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

Abstract

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 1 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 O m −2 h −1 ), followed by Pocillopora spp. (16 and 25 mmol O m −2 2 2 h −1 ), CCA (9 and 15 mmol O m −2 2 h −1 ), and C. sertularioides (8 and 11 mmol O 2 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 O 2 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.

Parsing human and biophysical drivers of coral reef regimes

“…By contrast, regime 3, which displays substantial coral cover, occurs most commonly in sheltered environments with small pulses of chlorophyll- a in an otherwise rather oligotrophic background. This could illustrate how a pulsed delivery of oceanic-derived nutrients from physical processes such as internal waves or current-driven upwelling [37,38] may benefit corals on oligotrophic reefs by increasing ecosystem primary production and the energy available for coral growth [39].…”

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

“…Nutrient fluxes in reef ecosystems have important implications for coral community structure and function (Roder et al, ; Schmidt et al, ). Deep‐water upwelling and internal waves generate fluxes of inorganic nutrients that increase reef‐wide primary productivity and the availability of particulate resources, which can be an important factor for the growth of corals, especially in deep reefs (Leichter & Genovese, ; Leichter, Shellenbarger, Genovese, & Wing, ; Stuhldreier et al, ). Variation in nutrient and particulate concentrations can influence the trophic strategies of symbiotic corals, which obtain nutrients (carbon and nitrogen) from their photosynthetic algal endosymbionts (herein “symbionts”; autotrophy) and from coral host feeding (heterotrophy) on organic resources such as particulate organic matter (POM; Porter, ).…”

Monitoring elasmobranch assemblages in a data-poor country from the Eastern Tropical Pacific using baited remote underwater video stations

“…The upwelling brings cool nutrient-rich water from the bottom, enhancing coastal productivity and biodiversity 87 . During the upwelling, water temperature can drop from an annual average of 30-15 °C 88,89 .…”