tropical Pacific) for four months during the northern winter upwelling period (December 2013 to March 2014), and consecutively sampled after each month. Due to the upwelling environmental conditions within the Eastern Tropical Pacific, this region serves as a natural laboratory to study ecological processes such as bioerosion, which may reflect climate change scenarios. Time-series analyses showed a rapid settlement of bioeroders, particularly of lithophagine bivalves of the genus Lithophaga/Leiosolenus (Dillwyn, 1817), within the first two months of exposure. The observed enhanced calcium carbonate loss of coral substrate (>30%) may influence seawater carbon chemistry. This is evident by measurements of an elevated seawater pH (>8.2) and aragonite saturation state (Ωarag >3) at Matapalo Reef during the upwelling period, when compared to a previous upwelling event observed at a nearby site in distance to a coral reef (Marina Papagayo). Due to the resulting local carbonate buffer effect of the seawater, an influx of atmospheric CO2 into reef waters was observed. Substrates showed no secondary cements in thin-section analyses, despite constant seawater carbonate oversaturation (Ωarag >2.8) during the field experiment. Micro Computerized Tomography (μCT) scans and microcast-embeddings of the substrates revealed that the carbonate loss was primarily due to internal macrobioerosion and an increase in microbioerosion. This study emphasizes the interconnected effects of upwelling and carbonate bioerosion on the reef carbonate budget and the ecological turnovers of carbonate producers in tropical coral reefs under environmental change.

Among stories and snakes: more than a bay (Bahía Culebra, Guanacaste, Costa Rica).

Bahia Culebra (Golfo de Papagayo, Guanacaste, Costa Rica) es una unidad geomorfologica semicerrada y bastante protegida, que cuenta con una amplia diversidad de recursos naturales, favoreciendo el asentamiento de poblaciones humanas y su consecuente desarrollo marinocostero. La resena historica de Bahia Culebra indica que este ha sido un sitio muy importante desde la perspectiva historica, politica, cultural y economica. La consulta bibliografica incluyo documentos que datan de mediados del siglo XIX hasta el ano 2011, los cuales fueron recopilados del Archivo Nacional de Costa Rica, la Biblioteca Nacional, el Centro de Documentacion del Centro de Investigaciones Historicas de America Central y algunas colecciones privadas. Su notoria belleza escenica, la disponibilidad de redes viales en buen estado y la cercania a un aeropuerto internacional han facilitado que la bahia se convierta en un centro turistico intensivo, generando un acelerado desarrollo costero a raiz de la creacion del proyecto Polo Turistico Golfo de Papagayo (PTGP). Se debe fortalecer el marco juridico e implementar acciones que promuevan el bienestar de las poblaciones locales y la adecuada gestion de los recursos naturales, tomando en cuenta todos los factores y actores involucrados.